2016 CAP Congress / Congrès de l'ACP 2016

America/Toronto
University of Ottawa

University of Ottawa

SITE Building, 800 King Edward Ave, Ottawa, ON
Description

CAP BEST STUDENT PAPER COMPETITION 

Results of the 2016 CAP Best Student Paper Competition (Divisions and CAP overall, oral and poster)

Congratulations! If you haven't received your prize confirmation letter at the Recognition Gala, June 16, please contact Danielle at capmgr@uottawa.ca.

Click on the "Timetable" on the left to view the Congress program.

The 2016 CAP Congress is being hosted by the University of Ottawa (Ottawa, ON), June 13-17, 2016. This Congress is an opportunity to showcase and celebrate the achievements of physicists in Canada and abroad. Mark your calendars and bookmark the main Congress web site (http://www.cap.ca/en/congress/2016 ) for easy access to updates and program information.


Compétition de la meilleure communication étudiante de l'ACP

 

Résultats de la Compétition de la meilleure communication étudiante de l'ACP 2016 (de divisions et globale de l'ACP, orale et affiche)

Félicitations! Si vous n'avez pas reçu votre lettre de confirmation de prix au Gala de reconnaissance du 16 juin, veuillez communiquer avec Danielle au capmgr@uottawa.ca

Cliquez sur "Timetable" à gauche pour voir la programmation du Congrès.

Le Congrès 2016 de l'ACP se tiendra à l'Université d'Ottawa (Ottawa, ON) du 13 au 17 juin 2016 (des réunions de l'IPP, l'IPCN et du conseil de l'ACP auront lieu le dimanche 12 juin). Au cours de cet événement nous pourrons profiter des présentations et des réalisations de physiciens et physiciennes du Canada et d'ailleurs, et les célébrer. Inscrivez la date du congrès à votre agenda et créez un signet de l'adresse du site web du congrès http://www.cap.ca/fr/congres/2016) pour accéder facilement aux mises à jour et au contenu de la programmation.

    • 08:00 12:00
      **CANCELLED / ANNULÉ** IPP Town Hall I / Consultation publique de l'IPP I Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 12:30 17:00
      CAP Advisory Council (Old and New) / Conseil consultatif de l'ACP (ancien et nouveau) FSS 4004

      FSS 4004

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
    • 13:30 16:15
      Joint CINP-IPP Meeting / Réunion conjointe de l'ICPN et de l'IPP (DPN-PPD) Colonel By C03

      Colonel By C03

      University of Ottawa

      Conveners: Prof. Garth Huber (University of Regina), Michael Roney (University of Victoria)
    • 16:15 16:30
      Health Break / Pause santé
    • 16:30 19:00
      CINP AGM & Board Meeting / Réunion du conseil et AGA de l'ICPN Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Prof. Garth Huber (University of Regina)
    • 16:30 18:15
      IPP AGM / AGA de l'IPP Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 17:00 20:30
      **CANCELLED / ANNULÉ** CAP Board Dinner Meeting: CAP Board Dinner Meeting FSS 4004

      FSS 4004

      University of Ottawa

    • 19:30 21:30
      IPP Inst. Members and Board of Trustees Meetings / Réunions des membres inst. et du conseil de l'IPP Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 08:00 09:35
      IPP Town Hall II / Consultation publique de l'IPP II Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 09:30 10:20
      M-PLEN Plenary Session - Start of Conference - Hendrik Schatz, Michigan State Univ./NSCL / Session plénière - Ouverture du Congrès - Hendrik Schatz, Michigan State Univ. / NSCL Marion 150

      Marion 150

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 09:30
        Nuclear Astrophysics with Radioactive Beams 50m
        Stellar explosions and colliding neutron stars are important sources of the chemical elements in nature. The properties of very unstable isotopes that are created for fleeting moments in these extreme astrophysical sites, imprint themselves onto the nature of the explosion and the characteristic element patterns that are created and ultimately shape the composition of the visible universe. Accelerator facilities that produce beams of these short lived radioactive isotopes can now be used to study the relevant nuclear reaction rates and nuclear properties so one can understand in the laboratory how stars create elements. This also opens the door to using observed element patterns as a diagnostic tool to peek into the deep interiors of some of the most extreme stellar sites. I will review some of the current open questions related to astrophysical processes with unstable nuclei, and how experiments at current and planned rare isotope facilities in the US, Canada, and elsewhere, in concert with observations and astrophysical models, are addressing these questions.
        Speaker: Hendrik Schatz (National Superconducting Cyclotron Laboratory)
    • 10:30 12:00
      M1-1 Newish-faculty Workshop: So You Think You Can Teach Physics! (DPE) / Atelier pour nouveaux professeurs : vous pensez pouvoir enseigner la physique! (DEP) Colonel By D103

      Colonel By D103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Calvin Kalman (Concordia University)
    • 10:30 12:00
      M1-2 Material Growth and Processing (DCMMP) / Croissance et traitement des matériaux (DPMCM) Colonel By B205

      Colonel By B205

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Prof. Mohamed Siaj (UQAM)
      • 10:30
        Upconverting and Near-Infrared Emitting Nanoparticles: From Synthetic Strategies to Potential Applications 30m
        Lanthanide-based nanostructures are well known for their outstanding optical properties that are based on the electronic configuration of the trivalent lanthanide ions (Ln3+), which is characterized by an incompletely filled 4f shell, located inside the complete 5s2 and 5p6 shells. This results in a shielding of valence electrons, which are therefore only weakly affected by the environment. Consequently, when doped in appropriate host materials, the influence of the host lattice on the optical transitions within the 4f configuration is small, and narrow optical absorption and emission bands as well as long lifetimes of the excited electronic states of the Ln3+ are obtained. Following a stepwise excitation with near-infrared (NIR, typically 980 nm) light, Ln3+-doped nanostructures show upconversion (ultraviolet, visible and NIR light) emission. In addition, NIR light of longer wavelengths (> 1000 nm) can be emitted under excitation with NIR light when appropriate Ln3+ dopants are chosen (e. g., Er3+ or Ho3+). Based on this, Ln3+-doped nanostructures have been suggested for a whole gamut of applications including the field of bioimaging and sensing. Fluorides, such as NaGd4, NaYF4 or LiYF4, are commonly considered as suitable host materials and their preparation via the thermal decomposition process has been widely studied. Alternatively, oxides, such as Gd2O3 or Y2O3, have been suggested as host materials for Ln3+ ions resulting in upconverting and NIR emitting nanostructures. Ln3+-doped oxides of various sizes and shapes (nanoparticles, nanorods) can for instance be obtained by precipitation or solvothermal approaches. In this presentation, various synthetic strategies leading to upconverting and NIR emitting Ln3+-doped nanostructures will be discussed, and their application of the resultant materials in optical bioimaging and nanothermometry will be presented.
        Speaker: Prof. Eva Hemmer (University of Ottawa)
      • 11:00
        Custom low-dimensional material systems explored from atom to bulk 30m
        The ability to controllably layer atomically thin crystals into custom-made materials holds promise for realizing physical systems with distinct properties, previously inaccessible. The experimental results described in this talk seek to uncover the unique nature of the charge carriers in such few-atoms-thick materials as well as effects that interlayer coupling and disorder have on their properties. In the first part of the talk I will discuss scanning tunneling microscopy (STM) and spectroscopy (STS) experiments performed on graphene systems at low temperatures and in magnetic field. We find that twisting graphene layers away from the equilibrium Bernal stacking leads to the formation of Moiré patterns and results in a system with novel electronic properties tuned by the twist angle. Moreover, we study Landau quantization in graphene and by performing spatially resolved STM/STS we demonstrate the true discrete quantum mechanical electronic spectrum within the Landau level band near an impurity in graphene in the quantum Hall regime. In the second part of the talk I will focus on the 1T polymorph of TaS2, which has one of the richest phase diagrams among the layered transition metal dichalcogenides. We address the question of how the transition from bulk to few layers affects the different phases in this material. Specifically, we use variable temperature Raman spectroscopy measurements and show that the existence of the most highly ordered phases depend on having a critical number of stacked 1T-TaS2 layers. Furthermore, using low temperature STM/STS, we explore the spatial variation of the electronic properties of the commensurate charge density wave phase at the atomic level.
        Speaker: Prof. Adina Luican-Mayer (University of Ottawa)
      • 11:30
        Atomic Force Microscopy Study of the Effect of Poly(aspartic acid) on Calcium Oxalate 15m
        Kidney stone disease is a urological disorder that affects 10% of the human population, resulting in considerable pain and potential renal failure. It is known that certain macromolecules, such as osteopontin (OPN), can limit the formation of calcium oxalate monohydrate (COM) crystals, the major constituent of kidney stones. An explanation for this effect is provided by the Cabrera-Vermilyea (C-V) model, which proposes that trace amounts of adsorbed impurities can pin growth steps, forcing them to curve, thereby reducing the effective supersaturation. This “kinetic inhibition” is distinct from the well-known freezing-point depression, in which the thermodynamic phase diagram is altered by the presence of impurities. However, microscopic evidence for the C-V model is limited. We have been using the atomic force microscope (AFM) to investigate COM crystallization in situ in the presence of OPN, peptides derived from OPN, and synthetic macromolecules such as poly(aspartic acid) (poly-ASP). The presence of poly-ASP causes a rapid change in growth-step morphology and drastically slows the growth. At low poly-ASP concentrations, we see a dependence on crystallographic direction, with one direction displaying strong pinning while others continue to grow. This results in “finger-like” features at a threshold concentration that depends strongly on the polymer length. In this talk, we model these growth features using inhibitor diffusion, adsorption to growth steps, and incorporation into the growing crystal. An understanding of the microscopic details of calcium oxalate crystallization is not only important for the development of potential therapies for kidney stone disease, but will also provide insights into the inhibition mechanism that will be transferable to other natural and commercial crystallization systems.
        Speaker: Ms Himasha Wijesekara (University of Western Ontario)
      • 11:45
        Maximizing electrophoretic mobility differences among polymorphic materials 15m
        Physical separation of different polymorphs is a serious experimental challenge, but success would help efforts in applications as diverse as drug discovery, environmental remediation, and cultural conservation. To meet this challenge, we demonstrate a proof-of-principle method to separate polymorphic materials by tuning their electrophoretic mobility differences. Our test case involved two different phases of calcium carbonate (aragonite and calcite, both CaCO3) in aqueous suspensions. Two serendipitous benefits arose when we used conventional additives in the suspension to prevent particle aggregation. First, phosphate-based additives increase the magnitude of the electrophoretic mobility differences between calcite and aragonite. This is advantageous because the greater the electrophoretic mobility difference, the less time and distance would be required for polymorph separation. Second, the phosphate additives prevent aragonite dissolution, even when the particles remain in aqueous suspension for many months. This is very fortuitous because it makes electrophoresis a non-destructive separation strategy for these calcium carbonate polymorphs.
        Speaker: Kristin Poduska (Memorial University of Newfoundland)
    • 10:30 12:00
      M1-3 Theory, Modelling, and Forecasting I (DASP) / Théorie, modélisation et prévisions I (DPAE) Colonel By B012

      Colonel By B012

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Prof. David Knudsen (University of Calgary)
      • 10:30
        The “Impenetrable Barrier” Revisited: Bursting the VLF Bubble 15m
        In a recent paper, Baker et al. (Nature, 2014) reported the observation of an “impenetrable barrier” to the inner edge of the ultra-relativistic electron radiation belt. These authors demonstrated that this barrier location was not coincident with the location of the plasmapause nor any other identifiable magnetospheric boundary; nor could it be explained by the scattering of ultra-relativistic electrons into the loss cone by ground-based VLF transmitters. Here we show that the transport and energization timescales depend on gradients in the phase space density and not simply by timescales derived from the magnitude of the radial diffusion coefficient alone. Using these correctly formulated transport timescales, we show how the location of the “impenetrable barrier” can be explained in terms of radial diffusion, including the impacts of dynamical variations in phase space density gradients. Contrary to the suggestion by Baker et al., 2014 there does not appear to be any need for active local wave particle acceleration between the plasmapause and the edge of the barrier at L~2.8 since the radial diffusion rates appear to be sufficient to transport particles there during the most active times. The “impenetrable barrier” is explained as being the location where phase space density gradient and the diffusion coefficient combine to effectively block further inward ULF wave radial transport. During more active times the timescale for transport around L~2.8 can be increased allowing penetration of electrons into the slot. However, under typical conditions the activity does not remain high enough for a sufficiently long time to enable electron penetration below L~2.8. Overall, the “impenetrable barrier” is explained as a simple and natural consequence of the activity-dependent rates of ULF wave diffusive transport and significantly no local acceleration processes are required to explain how the particles reach the inner edge of the “barrier” at L~2.8.
        Speaker: Dr Stavros Dimitrakoudis (University of Alberta)
      • 10:45
        Determination of global-scale diffusion coefficients in the stratosphere using a new model of local mixing 15m
        Due to the intermittency and spatial distribution of small layers of turbulence in the stratosphere, determination of large-scale diffusion coefficients is a non-trivial process. Previous models have assumed that all layers are perfectly mixed, but generally spatio-temporally disconnected. Our new model allows for partially mixed layers, especially for large and intense layers, which has profound effects on the global-scale diffusion coefficient. We also better represent the spatio-temporal distribution using a 2-dimensional model, as distinct from the more common one-dimensional model. Our newer model is used in combination with balloon and aircraft measurements of layer thicknesses and distributions to place limits on the possible values of large-scale diffusion in the stratosphere and upper troposphere. The values in the stratosphere are particularly well confined.
        Speaker: Wayne Hocking (University of Western Ontario)
      • 11:00
        Development of the Canadian Ionosphere and Atmosphere Model 15m
        Current status of the Canadian Ionosphere and Atmosphere Model (C-IAM) project is described. The C-IAM has been composed from two pre-existing first principles models: the extended Canadian Middle Atmosphere (CMAM) and the ionospheric part of the Upper Atmosphere Model (UAM). The model domain extends from the surface to the inner magnetosphere and two-way coupling between the neutral atmosphere and ionosphere is implemented. These features make the C-IAM a self-consistent whole atmosphere model that is capable of studying both the impact of the lower atmosphere on the thermosphere and the ionosphere and the impact of geomagnetic conditions on the neutral atmosphere. In addition to the first principles modelling blocks, the C-IAM includes alternative empirical models (e.g., MSISE) which can optionally be used for specific studies. In order to reproduce the response to specific space weather events, the model has an option to accommodate the real (observed) high-latitudinal electric field and auroral energetic electron distribution. The C-IAM has been successfully applied to reproducing a number of observed thermospheric/ionospheric features. These include simulating the wave number 4 features observed in the nighttime O ionospheric emission at 135.6 nm, modeling the 732 nm O+ daytime emission and retrieving from it the atomic oxygen concentration, and explaining disturbances measured by the GOCE satellite accelerometers over high latitudes during geomagnetically active days. The presentation will introduce the model and describe these results.
        Speaker: Oleg Martynenko (York University)
      • 11:30
        Farley-Buneman waves at large aspect angles 15m
        The Farley-Buneman (FB) instability mechanism provides an excellent explanation for the presence of large amplitude plasma waves in the cm to few m wavelength range in the high latitude E region whenever the ambient electric field exceeds 20 mV/m. Observations suggest that the instabilities are observed at their threshold speed when they reach their largest amplitudes. This can be explained in terms of a combination of decreasing electric field and increasing aspect angle inside individual structures. However, another feature of observations is that linear theory predicts instability for aspect angles smaller than 1.5 degree, up to maybe 2 degrees even though there is plenty of evidence to show that large amplitude structures exist at aspect angles well beyond 2 degrees during Farley-Buneman events. We show that this observational feature is caused by the weak altitude dependence of the eigenfrequency, which forces the aspect angle to grow monotonically with time. This means that after the structures have reached their maximum amplitude, they continue to exist, but with the caveat that their aspect angle increases while their amplitude decreases. This allows damped modes at large aspect angles to be observed. However, as the aspect angle increases, the phase velocity of the waves will also change, although that change is actually a strong function of the wavelength of the structures. This means that we must assess the real and imaginary part of the eigenfrequency to query the Doppler shift of the structures and see how they compare with observations at different radar frequencies. To this goal, we have studied both the simple fluid isothermal dispersion relation, as well as the full kinetic dispersion. Our results for sub-meter wavelengths show that the phase velocity remains very constant at only slightly less than the ion-acoustic speed as the aspect angle increases. At larger wavelengths, the transition to zero phase velocity proceeds according to Vd/(1+psi), a result in agreement with the simple fluid predictions based on small growth rate considerations. The transition wavelength is controlled by the ion collision frequency. We have used our calculations to determine how the phase velocity and the growth/decay rate depend on altitude (or collision frequency) and electric field conditions. The phase velocity calculations compare favorably with observations.
        Speaker: patrick perron (RMCC)
      • 11:45
        Magnetosphere-Ionosphere Coupling at Substorm Expansion Phase Onset 15m
        With the explosive release of energy within a substorm, stored magnetic energy is quickly converted to plasma kinetic energy, resulting in dramatic changes in the large-scale magnetic topology of the Earth’s night-side magnetic field and in increases in the flux of energetic particles in near-Earth space, and generates an apparently repeatable time series of events in the dynamic aurora spanning many degrees of latitude and hours of local time. Whilst the processes leading to energy storage in the magnetotail are well-understood, the same cannot be said for the conditions which lead to rapid energy release rather than a more gradual dissipation of stored energy. Without an improved understanding of the conditions leading to the triggering of rapid destabilisation of the tail, the forecast of the timing and geographical region affected by large GICs remains largely impossible. Here we examine the potential role of magnetosphere-ionosphere coupling (MIC) in triggering large scale morphological changes in the magnetotail across many hours of local time. We present ground-based magnetometer and all-sky imager observations combined with conjugate in-situ observations of the magnetic fields and temperature anisotropies of electrons and ions from GOES as well as the NASA Van Allen Probes and THEMIS satellites. By utilising the extensive ground coverage available from the Geospace Observatory (GO) Canada array we resolve longitudinal and relative timing uncertainties between the measurement platforms at onset. We seek to establish a causal sequence of events and thereby examine especially the potential role of near-Earth MIC processes in the substorm sequence, particularly that of the Akasofu auroral evolution at onset – independent of whether this precedes or follows the onset of magnetic reconnection at the near-Earth neutral line.
        Speaker: Dr Stavros Dimitrakoudis (University of Alberta)
    • 10:30 12:00
      M1-4 Neutrinoless Double Beta Decay I (PPD-DNP-DTP) / Double désintégration beta sans neutrino I (PPD-DPN-DPT) Colonel By C03

      Colonel By C03

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Tony Noble (Queen's University)
      • 10:30
        Neutrino-less double beta decay search with EXO-200 and nEXO 30m
        The Enriched Xenon Observatory (EXO) is an experimental program designed to search for the neutrinoless double beta decay of $^{136}$Xe. Observation of this decay would prove that neutrinos are massive Majorana particles (i.e. they are their own anti-particles), and constitute physics beyond the Standard Model. The first phase experiment, called EXO-200, has re-started operation at the WIPP mine in New Mexico, USA, using 200 kg of liquid xenon enriched to 80% in $^{136}$Xe in an ultra-low background time-projection chamber (TPC). The detector performance and response has been thoroughly tested and is well understood. With the EXO-200 detector sensitive searches for neutrinoless and two neutrino double beta decays have been performed along with searches for exotic decay modes and decays to excited states. Some of these searches provided the most stringent limits on these decay modes. In parallel to the operation of EXO-200, the development of nEXO, a next-generation liquid xenon TPC has started. The nEXO detector will consist of 5T enriched xenon and will be deployed at a selected underground laboratory, ideally the SNOLab facility in Sudbury. Advanced detection technologies are being developed to read out charge and scintillation signals from the xenon TPC, such as charge readout tiles and Si photo multipliers, respectively. With these technologies and the increased target mass, the nEXO detector has the potential to completely probe the inverted neutrino-mass scale. The status of the EXO-200 detector, detector performance, and analysis techniques applied to achieve the current results will be discussed. In addition, current design efforts for the future multi-ton experiment nEXO will be discussed.
        Speaker: Thomas Brunner (McGill University)
      • 11:00
        Ba-ion extraction and identification from high pressure Xenon gas for nEXO 15m
        The Enriched Xenon Observatory (EXO) is searching for the lepton-number violating double beta decay ($0\nu\beta\beta$) in $^{136}$Xe. If experimentally confirmed, $0\nu\beta\beta$ will require the neutrino to be its own anti-particle, i.e. Majorana particle, and shed light on the neutrino-mass hierarchy. The currently running EXO-200 experiment uses 200 kg of Xenon enriched to more than 80% in $^{136}$Xe and obtained the limit of $T_{1/2}^{0\nu\beta\beta}≥1.1\times10^{25}$ years. In parallel, the development of nEXO has started which will deploy 5 tonnes of liquid xenon in a time-projection chamber and is expected to probe the inverted mass hierarchy of neutrino. One of the design goals of nEXO is to unambiguously differentiate true double beta decay events from background contributions through Ba-tagging, i.e. by identifying the daughter isotope $^{136}$Ba of the $^{136}$Xe decay. With an efficient Ba-tagging technique, the backgrounds can be virtually eliminated which dramatically increases the sensitivity of the $0\nu\beta\beta$ search. The nEXO collaboration is developing various Ba-tagging techniques for liquid and gas phase xenon. A setup is being developed for Ba-tagging in xenon gas. Its central component is an RF-funnel to extract Ba-ions from high pressure xenon gas (up to 10 bar) to a vacuum environment. The second stage, a linear Paul trap, cools the ions through buffer gas cooling and bunches them into a multi-reflection time-of-flight mass spectrometer to identify the Ba-ion by precision mass spectrometry. The RF-funnel has been built and tested to extract ions from xenon gas of up to 10 bar. The liner Paul trap is currently under development. The Ba-tagging setup will be presented and future works will be discussed.
        Speaker: Yang Lan (TRIUMF/UBC)
      • 11:15
        SNO+ status 30m
        The SNO+ experiment is located at SNOLAB and is a multi-purpose scintillator neutrino detector. Currently the detector is being filled with water and prepared for commissioning. The first phase of the experiment will be the search for neutrinoless double beta decay with a 130Te loaded scintillator. Other physics goals include: lower energy solar neutrinos, reactor- and geo-antineutrinos as well as neutrinos from a potential nearby supernova. This presentation will give an overview over the experiment and give the current status.
        Speaker: Dr Christine Kraus (Laurentian University)
      • 11:45
        Rn-222 Assays for SNO+ 15m
        SNO+ is a large, underground neutrino detector, redesigned from the SNO detector. Three separate phases of SNO+ will provide a diverse study of neutrinos, with one phase specifically dedicated to the search for neutrinoless double beta decay in Te-130. At a depth of 2 km underground, SNO+ is shielded from many cosmogenics, yet the decay of U-238 within the surrounding rock leads to high (∼3.54 pCi/L) levels of Rn-222 in the air. Two cryotrapping units capable of collecting Rn-222 into Lucas cells are under development: one for the water shielding tank surrounding the cavity, the other for the scintillator fluid inside the detector. Once radon has been collected the Lucas cells are then taken to surface and counted, which will verify if the targets of 3.5E−13 g U/g water and ∼1E−17 g U /g scintillator are met. The status of both units and the Lucas cell counting system are discussed. The scintillator collector is under construction, the water unit is undergoing recommissioning, and the Lucas cell counting system will be updated.
        Speaker: Janet Rumleskie (Laurentian University)
    • 10:30 12:00
      M1-5 Soft Matter and Polymers (DCMMP-DPMB) / Matière molle et polymères (DPMCM-DPMB) Colonel By D207

      Colonel By D207

      University of Ottawa

      Convener: Naomi Matsuura (University of Toronto)
      • 10:30
        On the coalescence of two drops undergoing a head-on collision in a Bingham fluid 30m
        In this work, we consider the canonical problem of the drainage of a thin film of Bingham fluid squeezed out between two spherical, Newtonian drops pushed against each other under the action of an external force. The only prior research to have studied this problem is the analytical work due to Jeelani and coworkers (Can. J. Chem. Eng., vol. 65, pp. 384-390, 1987, and J. Phys. Chem., vol. 90, pp. 6054-6059, 1986.). Unfortunately, these results have been obtained from a simplistic lubrication analysis for nearly planar films, or for dimpled films with ad-hoc assumptions about the film shape. In this work, we have performed detailed numerical simulations of the evolution of the shape of a thin, Bingham film with an immobile interface based on the lubrication equations, and compare our trends with existing work on the drainage of Newtonian films. The drainage of a film of Bingham fluid between two colliding Newtonian drops differs from that of a Newtonian film in two principal ways. First, drainage rates are slower for Bingham films as compared to Newtonian films of the same viscosity. The difference becomes strong for low capillary numbers in the spherical configuration of the film, and for large capillary numbers in the dimpled configuration. Second, once the Bingham film becomes dimpled, it can freeze completely once it reaches a critical thickness. Counterintuitively, this critical thickness is independent of the force pushing the drops against each other! Our results suggest that on a map of drop radius vs. shear rate, the parameter regime for coalescence for Bingham films will be shrunk relative to Newtonian films, and will be completely hindered below a critical shear rate and above a critical drop size.
        Speaker: Dr Arun Ramachandran (University of Toronto)
      • 11:00
        Assembly of Gold Nanoparticles in Blue Phase Liquid Crystals: Towards New Generation of Soft Nanocrystals 30m
        The use of nanoparticles in the field of nanotechnology is one of the most promising approaches for novel technological applications through the development of reconfigurable ordered structures with rich properties. As well, the coupling of nanoparticles within liquid crystals is an emerging topic in the field of soft matter that offers new possibilities for designing reconfigurable nanomaterials that respond to a wide range of external stimuli. In this work, we report the spontaneous formation of thermally reversible, cubic crystal nanoparticle assemblies in Blue Phases. Gold nanoparticles, functionalized to be highly miscible in cyanobiphenyl-based liquid crystals, were dispersed in Blue Phase mixtures and characterized by polarized optical microscopy and synchrotron small-angle X-ray scattering (SAXS). The nanoparticles assemble by selectively migrating to periodic strong trapping sites in the Blue Phase disclination lines. At the Blue Phase I to Blue Phase II phase transition, the nanoparticle lattice reversibly switches between two different cubic structures. The simultaneous presence of two different symmetries in a single material presents an interesting opportunity to develop novel dynamic optical materials. Recent progress in understanding the mechanism of nanoparticle self-organization is presented.
        Speaker: Mohamed Amine Gharbi (McGill University)
      • 11:30
        Vibrating-Wire Rheology 15m
        We are investigating the use of a vibrating wire device to measure the viscoelastic moduli of non-Newtonian fluids. Our device consists of a tungsten wire under tension and immersed in a fluid. When a magnetic field is applied and an alternating current is passed through the wire, it vibrates at the driving frequency. The resonance frequency of the wire can be tuned by varying its length and the applied tension. We measure the voltage induced across the wire as a function of frequency. An analytic expression can be derived relating the voltage across the wire to viscosity. For non-Newtonian fluids we modify the Newtonian expression to include a complex viscosity, allowing the viscoelastic moduli to be determined from the measured voltage. We discuss the design and operation of our vibrating wire rheometer and demonstrate its ability to accurately measure the properties of Newtonian and non-Newtonian fluids.
        Speaker: Cameron Hopkins (The University of Western Ontario)
      • 11:45
        Deuterium NMR and Rheology of Microgel Colloids at Ambient and High Pressure 15m
        Microgel colloids exhibit a polymer collapse transition resulting in a large reduction in colloid size at high temperatures or pressures. They have potential for drug delivery and chemical separation applications that involve uptake and release of small or biological molecules. Our goal is to obtain a microscopic understanding of the structure and dynamics of the microgels by examining the temperature and pressure dependence of collapse transition in order to investigate the energetic and entropic contributions to polymer collapse. The nature of this collapse transition can be controlled by crosslink density (Cd) thus we plan a systematic study as a function of Cd. We have used deuterium NMR (2H-NMR) to probe the microscopic dynamics of cross-linked poly-N-isopropylacrylamide (p-nipam) chains, in microgel colloids, as a function of temperature and pressure. Dynamic light scattering (DLS) and rheology were employed to characterize the microgels and probe their macroscopic properties. The observed changes in particle size and viscosity by DLS and rheology measurements with temperature were related to changes in the internal structure of the microgel particle investigated by 2H-NMR. Microgels colloids were synthesized with deuteron labels on the nipam side chains (d7-nipam) or on the backbone (d3-nipam). 2H-NMR spectra of both suspensions indicated freely moving chains in the microgel particle at low temperature, and a nearly immobilized fraction of the d3-nipam suspension above 35°C, consistent with DLS observations of transition from swollen to collapsed colloids. We continue to investigate the role of crosslink density in microstructure and macroscopic response by 2H-NMR, rheology and DLS.
        Speaker: Ms Suhad Sbeih (Memorial University of Newfoundland)
    • 10:30 12:00
      M1-6 Laser-Plasma Interactions (DPP-DAMOPC) / Interactions laser-plasmas (DPP-DPAMPC) SITE C0136

      SITE C0136

      University of Ottawa

      Convener: Lora Ramunno (University of Ottawa)
      • 10:30
        MicPIC perspectives on light-matter interactions in strongly-coupled systems 30m
        A key challenge in modelling laser-driven strongly-coupled plasmas is to properly resolve both microscopic and macroscopic phenomena. Atomic collision processes require angstrom spatial resolution, whereas the macroscopic length scale is determined by the wavelength of the incident light. For example, modelling the complete dynamics of a near-infrared laser pulse driving a solid-density plasma requires to resolve about four orders of magnitude in space (from angstrom to micron) and to trace about $10^{10}$ classical particles, in combination with radiation and laser propagation. In this talk, I present an overview of the microscopic particle-in-cell (MicPIC) approach whose parallel implementation, designed for large-scale distributed computations, can fulfill all of these demands. Parallel MicPIC is an important step toward a better understanding of the links between the atomic-scale origin of optical phenomena and their observable manifestations. Our ultimate goal is to bring a complete description of light-matter interactions in strongly-coupled systems that includes all the relevant physics, from atomic dynamics to wavelength-scale phenomena, like scattering and diffraction.
        Speaker: Charles Varin (University of Ottawa)
      • 11:00
        Dynamics of ultrafast laser processing of materials 30m
        Transient free electron plasma is created during the leading edge of an intense ultrafast laser pulse irradiation of a material. Subsequent interaction of this plasma with the rest of the incident light is often ignored in laser processing of materials. We will show that light-plasma interaction plays an important role resulting in polarization dependent features both on the surface and inside the bulk. Local field enhancement leads to asymmetric electron density distribution that is either parallel or perpendicular to the laser polarization depending on the transient plasma density. We demonstrate polarization effects in ablation of silicon and polymethylmethacrylate, and in refractive index modification of silica glass.
        Speaker: Ravi Bhardwaj (University of Ottawa)
    • 10:30 12:00
      M1-7 Atomic and Molecular Spectroscopy and Precision Measurements I (DAMOPC) / Spectroscopie atomique et moléculaire et mesures de précision I (DPAMPC) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Alan Madej
      • 10:30
        **WITHDRAWN** Optical atomic clocks for gravitational wave physics 30m
        Gravitational wave (GW) astronomy has entered a new era with the direct detection of dekahertz-band GW signals by laser interferometers. As with the electromagnetic spectrum, observing gravitational waves in a range of different frequency bands will yield complementary insights into the astrophysics of gravitating objects. Gravitational waves at micro-hertz to milli-hertz frequencies can be detected using an array of optical atomic clocks on satellites, by leveraging the extreme precision available with these clocks. This method affords a technologically feasible approach to imaging the universe in a novel GW band. To enable this method, we are developing optical atomic clocks for use on board satellites, using a simplified scheme based on two-photon transitions. In this talk, I will describe the method of GW detection using optical atomic clocks, and present our progress towards building a portable clock.
        Speaker: Dr Amar Vutha (University of Toronto)
      • 11:00
        Experimental and Theoretical He-Broadened Line Parameters of Carbon Monoxide in the Fundamental Band 15m
        We will discuss recent spectroscopic results for He-broadened transitions of carbon monoxide in the fundamental band, performed over a range of temperatures from 80 to 296 K. Experimentally, the spectral line parameters and their temperature dependencies were retrieved using a multispectrum analysis software and different line shape models (Voigt, speed dependent Voigt, Rautian, Rautian with speed dependence). In addition, we have performed theoretical calculations for He-broadened Lorentz half-width coefficients and He- pressure-shift coefficients for the same transitions. The line mixing coefficients were calculated using the exponential power gap and energy corrected sudden scaling laws. Our results were compared with published results.
        Speaker: Adriana Predoi-Cross (Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB, T1K 6R4 Canada)
      • 11:15
        Self- and Hydrogen-Broadened Line Parameters of Carbon Monoxide in the First Overtone Band 15m
        We have re-analyzed room-temperature spectra of first overtone band of CO and CO broadened by hydrogen. We have employed the Voigt, speed depended Voigt, Rautian, and Rautian with speed dependence line shape models and a multispectrum fit software [1]. The line mixing coefficients have been calculated using scaling laws. The CO line widths in CO-Hydrogen and CO-CO collisions were calculated using the classical impact theory [2] to determine the dipole absorption half-widths and exact 3D Hamilton equations to simulate molecular motion. We used Monte Carlo averaging over collision parameters and simple interaction potential (Tipping-Herman + electrostatic) [3-4] and assumed the molecules to be rigid rotors. The dependencies of CO half-widths on rotational quantum number J<24 are computed and compared with measured data at room temperature. REFERENCES 1. D.C. Benner, C.P. Rinsland, V. Malathy Devi, M.A.H. Smith, D. Atkins, J. Quant. Spectrosc. Rad. Transfer 53(6) 705-721 (1995). 2. R.G. Gordon, J. Chem. Phys. 44, 3083-3089 (1966); ibid., 45, 1649-1655 (1966). 3. J.-P. Bouanich, A. Predoi-Cross, J. Molec Structure 742, 183-190 (2005). 4. A. Predoi-Cross, J.P. Bouanich, D. Chris Benner, A.D. May, J.R. Drummond, J. Chem. Phys. 113, 158-168 (2000).
        Speaker: Prof. Adriana Predoi-Cross (Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB, T1K 6R4 Canada)
      • 11:30
        Tune-out Wavelengths and Polarizability for the Helium $\mathbf{1s2s}\;\mathbf{^{3}}$S State.$^*$ 15m
        This paper is part of a joint theoretical/experimental project to test QED by measuring the tune-out wavelength of helium near the 413 nm line where the frequency-dependent polarizability vanishes [1]. As a first strep, we calculate a high-precision value for the static polarizability defined in the nonrelativistic limit as the second-order perturbation energy due to the perturbation $V=eFr\cos{\theta}$ where $F$ is the electric field strength. For a two electron atom such as helium, high precision results are obtained by use of an explicitly correlated Hylleraas basis set to represent the complete set of intermediate states. We also include for the first time relativistic corrections due to the Breit interaction terms proportional to $p_1^4+p_2^4$, $\delta(r_{12})$, $\delta(r_1)$ and the orbit-orbit interaction [2]. For the $2$ $^3S$ state of helium, we find a relativistic contribution to the polarizability with finite nuclear mass corrections included of $-0.098\,765770(9)$ $a_0^3$ atomic units, where $\alpha$ is the fine structure constant.\\[0pt] [1] B.M. Henson et al. Phys.\ Rev.\ Lett.\ {\bf 115}, 043004 (2015).\newline [2] K. Pachucki and J. Sapirstein, Phys. Rev. A \textbf{63}, 012504, (2000).\newline $^*$Research supported by NSERC.
        Speaker: Mr Jacob Manalo (University of Windsor)
      • 11:45
        FTIR Synchrotron Spectroscopy of the Asymmetric C-H Stretching Bands of Methyl Mercaptan (CH$_{3}$SH) – A Perplexity of Perturbations 15m
        The infrared Fourier transform spectrum of the asymmetric C-H stretching bands of CH$_{3}$SH has been recorded in the 2950-3100 cm$^{-1}$ region using synchrotron radiation at the FIR beamline of the Canadian Light Source in Saskatoon. Assignment of numerous torsion-rotation sub-bands for the asymmetric stretches has revealed a surprising pseudo-symmetric behavior, in which each band is seen in only one of the two possible $\Delta$$K$ selection rules. The upper states of the two asymmetric stretching vibrational bands thus appear to behave more like $l$ = $\pm$1 components of a degenerate $E$ state of a symmetric top rather than distinct vibrational states. The two components are separated by about 1.5 cm$^{-1}$ at $K$ = 0, and then diverge linearly at higher $K$ with torsional oscillation amplitude similar to that of the ground state of about 1.3 cm$^{-1}$. The divergence is consistent with an $a$-type Coriolis splitting picture with an effective Coriolis constant $\zeta$ $\approx$ 0.075.
        Speaker: Dr Li-Hong Xu (Physics Dept., University of NB)
    • 12:00 13:00
      Lunch / Diner
    • 12:00 13:00
      New Faculty Lunch Meeting with NSERC / Dîner-rencontre des nouveaux professeurs avec le CRSNG SITE C0136

      SITE C0136

      University of Ottawa

      Convener: Donna Strickland (University of Waterloo)
    • 12:00 13:00
      Science Policy Workshop / Atelier Politique scientifique Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Kristin Poduska (Memorial University of Newfoundland)
    • 13:00 14:30
      M2-1 Nuclear Structure I (DNP) / Structure nucléaire I (DPN) Colonel By B012

      Colonel By B012

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Dennis Muecher (University of Guelph)
      • 13:00
        Half-life measurements of nuclei around the doubly-magic 100Sn 15m
        $^{100}$Sn is the heaviest self-conjugate doubly magic nuclei with $N = Z = 50$. Research on this nucleus has been aggressively pursued, for its properties yield valuable information on many topics of nuclear physics: the robustness of the magic number 50 far from stability, the effect of proton-neutron interaction, and the location of the proton dripline and the end of the rapid proton-capture process path, to name a few. Due to the lack of experimental information on the structure of $^{100}$Sn itself, the properties of $^{100}$Sn have to be inferred from spectroscopy results of the neighbouring isotopes. As one of the experimental observables, half-life measurements of these radioactive nuclei reflect their general stability, while enabling the calculation of transition strengths for decay matrix elements. These results serve as benchmark tests against modern shell model calculations and inputs for astrophysical rapid proton-capture models of nucleosynthesis. Record quantities of $N \sim Z \leq 50$ nuclei were produced at RIKEN Radioactive Isotope Beam Factory, via fragmentation of an intense $^{124}$Xe beam on a thin $^{9}$Be target. Their decay products were measured with EURICA, consisting of high-purity germanium detectors for $\gamma$ rays, and WAS3ABi, a set of position-sensitive silicon detectors for positrons and protons. Half-lives of exotic $^{91}$Pd, $^{95}$Cd, $^{97}$In, and $^{99}$Sn isotopes were measured for the first time, and higher precision in half-lives of several isotopes in the vicinity of $^{100}$Sn was achieved. A systematic study of the measured half-lives will be presented, probing the robustness of the magic number 50 in nuclei near the proton dripline.
        Speaker: Mr Joochun (Jason) Park (University of British Columbia/TRIUMF)
      • 13:15
        Single Particle Structure and Shapes of Exotic Sr Isotopes 15m
        Nuclei near the so called magic numbers of protons and neutrons are observed to have a spherical shape in their low lying states. Nuclei between magic numbers, where the binding energy tends to be less, are often observed to show deformation in low lying states. These deformations have either a prolate or oblate nature. States within a nucleus that have different shapes that are close in energy are colloquially referred to as shape coexisting. A dramatic occurrence of shape coexisting states is observed in nuclei in the vicinity of Z=40, N=60, which is the subject of substantial current experimental and theoretical effort. An important aspect in this context is the evolution of single particle structure for N<60 leading up to the shape transition region, which can be calculated with modern large scale shell model calculations using a $^{78}$Ni core or Beyond Mean Field Models. One-neutron transfer reactions are a proven tool to study single-particle energies as well as occupation numbers. Here we report on the study of the single-particle structure in $^{95,96,97}$Sr via (d,p) one-neutron transfer reactions in inverse kinematics. The experiments presented were performed in the ISAC facility using the TIGRESS gamma-ray spectrometer in conjunction with the SHARC charged-particle detector. Highly charged beams of $^{94,95,96}$Sr, produced in the ISAC UCx target and charge-bred by an ECR source were accelerated to 5.5 MeV/A in the superconducting ISAC-II linac before delivery to the experimental station. Other than their clear scientific value, these measurements were the first high mass (A>30) post-accelerated radioactive beam experiments performed at TRIUMF. A thorough analysis of single particle states will improve our understanding of the onset of these unique structures, encouraging the ongoing theoretical discussions. Through $^{95}$Sr(d,p) a strong occupation of the first excited 0$^{+}$ state and a weak population of the second 0$^{+}$ state was measured. This suggests that there is strong mixing between the ground state and the first 0$^+$. These results discussed in the context of the evolution of single-particle structure will be presented.
        Speaker: Steffen Cruz
      • 13:30
        A Study on Low Spin States in 154Gd Using (p,p') Reaction 15m
        Located at the stability line, the low lying spin states of the 154Gd nucleus were investigated at the University of Jyväskylä accelerator laboratory in Finland using the 154Gd(p,p'γ) reaction. A proton beam of 12 MeV was used to excite the 154Gd target, with the gamma-rays from the reaction detected with the JUROGAM II array, while the LISA charged-particle spectrometer was used for detection of the inelastically scattered protons. This experiment marked one of the first uses of the LISA spectrometer at Jyväskylä, and enabled the efficient tagging of the proton-emitting reactions, thus helping to distinguish between the (p,p'), and the much more copious (p, xn) channels. By analyzing the peaks obtained from the gamma-gamma, and gamma-gamma-proton, coincidence matrices, a decay scheme has been built using the RadWare software Escl8r. Experimental methods, new transitions, and future steps will be discussed.
        Speaker: Mr Harris Bidaman (University of Guelph)
      • 13:45
        Investigating the nature of excited 0$^+$ states populated via the $^{162}$Er(p,t) reaction 15m
        Many approaches have been implemented in nuclear structure physics to interpret the nature of excited states in well-deformed nuclei, such as vibrational excitations in $\beta$ phonons and $\gamma$ phonons, as well as pairing excitations. However, due to a paucity of data about excited states in rare earth nuclei, in many cases even the first excited state, 0$^+_2$, is not known. Direct two-neutron transfer reactions are a valuable tool for probing $0^{+}$ $\rightarrow$ $0^{+}$ transitions in well-deformed nuclei. Excited $0^+$ states in the $N=92$ nucleus $^{160}$Er have been studied via the ($p,t$) reaction with a highly-enriched $^{162}$Er target at the Maier-Leibnitz Laboratory in Garching, Germany, using a proton beam energy of 22 MeV and 24 MeV supplied by a Tandem Van de Graaff. Reaction products were momentum-analyzed with a Quadrupole-3-Dipole magnetic spectrograph. Strong population of the 0$^+_2$ state was observed with a large cross section greater than any other excited $0^+$ state. Preliminary results of the relative population of excited 0$^+$ states in $^{160}$Er and a possible intepretation will be presented.
        Speaker: Christina Burbadge (University of Guelph)
      • 14:00
        Simulating the DESCANT Neutron Detection Array with the Geant4 Monte Carlo Toolkit 15m
        The DEuterated SCintillator Array for Neutron Tagging (DESCANT) is a newly developed high-efficiency neutron detection array composed of 70 hexagonal deuterated scintillators. Due to the anisotropic nature of elastic neutron-deuteron (n,d) scattering, the pulse-height spectra of a deuterated scintillator contains a forward-peaked structure that can be used to determine the energy of the incident neutron without using traditional time-of-flight methods. Simulations of the array are crucial in order to interpret the DESCANT pulse heights, determine the efficiencies of the array, and examine its capabilities in conducting various nuclear decay experiments. To achieve this, we plan: (i) a verification of the low-energy hadronic neutron physics packages in Geant4, (ii) a comparison of simulated spectra with data from a simple cylindrical “test can” detector geometry, (iii) expanding the simulated light response to a prototype DESCANT detector, and (iv) simulating the entire DESCANT array.
        Speaker: Mr Joseph Turko (University of Guelph)
    • 13:00 14:30
      M2-2 Molecular Biophysics (DPMB) / Biophysique moléculaire (DPMB) Colonel By B205

      Colonel By B205

      University of Ottawa

      Convener: Francis Lin (University of Manitoba)
      • 13:00
        Femtomedicine in Cancer: Discovery of New Antitumor Molecules for Natural Targeted Chemotherapy and Radiotherapy of Cancers 30m
        The conquest of cancer continues to pose great challenges to medical science. There is a compelling need for innovative cancer research integrating biomedical sciences with physical sciences in order to ultimately conquer cancer. Femtomedicine (FMD), which integrates femtosecond time-resolved laser spectroscopy with biomedical sciences, was recently coined to advance fundamental understanding and therapies of human diseases notably cancer [1,2]. Our studies in FMD have led to the discoveries of the reductive damaging mechanism in DNA and living cells and the molecular mechanisms of action of existing anti-cancer agents. These have offered unique opportunities to develop new effective drugs for high-performance therapy of cancer[3,4]. We have particularly found a new class of non-platinum-based anticancer compounds (called FMD compounds) for natural targeted chemotherapy and radiotherapy of a variety of cancers, e.g., cervical cancer, ovarian cancer, head and neck cancer, breast cancer, lung cancer, etc. Treatments of various cancer cells in vitro and in vivo mouse xenograft models with FMD compounds led to effective chemotherapy and enhanced radiotherapy, while the compounds themselves induced no or little systemic and radiation toxicity. These compounds are therefore a new class of potent antitumor agents that can be translated into clinical trials for targeted chemotherapy and radiotherapy of multiple types of cancer. The results also show that FMD can bring breakthroughs in understanding fundamental biological processes and lead to advances in cancer therapy. This presentation will discuss some progress in this new frontier—FMD in Cancer. 1. QB Lu, Mutat. Res.: Rev. Mutat. Res. 704, 190-199 (2010). 2. J Nguyen et al., PNAS 108, 11778-11783 (2011). 3. QB Lu et al., EBioMedicine 2, 544-553 (2015). 4. CR Wang et al., Mol. Cancer Ther. (2016). doi: 10.1158/1535-7163.MCT-15-0862.
        Speaker: Prof. Qing-Bin Lu (University of Waterloo)
      • 13:30
        Observation of coupling between microscopic diffusion and macroscopic elasticity in soft matter 15m
        Material diffusion processes are fundamentally driven by local microscopic interactions. Many important applications of diffusion, including drug delivery, are based on this concept. However, some orientational microscopic interactions can generate a collective macroscopic organization. Thus, macroscopic boundary conditions may affect the microscopic diffusion if orientational interactions are involved in the diffusion process. Liquid crystalline materials are the best examples of orientationally correlated (oriented) molecular complexes where we can observe such phenomena. However, many other self-organized (oriented) material systems, particularly those present in the biological tissue, have similar behavior. My presentation will describe the experimental observation and theoretical modeling of the diffusion of chiral guest molecules in a nematic liquid crystal host and will discuss the possible implications of our observation in the drug diffusion phenomena in the biological tissue. Future developments will be also shortly discussed.
        Speaker: tigran galstian (Laval University)
      • 13:45
        The Lipid Bilayer Provides a Site for Cortisone Crystallization at High Cortisone Concentrations 15m
        Cortisone is an injected anti-inflammatory drug that is used to treat inflammation. Cortisone’s mechanism of action involves binding to an intracellular receptor which transduces a biochemical cascade to reduce the production of inflammatory prostaglandins. However, cortisone is known to confer side effects, such as pain, known as a “steroid flare” for which the mechanism is unknown. Using X-ray diffraction of highly oriented, multi lamellar stacks of lipid membranes and molecular dynamics (MD) simulations, we locate the cortisone molecules within the bilayer, quantified its crystallization, and measured the respective insertion dynamics [1]. At low cortisone concentrations, the molecules localize near the glycerol group of the lipid, and decreased membrane width in a dose-dependent manner. The formation of the cortisone crystallites was observed at higher concentrations, which conferred to a cubic lattice. While the cortisone molecules align parallel to the bilayers at low concentrations, they start to penetrate the hydrophobic core at higher concentrations. Trans-membrane crystallites start to nucleate when the membrane thickness has decreased such that cortisone molecules in the different leaflets can find partners from the opposite leaflet. The results manifests to potentiate a mechanism of action for “steroid flares” by forming crystallites in the bilayer, and offers greater understanding of the drug’s action. [1] RJ Alsop, **A Khondker**, JS Hub, MC Rheinstädter,. Sci. Rep. 6, 22425 (2016).
        Speaker: Adree Khondker (McMaster University)
      • 14:00
        Coarse-grained simulations of highly driven DNA translocation from a confining nanotube 15m
        Driven DNA translocation through a nanoscopic pore has been the focus of many studies in recent years both due to its importance in biological processes and as a promising new technology to probe single DNA molecules. However, the simple process of driving monodisperse DNA chains through a pore often leads to surprisingly wide distributions of translocation times. In the regime where the driving force is high, such that translocation occurs much faster than the time required for the chain to relax, the different conformations that a DNA chain can have at the initiation of the translocation is a major contributor to this broadening. As an effort to reduce the broad distribution of translocation times, we test a situation where the DNA is placed inside a small nanotube whose purpose is to limit the range of initial conformations. We present the results of coarse-grained Langevin Dynamics simulations where the DNA is confined inside both infinitely long tubes and finite-length end-capped tubes. We demonstrate that the results for both tube geometries can be reproduced by a theoretical Tension-Propagation model. Since the end-capped tube contains an extra degree of freedom compared to the semi-infinite tube, we show how both cases need different strategies in order to minimize the coefficient of variation, and obtain tighter distributions of the translocation time.
        Speaker: David Sean (University of Ottawa)
      • 14:15
        Organization of Nucleotides in Different Environments: Implications for the Formation of First RNA under Prebiotic Conditions 15m
        How nucleic acids first assembled and then incorporated into the earliest forms of cellular life 4 billion years ago remains a fundamental question of biology. It is postulated that prior to today's DNA, RNA, and protein-dominated world, RNA was used for genetic storage and as a catalyst for reactions, such as polymerization. RNA is a polymer chain of nucleotides linked to a ribose-phosphate backbone. Polymerization of nucleotides occurs in a condensation reaction in which phosphodiester bonds are formed. However, in the absence of enzymes and metabolism there has been no obvious way for RNA-like molecules to be produced and then encapsulated in cellular compartments, an essential first step in the origin of cellular life. To support the hypothesis that environmental conditions in the neighbourhood of volcanic hydrothermal springs could act to organize monomeric nucleotides through various noncovalent interactions and chemical reactions in the prebiotic era, we investigated 5'-adenosine monophosphate (AMP) and 5'-uridine monophosphate (UMP) molecules captured in different matrices that have been proposed to promote polymerization, namely multi-lamellar phospholipid bilayers, nanoscopic films, ammonium chloride salt crystals and Montmorillonite clay [1]. Two nucleotides signals were observed in our X-ray diffraction experiments, one corresponding to a nearest neighbour distance of around 4.6 Å and a second, smaller distance of 3.45 Å. While the 3.45 Å distance agrees well with the distance between stacked base pairs in the RNA backbone, the 4.6 Å distance can be attributed to un-polymerized nucleotides that form a disordered, liquid-like structure. From the relative strength of the two contributions, the effectiveness of the different environment for producing RNA-like polymers was determined. [1] S Himbert, M Chapman, DW Deamer, Maikel C. Rheinstädter, submitted to PLOS ONE.
        Speaker: Sebastian Himbert (Mcmaster University)
    • 13:00 14:30
      M2-3 Ultrafast and Time-Resolved Processes (DAMOPC) / Procédés ultrarapides et résolus dans le temps (DPAMPC) Colonel By D207

      Colonel By D207

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Lindsay LeBlanc (University of Alberta)
      • 13:00
        Nonlinear Optical Response of Arrays of Metamolecules: New Observations and Ways of Enhancement 30m
        Recent advances in nanofabrication made it possible to produce arrays of artificial structures (metamolecules) with good optical quality. This, in turn, enabled the observation of many unusual phenomena, such as invisibility cloaking, negative refraction, generation of beams with orbital angular momentum and other modifications to the polarization state of the incoming light. Of special importance is the nonlinear optical response of such arrays. Since there is a lot of flexibility in the choice of the materials and shapes of individual metamolecules, it is expected that the nonlinear optical properties of such arrays could be largely controlled and tailored. In this talk, we will be discussing two methods of such tailoring. One of the methods involves the resonant enhancement of the overall nonlinear optical response enabled by the coupling between the metamolecules in the arrays. Another method of tailoring the nonlinear optical properties of an array of metamolecules relies on local-field effects. It has been recently shown that such effects are capable of inducing an additional contribution to a higher-than-the-lowest-order nonlinear optical response present in a material medium. This contribution is of cascaded nature: it relies on the multistep contribution of a lower-order nonlinearity to a higher-order susceptibility. When induced by local-field effects, such a cascading is of local nature: it occurs at the scale of the neighboring metamolecules forming the array. This unique feature distinguishes this effect from a better known macroscopic cascading. Microscopic cascading is a relatively new effect that has not been studied in detail yet. We present our resent efforts at identifying the conditions under which this effect could become the dominant contribution to a higher-order nonlinear optical susceptibility.
        Speaker: Prof. Ksenia Dolgaleva (University of Ottawa)
      • 13:30
        Effects of Refractive Index Mismatch on Stimulated Raman Scattering And Coherent Anti-Stokes Raman Scattering Microscopy 15m
        Nonlinear optical microscopy techniques, such as stimulated Raman scattering (SRS) and coherent anti-Stokes Raman scattering (CARS), allow for label-free chemically-sensitive non-destructive video-rate imaging of biological processes[1]. SRS is of particular interest due to its improved image contrast, high spectral sensitivity and low acquisition times. Correctly interpreting images produced by nonlinear optical processes is of vital importance. Earlier we showed AM-SRS signals depend upon the structure of $\chi^{(3)}$ in the background medium, and thus is not background free[2]. We now show that even for the modest linear refractive index mismatches typically found in biological tissues, near-field enhancements can cause significant signal distortions in both CARS[3] and SRS. We employ finite-difference time-domain simulations to determine the near- and far-fields of wavelength-sized spherical Raman-active objects in a nonresonant Kerr medium illuminated by a tightly-focused laser source. We find that, depending upon the shape of the Raman scatterer, enhanced near-fields can create a signal an order of magnitude larger than what would be expected, and with a peak in the image that does not directly correspond to the object location. Additionally, the radiation pattern is heavily influenced and as a consequence we find that the numerical aperture of the collecting lens becomes important. Filtering techniques will not eliminate any of these effects as these distortions are caused by a microlensing effect within the scatterers. Understanding these distortions is key to correctly interpreting both CARS and SRS images. Even without any Raman-active material present, the underlying $\chi^{(1)}$ structure can introduce background signals in AM-SRS and CARS. This highlights the need for frequency-based filtering methods such as FM-SRS and FM-CARS or hyperspectral analysis. **References** 1. B. Saar et al., **Science** 330, 1368–1370 (2010). 2. K. Popov et al., **Opt. Lett.** 37, 473–475 (2012). 3. J. Lin et al., **Opt. Express** 17, 2423–2434 (2009).
        Speaker: Jarno Nicolaas van der Kolk (University of Ottawa)
      • 13:45
        Super-Critical Phase-Matching for Generation of Structured Light Beams 15m
        Radially and azimuthally polarized light beams have garnered increased interest for their properties and uses in fundamental and applied optics. Radial polarizations are parallel to the central axis of the beam (at all points pointing toward the beam center); azimuthal polarizations are orthogonal to this, running perpendicular to the central axis of the beam. Photon pairs with these polarizations have applications in quantum information, such as alignment-free quantum key distribution and superdense coding. We present a method to directly produce, through spontaneous parametric down-conversion (SPDC), photon pairs with radial and azimuthal polarizations. In SPDC, a pump photon is absorbed and two lower-frequency photons, the signal and idler, are produced such that energy and momentum are conserved (i.e. phasematching). These photons may be produced in the same direction as the pump beam, in collinear phase-matching, and may have polarizations that are parallel (type I) or orthogonal (type II). In our new geometry, the pump beam is a Bessel-Gauss beam, which we have modeled as a distribution of Gaussian beams forming the surface of a cone. This cone is centered on the crystal axis, which is parallel to the central pump propagation direction. The opening angle of this cone is set so that each Gaussian pump beam in the pump distribution meets the phase-matching conditions. We have simulated the output distributions for the signal and idler photons in type I and type II phase-matching. For type II phase-matching, the signal and idler photons are emitted along three concentric cones, which we have named ‘super-cones’. These photons will have orthogonal polarizations: one will be radially polarized and the other azimuthally polarized. In type I phase-matching, the signal and idler photons will both be azimuthally polarized, and will be emitted along a single super-cone that is collinear with the pump beam. We have demonstrated a novel method to directly produce radially and azimuthally polarized photon pairs. These unique polarization states have applications in quantum information and quantum metrology, and are opening new research directions in these fields. Boeuf, N., et. al. Opt. Eng. 39(4): 1016-1024, 2000. Quabis, S., et. al. Opt. Comm. 179(1):1-7, 2000.
        Speaker: Rebecca Saaltink (University of Ottawa)
      • 14:00
        A Method to Arbitrarily Transform the Polarization of Light Variably Across a Beam 15m
        Light fields with spatially varying polarization have a wide range of potential uses in the areas of telecommunication, imaging, lithography, and quantum information. A spatial light modulator (SLM) is a two dimensional array of liquid crystal cells that can control phase, polarization, and intensity of light point by point across a beam’s spatial profile. We have developed methods to implement general polarization transformations using SLMs. That is, we can apply arbitrary polarization rotations that vary controllably across a beam. In quantum information, our methods in principle could enable the parallel processing of millions of optical modes, one for each cell. As an experimental example of the power of these methods, we take a beam with a non-uniform polarization across its spatial profile and convert it to be uniform. Such a correction could be useful for astronomy or microscopy imaging systems that suffer from polarization aberrations. In order to demonstrate the procedure’s effectiveness we present point by point measurements of the polarization before and after the correction.
        Speaker: Mr Matthew Runyon (Department of Physics and Max Planck Centre for Extreme and Quantum Photonics, University of Ottawa, Canada)
      • 14:15
        Single-shot holographic measurement of attosecond pulses and the time-dependent field of an ultrashort pulses 15m
        We demonstrated simultaneous all-optical, single-shot holographic measurement of attosecond high harmonic pulses and a femtosecond laser pulse. To achieve this, we introduce a weak laser beam into the harmonic generation medium together with the strong driving laser field. The weak laser field perturbs the trajectories of ionized electrons that are responsible for high harmonic generation and therefore diffracts the harmonic radiations. Since the periodic structure in the near-field harmonic radiations implies cross-correlation between the attosecond pulse and the perturbing laser pulse, we can achieve temporal characterization by measuring the diffracted high harmonic radiations. However, since the far-field intensity distribution is insensitive to the near-field harmonic radiations, we superposed a reference X-ray beam generated from a secondary harmonic source. The measured harmonic spectrograph shows dense fringes that originate from two-source interference. The rapid oscillation enables us to reconstruct the near-field harmonic radiations by applying Fourier transform. As a result, we determined the attosecond pulses, showing a pulse duration of 390 as, and the time-dependent electric field of the perturbing pulse from the retrieved near-field image. The duration of the perturbing pulse that we obtain is consistent with the result achieved by a conventional FROG measurement. The single-shot measurement method is a fast, robust and effective way to monitor high harmonic or attosecond pulses. Consequently, it will be a new technique to probe ultrafast strong-field interactions in many materials.
        Speaker: Dr Dong Hyuk Ko (Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada)
    • 13:00 14:30
      M2-4 Mathematical Physics (DTP) / Physique mathématique (DPT) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Jean-Francois Fortin (Laval University)
      • 13:00
        A Farewell to Symmetries: Quasilocal Frames in General Relativity 30m
        In this talk, I will give a brief introduction to rigid quasilocal frames (RQF) which have been proposed as a geometrically natural way to define spatially extended reference frames in general relativity. In particular, I will explore their usefulness as a tool for constructing completely general conservation laws that do not rely on the presence of spacetime symmetries and include both matter and gravitational contributions without the need for any ad hoc structures such as pseudotensors. In doing so, I show how the RQF approach affords a deeper understanding of the nature of gravitational fluxes via the equivalence principle and discuss more concrete potential applications.
        Speaker: Dr Paul McGrath
      • 13:30
        The Moyal Equation for open quantum systems 30m
        We generalize the Moyal equation, which describes the dynamics of quantum observables in phase space, to quantum systems coupled to a reservoir. It is shown that phase space observables become functionals of fluctuating noise forces introduced by the coupling to the reservoir. For Markovian reservoirs, the Moyal equation turns into a functional differential equation in which the reservoir's effect can be described by a single parameter.
        Speaker: Karl-Peter Marzlin (St. Francis Xavier University)
      • 14:00
        Citation Networks in Law: Detection of Hierarchy and Identification of Key Events 15m
        Citation networks can be used to make powerful analyses about human intellectual activity in diverse fields. However, universal rules governing their structure and dynamics have not yet been discovered. To address this, my research probes the influence of social and institutional hierarchy on the structure and dynamics of citation networks. Hierarchy is a fundamental feature of all human social organizations; therefore, any citation network is necessarily embedded in an “underlying” hierarchy that in turn determines properties of the network. Through this new way of analyzing citation networks, my research seeks to advance the understanding of phenomena central to societal progress, such as: the emergence of research fronts and seminal publications; how paradigms form, take hold, become unstable, and collapse; innovation and the emergence of new technologies; and the emergence of new legal doctrine and the evolution of the law. I will present an analysis of a novel data set (that I have created) that covers all hierarchical levels of the Canadian legal system for a specific area of law (defamation law). My presentation will show: 1) an evaluation of a recently published method for inferring hierarchies among scientific journals based on scientific citation networks by applying that method to my novel data set, in order to determine if the method is capable of detecting the known underlying court hierarchy; and 2) ways in which network analysis methods (node-ranking via authority scores and node-grouping via community detection/clustering) can identify important periods in the evolution of the law (e.g. turning-points in legal “eras”, in which the law is applied in a new way). Points 1 and 2 will be discussed in relation to the overarching goal of understanding the influence of underlying hierarchy on the structure and evolution of citation networks in law and other fields.
        Speaker: Mr Joseph Hickey (University of Calgary)
    • 13:00 14:30
      M2-5 Energy Frontier: SUSY and Exotics (PPD) / Frontière d'énergie: supersymétrie et particules exotiques (PPD) MacDonald 146

      MacDonald 146

      University of Ottawa

      Convener: Brigitte Vachon (McGill University (CA))
      • 13:00
        Operation and Performance of the ATLAS detector in LHC Run II 30m
        The ATLAS detector at CERN in Geneva, Switzerland, detects the particles produced in proton-proton collisions created by the Large Hadron Collider. Following the very successful Run I data taking period during 2009-2012 where the proton-proton collision energy was at maximum 8 TeV, we have now started the Run II data taking period with the significantly higher collision energy of 13 TeV. This talk will present the status of the operations and performance of the ATLAS detector, including details on data acquisition, trigger, reconstruction and calibration performance. Particular focus will be given to the Canadian contributions.
        Speaker: Dag Gillberg (Carleton University)
      • 13:30
        Helium-3 thermal neutrons counters in the SuperKEKB commissioning detector 15m
        Thermal neutron detectors have been installed into BEAST II, the commissioning detector of the SuperKEKb accelerator. These detectors use helium-3 to detect neutrons via the capture process $^{3}$He$ + n \rightarrow ^{3}$H$+p+720keV$ and are only sensitive to thermal neutrons, and are therefore an excellent means of monitoring the thermal neutron flux in the BEAST. Commissioning began in February and continued until the end of May, providing a large variety of beam conditions in which to measure the neutron flux. These flux measurements are compared with simulation in order to test the validity of the simulations.
        Speaker: Samuel de Jong (University of Victoria)
      • 13:45
        Measurement of the electromagnetic background radiation during SuperKEKB commissioning 15m
        The SuperKEKB electron-positron collider, aiming to deliver an unprecedented peak instantaneous luminosity to the Belle-II experiment, was operated for the first time at the beginning of this year. The expected luminosity --- 40 times that delivered to the Belle experiment --- demands careful prediction and characterization of the machine-induced background radiation and its effect on the detector. Of particular interest is the prediction of the impacts on the performance and longevity of the electromagnetic calorimeter. To rely exclusively on simulation of the new and unknown SuperKEKB machine for such predictions would be rather daring, therefore the goal of the experiment is to measure the electromagnetic background rate and spectra in the so-called end-cap regions of the calorimeter, where it is predicted to be the largest. We used six calorimeter units each containing three types of crystal scintillators, all read out by photo-multiplier tubes. These units were placed in the forward and in the backward regions of the interaction region, at positions reproducing those of the Belle-II calorimeter end-cap crystals. We record the arrival time and deposited energy for each hit, and the different crystal materials will provide sensitivity to different parts of the spectra. We are taking data since February, during the accelerator commissioning and always changing beam conditions. We want to capture the relationships between the background observables and accelerator quantities such as the bunch size, the beam current, and the pressure in the vacuum chamber. It is the scaling of the background compared to the beam parameters that will enable us to disentangle the dominant physical processes behind observed beam loss events, and test how well each of these processes is simulated. The measurement campaign coincides with the first phase of SuperKEKB commissioning, and is planned to end on June 30th, 2016.
        Speaker: Alexandre Beaulieu (University of Victoria)
      • 14:00
        Search for supersymmetry in final state with jets and two same-sign leptons or three leptons with the ATLAS detector. 15m
        Supersymmetry (SUSY) is one of the most popular and the most studied theory proposed as an extension to the Standard Model (SM). If R-parity is conserved the lightest supersymmetric particle (LSP) is stable and in many models LSP can be a good candidate for dark matter. I will present the method and the results about the search of strongly produced supersymmetric particles using a specific signature involving final states with multiple hadronic jets and either two isolated leptons ($e$ ou $\mu$) with the same electric charge or at least three isolated leptons. This signature is present in many SUSY scenarios and Standard Model processes leading to such final states have a very small cross-section. The analysis uses a data sample of proton-proton collisions at $\sqrt{s}=13$ recorded with the ATLAS detector at the Large Hadron Collider (LHC) in 2015 corresponding to a total integrated luminosity of 3.2 $fb^{-1}$. During the talk, I will cover different aspects of the analysis such as the detector, the dataset and simulated event samples, the event selection, the background estimation (and validation) and finally the results, interpreted in several simplified SUSY models.
        Speaker: Hubert Trepanier (Universite de Montreal (CA))
      • 14:15
        Collecting events based on jet substructure with the ATLAS detector 15m
        The most common feature produced in the proton-proton collisions of the Large Hadron Collider (LHC) are collimated sprays of particles referred to as jets, which are typically produced from quarks or gluons. The large centre-of-mass energy of the LHC collisions also enables the production of heavy particles with a significant Lorentz-boost. The decay products of such a boosted heavy particle can be reconstructed as a single jet, and hence at a first glance, look very similar to the jets produced from quarks and gluons. However, these classes of jets have different internal structure. The study of the internal jet substructure is currently a hot topic within High Energy Physics. A long list of analyses at the LHC exploit features of the radiation pattern within jets to identify jets from heavy boosted objects, often in searches for new physics phenomena. A significant limitations for some of these analyses at the ATLAS experiment is that many of the interesting collision events are never recorded since they are not accepted by the trigger system that filters out the vast majority of collisions only keeping the ones deemed most interesting. This presentation will give an overview of jet substructure used in physics studies of boosted objects with particular emphasis on the development of dedicated, optimized triggers that select data events based on features of the substructure of jets. This has potential to significantly improve the sensitivity of several analyses that search for new physics phenomena.
        Speaker: Mr Nima Sherafati (Carleton University)
    • 13:00 14:30
      M2-6 Theory, Modelling, and Forecasting II (DASP) / Théorie, modélisation et prévisions II (DPAE) Colonel By D103

      Colonel By D103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: patrick perron (RMCC)
      • 13:00
        Harnessing butterflies for climate closure and for improved monthly, seasonal, and interannual forecasts 30m
        Although the butterfly effect – sensitive dependence on initial conditions - fundamental limits deterministic weather forecasting to horizons of about 10 days, it has not prevented deterministic Global Circulation Models (GCM’s) from being used way past this limit for monthly, seasonal and interannual forecasts. When such models are used for these longer term “macroweather” forecasts, they can only be interpreted statistically. However at monthly, seasonal and multiyear (“interannual”) scales, the atmosphere is governed by new (higher level) stochastic (statistical) laws which imply a huge memory which can be directly exploited by the Stochastic Seasonal and Interannual Prediction System (StocSIPS). StocSIPS is a straightforward, highly efficient forecasting system that makes global, monthly, seasonal and interannual forecasts. For these horizons, StocSIPS is significantly more accurate than the conventional models. StocSIPS’ advantages include: * Convergence to the real – not model - climate: The key to StocSIPS skill is the ScaLIng Macroweather Model (SLIMM) forecasting module that uses past data – and the huge memory in the system - to ensure that the forecast converges to the real world climate. * Speed: In order to get good statistics, conventional seasonal to annual forecasts typically re-forecast over ten to twenty realizations, each time using slightly different initial data typically taking the equivalent of a million CPU hours on the world’s fastest computers. In comparison, StocSIPS uses only a few minutes of CPU time to directly calculate the statistics of an infinite number of realizations. * No data assimilation: StocSIPS can directly forecast either gridded or individual station data, there is no need to transform the input data to make it digestible by the numerical model; StocSIPS avoids complex data “assimilation” techniques. * No ad hoc post processing: The raw temperatures and precipitation rates forecast by conventional models have unrealistic variability. This is usually “corrected” using complex ad hoc post processing algorithms that use hindcasts to incorporate past information in order to make the forecasts more realistic. StocSIPS uses only past information with a theoretically justified forecast procedure. * No need for downscaling: Conventional models have pixels of 100,000 km2 or more in size and must be “downscaled” to adapt them to local conditions. Whenever long station temperature series are available, StocSIPS can forecast them directly. Finally, the global temperature – including the “pause” can be accurately forecast and this can be used to show that the probability that the post industrial warming was simply a giant fluctuation is less than 0.1%, thus closing the climate debate.
        Speaker: Shaun Lovejoy (McGill University)
      • 13:30
        The importance of an accurate magnetic field for the estimation of Faraday rotation from total electron content. 15m
        A plane polarized wave that propagates through a plasma, parallel to a magnetic field, suffers a gradual rotation of its plane of polarization called Faraday rotation. Likewise, radio beacon signals that traverse the ionospheric plasma encounter a parallel component of Earths geomagnetic field and the anisotropy of the medium. Many authors use the average value of the parallel magnetic field for estimation of Faraday rotation (FR) from ionospheric total electron content (TEC) measurements. Although it is known that the strength of Earth's geomagnetic field varies slowly at ionospheric altitudes, a reference height characteristic value or reference mean value may not always be sufficient. though commonly used. Numerical modelling has demonstrated that FR, independent of carrier frequency, can be calculated more accurately by applying a weighted average in favour of the ground based values when using an average value of the magnetic field. Values for the electron density from the International Reference Ionosphere (IRI) and magnetic field from the International Geomagnetic Reference Field (IGRF) were sampled for several different days at different latitudes. The TEC was computed from the convolution of the electron densities from IRI and magnetic field values from IGRF. The effect on the conversion of the modelled TEC to FR along vertical paths for different values of the magnetic field, including the average, reference altitude and weighted average. They were compared with the conversion using IGRF as a function of altitude as the ideal solution. For all conditions, an average value for the magnetic field tends to underestimate the degree of FR. This work found that a weighted average in favor of the magnetic field values from lower altitudes improved results.
        Speaker: Alex Cushley
      • 13:45
        The Empirical Canadian High Arctic Ionospheric Model (E-CHAIM): NmF2 and hmF2 specification 15m
        It is well known that the IRI suffers reduced accuracy in its representation of monthly median ionospheric variability at high latitudes (Themens et al. 2014, Themens et al. 2016). These inaccuracies are believed to stem from a historical lack of data from these regions. Now, roughly thirty and forty years after the development of the original URSI and CCIR foF2 maps, respectively, there exists a much larger dataset of high latitude observations of ionospheric electron density. These new measurements come in the form of new ionosonde deployments, such as those of the Canadian High Arctic Ionospheric Network, the CHAMP, GRACE, and COSMIC radio occultation missions, and the construction of the Poker Flat, Resolute, and EISCAT Incoherent Scatter Radars systems. These new datasets afford an opportunity to revise the IRI’s representation of the high latitude ionosphere. For this purpose, we here introduce the Empirical Canadian High Arctic Ionospheric Model (E-CHAIM), which will incorporate all of the above datasets, as well as the older observation records, into a new climatological representation of the high latitude ionosphere. In this presentation, we introduce the NmF2 and hmF2 portions of the model and present a validation of the new model with respect to ionosonde observations in Alert, Canada. A comparison with respect to IRI performance will also be presented.
        Speaker: David Themens (University of New Brunswick)
      • 14:00
        Calculation and Analysis of High Rate Total Electron Content in the Canadian High Arctic 15m
        The Canadian High Arctic Ionospheric Network (CHAIN) [1] includes Global Positioning System (GPS) receivers capable of sampling specific observables at very high rates, up to 100 Hz. With these high rate observables, 100 Hz Total Electron Content (TEC), and Rate of TEC index (ROTI), can be calculated. This study outlines the methods and limitations of calculating both relative and absolute 100 Hz TEC, specifically from the observables provided by the Septentrio PolaRxS Pro GPS. Spectral analyses of the high rate TEC and ROTI is also presented, determining whether important results can be obtained within the higher frequency data. The expected hardware noise is predicted to aid in the determination of important results in the data, in an attempt to extract ionospheric information from possible sources of noise. [1] Jayachandran, P. T., R. B. Langley, J. W. MacDougall, S. C. Mushini, D. Pokhotelov, A. M. Hamza, I. R. Mann, D. K. Milling, Z. C. Kale, R. Chadwick, T. Kelly, D. W. Danskin, and C. S. Carrano (2009), The Canadian high arctic ionospheric network (CHAIN), Radio Sci., 44, RS0A03, doi:10.1029/2008RS004046, 2009.
        Speaker: Anthony McCaffrey (University of New Brunswick)
      • 14:15
        A Neural Network (NN)-based foF2 model for a single station in the polar cap 15m
        The work on neural networks (NN) by several authors has shown promising results in modeling nonlinear and complex processes in the near Earth space. For instance, NN-based models have been developed to forecast solar and magnetic activity indices, and different ionospheric parameters. However, the developed models have been faced with the challenge of data paucity in the polar region, a major drawback in obtaining suitable relevant models for various geophysical applications in the region. A neural network based model for the critical frequency of the F2 layer (foF2) has been developed using selected geophysical inputs and observed data from Resolute (74.75° N, 265.00° E) spanning from 1975 – 1995 and 2009 – 2012, obtained from the Space Physics Interactive Data Resource (SPIDR) and the Canadian High Arctic Ionospheric Network (CHAIN), respectively. A comparison between the NN and the IRI (International Reference Ionosphere) model values with observations was investigated. Both models reproduce the observed diurnal and seasonal variations in foF2 except that the IRI model tends to underestimate the values during low solar activity. The NN model is able to reproduce the enhancements in the foF2 observed in the measurements during the equinoxes, and also shows an improvement in foF2 predictions during disturbed days. An analysis of the root mean square errors (RMSE) computed between the model predictions and observed values show a noticeable margin between the NN and IRI – predicted foF2 values.
        Speaker: Racheal Athieno (University of New Brunswick)
    • 13:00 14:30
      M2-7 Carbon-based Nanomaterials (DCMMP-DSS) / Nanomatériaux à base de carbone (DPMCM-DSS) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Rafik Naccache (Concordia University)
      • 13:00
        2D Materials Growth: Applications and Challenges 30m
        Two-dimensional (2D) materials have attracted much attention due to their unique properties. Controllable synthesis of 2D materials with high quality and high efficiency is essential for their large-scale applications. In parallel to the chemical synthesis route, chemical vapor deposition (CVD) has been one of the most important techniques for the synthesis of 2D materials. The present talk will be devoted to the CVD growth of graphene, boron nitride, core-shell nanoparticles@graphene and transition metal dichalcogenides (TMDs) in our research group. The Hydrogen-induced effects during the growth will be discussed. In parallel, we will show that the use of these resulting 2D materials as electrodes leads to an enhancement of the overall reactivity and sensors sensitivity which is favorable for many applications.
        Speaker: Prof. Mohamed Siaj (UQAM)
      • 13:30
        Terahertz Response of Monolayer Graphene:Velocity Gauge Vs Length Gauge 15m
        Graphene, as a zero-bandgap two-dimensional semiconductor with a linear electron band dispersion near the Dirac points has potential to exhibit very interesting nonlinear optical properties [1]. In particular, third harmonic generation of terahertz (THz) radiation should occur both due to the nonlinear relationship between the crystal momentum and the current density, and due to the interaction between interband and intraband parts of the current densities due to the vanishing bandgap [2]. In this work, we investigate two different ways of calculating the nonlinear response of graphene to THz radiation. There are two different gauges that are commonly employed to study the interaction of electrons in a semiconductor with a THz or optical field: the velocity gauge and the length gauge [3,4] In the length gauge, the interaction of the electrons with the field is given by $\vec{r}\cdot\vec{E(t)} $, while in the length gauge, it is given by $\vec{p}\cdot\vec{A(t)} $. In this work, we derive the nonlinear density matrix equations and current density expressions in the two gauges for graphene in a two band model. We show that if one uses the mass sum rule for the bands, the two methods yield very similar linear conductivities. However, we find that the nonlinear response can be quite different for the two approaches, due in large part to the divergences that arise at zero frequency in the velocity gauge when one uses a basis with a finite number of bands. We conclude that one should use the the length gauge for graphene when calculating the nonlinear THz response. References: [1] S. A. Mikhailov, Phys. Rev. Lett. \textbf{105} ,097401 (2010). [2 ]I. Al-Naib, J. E. Sipe, M. M. Dignam, Phys. Rev. B \textbf{90 }, 245423 (2015). [3] A. Chacona , M. Lewensteina,b, M. F. Ciappina,Journal of Computational Physics. \textbf{1 },1508.04889 (2015). [4] I. Al-Naib, J. E. Sipe, M. M. Dignam, New J. Phys. \textbf{17 }, 113018 (2015).
        Speaker: Parvin Navaeipour (Queen's University)
      • 13:45
        Spontaneous polarization of the two-dimensional electron gas in WS$_2$ 15m
        Tungsten disulfide represents a class of 2D materials, transition metal dichalcogenides (TMDC), which exist as layers of atomic thickness with atoms organized in a honeycomb lattice. Similarly to graphene, in TMDCs the minimum of the conduction band and the maximum of the valence band are found at the K and K’ points in the Brillouin zone. Unlike graphene, these systems exhibit (i) a large direct bandgap, and (ii) strong spin-orbit interaction, which locks the spin and valley degrees of freedom of quasielectrons and quasiholes. The two-dimensional character of TMDCs results in a significant enhancement of Coulomb interactions. In Hartree-Fock (HF) approximation, this leads to a spontaneous valley polarization of the two-dimensional electron gas (2DEG) driven by electron-electron exchange. The valley polarization translates into spontaneously circularly polarized emission recently detected in magnetooptical measurements [1]. We present here a microscopic theory of the two-dimensional electron gas in WS$_2$ . We develop an atomistic tight-binding (tb) model for single-quasielectron and quasihole states accounting for the spectral content of the subbands in terms of linear combinations of atomistic orbitals. The tb parameters are obtained from ab-initio calculations. The spin-orbit coupling and resulting reversal of the spin order of the conduction band are treated phenomenologically. This allows to formulate the optical selection rules and calculate Coulomb interaction matrix elements atomistically. Using these elements, we calculate the HF phase diagram of the system of N interacting electrons in doped WS$_2$ and demonstrate the formation of a valley polarized 2DEG state for low enough electronic densities, and a valley-singlet state for larger densities. The effect of correlation and Q minima are also included. The effect of a magnetic field is discussed in terms of Landau levels of interacting massive Dirac Fermions. Finally, we relate the formation of the valley polarized state with magnetooptical experiments. [1] T. Scrace, Y. Tsai, B. Barman, L. Schweidenback, A. Petrou, G. Kioseoglou, I. Ozfidan, M. Korkusinski, and P. Hawrylak, Nature Nanotechnology 10, 603 (2015).
        Speaker: Dr Marek Korkusinski (National Research Council)
      • 14:00
        Contactless thermal conductivity imaging in nanoscale semiconductors 15m
        Pulsed thermoreflectance (PTR) and photothermal deflection spectroscopy (PDS) are powerful and contactless methods to simultaneously determine the thermal diffusivity and thermal conductivity of thin solid films. In PTR, the heat generated in an optically absorbing thin film by a pulsed and monochromatic light beam creates a change of reflectance in the material, which is detected via a lock-in amplifier. In PDS, the heat generated in the thin film diffuses through a transparent photothermal fluid in which the film is embedded and the thermal gradient experienced at the interface between the film and the adjoining fluid can be probed by a laser beam grazing the film surface and periodically deflected away from the surface by modulated changes of refractive indexes at the interface. In both PTR and PDS, the phase and amplitude of the signals are measured using position-sensitive photodetectors. From the two measured parameters, phase and amplitude, the thermal diffusivity and thermal conductivity of the sample can be simultaneously inferred without any needs of contacts on the thin film sample. Consequently, the thermal properties investigated in this way are not dependent on interface effects between the solid and metallic contacts. We demonstrate that PTS and PDS are also capable of mapping the thermal properties of thin films at the microscopic level and beyond, if PTS and PDS are coupled with a system comprising two optical microscopes, an upright optical microscope, in which pulsed monochromatic light is focussed, and an inverted optical microscope from which the signal is probed and detected. This setup will be used for imaging the thermal properties of thin films that are composite at the nanoscale and will include collections of graphene flakes on glass and polymer-fullerene blends for organic photovoltaic applications. In case of graphene flakes on glass, different interface thermal resistivities can be observed for different types of edges, armchair and zigzag. The ultimate resolution of our imaging techniques will be discussed as well.
        Speaker: Mr Sina Kazemian (PhD student)
    • 14:45 15:15
      M-MEDAL CAP Medal Talk - Roger Melko, U. of Waterloo / Perimeter Institute (CAP Herzberg Medal Recipient / Récipiendaire de la médaille Herzberg de l'ACP) Marion 150

      Marion 150

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 14:45
        The Information Age in Condensed Matter Physics 30m

        Monte Carlo simulations have been ubiquitous in efforts to simulate and characterize properties of matter and materials since the advent of computers themselves. In the last decade, condensed matter physicists have turned simulation technology to the study of a new set of phenomena, loosely termed as "emergent", with correlations not manifested in traditional correlation functions. Motivated by this, a new set of tools was recently developed that allows one to probe emergent phenomena in Monte Carlo simulations through their entanglement entropy - a concept borrowed from quantum information theory. Remarkably, since certain scaling terms in the entanglement entropy are universal, this provides a powerful general method to characterize phases and phase transitions in a wide variety of physical theories. Thus, Monte Carlo simulations are beginning to play a central role for physicists who increasingly rely on information quantities to study correlations not only in condensed matter systems and quantum devices, but even in quantum fields and theories of quantum gravity.

        Speaker: Prof. Roger Melko (University of Waterloo)
    • 15:15 15:45
      Health Break / Pause santé
    • 15:45 17:30
      CAP-NSERC Liaison Cttee Mtg / Réunion du comité de liaison ACP-CRSNG Colonel By A707A

      Colonel By A707A

      University of Ottawa

      Convener: Bill Whelan (University of Prince Edward Island)
    • 15:45 17:15
      M3-1 Nuclear Astrophysics (DNP) / Astrophysique nucléaire (DPN) Colonel By B205

      Colonel By B205

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Barry Davids (TRIUMF)
      • 15:45
        Neutron star mergers: neutrino emission and nucleosynthesis 30m
        Neutron-star binary mergers are interesting for several reasons: they are proposed as the progenitors of short gamma-ray bursts, they have been speculated to be a site for the synthesis of heavy elements, and they emit gravitational waves possibly detectable at terrestrial facilities. Our current understanding of the merger evolution and the production of new elements is linked to details of nuclear physics and gravity. In particular, a key ingredient is the neutrino emission which is subjected to a strong gravitational field and influences the matter neutron-richness. In this talk, I shall discuss some aspects of the binary system evolution and the impact of neutrinos on the synthesis of elements.
        Speaker: Olga Caballero
      • 16:15
        Constraining neutron capture rates far from stability and astrophysical implications 30m
        The astrophysical r-process is responsible for the synthesis of about half of the isotopes of the heavy elements. Despite its well-known role in nucleosythesis, the astrophysical site where it takes place has not been unambiguously determined. Efforts for the better understanding of this important process span across many fields, from astronomical observations of metal-poor stars, and modeling of the possible scenarios, to sensitivity studies to input parameters, nuclear theory calculations and nuclear experiments. The present talk will focus on the experimental efforts for providing nuclear input information to help improve our understanding of the r-process. One of the important inputs, that is practically unconstrained by experiment, is neutron capture reactions. The talk will focus on the development of a new technique (β-Oslo) to experimentally constrain these important (n,γ) reaction rates far from stability. The experiments were done at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University using the γ-calorimeter SuN. The validation of the β-Oslo technique, first physics results and implications for astrophysical calculations will be presented.
        Speaker: Artemis Spyrou (Michigan State University)
      • 16:45
        **WITHDRAWN** Phase-imaging mass measurements with the Canadian Penning trap mass spectrometer 15m
        Roughly half of the elements heavier than iron are thought to be produced through the astrophysical rapid-neutron capture process of nucleosynthesis. Despite its large influence in explaining the observed abundance of heavy elements, much of the *r* process is still poorly understood. A more thorough library of nuclear data, particularly masses, of neutron-rich nuclei is needed to improve the accuracy and progression of r-process calculations. The Canadian Penning trap mass spectrometer (CPT) is currently located in the CARIBU facility at Argonne National Laboratory where intense radioactive beams of neutron-rich nuclei are produced from the spontaneous fission of $^{252}$Cf. Since its move to CARIBU in 2010, the CPT has successfully measured the masses of more than 110 isotopes to a typical precision of 15 keV/c$^2$ by measuring the cyclotron frequency of ions through a time-of-flight (TOF) technique. An upgrade to a position-sensitive microchannel plate detector at the CPT has facilitated a contemporary technique in the determination of masses by measuring the phases of orbital motion of trapped ions. This phase-imaging method is intrinsically more efficient than the TOF technique, and provides an order of magnitude improvement in mass-resolving power without loss in precision, allowing access to more weakly produced isotopes with shorter half-lives than was previously achievable at CARIBU. The low-energy beamline at CARIBU was recently fitted with a multi-reflection time-of-flight mass separator (MR-TOF) which improved beam purity by more than an order of magnitude. In a preliminary measurement campaign the phase-imaging technique, buoyed by the MR-TOF, has yielded the masses of eight previously unmeasured ground-state rare-earth isotopes, and another three nuclear isomers whose masses were directly measured for the first time. These results and future plans to probe another 1-3 neutrons from stability will be discussed.
        Speaker: Rodney Orford (McGill University)
      • 17:00
        Decay Spectroscopy of Neutron-Rich Cd Around the N = 82 Shell Closure 15m
        The neutron-rich region around A = 132 is of special interest for nuclear astrophysics and nuclear structure. From an astrophysics perspective, this region is connected with the second r-process abundance peak at A$\approx$130 and the waiting-point nuclei around N = 82. For nuclear structure studies, the neighbours of the doubly-magic $^{132}$Sn (Z = 50, N = 82) are an ideal test ground for shell model predictions. The beta-decay of the N = 82 isotope $^{130}$Cd into $^{130}$In was first investigated a decade ago, but the information for states of the lighter indium isotopes ($^{128,129}$In) is still limited. In the present experiment, a detailed gamma-spectroscopy of the beta-decay of $^{128-132}$Cd was achieved with the newly commissioned GRIFFIN (Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei) gamma-ray spectrometer, which is capable of measuring down to rates of 0.1 pps. The low-energy cadmium isotopes were implanted into a movable tape at the central focus of the array from the ISAC-I facility at TRIUMF. The beta-tagging was performed using the auxiliary beta-particle detector SCEPTAR. The required beta-gamma(-gamma) coincidence data in high statistics needed to fill the spectroscopic gaps described in literature were obtained. Timing information needed to measure the half-lives of $^{128-130}$Cd was collected to resolve previously published discrepancies in those values. The ongoing analysis of these data will be presented.
        Speaker: Nikita Bernier (TRIUMF)
    • 15:45 17:15
      M3-2 Atomic and Molecular Spectroscopy and Precision Measurements II (DAMOPC) / Spectroscopie atomique et moléculaire et mesures de précision II (DPAMPC) Colonel By D207

      Colonel By D207

      University of Ottawa

      Convener: Dr Amar Vutha (University of Toronto)
      • 15:45
        Welcome to the New Age: Realization of an Ultra-Accurate, Single Ion Clock at the Quantum Mechanical Stability Limit 30m
        There is now a revolution underway in ultra-accurate measurements of frequency and time using optical atomic transitions probed with highly coherent laser light. By suspending a single atomic ion using an electro-dynamic trapping field and reducing its velocity by laser cooling, we can approach, as close as possible, the ideal situation of an isolated and unperturbed quantum system. Laser sources that probe the atom can now be made so spectrally pure that they can be used as phase-stable sources of electro-magnetic radiation. In addition, the use of femtosecond laser technology now enables us to continuously measure the cycles of light from the reference and provide a working standard for time. Using such powerful methods, our team has realized an optical atomic frequency/time reference at 445-THz (674 nm) based on a single atomic ion of strontium. This talk will overview some of the exciting concepts making up such experiments and will include evaluated accuracies of this system (at 1.2 × 10$^{-17}$ fractional uncertainty) that exceed by over a factor of ten the best current realizations of the definition of the SI second. Recently, we have demonstrated that such a single ion frequency standard can reach the level of stability limited by the principles of quantum mechanics. At this level of accuracy and stability, it is now possible to measure the distortion of local time due to Earth’s gravitational field by changes of the clock height at the sub-meter level. Further refinement of the systematic shift evaluation promises to bring the evaluated uncertainty down into the 10$^{-18}$ fractional uncertainty level. Some observations will be made as to what we expect these new generation optical clocks to yield in terms of the redefinition of the SI unit second, probing nature’s weakest force (gravity), and other sensitive tests of Physics.
        Speaker: Prof. Alan Madej (NRC/ MSS, York University, University of Ottawa)
      • 16:15
        Ro-Vibrational Emission Spectra of DCN Revisited 15m
        We present a study of the infrared emission spectra of Deuterium Cyanide (DCN) in the 450 to 850 wavenumbers range at 1370 K. Hydrogen Cyanide (HCN) was present as an impurity in the sample. The spectra were recorded using a Fourier transform spectrometer Bruker IFS 120 HR at the Justus-Liebig Universität, Giessen, Germany. A spectrum analysis software called SyMath developed by one of the authors (G. Mellau) was used to analyze the spectra and obtain improved spectroscopic constants. We report the ro-vibrational constants for the DCN molecule and compare them with a previous study published by E. Mӧllmann *et al*. [1] in 2002. REFERENCES 1. E. Mӧllmann, A. G. Maki, M. Winnewisser, B. P. Winnewisser, W. Quapp, J. Mol. Spectrosc. 212, 22–31 (2002).
        Speaker: Prof. Adriana Predoi-Cross (Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB, T1K 6R4 Canada)
      • 16:30
        The Oxygen A-Band Spectra Revisited 15m
        We have re-analyzed the A-band spectra of oxygen and oxygen broadened by nitrogen previously published by our research group [1,2]. We have used a multispectrum fit analysis [3] and different line shape models. The line shape narrowing (Dicke) effects were incorporate using theoretical calculations for the self diffusion coefficients and Maxwell–Stefan diffusion coefficients discussed. We have compared our re-analysis results with published results available in the literature. REFERENCES 1. A. Predoi-Cross, C. Holladay, H. Heung, J.-P. Bouanich, G.Ch. Mellau, R. Keller, D.R. Hurtmans, Nitrogen-broadened lineshapes in the oxygen A-Band: experimental results and theoretical calculations, J. Mol. Spectrosc. 251 (2008) 159-175. 2. A. Predoi-Cross, K. Hambrook, R. Keller, D. Hurtmans, C. Povey, H. Over, G. Mellau, Spectroscopic Lineshape Study of the Self-Perturbed Oxygen A-Band, J. Mol. Spectrosc. 248 (2008) 85-110. 3. 1. D.C. Benner, C.P. Rinsland, V. Malathy Devi, M.A.H. Smith, D. Atkins,A multispectrum nonlinear least squares fitting technique, J. Quant. Spectrosc. Rad. Transfer 53(6) 705-721 (1995).
        Speaker: Prof. Adriana Predoi-Cross (Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB, T1K 6R4 Canada)
      • 16:45
        FTIR Synchrotron Spectroscopy of the Lower Vibrational Modes of Methyl Mercaptan at the Canadian Light Source 15m
        The Fourier transform infrared spectra of the lower infrared vibrational bands of CH$_{3}$SH have been investigated from 650 to 1200 cm$^{-1}$ at 0.001 cm$^{-1}$ resolution employing synchrotron radiation at the Canadian Light Source in Saskatoon. The relative band strengths and structures are remarkably different from those for the analogous CH$_{3}$OH relative, with the CSH bend being very weak and both the in-plane and out-of-plane CH$_{3}$ rocks being strong with comparable intensities. The CSH bend has parallel $a$-type character with no detectable $b$-type component. The out-of-plane CH$_{3}$ rock is a purely $c$-type perpendicular band, whereas the in-plane rock around is of $a$/$b$ character. The $K$-reduced $v_{t}$ = 0 sub-state origins for the CSH bend follow the normal oscillatory torsional pattern as a function of $K$ with an amplitude of 0.362 cm$^{-1}$, as compared to 0.653 cm$^{-1}$ for the ground state and 0.801 cm$^{-1}$ for the C-S stretching mode. The torsional energy curves for the out-of-plane rock are also well-behaved but are inverted, with an amplitude of 1.33 cm$^{-1}$. In contrast, the sub-state origins for the in-plane rock do not display a clear oscillatory structure but are scattered over a range of about 2 cm$^{-1}$, with indications of some significant perturbations. Our sub-band assignments extend up to about $K$ = 10 for all the modes and are well-determined from GSCD relations, particularly for the $a$/$b$ in-plane rock for which $\Delta$$K$ = 0, +1 and $-$1 transitions are all observed.
        Speaker: Dr Ronald M. Lees (Physics Dept., University of New Brunswick)
    • 15:45 17:15
      M3-3 Fields and Strings (DTP) / Champs et cordes (DPT) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Luc Marleau (Université Laval)
      • 15:45
        Induced False Vacuum Decay by Topological Solitons 30m
        We review our work concerning the decay of the false vacuum by quantum tunnelling transitions. When the false vacuum manifold is non-trivial, it can lock in topological defects. We have considered the possibility that these are magnetic monopoles, cosmic strings, domain walls and most recently, Skyrmions. In all of these cases, the topological defect must realize the true vacuum inside its core. The dynamics generically traps the true vacuum in the core of the defect in a meta-stable state which is unstable to quantum tunnelling transitions. The transition typically inflates the core region until the region of true vacuum is large enough to inflate without restriction. We show how to compute the corresponding instanton and the decay rate using the path integral. Our analysis can be applied to phase transitions in cosmology within the context of field and string theory but also to condensed matter systems.
        Speaker: Manu Paranjape (Université de Montréal)
      • 16:15
        Conformal Bootstrap in Embedding Space 15m
        We show how to obtain all conformal blocks from embedding space with the help of the operator product expansion. The minimal conformal block originates from scalar exchange in a four-point correlation functions of four scalars. All remaining conformal blocks are simple derivatives of the minimal conformal block. With the help of the orthogonality properties of the conformal blocks, the analytic conformal bootstrap can be implemented directly in embedding space, leading to a Jacobi-like definition of conformal field theories.
        Speaker: Prof. Jean-Francois Fortin (Laval University)
      • 16:30
        Relativistic quantum reference frames 15m
        Progress in physics, from Aristotelian physics, to Galilean and Newtonian physics, and then to both special and general relativity, can be viewed as a continual refinement of the notion of a reference frame. The next natural step in this progression is the idea of a quantum reference frame. In this talk, I will introduce the basic tools that have been developed to study quantum reference frames and examine how they may be applied to relativistic scenarios. In particular, I will look at how two observers in different Lorentz frames that are partially correlated can communicate via the exchange of a single massive spin-1/2 particle. I will then construct an alternative approach to quantum reference frames involving a trace over global degrees of freedom, rather than an average over all possible orientations of a system with respect to an external reference frame. This approach is anticipated to help deal with reference frames associated with non-compact groups, such as the Galilean group and Poincare group.
        Speaker: Alexander Smith (University of Waterloo)
      • 16:45
        Quantum tunneling of Fermions from Black Strings 15m
        In this work I would like to give semi-classical derivation of Hawking temperature from cylindricaly symmetric charged rotating black strings. I will use Hamilton Jacobi method and WKB approximation to get analytic expression for Hawking temperature of fermions tunneling from charged black strings.
        Speaker: Mr Jamil Ahmed (Quaid-i-Azam University, Islamabad)
      • 17:00
        Constraints on the spectrum of W algebras 15m
        A conformal field theory is a quantum field theory whose symmetries are extended from the Lorentz group to the conformal group, thus putting more constraints on the theory than what we normally have in regular quantum field theory. In 2 dimensions, the conformal symmetries are infinite dimensional so it is easier to characterize the properties of 2d CFTs than it is in higher dimensions. Extensions of these symmetry algebras that include higher spin generators in addition to the energy-momentum tensor have been built a long time ago and they have found applications in string theory, statistical mechanics and holography. In this talk I will discuss a way of constraining the spectrum of operators in unitary representations of these so called W algebras. In particular, I will study the W(2,4) algebra, which has an extra spin 4 generator, and I will search for representations with negative norm states. This will give various new constraints on the scaling dimensions and charges of the states in the theory. This kind of results can be translated to higher spin theories of gravity using the AdS/CFT correspondence and give new insights on the allowed theories.
        Speaker: Yan Gobeil (McGill University)
    • 15:45 17:15
      M3-4 Materials Characterization: Microscopy and Imaging (DCMMP) / Caractérisation des matériaux: microscopie et imagerie (DPMCM) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Dr Arun Ramchandran (University of Toronto)
      • 15:45
        Colloidal systems for smarter cancer imaging and adaptive therapy 30m
        Imaging is a fundamental tool in the practice of medicine. The interaction of medical imaging radiation with new materials has long been exploited to develop new and improved imaging systems and techniques. In parallel with these advances, there is increasing interest in developing new contrast agents for the diagnosis of disease. Exogenous contrast agents are non-native sources of contrast that differentially scatter, absorb, or emit medical imaging radiation (e.g., sound waves for ultrasound imaging, radiofrequency waves for magnetic resonance imaging, near IR light for photoacoustic imaging, and x-rays for computed tomography and mammography) as compared to surrounding tissues and inherent background noise such that their location can be tracked upon introduction into a patient. At the forefront of new contrast agent development are new, clinically-relevant, colloidal materials that can be activated by medical imaging radiation external to the patient and under image guidance, to characterize and treat cancer. Since the contrast agents’ *in vivo* distribution and interaction with radiation are strongly size- and material-dependent, a new opportunity in materials science is the creation of new colloidal systems that can be tailored for specific contrast imaging and with therapeutic properties. This talk will focus on the development of new contrast agents that can facilitate more focused and targeted delivery of cancer therapies to tumours for higher therapeutic ratios, and can permit the treatment of hard-to-access organs like the brain in a minimally-invasive manner. Specific examples of different hierarchical and composite contrast agents that are assembled to address and balance biological and physical challenges of contrast agent development will be given, with a focus on the use of perfluorocarbon bubbles, droplets and nanoparticles as multifunctional contrast agents for ultrasound imaging and therapy applications.
        Speaker: Naomi Matsuura (University of Toronto)
      • 16:15
        Magnetic Dipole-Dipole Sensing at the Atomic Scale 15m
        High-resolution magnetometry is an essential tool used across the sciences. The recent development of electron spin resonance scanning tunnelling microscopy (ESR-STM) opens the door on a new type of magnetometry, one with the ability to coherently manipulate quantum spins with neV energy resolution and sub-nanometre spatial resolution [1]. In this talk I will show recent results obtained from ESR-STM experiments of Fe and Co atoms deposited on an MgO thin film. By characterizing the magnetic dipole-dipole interaction between atoms we are able to determine their magnetic moment to within 40 neV [2]. Combining this energy resolution with the STM's ability to manipulate atoms we then create and characterize the properties of magnetic nanostructures. Lastly, I will discuss the development of a pulsed ESR-STM scheme and it's relevance for future experiments in quantum computing and quantum simulation. [1] S. Baumann, W. Paul, T. Choi, C.P. Lutz, A. Ardavan, and A.J. Heinrich, Science 350, 417 (2015) [2] T. Choi et al., in preparation
        Speaker: Mr Andrew Macdonald (University of British Columbia)
      • 16:30
        "Macroporous Silicon as an IR Filter" 15m
        Authors: T. Beniac, C. Vendromin, N. Dwyer, N. Majtenyi, M. Reedyk. Currently, optical cutoff filters in the infrared range are primarily based on scattering or multilayers. These types of filters, however, come with disadvantages. In multilayer filters the varying material properties between the different layers causes mechanical instability at extreme temperatures. Scattering-type filters can be very fragile; the filters may be damaged by exposing them to high pressure gradients or by accidental mechanical removal of the scatterers. It has recently been found that macroporous Silicon can act as an optical cutoff filter in the infrared range.[1] Filters constructed from porous Silicon do not exhibit the same disadvantages as do the scattering and multilayer filters. Macroporous Silicon is created via an electrochemical etching process using an anodic (i.e. the Silicon sample acts as the anode) electrochemical cell containing an electrolyte solution of hydrofluoric acid and ethanol. When a current is passed across the cell, it is observed that pores form on the surface of the sample over time. The morphological properties of these pores seem to differ depending on etching conditions such as the concentration of acid in the electrolyte, the electronic and crystallographic properties of the sample, the current, and the etching time. The cutoff wavelength of the porous silicon filters appears to be dependent on the morphological properties of the sample. Silicon samples of differing resistivity and crystal orientation have been etched under various conditions in order to perform a systematic investigation of the relationship between the optical and morphological properties of porous Silicon filters. The cutoff wavelength of the filter is determined by transmission spectroscopy while the morphological properties are investigated by SEM imaging to extract the pore-to-area density of the samples. [1] V. Kochergin, and H. Foell, `Novel Optical Elements Made From Porous Si', Materials Science and Engineering, R 52, (2206) 93-140.
        Speaker: Thomas Beniac (Brock University)
      • 16:45
        Imaging and Temperature Sensing using Submillimeter Radiation 30m
        In recent years, nanomaterials have garnered significant attention in the effort to develop novel applications and technologies, or for the improvement of already existing ones. In particular, a strong emphasis has been placed on nanoparticle-based probes than can be used in imaging and therapeutics. Of particular interest are metal nanoparticles such as silver, platinum and gold, which following resonant excitation with light, show a surface plasmon resonance effect. An interesting by-product of this effect is the transfer of energy to the environment in the form of heat. This typically increases the temperature of a system and finds interesting applications particularly in photothermal therapy. We have used gold nanoparticles as “contrast agents” in combination with terahertz radiation to develop a contact-free approach for heating, temperature sensing and imaging. More specifically, we exploit the change in the refractive index of water, induced by localized NIR heating of plasmonic nanostructures. The latter, namely gold nanorods, were prepared using a conventional bottom up seed-mediated technique. We observe a linear relationship correlating change in the reflected terahertz amplitude and area under the curve as a function of increasing temperature. This was translated to a thermometric relationship allowing for temperature sensing following an induced heat stimulus. We extended our results to the porcine skin model system in order to mimic the photothermal effect and demonstrated the capacity to sense the temperature and map its distribution in the localized injection site, following controlled NIR plasmonic heating. As a result, we have developed a terahertz biological thermometer.
        Speaker: Prof. Rafik Naccache (Concordia University)
    • 15:45 17:15
      M3-5 Cosmic frontier: Dark matter I (PPD) / Frontière cosmique: matière sombre I (PPD) MacDonald 146

      MacDonald 146

      University of Ottawa

      Convener: Dr Ian Lawson (SNOLAB)
      • 15:45
        Recent Results and Future Plans for Dark Matter Searches with PICO 30m
        The PICO experimental program at SNOLAB uses superheated bubble chambers to search for evidence of dark matter primarily through spin-dependent interactions on 19F in C3F8. Recoiling nuclei from WIMP-nucleon interactions in the active fluid deposit enough energy locally to initiate a phase transition in the fluid. The bubbles which form are observed with stereo cameras and their acoustic signature is recorded by sensitive piezo-electric transducers. By controlling the degree of superheat, the detector can be made insensitive to gamma and electron backgrounds. Alpha particles with relatively longer tracks have a distinctly different acoustic signal when compared to nuclear recoils which enables this background to be identified and discriminated against. The recent results from the PICO collaboration will be presented, along with an outlook for the future program with this unique technology.
        Speaker: Tony Noble (Queen's University)
      • 16:15
        Study and Development of Pulse-shape Discrimination Firmware for Background Mitigation in the DEAP-3600 Experiment 15m
        DEAP-3600 is particle detector looking for weakly interacting massive particles (WIMPs) as a source of dark matter. Incident particles colliding with the 3600 kg argon target in DEAP will produce excited dimers which decay releasing scintillation light. The proportion of singlet and triplet excited states of the dimers produced depends on the interacting particle type, with the result that events can be characterized by the timing distribution of the scintillation light. The intrinsic Ar-39 in natural argon produces approximately 1 Hz/kg of beta decays. To reduce the background rate from beta decay, the DEAP trigger removes a proportion of these events. It is crucial that potential WIMP events and rare background events are not miscategorized as beta decays by the trigger, and thus the trigger calibration is essential to achieve the dark matter sensitivity goal of the experiment. This talk will explain the trigger algorithm, its parameters, and present results from the trigger calibration.
        Speaker: Mr Simon Norman-Hobbs (TRIUMF)
      • 16:30
        **WITHDRAWN** Application of Wavelength Shifter to the Acrylic Vessel in the DEAP-3600 Dark Matter Search 15m
        DEAP-3600 is a single phase liquid argon dark matter search experiment. The target consists of 3600 kg of liquid argon, contained in a spherical acrylic vessel and viewed by a surrounding array of photomultiplier tubes (PMTs). Particle interactions in liquid argon produce scintillation light in the vacuum ultraviolet (VUV) spectrum, which is efficiently absorbed by the surrounding acrylic. To make interactions in the target volume visible to the PMTs, the inner surface of the acrylic sphere was coated with the organic wavelength shifter, 1,1,4,4-tetraphenyl-1,3-butadiene (TPB), which has a re-emission spectrum for VUV light in the blue-visible regime. During the final stage of construction, a 3 micrometer thick coating of TPB was applied to the vessel's inner surface using vacuum deposition. This talk will present details on the final deposition, thickness considerations, and ex-situ sample analysis results.
        Speaker: Benjamin Broerman (Queen's University)
      • 16:45
        Improved dark matter search results from PICO-2L Run 2 15m
        New data are reported from a second run of the 2-liter PICO-2L $C_3F_8$ bubble chamber with a total exposure of 129 kg-days at a thermodynamic threshold energy of 3.3 keV. These data show that the measure taken to control particulate contamination in the superheated fluid resulted in the absence of the anomalous background events observed in the first run of this bubble chamber. One single nuclear-recoil event was observed in the data, consistent both with the predicted background rate from neutrons and with the observed rate of unambiguous multiple-bubble neutron scattering events. The chamber exhibits the same excellent electron-recoil and alpha decay rejection as was previously reported. These data provide the most stringent direct detection constraints on weakly interacting massive particle (WIMP)-proton spin-dependent scattering to date for WIMP masses < 50 GeV/c$^2$.
        Speaker: Chanpreet Amole (Queen's University)
      • 17:00
        **WITHDRAWN** Two-Hit and Two-Track Resolution of a Micromegas TPC with a Resistive Layer Including the Effects of Charge Induction 15m
        The Time Projection Chamber (TPC) for the International Linear Collider (ILC) will need to measure about 200 track points with a spatial single-hit resolution close to 100 microns. A Micro Pattern Gas Detector (MPGD) readout TPC with a resistive layer can achieve the desired resolution. A new readout technique using the principle of charge dispersion with a resistive layer on a Micromegas has indeed demonstrated that the single-hit transverse and longitudinal resolution goals have been met. The next step of the R&D for a TPC at the ILC is concerned with two-hit and two-track separation. In this presentation, a detailed simulation of two-hit and two-track resolution study will be presented. Previous simulations of the ILC TPC have not taken into account the induction of charge on the neighboring readout pads caused by the electrons when they traverse the induction region. The goal of this project is to build and run simulations that take the complete charge induction signals convoluted with the resistive layer response into account for the calculation of the bias correction and pad response function required for a detailed reconstruction of tracks at the ILC TPC.
        Speaker: Roger Odell (Carleton University)
    • 15:45 17:15
      M3-6 Computational Biophysics: Methods and Concepts (DPMB) / Biophysique numérique : méthodes et concepts (DPMB) Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Francis Lin (University of Manitoba)
      • 15:45
        Finding the rules of blood regeneration 30m
        Much of complex biology results from interactions among a large number of individually simpler elements. Blood regeneration is no different. About 100 billion new blood cells are made everyday from a much smaller yet a large population of diverse stem cell population. I will present a phenomenological model of blood regeneration, which provides a framework to understand large variation (~3 orders of magnitude) among contributions from individual stem cells observed in recently reported experiments with primates. We show that a combination of slow stem cell differentiation to progenitor followed by their bursty amplification is at the heart of this observed variability. With our model we develop a counter hypothesis to the role of cell-level differences as an explanation for the large variability and highlight the role of progenitors in maintaining blood homeostasis.
        Speaker: Prof. Sidhartha Goyal (Univ of Toronto)
      • 16:15
        Computer Simulation Model of Polymorphisms of Beta-Amyloid Crystals 15m
        Research has established a strong link between symptoms of Alzheimer's disease (AD) to 36-43 amino acid residues peptides, called the amyloid beta (A$\beta$) peptides. Patients with AD are usually diagnosed with aggregates of A$\beta$ peptides, also called plaques, which can be as large as several $\mu$m. The structures of the plaques display a wide variety of polymorphisms that depends on the environments, and are very difficult to reproduce in experiments. This has greatly hindered the efforts to discover the microscopic origin of AD. Recently, Eisenberg *et al.* (Proc Natl Acad Sci USA, 108, 16938-16943, 2011) resolved the structures of segments of A$\beta$ of 5 to 10 amino acid residues. The crystals are very stable, and display a complex polymorphisms of stacked parallel and anti-parallel $\beta$-sheet that may be in-register or out-of-register. At this point over 20 micro-crystals have been identified, and in many cases the same segment of A$\beta$ can form several structures. This submission considers an all-atom simulation model that uses an interaction force field based on the Eisenberg's crystal structures. In the spirit of Go models of folding of single proteins, the force field biased the peptides to the micro-crystal structures, but also exploit the symmetry of the crystals.The model has two adjustable parameters: the strength of the hydrogen bonds that stabilize the $\beta$-sheet structure, $\epsilon$$_{HB}$ ; the strength of van der Waals (vdW) interactions that stabilizes the stacking of the $\beta$-sheet, $\epsilon$$_{vdW}$. Computer simulations of the model found that for $\epsilon$$_{vdW}$/$\epsilon$$_{HB}$ > 0.5, and at low temperature the layers tends to form stacked three-dimensional structures. However, for $\epsilon$$_{vdW}$/$\epsilon$$_{HB}$ < 0.5, the A$\beta$ segments long single-layer $\beta$-sheet similar plaques observed in full length A$\beta$. The implication of the results to AD will be discussed.
        Speaker: Apichart Linhananta (Lakehead University)
      • 16:30
        Exploring conformational switching in proteins with coarse-grained molecular simulations 30m
        The traditional view holds that proteins fold into essentially unique and stable 3-dimensional structures which, in turn, determine their biological functions. Evidence is mounting, however, for a pervasive role of large-scale conformational changes for how proteins carry out their functions. Examples include the ability of some proteins to switch between entirely different folded structures, and the disorder-order transitions exhibited by so-called intrinsically disordered proteins. I will introduce a coarse-grained approach that allows the physics of such conformational switching in proteins to be studied on the computer. The approach is characterized by an intermediate level of geometric detail and a procedure for determining effective model parameters based on the properties of proteins’ global free energy landscapes. I will discuss the implications of our results for the mechanisms underlying molecular recognition and the evolution of new protein folds.
        Speaker: Stefan Wallin (Memorial University of Newfoundland)
      • 17:00
        All-Atoms simulations of Huntingtin’s N-terminal: solvent and membrane effects 15m
        The Huntingtin protein has drawn considerable attention as its aggregation into amyloid fibrils is related to the Huntington disease, a neurodegenerative disease characterized by motor and emotional dysfunctonalities and the loss of cognitive functions. Of its 3000 plus residues, attention has focused mostly on the first exon of Huntingtin, composed of a amphipatic region of 17 amino acids (Htt17), a polyglutamine repeat domain (Q$_N$) and a proline rich domain (C$_{38}$), that modulates its aggregation and localization within the cell. The Htt17 segment is particularly important because it serves as a membrane anchor that could accelerate the fibrilation process. Following recent solution and solid-state NMR experiments that unveiled Htt17’s structure and orientation in micelles and POPC bilayer [1], we refine these experimental finds using a state-of-the-art approach combining molecular dynamics (MD), Hamiltonian replica exchange (HREX) and Metadynamics (MetaD). We focus primarily on the characterization of the dynamics and thermodynamics of Htt17 in solution and in a phospholipid bilayer. In solution, we find that Htt17 samples a broad ensemble of alpha-helix, coil and two-helix bundle structures in agreement with NMR chemical shifts. The addition of the Q$_N$ domain shifts the helical propensity from the amino terminus to the carboxy terminus. Finally, the addition of a polyproline domain stabilizes the helical conformation. Many of the observed structural features could play a crucial role in the aggregation or in the interaction with the membrane [2]. In the phospholipid bilayer, we find that Htt17 could be more structured than the proposed NMR model. Htt17 leads to local deformation of the membrane due to the extension of the neighbor phospholipid acyl chains to cover its nonpolar surface These deformations were shown to promote dimerization of the inserted peptide and could favor the formation of large aggregates [3]. 1. Michalek, M. et al. (2013). Biophysical journal, 105(3), 699-710 2. Côté, S. et al. (2015). Biophysical Journal, 108(5), 1187-1198 3. Binette, V. et al. (2016). Biophysical Journal (In press)
        Speaker: Vincent Binette (Université de Montréal)
    • 15:45 17:15
      M3-7 Atmospheric and Space Physics I (DASP) / Physique atmosphérique et de l'espace I (DPAE) Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Shaun Lovejoy (McGill University)
      • 15:45
        The Earth's Hum Comes from the Sun 30m
        It was established over a decade ago that the normal modes of the Earth are continuously excited at times without large earthquakes, but the sources of the ‘seismic hum’ have remained unresolved. In addition to the normal modes of the Earth, we show spectral lines in seismic data with frequencies which correspond closely to normal modes of the Sun. Moreover, the widths of the low-frequency lines in the seismic spectra are similar to those of solar modes and much narrower than those of the Earth’s normal mode peaks. These seismic lines are highly coherent with magnetic fields measured on both the Geostationary Operations Environmental Satellite (GOES)–10 satellite and the Advanced Composition Explorer (ACE) spacecraft located at L1, 1.5 million km sunward of Earth suggesting that the solar modes are transmitted to the Earth by the interplanetary magnetic field and solar wind. The solar modes are split by multiples of a cycle/day and, surprisingly, by the ‘quasi two-day’ mode and other frequencies. Both the phase of the coherences and slight frequency offsets between seismic and geomagnetic data at observatories exclude the possibility that these effects are simply spurious responses of the seismometers to the geomagnetic field. We emphasize data from low-noise seismic observatories: Black Forest (BFO), Pin ̃on Flat (PFO), Eskdalemuir (ESK) and Obninsk (OBN). Horizontal components of seismic velocity show higher coherences with the external (ACE) magnetic field than do the vertical components. This effect appears to be larger near the seismic torsional, or T-mode, frequencies.
        Speaker: Dr Frank Vernon (Scripps Institute of Oceanography, UCSD, La Jolla, California)
      • 16:15
        Advancing Methane Mitigation by Understanding the Physics and Chemical Kinetics of Ultra-lean Combustion Dynamics 15m
        The recent climate change discussions between Canada and the United States of America and other international agreements target methane a potent GHG. The U.S. Environmental Protection Agency will begin developing regulations for methane emissions from existing oil and gas sources while Environment and Climate Change Canada will publish proposed initial phase regulations by early 2017. Although goals are set for anthropogenic methane emissions they should not be the only target for mitigation, thus technology to mitigate naturally occurring methane is required. At present the wetlands emissions, 150–180 TgCH4 per year, are thought to dominate, but the levels of permafrost emissions are potentially much greater. It has been estimated that the methane stored in the permafrost and clathrates may be greater than all other fossil fuels combined and may be poised to be atmospherically released as the Arctic temperature increases. Methane is typically quoted as having about 25 times the forcing factor of carbon dioxide, but that is over a century, it can be more than 84 times that of carbon dioxide over 20 years. The impact is immediate, which may accelerate a positive Arctic feedback loop causing much greater temperatures and rapid release of the stored methane. As reported in Nature, the cost of this methane release could be $60 trillion and the outcome could be disastrous for the climate and world economy. The impetus of this work is on modelling and simulation of ultra-lean methane oxidation/combustion. The challenges associated with ultra-lean methane oxidation are the conditions for ignition of the ultra-lean mixture and sustainability of the combustion process. The interest in MILD combustion has been mainly driven by the need for low emission combustion technology, but methane capture and energy utilisation requires a deeper understanding of ultra-lean combustion. The fundamental studies of the chemical kinetics, physical process and reliable kinetic schemes of ultra-lean methane combustion are sparse, but are required to do proper computational fluid dynamics studies in support of designing and developing advanced mitigation systems. Ultra-lean methane combustion cannot be achieved using traditional combustion technologies because the thermal energy available in the system may not be sufficient to ignite the fuel or even sustain the chemical reactions; thus, the concept of moderate or intense low-oxygen dilution (MILD) combustion is of great relevance. A discussion of the modelling approach in the context of low concentration methane oxidation/combustion is provided. A brief review of anthropogenic emissions of methane and some combustion mitigation and utilisation technologies will be discussed with the view toward developments focused on innovative technologies to achieve sustainable oxidation/combustion and energy capture is discussed.
        Speaker: Dr Daniel Cluff (University of Exeter)
      • 16:30
        The Influence of Turbulence on the Transport of Energetic Particles 15m
        We explore the influence of magnetic turbulence on the transport of energetic particles, mainly cosmic rays, by using test-particle simulations. We compute parallel and perpendicular diffusion coefficients for two-component turbulence, isotropic turbulence, a model based on Goldreich-Sridhar scaling, noisy reduced magneto-hydrodynamic turbulence, and a noisy slab model. We have shown that for all considered turbulence models, the diffusion coefficients are similar. They have the same rigidity dependence and only the absolute values of the diffusion coefficients are different. This conclusion is in agreement with recent analytical findings based on the unified nonlinear transport theory indicating that only fundamental properties of turbulence such as the length scales and magnetic fields control the diffusion coefficients. To double-check the validity and accuracy of our numerical results, we use a second test-particle code. We show that both codes provide very similar results confirming the validity of our conclusions.
        Speaker: Mr Martin Heusen (University of Manitoba)
      • 16:45
        SIMULATIONS OF ENERGETIC PARTICLES INTERACTING WITH DYNAMICAL MAGNETIC TURBULENCE 15m
        We explore the transport of energetic particles in interplanetary space by using test-particle simulations. In previous work such simulations have been performed by using either magneto-static turbulence or undamped propagating plasma waves. In the current work we simulate for the first time particle transport in dynamical turbulence. To do so we employ three models, namely the damping model of dynamical turbulence, the random sweeping model, and the nonlinear anisotropic dynamical turbulence. We also added dissipation effects to the power spectrum, an effect which is usually neglected. We compute parallel and perpendicular diffusion coefficients and compare our numerical findings with solar wind observations. We show that good agreement can be found between simulations and the Palmer consensus range for all dynamical turbulence models if using appropriate values for different parameters in consistent with interplanetary space at 1 AU heliocentric distance. In particular we show that best fit between simulations and observation occurs when the ratio of turbulent magnetic field and mean field is δB/B0 = 0.75.
        Speaker: Mr Martin Heusen (University of Manitoba)
      • 17:00
        A Prototypical Substorm with Conjugate Ground and Space Data 15m
        The substorm at about 5 UT on February 26, 2008 (Angelopoulos et al., Science, 2008) has been taken as prototypical of reconnection in the Near-Earth Neutral Line model. Further examination by Pu et al. (JGR, 2010) showed that the event was preceded an hour earlier by one with very similar signatures. Traditional use of AE-related indices suggests that the first event was smaller in terms of electric currents than the second. More detailed examination of ground magnetic data shows that it was in fact comparable: in addition, the second event was considerably further to the west. The ensemble of data suggests more similarity than differences for the two sub-events. We investigate the potential of inclusion of SCW currents themselves to improve mapping of THEMIS footpoints to Earth poleward of where quasi-static models map, to better match ground and CHAMP observations. Automated Meridian Modeling shows that a simple electrojet model with only three parameters (electrojet borders and current) matches data well with approximately 0.2 MA cross-meridian current in both subevents. GOES spacecraft approximately conjugate to eastern North America show dipolarization signatures consistent with this magnitude of current. There was good conjugacy between hemispheres, as indicated by Antarctic magnetometers and inversion based on them. SuperMag data gives dense enough magnetometer coverage that the layout of the substorm current wedge, with auroral zone westward electrojet and subauroral perturbations mainly due to field-aligned current, can be determined. The quantitative data from the ground provides a context in which flows, magnetic fields, and other parameters at the THEMIS constellation and other conjugate spacecraft may be interpreted.
        Speaker: Martin Connors (Athabasca University)
    • 17:30 19:00
      Welcome BBQ Reception / Réception d'accueil avec BBQ SITE Lawn

      SITE Lawn

      University of Ottawa

    • 19:30 20:30
      Herzberg Memorial Public Lecture - Victoria Kaspi, McGill Univ. / Conférence commémorative publique Herzberg - Victoria Kaspi, Univ. McGill Shaw Centre

      Shaw Centre

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 19:30
        The Cosmic Gift of Neutron Stars 45m
        Although they are thousands of light years away, neutron stars can act as very precise cosmic beacons -- a celestial gift that sheds light on some of the most interesting problems in modern science. We will explore these strange objects, explain how astronomers are using them to study issues ranging from the origins of the Universe to the very nature of matter, and even listen to the cosmic symphony they create.
        Speaker: Victoria Kaspi (Department of Physics, McGill University)
    • 20:30 22:00
      Post-talk Reception Shaw Centre

      Shaw Centre

      University of Ottawa

    • 07:30 08:30
      Science Policy Committee Breakfast Meeting / Réunion-déjeuner du Comité de politique scientifique SITE 5084

      SITE 5084

      University of Ottawa

      Convener: Kristin Poduska (Memorial University of Newfoundland)
    • 08:15 17:15
      Teachers' Day / Journée des enseignants MacDonald 146

      MacDonald 146

      University of Ottawa

    • 08:30 16:15
      Exhibit booths open 08:30-16:15 / Salle d'exposition ouverte de 08h30 à 16h15 SITE Atrium

      SITE Atrium

      University of Ottawa

    • 08:30 10:00
      T1-1 Medical Imaging (DPMB) / Imagerie médicale (DPMB) Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Melanie Martin (University of Winnipeg)
      • 08:30
        Magnet and Radiofrequency Technology for Low Cost Magnetic Resonance Imaging 30m
        MRI is a highly effective, but expensive imaging modality. Lower strength magnetic field and lower cost variants of MRI are being developed for specific applications. We will focus on one approach, ‘Transmit Array Spatial Encoding’ (TRASE), which uses only a resonant radiofrequency (RF) field to produce Fourier spatial encoding equivalent to conventional MRI. The usual audio frequency switched magnetic field gradient coils are not needed. We will review different magnet experimental configurations and the MHz RF technology needed to implement these low-cost MRI experiments. High-resolution two-dimensional-encoded in vivo MR images of hand and wrist have been obtained using a uniform 0.2T main magnetic field (B0). An alternative approach is to use an inhomogeneous but very low cost main magnet, in combination with the RF-based image encoding. The mechanism used by TRASE exploits RF field phase gradients to encode image information into echo train NMR pulse sequences. The RF transmit field must be designed to produce these phase gradients, but also must be changed between RF pulses. This can be achieved by multichannel transmitters, or by RF switching, or a combination of approaches. In addition to the low cost advantage, novel experiments exploiting unique capabilities, such as imaging without disturbance of the main B0 magnetic field are possible.
        Speaker: Prof. Jonathan Sharp (University of Alberta)
      • 09:00
        Frequency-Domain Synthetic Aperture Focusing Techniques for Imaging with Single-Element Focused Transducers 15m
        The resolution of conventional single-element ultrasound imaging varies spatially and depends on several factors, such as the central frequency, bandwidth, and the transducer’s active aperture size. Synthetic aperture focusing techniques (SAFT) enable dynamic focusing, which, among others, could lead to improvements in the spatial resolution of ultrasound imaging systems. In SAFT, a large effective aperture is mathematically synthesized by lateral scanning a single-element transducer. Several time-domain SAFT algorithms have been proposed for a single-element focused transducer. In this work, two new frequency-domain SAFT algorithms are proposed, which are based on matched filtering technique and taking into account the diffraction effects of a single-element transducer. The performance of the proposed SAFT algorithms is evaluated for single-element focused transducers with frequencies of 5 MHz, 25 MHz, and 55 MHz. The spatial resolution, signal-to-noise ratio (SNR) and contrast of the proposed frequency-domain SAFT algorithms are compared with conventional B-mode and time-domain SAFT using simulated and experimental data. Preliminary simulation results have shown that the proposed SAFT algorithms yield improved spatial resolution and SNR compared to conventional B-mode and time-domain SAFT. However, the contrasts of the proposed SAFT algorithms are similar to the conventional B-mode and time-domain SAFT.
        Speaker: Mr Elyas Shaswary (Dept. of Physics, Ryerson University)
      • 09:15
        Feasibility of noninvasive temperature estimation using acoustic harmonics 15m
        In this study, the feasibility of obtaining 2D temperature change maps was investigated by estimating the change in backscattered energy of the acoustic harmonics and comparing it with the standard RF echo shift technique. A commercial high-frequency ultrasound scanner (Vevo® 770, Visualsonics Inc., Toronto, ON, Canada) with a 25-MHz center frequency wide-band single-element transducer (RMV-710B, f-number 2.1, 15 mm focal length) was used to transmit signals at 13 MHz. The experiments were performed on gel phantoms composed of 8% (by weight) gelatin. A 1.6 mm thick stainless steel needle was inserted in the gel phantom and hot water was circulated in the needle in order to increase the temperature of the phantom only locally around the needle. Hot water was circulated in the needle by using a peristaltic pump (Masterflex® L/S®, Cole Parmer, Chicago, IL). The needle was not placed within the imaging plane of the transducer in order to minimize the RF signal distortion. The region of imaging was heated from 26°C to 46°C. The experiments were performed with and without a water reservoir and a pulse dampener (Masterflex® L/S®, Cole Parmer, Chicago, IL) in the flow circuit in order to study the effect of motion on both thermometry techniques. The water reservoir and the pulse dampener were used to eliminate vibration in the flow caused by the peristaltic pump. For the proposed method, the backscattered energies of the fundamental frequency (E1), the second (E2) and the third (E3) harmonics were obtained by squaring the envelope of the filtered RF echo signal at each harmonic. The standard echo shift technique was performed by taking cross-correlation between each two frames with a window size of 1×τ (0.07 μs) and an overlap of 50%. In the absence of vibration in the sample, we were able to obtain 2D temperature change maps using both techniques. However, in the presence of vibration, noninvasive thermometry was feasible only by using the backscattered energies of the harmonics.
        Speaker: Mr Elyas Shaswary (Dept. of Physics, Ryerson University)
      • 09:30
        Cholesterol Expels Ibuprofen from the Hydrophobic Lipid Membrane Core 15m
        All drugs must cross the lipid membrane to enter the cell, either by passive or active transport. Diffusing drug molecules may interact with, or embed in, the bilayer and change membrane structure and function. We have observed a significant interaction between cholesterol and the common analgesic, ibuprofen, in model lipid membranes [1]. Using X-ray diffraction in highly oriented, multi-lamellar stacks of lipid membranes, we located the ibuprofen molecule within the bilayer and determined that the drug induces a lamellar to cubic phase transition at concentrations of more than 5 mol%. The phase transition is caused by the presence of ibuprofen in the hydrophobic membrane core, where it induces negative membrane curvature. Cholesterol is a stiff, hydrophobic sterol molecule which also embeds within the membrane core and stiffens lipid tails [2]. When ibuprofen is introduced into membranes prepared with 20 mol% cholesterol, the cubic phase transition is suppressed, as ibuprofen is not able to partition into the core of cholesterol-containing membranes. The results indicate that ibuprofen-membrane interactions strongly depend on membrane composition and properties. The work adds to the growing evidence that amphiphilic molecules, such as aspirin or ibuprofen, significantly disrupt membrane structure [3,4]. [1] **RJ Alsop** *et al*. Soft Matter (2015). 11(24) 4756-4767. [2] MA Barrett, S Zheng, LA Toppozini, **RJ Alsop**, *et al*. Soft Matter (2013). 9(39) 9342-9351. [3] **RJ Alsop** *et al*. Soft Matter (2014). 10(24) 4275-4286. [4] **RJ Alsop** *et al*. BBA-Biomembranes (2015). 1848. 805-812.
        Speaker: Richard Alsop (McMaster University)
      • 09:45
        NEMA Standard Measurements in Pre-clinical PET Imaging 15m

        NEMA (National Electrical Manufacturers Association) Standard Measurements are used for evaluating the performance of the positron emission tomography scanners used in animal imaging. There are various measurements, including spatial resolution, scatter fraction, sensitivity, and image quality.
        In this study the effects of varying the testing procedures of the NEMA NU4-2008 standard for measuring sensitivity and image quality for a small animal PET scanner were examined. In the current NEMA NU4 2008 standard, the sensitivity is measured by stepping a Na-22 point source through the field of view of the scanner along the central Z axis. In some scanners it is not possible to automate the collection of this data, making it very tedious, if not impossible, to acquire the necessary data. As an alternative method, we explore using a long uniform line source extended beyond the field of view in the axial direction and validated this method by comparing our results with those obtained from the standard method. Two line sources were imaged, the first a 70-cm long plastic tube filled with 6 MBq of F-18 (NEMA line source for clinical scanners) and the second a standard 20-cm long Ge-68 sealed line source (0.90 MBq). Point source data were sorted and analysed following the NEMA NU4-2008 method to calculate sensitivity profiles to be plotted as a function of axial distance relative to the center of the field of view. Line source data were analyzed in a manner analogous to the NEMA NU2-2001 method for calculating sensitivity for clinical PET systems. The results from the F-18 and Ge-68 are in good agreement with those from a Na-22 point source (0.93 MBq) using the NEMA standard methods. The difference in absolute sensitivity between Na-22 and the line sources are 0.90% for F-18 and 1.7% for Ge-68 line source. These results represent the equivalence of the sensitivity measurements using a line source or a point source.

        Speaker: Esmat Elhami (University of Winnipeg)
    • 08:30 10:00
      T1-2 Lab Revitalisation: Innovative and Distance Undergraduate Labs (DPE) / Revitalisation de labos : laboratoires de premier cycle innovateurs et à distance (DEP) Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Martin Williams (University of Guelph)
      • 08:30
        How redesigning our first-year labs grew into a “Gesamtkunstwerk” in Physics Education 15m
        In this talk, we’ll tell the story of how an initial idea for course redesign grew into something much bigger, incorporating ideas from Physics Education research and the Physics Education community, design of learning spaces, SOTL (scholarship of teaching and learning), building a community of practice etc. along the way – thus “Gesamtkunstwerk”. We will describe how funding for teaching lab renovation and new equipment was combined with turning the lab courses from cookbook style to inquiry-based, including group work with assigned roles, and in-class feedback and assessment. The design team, in consultation with a large number of faculty members, shifted the learning focus towards a more reflective approach to making measurements and analyzing data, and made an introduction to the iterative process of doing science explicit in the course learning goals. This focus allowed much shorter lab instructions, now completely online instead of printed, which required thorough exploration of the technical possibilities of our learning management system, Canvas. We tested our original design in a two-stage process involving faculty, high school/first year students and grad students, using pre-/post-tests, focus groups and observations. We’ll show examples for the labs, results from the two-stage testing (specifically on alignment of the activities and assessment methods with the learning goals) and how they were included in the course design, as well as observations from the first round of implementations. We’ll also point out some spin-off projects, such as the need for an Excel tutorial and restructuring of the teaching materials archive.
        Speaker: Daria Ahrensmeier (Simon Fraser University)
      • 08:45
        Astronomy in the undergraduate advanced laboratory: Studying delta-Scuti variable stars 15m
        Astrophysics concepts acquired in undergraduate courses are sometimes difficult to explore in a teaching laboratory for upper year physics students. We will share our experience developing an experiment on variable stars offered as part of an undergraduate advanced lab courses at Carleton University. The stars studied were mainly of the delta-Scuti type (Dwarf Cepheid), because of their high amplitude variability and fairly short period. With an amateur level telescope and CCD camera, students collect a sequence of variable star images over the period of a few hours, then process and calibrate the images and extract information related to the star. In addition to the technical aspects of data processing in astronomy, students also learn how differential photometry works, investigate the relationship between the period and the luminosity of the star, calculate the distance of the star and, with photometric filters, study its temperature and radius variations.
        Speaker: Etienne Rollin (Carleton University)
      • 09:00
        Introductory Experiments from Scratch 15m
        The Augustana Campus of the University of Alberta will be introducing two major pedagogical initiatives in 2017 that will provide opportunities to reimagine the student experience. One such opportunity will be the creation of an exclusively lab-based, multidisciplinary, compressed-term science course designed for non-science students. I will begin by outlining the context of this new course and its probable features. In particular, I intend to bookend the course with some sort of PER-like testing to investigate the state and evolution of students' attitudes towards science. Next, I'll flip things so that you can provide me with feedback, ideas, or suggestions that might be incorporated into upcoming design phases.
        Speaker: Ian Blokland (University of Alberta)
      • 09:15
        From Particle Physics to Education: The Role of Tinkering 30m
        The love of tinkering is perhaps the single most universal trait among scientists. From designing an experiment to building a computer application to solving a differential equation, the cycle of "observe - explain - test - revise” is at the root of the scientific creative process. Driven by the love of tinkering, we have developed a small low-cost wireless lab system with the goal of putting powerful scientific instrumentation in the hands of every student, both inside and outside of the classroom. I will describe this project and how it is radically changing our view of introductory physics labs at the University of Illinois.
        Speaker: Mats Selen (Universiry of Illinois)
    • 08:30 10:00
      T1-3 Materials Characterization: Electrical, Optical, Magnetic, Thermal (DCMMP) / Caractérisation des matériaux: électrique, optique, magnétique et thermique (DPMCM) Colonel By D207

      Colonel By D207

      University of Ottawa

      Convener: Prof. Eva Hemmer (University of Ottawa)
      • 08:30
        Photon-in Photon-out Spectroscopy of Functional Materials using Synchrotron Radiation 30m
        Using a phosphor to “see” X-rays is as old as the discovery of X-rays and is practiced everyday worldwide. The advent of maturing third generation synchrotron light source technology has made it possible to conduct investigations of X-ray excited optical luminescence (XEOL)from solid in both energy and time domain in much greater details than ever before. In parallel with this development are the advancement of optics and detectors, making it possible to provide energy resolution to an unprecedented level. This together with the brightness of the SR source has made the previously difficult experiments such as high resolution X-ray emission/ resonant inelastic X-ray scattering nearly routine. In this talk, I’ll describe some of these developments and their implications.
        Speaker: Prof. Tsun Sham (Western University)
      • 09:00
        Evolution of electronic structure on transition metal and transition metal doped titanium disulphide by high resolution photoemission spectroscopy study 30m
        In this presentation, I will present the many-body interactions in solids studies by high resolution ARPES. High-resolution angle-resolved photoemission spectroscopy studies of Fe(110) and Ni(110) single crystals has been conducted to clarify the role of many-body interactions acting on the quasi-particles at the Fermi level at low temperatures. We have evaluated the real and imaginary parts of the self-energy for the bulk-derived majority-spin Fermi surface around the Γ point, and found two characteristic energy scales, at ∼40 and ∼270 meV. The former corresponds to the energy scale of the Debye temperature. As for the latter, we found that it is close to the cut-off energy of the calculated magnon density-of-states. This correspondence indicates that the energy scale is related to the magnetic excitation. I will also present our high-resolution photoemission measurements on the transition metal doped dichalcogenides system. TiS$_2$ is proved to be a semiconductor with indirect gas around 600 meV. We confirmed that there is no CDW transition happen. Upon iron atoms intercalation, the strong modification of the valence band structures and the band dispersion in the intercalated com-pound are observed. The hybridization of the S derived states with Fe 3d states is thought to be predominantly the reason. The mechanism of these hybridized bands’ modification has been explained well by Vienna ab initio simulation program and the projected augmented wave poten-tials; the Perdew-Burke-Ernzerhof exchange correlation functional. Finally I will present some of our latest photoemission work in Canadian Light Source Inc.
        Speaker: xiaoyu cui (Canadian Light Source)
      • 09:30
        Enhancing the Luminescence of Silicon Nanoclusters embedded in Silicon Nitride 15m
        In the quest to develop a silicon (Si) based light source, for optical and optoelectronic applications, researchers have explored various techniques. One such technique is the use of self-assembled Si-nanoclusters (Si-NC) embedded in a silicon nitride (Si3Nx) matrix. This system has shown great promise, displaying both photoluminescence and electroluminescence.[1,2] Despite such achievements, the luminescence of Si-NC/Si3Nx devices is still too low in intensity to be used in a commercial light source. An approach that has recently gained interest is the luminescence enhancement of Si-NCs using the localized surface plasmon resonance (LSPR) of metallic nanostructures (m-NS). The majority of research in this area has focused on the use of metals such as gold (Au) and silver (Ag), which are expensive and would increase the cost of any device made using them.[3-6] In our group, we explore how m-NS made using aluminum (Al) can be tailored to enhance the luminescence of Si-NC/Si3Nx devices. Al has the added advantage of being compatible with current manufacturing techniques. To fabricate these m-NS we use nanosphere lithography (NSL). We also examine the mechanisms of luminescence of our Si-NC/Si3Nx devices, to facilitate improvements in luminescence intensity.[7] The results of our work will facilitate the development of commercially viable and cost efficient Si-based light emitting devices. 1. Wang, Y. Q., et al. Applied Physics Letters, 83, 3474 (2003). 2. Cen, Z. H., et al. Journal of Applied Physics, 105, 123101 (2009). 3. Benami, A., et al. AIP Advances, 2, 012193 (2012). 4. Wang, F., et al. Journal of Nanoparticle Research, 15, 1 (2013). 5. Philip, R., et al. Nano Lett, 12, 4661 (2012). 6. Wang, F., et al. Applied Physics Letters, 100, 031113 (2012). 7. Goncharova, L. V., et al. Journal of Applied Physics, 118, 224302 (2015).
        Speaker: Ms Carolyn Cadogan (The University of Western Ontario, Department of Physics and Astronomy)
      • 09:45
        Impurity-based Quantum Circuits in Si 15m
        Recent advances in manipulation of impurities in Silicon by STM techniques, both dangling bonds on Si surface [1] and dopant atoms in Si [2], enable the realization of atomic scale circuits in Si. In this work we focus on phosphorus (P) donors in Si [3]. The 6-fold degenerate conduction band of Si combined with valley-orbit coupling results in a manifold of 6 states of a single P donor. We describe a quantum circuit of P atoms in Silicon with electron population controlled by external gate in analogy to gated quantum dots in GaAs [4]. The electronic properties of these atomic scale quantum dot circuits (QDC), including intra- and inter donor exchange, are described by an extended Hubbard-Kanamori Hamiltonian (HK). The HK parameters show strong dependence on the position of substitutional donors in the Si lattice including on site Coulomb repulsion (U), interdot hopping (t), direct interaction (V) and exchange (J) terms. The interdot, t, V and J, terms strongly depend on dopant position (R_D) in Si lattice—small changes in R_D strongly impact these parameters. We study the influence of QDC design, chains and rings, and how disorder in R_D impacts QDC electronic properties, in particular the interplay of disorder and interactions. With no disorder in R_D the energy spectrum (ES) of quantum dot chain at half-filling as a function of U/t (V,J =0) shows a transition from spectrum dominated by kinetic energy (U/t≪1) to ES dominated by Coulomb interactions for U/t≫1. For weak (strong) interactions the excited states group by single particle energy spacing (Hubbard bands). In the noninteracting regime, disorder leads to electron localization. Using Lanczos and Density Matrix Renormalization Group approaches we explore the effect of interactions and disorder on atomic scale circuits in Si and potential many-body localized phases in the HK model [5]. References [1] M. B. Haider et al. Phys. Rev. Lett. 102 (2009). [2] B. Weber et al. Science 335, 64 (2012). F.A. Zwanenburg et al. Rev. Mod. Phys. 85, 961 (2013). [3] A. L. Saraiva et al, Journal of Physics: Condensed Matter 27, 154208 (2015). [4] C-Y. Hsieh et al, Rep. Prog. Phys. 75, 114501 (2012). [5] D.M. Basko et al. Annals of Physics 321, 1126–1205 (2006). R. Nandkishore and David A. Huse. Annu. Rev. Condens. Matter Phys. 6:15–38 (2015). M. Schreiber et al. Science 21 August 2015: 842-845.
        Speaker: Mr Amintor Dusko do Amaral Oliveira (University of Ottawa)
    • 08:30 10:00
      T1-4 Ground-based and In Situ Observations I (DASP) / Observations sur terre et in situ I (DPAE) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Daniel Cluff (University of Exeter)
      • 08:30
        Transionospheric Radio Propagation Research with CASSIOPE/ePOP 15m
        The Radio Receiver Instrument (RRI) launched in 2013 as part of the Enhanced Polar Outflow Probe (ePOP) payload on the Canadian CASSIOPE small satellite has been successfully operated in a number collaborative transionospheric propagation experiments. The RRI is a digital receiver that operates in the frequency range from 10 Hz to 18 MHz and connects to 4 tubular monopoles usually configured as two orthogonal 6-m dipoles. CASSIOPE's elliptical (325 km - 1500 km) high-inclination (81°) orbit has presented a variety of experimental opportunities in plasma-wave research. Experiments have featured the reception of EM signals from coordinated ground transmitters of various radiated powers in the very-low-frequency to high-frequency range, including VLF communication transmitters, HF ionospheric heaters, HF over-the-horizon radars, HF coherent-backscatter radars, ionosondes and amateur radio sources. In many cases, the distortion of signals in transionospheric propagation observed by the RRI inside the ionosphere may be used to test long-held interpretive assumptions about propagation that normally is only observed when reflected or scattered back to the ground. Special interest arises with radio propagation detected at low altitudes near perigee at 325 km altitude, a height range rarely visited by orbital observatories. The RRI is also used to detect the results of plasma instabilities that occur in different locations in the ionosphere-magnetosphere system and give rise to EM radiation seen on the ground. In many cases, the RRI measurements are part of collaborative studies exploiting other field and particle instruments on the ePOP payload .
        Speaker: Dr Gordon James (University of Calgary)
      • 08:45
        A selection of results from e-POP RRI polarimetry experiments 15m
        Since the outset of science operations with the Enhanced Polar Outflow Probe (e-POP) Radio Receiver Instrument (RRI) in September 2013, over 100 conjunctions with Super Dual Auroral Radar Network (SuperDARN) radars have been completed. With the cross-dipole configuration of RRI's four monopole antennas, and the receiver's high sampling rate, it is possible to determine the polarization state of an individual SuperDARN pulse incident on the receiver. The SuperDARN Saskatoon system transmits a linearly polarized radar pulse which can become separated into packets of elliptically polarized O- and X-mode polarization states as the pulse propagates through to the birefringent ionosphere. Therefore, the full analysis of a SuperDARN pulse may require resolving its O- and X-mode components. We present the results from a selection of e-POP RRI polarimetry experiments with the SuperDARN Saskatoon system, and compare them to past theoretical predictions. The importance of the geometry of an experiment to the resulting polarization measured is discussed.
        Speaker: Dr Gareth Perry (University of Calgary)
      • 09:00
        Initial Results from the AUTUMNX Magnetometer Array 15m
        Most AUTUMNX sites were installed in late 2014, forming a meridian chain along the eastern shore of Hudson Bay. In early 2015, a second, more widely spaced, chain became operational at the longitude of Iqaluit/Kuujauq. These chains provide good coverage in longitude and latitude in eastern Canada, using highly accurate and reliable THEMIS class magnetometers from UCLA. Many substorms have been observed, along with activity characterized as convection bays or steady magnetospheric convection, which may dominate. Isolated impulsive events observed at many stations appear to be related to detectable signals in nearby power grid systems. The meridian chain is conjugate to GOES East and to Antartica, and some events have been observed to have conjugate signatures. The AUTUMNX array was funded by the GO Canada initiative of the Canadian Space Agency.
        Speaker: Martin Connors (Athabasca University)
      • 09:15
        Plasma motion in the equatorial ionospheric F2-layer 15m
        Oyedemi S. Oyekola Etobicoke, ON M8V 3C8 Canada Email: ooyekola@gmail.com Abstract. The structure of evening and nighttime F-region vertical drift component of is vital for understanding the physics of the development of the occurrence of equatorial irregularities. In addition, postsunset ionospheric height has also been attributed as one of the most important factors for the occurrence of equatorial irregularities. We report vertical plasma drift velocities derived from the base (h’F) and the peak height (hmF2) of F-layer using 1-year of data obtained at Ibadan (Geog Long 3.9oE) during International Geophysical Year (1957-58) period for geomagnetic quiet-time and high solar activity conditions. We compared our results with International Reference Ionosphere 2012 model (IRI-2012). The results of this investigation include: (a) overall local- time characteristics of vertical drift between 1800 LT and 0600 LT are in good agreement for equinoxes, December, and June; (b) annual vertical drift derived from time variation of h’F and hmF2 and the corresponding annual variation of h’F and hmF2 variation indicate low correlation (R = 0.30), while IRI-2012 model vertical drift and IRI-2012 model of hmF2 show fairly good correlation ( R = 0.67); (c) regression analysis between time variation of h’F and Scherliess / Fejer model demonstrate correlation coefficient of approximately 0.74 (equinox), 0.85 (December), 0.57 (June) and 0.74 (all-year), while that of time variation of hmF2 and IRI-2012 vertical velocities show 0.95 (equinox), 0.74 (December), 0.43 (June), and 0.74 (all-year); (d) plasma motion derived from the time rate of change of h’F and those of hmF2 are correlated at 0.94, 0.88, 0.63, and 0.90 for equinoxes, December, June, and all-year, respectively; (e) the evening prereversal vertical drifts enhancement rage between ~20 - 45 m/s, ~18 - 46 m/s, ~20 – 50 m/s for time variation of h’F, hmF2, and Scherliess / Fejer model, respectively; (f) the corresponding peak altitudes vary between 430 - 540 km (h’F), 560 – 740 km ( hmF2), and 570 – 620 km (IRI-2012 model).
        Speaker: Dr Oyedemi Oyekola (Private)
      • 09:30
        Swarm Canada: Accomplishments and Opportunities 15m
        Launched in November 2013, European Space Agency's Swarm mission* is now halfway through its nominal science mission. Swarm's on-board experiments, including the Canadian Electric Field Instruments, continue to collect scientific data daily in conjunction with ground-based observatories in Canada and elsewhere. Numerous scientific investigations have been completed or are underway, covering topics from electrodynamics of auroral arcs and pulsations to polar cap patches, Poynting flux, ionospheric structure and thermal balance, and ULF waves. However, only a small fraction of Swarm data have been exploited scientifically, and countless opportunities remain. This talk will summarize the capabilities and potential of the Swarm data with the aim of stimulating new projects and collaborations. Acknowledgement: Canada's participation in Swarm is supported by the Canadian Space Agency and NSERC.
        Speaker: Prof. David Knudsen (University of Calgary)
      • 09:45
        Using Langmuir Probe and faceplate current measurements to validate Swarm Electric Field Instrument bulk ion drifts 15m
        The 3D ion drift measurements from the Electric Field Instruments (EFI) of the European Space Agency’s Swarm mission provide excellent opportunities for multi-satellite and ground-conjunction investigations of ionospheric and auroral physics. Ion drifts are derived from estimates of low-energy (<10 eV) ion energy/angle distributions obtained by Thermal Ion Imagers. In practice, the EFI datasets exhibit sometimes large and often time-varying offsets in the ion drift vector components. Measurements parallel to the satellite velocity vector typically have the greatest uncertainty, with significant contributions from uncertainties in spacecraft-to-plasma potential and ion atomic mass, as well as other sources. Here we present initial findings of an investigation into the feasibility of using simultaneous estimates of ion flux from the EFI Langmuir probes and faceplate current measurements to validate the Swarm along-track ion drifts. Under certain conditions a comparison of TII ion drifts with LP-derived drifts can reveal variations in the mean ion atomic mass in the topside F region ionosphere.
        Speaker: Johnathan Burchill (University of Calgary)
    • 08:30 10:00
      T1-5 Neutrinoless Double Beta Decay II (PPD-DNP-DTP) / Double désintégration beta sans neutrino II (PPD-DPN-DPT) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Thomas Brunner (McGill University)
      • 08:30
        Towards new discoveries with neutrinos and dark matter 30m
        Next generation experiments are poised to help answer fundamental questions about neutrinos and dark matter, but rely on a quantitative understanding of perturbative and nonperturbative QCD. I briefly review the status of experimental searches and theoretical calculations in searchers for lepton number and CP violation in the neutrino sector, and for WIMP dark matter direct detection.
        Speaker: Richard Hill (TRIUMF, Perimeter Institute and University of Chicago)
      • 09:00
        A Scintillator Purification Plant and Fluid Handling System for SNO+ 15m
        A large capacity purification plant and fluid handling system has been constructed for the SNO+ neutrino and double-beta decay experiment, located 6800 feet underground at SNOLAB, Canada. SNO+ is a refurbishment of the original SNO detector to fill the acrylic vessel with liquid scintillator based on Linear Alkylbenzene (LAB) and 2 g/L PPO, and also has a phase to load natural tellurium into the scintillator for a double-beta decay experiment with Te-130. The plant includes processes multi-stage dual-stream distillation, column solvent-solvent extraction, steam stripping, and functionalized silica gel adsorption columns. The plant also includes systems for preparing the scintillator and metal-loading the scintillator for double-beta decay exposure. We review the basis of design, the purification principles, specifications for the plant, and the construction and installations. We also discuss the plant helium leak testing, the passivation and high-purity cleaning, and the plant safety systems. Currently the plant is undergoing testing and commissioning with water, with approvals for LAB commissioning to begin early summer 2016.
        Speaker: Richard Ford (SNOLAB)
      • 09:15
        Commissioning the SNO+ Detector 15m
        SNO+ is a multipurpose neutrino experiment at SNOLAB. Our main physics goal is searching for neutrinoless double beta decay in Tellurium-130. Much work had been done to transform a heavy water detector into a scintillator detector. We are currently commissioning the experiment with water and I will show some early data.
        Speaker: Erica Caden (Laurentian University)
      • 09:30
        Characterization of backgrounds in lucas cells 15m
        For the current generation of experiment on particle astrophysics low backgrounds are very important, which comes with the need for very sensitive measurement tools. A new generation of lucas cells has been produced and this presentation describes the characterization and first steps to simulating the cells performed in the summer 2015. This presentation won first prize at the SNOLAB undergaduate student talk competition.
        Speaker: Elspeth Cudmore (Carleton University)
      • 09:45
        Neutrino-less double beta decay search with Xe-136 and Ba ion tagging R&D 15m
        Neutrino oscillation experiments have shown that neutrinos have finite masses. The study of neutrino-less double beta decay may bring insight on the neutrino mass generation and determine the effective neutrino mass. The next generation neutrino-less double beta decay experiments, with a very large active mass and ultra low background, like the proposed nEXO, will have a sensitivity to the half-life on the order of 10e28 years. These detectors face tremendous challenges for reducing the background due to the trace radioactivity. Standard background reduction techniques have reached a limit and so a novel one must be developed. Double beta decay of Xe-136 produces a Ba-136 ion, the only element for which there is experimentally demonstrated single ion detection and identification capability using resonant light scattering. Tagging the Ba ion can lead to total elimination of the background from radioactive impurities or of cosmic origin. However, applying Ba ion tagging to a massive liquid Xe detector is a challenge. In this talk I will present the field of neutrino-less double beta decay search focusing particularly on Xe-136 as well as the Ba ion tagging efforts within the EXO collaboration.
        Speaker: Prof. Razvan Gornea (Carleton University)
    • 08:30 10:00
      T1-6 Nanostructured and Functional Nanomaterials (DCMMP-DIAP) / Nanomatériaux nanostructurés et fonctionnels (DPMCM-DPIA) Colonel By B205

      Colonel By B205

      University of Ottawa

      Convener: Prof. Adina Luican-Mayer (University of Ottawa)
      • 08:30
        Functional nanostructured surfaces for biomedical applications 30m
        Metals currently used for prosthetic reconstructions (e.g. titanium) enjoy a relatively good success rate, but their performance drops significantly in patients with compromised health status, and post-surgical infections still remain an important challenge. In addition, there are still no such metals that are able to respond to any deterioration of their relationship with the host tissue. To address these needs, different nanotechnology-based strategies have been exploited. Among these, the creation of nanoporous surfaces by simple yet efficient (electro)chemical treatments and the use of polymeric coatings, have emerged as a very effective approach to provide antibacterial properties, drug-delivery capacities and advantageous physicochemical cueing to cells. In this context, we investigated the effects of nanoporous surfaces generated by simple oxidative nanopatterning on the adherence of two common bacteria responsible of implant-associated infections and one yeast strain found in hospital settings. Nanoporous titanium surfaces are also very attractive for their capacity to act as metallic platforms for controlled drug release directly at the implantation site. In this context, we have loaded treated surfaces with Vancomycin, a commonly used antibiotic, and studied the elution profile engendered by the 3-dimensional network of nanosized pits. In order to adapt such technology towards the creation of ‘smart’ materials for in situ ‘gated’ release, we have employed a chitosan-poly(ethylene oxide) (PEG) hydrogel demonstrating a pH-dependent drug release. Such change has been associated with bone remodeling and infections as well as tissue inflammation. Nanoporous surfaces lend themselves to being an effective substrate to immobilize polymeric coatings because of their enhanced surface area and greater amount of binding sites. In this context, we employed a mussel-inspired polymer, poly(dopamine), and carried out extensive investigation of its biological in vitro effects to better understand its direct physicochemical cueing to adhering cells.
        Speaker: Fabio Variola (University of Ottawa)
      • 09:00
        XPCS studies of shear-induced rejuvenation and nano-plasticity in soft glassy materials 15m
        We present x-ray photon correlation spectroscopy experiments on a set of soft glassy solids, including concentrated nanocolloidal gels, nanoemulsions, and Laponite clay suspensions, subject to in-situ oscillatory shear strain that provide insight into particle rearrangements above yielding at the nanometer scale and their connection to dynamical and mechanical behaviour of the materials. The oscillatory strain causes periodic echoes in the x-ray speckle pattern, creating peaks in the intensity autocorrelation function. The peak amplitudes are attenuated above a threshold strain, signalling the onset of irreversible particle rearrangements. These materials generally exhibit macroscopic strain softening (as measured by mechanical rheometry) well below the XPCS peak attenuation threshold, indicating a range of strains at which deformations are nonlinear but reversible. In the gels, the peak amplitudes decay exponentially with the number of shear cycles above the threshold strain, demonstrating that all regions in the sample are equally susceptible to yielding and surprisingly that the probability of a region yielding is independent of previous shear history. However, in the Laponite clay suspensions, which exhibit characteristic mechanical aging behaviour during gelation, attenuation of echoes in he x-ray speckle pattern can be long lived for modest strain amplitudes, a hallmark of mechanical rejuvenation phenomena.
        Speaker: James L. Harden (University of Ottawa)
      • 09:15
        X-ray Speckle Measurements of a Shape Memory Alloy in Training 15m
        The deformation of most types of metals involves an irreversible flow of crystallographic dislocations. This allows for their ductility. The deformation of a metallic shape memory alloy (SMA), on the other hand, is accommodated by a solid-solid phase transition. If deformed in the low-temperature martensitic phase, an SMA can be returned to its original shape by raising its temperature to the point where it changes back to its high-temperature parent phase. When the reverse occurs and the transformation is from parent to martensitic phase, an SMA goes from a high-symmetry to a low-symmetry state in which a number of martensitic variants are produced. Using in situ X-ray Photon Correlation Spectroscopy (XPCS), we monitored the self-organization of martensitic variants in a CuAlNi SMA during thermal cycling. In high-angle scattering geometry, this technique uses correlation from X-ray speckle to quantify the degree of crystallographic change in a material. Our measurements revealed enhanced reversibility in the organization of the martensitic variants as the system became trained during repeated thermal cycling.
        Speaker: Michael Rogers (University of Ottawa)
      • 09:30
        Theory of Nanoscale Friction 30m
        In a nanoscale friction experiment, the tip of an atomic force microscope (AFM) cantilever is dragged along an atomically flat surface, and the resulting friction force is measured optically from the cantilever deformation. Due to the small size of the system, thermal noise effects coming from the atomistic degrees of freedom play an important role. In this talk, the ideas of stochastic modeling will be applied to atomic friction phenomena. We theoretically study atomic friction experiments in the stick-slip regime within the framework of the Prandtl-Thomlinson model. A differential equation describing the force probability distribution is derived. Analytical approximate solutions of this equation are found for the asymptotic cases of high and low effective spring constant, but for arbitrary pulling velocities. Excellent accuracy of these approximate expressions is demonstrated numerically. In particular, the theoretical expression for the mean force, although obtained for small spring constants, is shown to be accurate also somewhat outside of its expected validity range. Finally, the influence of friction aging effect on the experimental friction forces and the ways to include it into the theory are discussed.
        Speaker: Prof. Mykhaylo Evstigneev (Memorial University of Newfoundland)
    • 08:30 10:00
      T1-7 Mass spectrometry in nuclear waste management and control at the border (DIAP-DIMP) / Spectrométrie de masse dans la gestion des déchets nucléaires et surveillance à la frontière (DPIA-DPIM) SITE J0106

      SITE J0106

      University of Ottawa

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 08:30
        Measurement of $^{236}$U in Biota by accelerator mass spectrometry. 15m
        $^{236}$U (half-life 2.34$\times10^7$ y) is a radioisotope of uranium of key importance for tracing the movement of nuclear waste through the environment. Accelerator mass spectrometry (AMS) is the most robust and capable method for measuring $^{236}$U, which has a natural abundance range between 10$^{-8}$ to 10$^{-12}$ or lower. Here we study $^{236}$U uptake in biota samples (plants, animals) and river water samples collected in the region surrounding the Chalk River Nuclear laboratories (Chalk River, ON) by AMS. Plants included the common submerged aquatic waterweeds elodea, myriophyllum and vallisneria. Animals consisted of a variety of freshwater mussle (unionids), an amphipod crustacean (gammarus), a freshwater crustacean resembling small lobsters (crayfish), a small freshwater minnow (spot- tail), a freshwater fish (yellow perch) and a mayfly variety (heptageniids). Samples were ashed, digested, spiked with a $^{233}$U tracer and cleaned through a single-pass UTEVA chemistry in HNO3 followed by U elution in HCl. Post-load UTEVA washes were saved for $^{90}$Sr analysis (Francisco et al [this meeting]). A fraction of the final U eluent was removed for $^{235}$U/$^{238}$U isotopic composition measurements by multi-collector ICP-MS, and the remaining U fraction co-precipitated in iron hydroxide, calcinated, and pressed into AMS targets with an appropriate matrix to optimize uranium emission (Kazi et al [this meeting]). Water samples were processed by direct iron hydroxide co-precipitation of U followed by UTEVA chemistry. We present the AMS analytical testing and results of $^{236}$U partitioning and the $^{235}$U/$^{238}$U isotopic compositions of these biota and water samples.
        Speaker: Christopher Charles (University of Ottawa)
      • 08:45
        Optimization of a methodology to determine 90Sr in biota and water samples by ICP MS QQQ and LSC 15m
        90Sr (t1/2 = 28.80yr) has a relatively long life and due to its chemical similarity to calcium, 90Sr accumulates within the skeletal structure of animals and some plants. The aim of this work is optimize a methodology to determine stable Sr and 90Sr in environmental samples including plants, insects, animals and water. The 88Sr was measured by ICP-MS Triple Quad (8800, Agilent Technologies) and 90Sr by Liquid Scintillation Spectrometer (Quantalus 1220, Perkin Elmer). The Sr was separated from the matrix using the specific Sr EiChrom single resin method (Horwitz 1992). We modified this method to improve the yield and reproducibility of the results. Our optimization focused on adjusting the nitric acid concentration in samples, (8mol L-1) and the use of higher concentrations of hydrochloric acid (6mol L-1) to successfully elute the Sr from the resin. The proposed optimization showed that it is possible to obtain Sr recovery of about 92% if 6 mol L-1 HCl is used as an elution solution. Horwitz, E. P. C. R. D. M. L. (1992). "A Novel Stronium-Selective Extraction Chromatographic Resin." Solvent Extration and Ion Exchange 210(2): 313-336.
        Speaker: Barbara Francisco (University of Ottawa)
      • 09:00
        Contactless Real-time Dynamic Measurements with THz waves and a Rotary Delay Line 15m
        For several years, THz spectroscopy and imaging have been applied to many different fields. However, some burdens still remain in its commercial generalization, particularly for the industry sector. One of these difficulties lies in the acquisition time. In a typical THz time-domain spectroscopy system (THz-TDS), the THz pulse is sampled in time by the means of a micrometer linear delay line. This operation is highly time-consuming, often on the minute scale. We design and fabricate a fast rotary optical delay line (FRODL) consisting of two curvilinear reflectors directly connected to a rotating motor. The optical delay is linear with the rotation angle of the FRODL. The optical input and output are separate and stable to avoid the use of other moving components. We present an experimental implementation of such FRODL. The FRODL surface is made with a CNC machine. We fabricated four blades on the same disk to increase by four the total scan rate. We tested the FRLODL with speeds up to 48 Hz (192 Hz maximum). The total delay was experimentally evaluated to 100 ps. As a first application, we present contactless monitoring of spray painting process and thickness real-time evaluation of the thickness of the paint layer. As a second application, we present the simultaneous detection and thickness characterization of fast moving objects.
        Speaker: Hichem Guerboukha (École Polytechnique de Montréal)
      • 09:15
        Simultaneous Determination of Th and U in Urine by ICP-MS 15m
        ²³²Th is expected to be the major internal dose contributor for nuclear workers in the development of new Th fuels. Since new fuels are usually processed in the same facilities as U fuel is handled, U might also be a significant internal dose contributor. The development of rapid and sensitive analytical methods for the determination of these elements at the levels observed in bioassay samples such as urine is needed. Inductively coupled plasma mass spectrometry (ICP-MS) allows for fast and sensitive detection of these long-lived radionuclides. However, urine contains a significant amount of dissolved salts, organic matter, and suspended particles, which prevent the direct measurement of Th and U by ICP-MS. The traditional purification method for U consists in directly passing an acidified urine sample through an extraction chromatography (EXC) resin; however, this rapid method resulted in inconsistent and poor recoveries for Th. We have demonstrated that the salinity, ligands and suspended particles of urine were hindering the extraction of Th on UTEVA resin without significantly affecting U extraction. A calcium phosphate coprecipitation was first done to remove most of the interferents. Then, the precipitate was dissolved in 8M HNO₃ and the solution oxidized. The solution was passed through a UTEVA resin and the actinides were eluted with 5 mL of a dilute acidic solution. Using this method, a high and consistent recovery was obtained with a low detection limit of 80 and 230 pg•L⁻¹ for ²³²Th and ²³⁸U, respectively.
        Speaker: Mr Alexandre Gagné (Canadian Nuclear Laboratories)
    • 08:30 10:00
      T1-8 General Relaivity (DTP) / Relativité générale (DPT) Colonel By B012

      Colonel By B012

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Gabor Kunstatter (University of Winnipeg)
      • 08:30
        Observation of gravitational waves from a binary black hole merger 30m
        On September 14, 2015, the LIGO detectors observed gravitational waves from a merger of two black holes. This talk describes the LIGO instruments and the LIGO Scientific Collaboration. It presents details of the observed gravitational wave event and discusses implications to astrophysics and tests of general relativity.
        Speaker: Prof. Harald Pfeiffer (CITA, University of Toronto)
      • 09:00
        Universal Horizons in Collapsing Reissner-Nordstrom Metrics 15m
        An investigation of an analogous structure to an event horizon in theories which break Lorentz symmetry. Recent work has shown that in simple spacetimes Lorentz violating theories, such as Einstein-Aether or Horava-Lifshitz, singularities lie behind a *universal horizon* . In the limiting case, signals travel along an incompressible aether which results in an infinitely fast speed of propagation. Despite this property, a universal horizon always appears to form around a singularity disconnecting a region of spacetime from the larger universe. This talk will look at how these structures form during the collapse of a massive charged shell.
        Speaker: Michael Meiers
      • 09:15
        Thermal Mediated Phase Transition in Gauss-Bonnet Gravity 15m
        In this work, we will be introducing so called "thermalons"and studying them in 5 dimentional Gauss-Bonnet Gravity. Thermalons can mediate phase transitions between different vacua in higher curvature gravity, potentially changing the asymptotic structure of the spacetime. Treating the cosmological constant as a dynamical parameter, we study these phase transitions in the context of extended thermodynamic phase space. We find that in the AdS to dS case, thermal AdS can only undergo a phase transition if it is below the Nariai limit. The solutions found beyond Nariai are interpreted as "unphysical". We also find that thermal AdS space can undergo a phase transition to an asymptotically flat black hole geometry. In the context of AdS to AdS transitions, we comment on the similarities and differences between thermalon transitions and the Hawking-Page transition.
        Speaker: Saoussen MBAREK (University of Waterloo)
      • 09:30
        Numerically Obtaining the Black Hole Universality Class 15m
        I will discuss methods to find and extract critical exponents from numerical black holes. This procedure is nontrivial because numerically we compute only the temperature and entropy; assumptions will be made about the complete thermodynamical description via a First Law and Smarr Relation, and tools such as Padé Approximants will be examined. This procedure will be quite general, allowing for utility in scenarios ranging from higher curvature theories to anisotropic solutions.
        Speaker: Wilson Brenna (University of Waterloo)
      • 09:45
        Reentrant phase transitions and van der Waals behaviour for hairy black holes 15m
        The thermodynamics of black holes has remained a subject of interest for more than 40 years. Recently attention has been devoted to the thermodynamics of black holes in extended phase space where the cosmological constant is treated as a thermodynamic variable with the interpretation of pressure. Within this framework, Kubiznak and Mann demonstrated that the charged anti de Sitter black hole is thermodynamically analogous to the van der Waals fluid. A plethora of subsequent work deepened this connection, finding examples of van der Waals behaviour, triple points, and (multiple) reentrant phase transitions for AdS black holes. In my talk I will discuss recent work where we have applied this formalism for the first time to hairy AdS black holes by considering Einstein-Maxwell-AdS gravity conformally coupled to a scalar field in five dimensions. In the absence of electric charge we recover a van der Waals analogy for these black holes for particular configurations of the scalar field. More interesting behaviour is found in the charged case, where both van der Waals behaviour and reentrant phase transitions are seen to occur, the latter due to a modified Bekenstein-Hawking entropy of these black holes. These black holes have an interesting zero-entropy limit at which all critical behaviour ceases.
        Speaker: Robie Hennigar
    • 10:00 10:30
      Health Break (with exhibitors) / Pause santé (avec exposants) SITE Atrium

      SITE Atrium

      University of Ottawa

    • 10:30 11:00
      T-MEDAL CAP Medal Talk - James Fraser, Queen's U. (Teaching Undergraduate Physics / Enseignement de la physique au 1er cycle) Marion 150

      Marion 150

      University of Ottawa

      Convener: Richard MacKenzie (U. Montréal)
      • 10:30
        Going beyond “interactive”: developing scientist-apprentices in the physics lecture hall 30m

        Though an extensive amount of literature documents the improved learning gains made by interactive teaching compared to traditional lecture delivery, results vary widely between courses[1]. Part of the problem is that different instructors aim for active learning through widely varying (and sometimes conflicting) approaches[2]. In addition, even the most well-verified and effective teaching approach will fail without student buy in. I propose a simple framework that can help you identify effective active learning instructional strategies and how to implement them successfully. Results (both positive and less than positive) from a large first-year physics course will be discussed.
        [1] one example among 100s: Freeman et al., Proceedings of the National Academy of Sciences 111, 8410 (2014). For a contrasting view, Andrews et al., CBE-Life Sciences Education 10, 394-405 (2011)
        [2] Turpen and Finkelstein, Physical Review Special Topics-Physics Education Research 5, 020101 (2009)

        Speaker: Prof. James M. Fraser (Queen's University)
    • 11:00 11:30
      NSERC Presentation by Mario Pinto / Présentation du CRSNG par Mario Pinto Marion 150

      Marion 150

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 11:00
        NSERC 2020 Strategic Plan 30m
        I set a number of tasks for myself and for NSERC. Developing and launching NSERC 2020, our strategic plan for the next five years, stood at the top of the list. During a year-long consultation, NSERC benefitted greatly from the input and perspectives of our community through a variety of consultations. I will outline NSERC 2020 in my talk.
        Speaker: Dr Mario Pinto (NSERC)
    • 11:30 11:45
      NSERC EG Chair Report (L.-H. Xu) / Rapport de la présidente du GE (L.-H. Xu) Marion 150

      Marion 150

      University of Ottawa

      Convener: Donna Strickland (University of Waterloo)
    • 11:45 12:00
      CAP-NSERC Liaison Committee Report (W. Whelan) / Rapport du Comité de liaison ACP-CRSNG (W. Whelan) Marion 150

      Marion 150

      University of Ottawa

      Convener: Donna Strickland (University of Waterloo)
    • 12:00 13:00
      DAMOPC Annual Meeting / Assemblée annuelle DPAMC Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Matt Reid (University of northern british columbia)
    • 12:00 13:00
      DASP Annual Meeting / Assemblée annuelle DPAE SITE C0136

      SITE C0136

      University of Ottawa

      Convener: Prof. Richard Marchand (University of Alberta)
    • 12:00 13:00
      DNP Annual Meeting / Assemblée annuelle DPN SITE J0106

      SITE J0106

      University of Ottawa

      Convener: Reiner Kruecken (TRIUMF)
    • 12:00 13:00
      DPMB Annual Meeting / Assemblée annuelle DPMB SITE G0103

      SITE G0103

      University of Ottawa

      Convener: Melanie Martin (University of Winnipeg)
    • 12:00 13:00
      DPP Annual Meeting / Assemblée annuelle DPP Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Lora Ramunno (University of Ottawa)
    • 12:00 13:00
      IPP Scientific Council Meeting / Réunion du comité scientifique de l'IPP Colonel By E016

      Colonel By E016

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 12:00 13:00
      Lunch / Dîner
    • 12:00 13:15
      NSERC's Research Partnership Programs / Programmes de partenariat de recherche du CRSNG Colonel By D207

      Colonel By D207

      University of Ottawa

      Convener: Bill Whelan (University of Prince Edward Island)
      • 12:00
        NSERC's Research Partnership Programs / Programmes de partenariat de recherche du CRSNG 20m

        This is a moderated panel discussion and Q&A (with NSERC reps, physicists and industry partners) on NSERC funding opportunities available to support researcher-industry partnerships. Learn how to get started, the challenges/rewards and tips for a successful partnership.
        Panelists will be named as they are confirmed.

    • 13:15 14:45
      T2-1 Nuclear Structure II (DNP) / Structure nucléaire II (DPN) Colonel By D103

      Colonel By D103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Prof. Corina Andreoiu (TRIUMF/SFU)
      • 13:15
        Exploring the exotic landscape with direct reactions 30m
        Nuclei far from stability offer us the scope of exploring new features that surface prominently at large isospin and weak binding. This led to the discovery of the nuclear halo bringing a new era in nuclear science breaking the boundaries of conventional concepts. The halo properties elucidate new features that till date remain a challenge to decipher from fundamental principles. Defining the nuclear force from the foundations built on quantum chromodynamics remains one of the major tasks in nuclear physics. The nuclear force is manifested in the characteristics of the nuclei and hence new efforts are underway to couple experiments of the exotic nuclei to ab initio theories. Nuclear reactions are highly sensitive and definitive probes to unravel the unknown new features of the exotic nuclei and hence the nuclear interaction. In this presentation we will introduce a new reaction spectroscopy facility, IRIS, using a novel thin windowless solid hydrogen target. Recent experiments from the facility will be discussed to show observation of halo related excitation modes in the neutron halo nucleus, 11Li. To define the wavefunction of this Borromean halo nucleus, first exploration of its configuration with the unbound 10Li sub-component will be presented. New observations at the proton-drip line exploring the nuclear force will also be discussed.
        Speaker: Prof. Rituparna Kanungo (Saint Mary's University)
      • 13:45
        High-Statistics ${\beta^+/EC}$-Decay Study of $^{122}$Xe 15m
        The Xe isotopes are centrally located in the $Z>50$, $N<82$ region that displays an extraordinarily smooth evolution of simple collective signatures. However, the collectivity of excited states in this region is very poorly characterized because of a general lack of spectroscopic data for low-spin states that provide measures of collective properties such as relative and absolute $B(E2)$ decay strengths and the occurrence of $E0$ decays. There are spectroscopic hints to unusual structures in this region. The $0^+_3$ states in $^{124-132}$Xe are very strongly populated in $(^3He,n)$ reactions, suggesting a pairing vibrational structure influenced by proton subshell gaps, perhaps leading to shape-coexistence that could give rise to strong $E0$ transitions. Recent work on $^{124}$Xe [1] has established nearly identical quadrupole collectivity for the pairing vibrational $0^+_3$ band and the ground state band. However, in $^{122}$Xe, the $0^+_3$ state has not been firmly identified. A high-statistics $^{122}$Cs $\beta^+/EC$ decay experiment to obtain detailed spectroscopic data for low-spin states was performed at the TRIUMF-ISAC facility using the 8$\pi$ $\gamma$-ray spectrometer and its auxiliary detectors including PACES, an array of five Si(Li) detectors, for conversion electrons spectroscopy. The status of the data analysis and preliminary results will be presented. [1] A.J. Radich ${\it et\ al.}$, Phys. Rev. C ${\bf 91}$, 044320 (2015).
        Speaker: Badamsambuu Jigmeddorj (University of Guelph)
      • 14:00
        Doppler-shift lifetime measurements in $^{94}$Sr using the TIGRESS Integrated Plunger 15m
        Neutron-rich Sr isotopes are characterized by a sudden onset of quadrupole deformation at neutron number $N=60$ demonstrated by the dramatic drop in excitation energy of the first $2^+_1$ state. While theoretical calculations reproduce this onset of deformation qualitatively, they differ in the details of the deformation parameters and excitation energies. Though the emphasis is usually put on the sudden onset of collectivity at $N=60$, it is equally surprising that there is no onset of collectivity when adding up to 8 neutrons beyond the $N=50$ shell closure, which points to an amazing robustness of both the $Z=38$ and $Z=40$ proton (sub)-shell closures. This retardation of the onset of collectivity was first observed by Mach et al. [1] measuring extremely low $B(E2)$ values of $\approx 10$ W.u. in even-even Sr isotopes from $^{90}$Sr to $^{96}$Sr using the fast timing technique. These measurements have an uncertainty of $\approx 40\%$ and are at the limit of the fast timing technique with lifetimes of $\approx 10$ ps; a high precision lifetime measurement in $^{94}$Sr will elucidate whether the onset of collectivity is as sudden as generally assumed. Intense re-accelerated beams delivered by the ISAC-II facility at TRIUMF, Canada's national laboratory for particle and nuclear physics, permit access to nuclear structure information for a wide range of radionuclides via in-beam gamma-ray spectroscopy with TIGRESS, a high-efficiency and Compton-suppressed segmented HPGe array. To take advantage of this opportunity, the TIGRESS Integrated Plunger (TIP) has been constructed at Simon Fraser University [2]. The TIP infrastructure supports Doppler-shift lifetime measurements via the Recoil Distance Method (RDM) using a 24-element TIP CsI(Tl) wall for charged-particle identification. An experiment aimed towards a high-precision ($<10\%$) measurement of the $B(E2,2^+_1\rightarrow 0^+_1)$ reduced transition probability in $^{94}$Sr was performed in December 2015 using inelastic scattering near the Coulomb barrier coupled with an RDM lifetime measurement of a radioactive $^{94}$Sr beam. A Geant4-based code for TIP is being developed as a tool to aid the analysis and for the optimization of future experiments. The device, experimental approach, analysis, and preliminary results will be presented and discussed. This work is presented on behalf of the TIP and TIGRESS collaborations. [1] Mach et al., Nucl. Phys. A 523 (1991) 197. [2] P. Voss et al., Nucl. Inst. and Meth. A 746 (2014) 87.
        Speaker: Prof. Krzysztof Starosta (Simon Fraser University)
      • 14:15
        Study of 22Ne and 28Mg excited states using fusion-evaporation and Doppler shift measurements 15m
        Electromagnetic transition rate measurements serve as a fundamental probe of nuclear structure and provide a stringent test for theoretical models. Doppler shift lifetime measurements offer an opportunity to directly access information about electromagnetic transition rates and discriminate between model calculations. The TIGRESS Integrated Plunger device (TIP), constructed at SFU, supports Doppler shift lifetime measurements via gamma-ray spectroscopy with the TIGRESS segmented Ge array as part of the experimental program at the ISAC-II facility of TRIUMF. A recent study using TIP employs the fusion-evaporation reaction of 18O + 12C at beam energies of 56 and 48 MeV, with reaction channel selection provided via coincident charged particle detection using ancillary CsI(Tl) detectors. Transitions were identified belonging to the 2 alpha particle and 2 proton evaporation channels from the compound system 30Si, corresponding to 22Ne and 28Mg respectively. Lineshapes, from which lifetimes can be determined by comparison to simulated data, have been observed for these transitions. The experimental approach, analysis procedure, and preliminary comparison of lineshapes to simulations using the GEANT4 toolkit will be discussed.
        Speaker: Jonathan Williams (Simon Fraser University)
      • 14:30
        Investigating the nuclear structure of 33Al through β− decay of 33Mg to probe the island of inversion 15m
        Spectra resulting from the decay reaction of 33Mg were captured using the GRIFFIN γ-ray spectrometer coupled with the SCEPTAR β particle detector at the Canadian laboratory, TRIUMF. A radioactive beam of approximately 104 counts per second of 33Mg was delivered by the Isotope Separator and Accelerator (ISAC) facility. In the past, nuclei away from the valley of stability were experimentally found to have different ground state shell gaps and magic numbers than the ones of those near stability. For example, N=20 is a stable magic number, however the neutron rich 32Mg is known to have a deformed configuration, while 34Si displays a normal configuration. In order to corroborate the theoretical predictions of this inversion mechanism, the nuclear structure of the intermediate 33Al should be known accurately and in detail. A few recent studies have given conflicting results for the branching ratios, spin and parity of the ground state of 33Al. The end goal of this experiment is to determine a fine- grained, conclusive nuclear structure of 33Al through the decay spectroscopy of 33Mg. It is part of a larger experiment using Mg A=34 and 35 isotopes in efforts to map out the island of inversion around N=20. This presentation will focus on the preliminary results from the data processing and analysis done so far, and their significance.
        Speaker: Ms Tammy Zidar (University of Guelph)
    • 13:15 14:45
      T2-2 Nonlinear Dynamics (DPMB) / Dynamiques non linéaires (DPMB) Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Melanie Martin (University of Winnipeg)
      • 13:15
        Nonlinear Dynamics for the Translocation of fd Virus through Nanopores: Euler Buckling at the Nanoscale 15m
        The translocation of biopolymers such as DNA through nanopores has received a great deal of attention due to applications such as sequencing DNA or sorting polymers by size. In this presentation I will discuss results from a joint experimental-theoretical project examining the translocation of the filamentous fd virus through nanopores. The fd virus is relatively stiff with a persistence length on the order of its contour length. This is in contrast to typical translocation scenarios where the polymer is many Kuhn lengths in size. Experimental results for fd uncover complex nonlinear dynamics: the translocation speed increases superlinearly with the driving force, the mobility is force-dependent and transitions between scaling regimes with increasing virus length, and the variation in the translocation velocity increases dramatically with increasing driving force. All of these results can be explained by a simple physical picture in which the virus mechanically buckles as it is pushed through the pore and into the fluid on the opposite side of the membrane. This model is explored via Langevin dynamics simulations of the system. Consistent agreement between simulations and experiments verifies the underlying physics thus giving insight into heretofore unexplained experimental results. These findings demonstrate that for the translocation of semi-flexible polymers, the behaviour of the trans portion of the polymer — which is ignored in standard models — has a large impact on the translocation dynamics.
        Speaker: Hendrick de Haan (University of Ontario Institute of Technology)
      • 13:30
        Development of a tapered fiber probe 15m
        Recent advancements in nanotechnology have attracted worldwide attention. The potential applications of metallic nanoparticles, especially gold nanoparticles or nanorods (or gold colloids), are very promising and attractive. The unique optical, chemical, and physical properties of gold nanoparticles make them an ideal candidate for biochemical sensing, medical diagnostics/therapeutics, imaging contrast agents, and photonic devices. The Photonics Research Group at Lakehead University is working towards the development of a photonics device to detect chemicals (e.g., proteins) using Surface-Enhanced Raman Spectroscopy (SERS). We will present the design of a probe using an optical fiber and its application in sensing. The research was financially supported by Natural Sciences and Engineering Research Council of Canada (NSERC) and Agrium Inc.
        Speaker: Mr Joshua Trevisanutto (Lakehead University)
      • 13:45
        Nonlinear dynamics of sensory focussing 30m
        This talk will discuss a non-conventional neural coding task that may apply more broadly to many senses in higher vertebrates. We ask whether and how a non-visual sensory system can focus on an object. We present recent experimental and modeling work that shows how the electric sense can perform such neuronal focussing. This sense is the main one used by weakly electric fish to navigate, locate prey and communicate in the murky waters of their natural habitat. We show that there is a distance at which the Fisher information of a neuron's response to a looming and receding object is maximized, and that this distance corresponds to a behaviourally relevant one chosen by these animals. Strikingly, this maximum occurs at a bifurcation between tonic firing and bursting. We further discuss how the invariance of this distance to signal attributes can arise, a process that first involves power-law spike frequency adaptation. The talk will also highlight the importance of expanding the classic dual neural encoding of contrast using ON and OFF cells in the context of looming and receding stimuli.
        Speaker: Prof. Andre Longtin (Physics, U. Ottawa)
      • 14:15
        Modeling the high frequency electric organ discharge in the weakly electric fish, Eigenmannia 15m
        In the murky waters of the tropics, live weakly electric fish which use a continuous high frequency electric organ discharge (EOD) to sense nearby objects and communicate with conspecifics. Eigenmannia’s characteristic frequency is within the species range of 250 to 600 Hz which it shifts when necessary to avoid jamming. The nearly dipolar oscillating electric field is generated by parallel columns of identical, synchronously discharging electrocyte cells. Recent findings from whole fish respirometry (during high-frequency signaling over a range of frequencies) have renewed interest in the frequency-dependent energetics of the EODs (Lewis et al 2014 J Neurosci 34:197). Although some modeling for that analysis has been performed, many aspects of in vivo electrocyte operation remain unclear, including the role of each compartment of the electrocyte, the amplitude of the oscillatory excursions in voltage, and the optimal way to spread the cost between stimulus and AP generation. In this talk we focus on our model of the neurally-driven electrocyte action potentials (APs) in the innervated posterior membrane that underlie the EOD. Redressing excitability-related Na+ entry constitutes the major ATP-cost for electrocytes and thus for the electric organ. To guide experimental investigation we explored several mechanisms for the generation of the synchronous string of APs. Each scenario has characteristic properties that can be tested experimentally. A highly efficient mechanism involves a tonic subthreshold stimulus mixed with a pulsatile stimulus at the required frequency. This mechanism would reveal a devil’s staircase of responses with steps at periods multiple of the driving frequency and intermediate regions with more complex behavior, if the pulsatile component is insufficient to create a discharge at the required frequency.
        Speaker: Bela Joos (University of Ottawa)
      • 14:30
        The active ear: A ring of fire 15m
        The vertebrate ear both responds to and emits sound. Sounds from the ear, known as otoacoustic emissions (OAEs), provide a means to probe the biophysics of auditory transduction and amplification. Spontaneous emissions (SOAEs) can also be present, appearing as coherent peaks in the spectral domain. Statistical properties of SOAEs, such as the “ring of fire” (observed via a 2-D histogram of the analytic signal of a filtered peak), provide compelling evidence for an "active" ear. Yet the underlying mechanisms are still not well understood. The present study focuses on the lizard ear, a relatively simple case that exhibits robust SOAE. The approach is two-fold. First, we develop a theoretical description that combines active nonlinear oscillators with both local and global coupling. This framework is explored computationally and solved in the time domain. Second, we report recent measurements from lizards that characterize the dynamics of SOAE activity in response to transient external stimuli (e.g., chirps and tone bursts), primarily a depression effect where SOAEs are reduced towards the noise floor. While the model captures some features of the data (e.g., the generation of distinct SOAE spectral peaks) but not others (e.g., SOAE bandwidths and the dynamic range of their response to stimuli), it provides insight into the depression effect. Specifically, SOAEs appear to undergo some combination of entrainment (i.e., synchronization to the external stimulus), suppression (i.e., pushed out of the limit cycle into a quiescent state), or a decoherence (i.e., loss of a clustered group effect that forms a peak).
        Speaker: Christopher Bergevin (York University)
    • 13:15 14:45
      T2-3 Cosmic Frontier: Dark Matter II (PPD) / Frontière cosmique: matière sombre II (PPD) SITE A0150

      SITE A0150

      University of Ottawa

      Convener: Fabrice Retiere (TRIUMF)
      • 13:15
        DEAP-3600 Dark Matter Search with Argon 30m
        The DEAP-3600 experiment will search for dark matter particle interactions on 3.6 tonnes of liquid argon at SNOLAB. The argon is contained in a large ultralow-background acrylic vessel viewed by 255 8-inch photomultiplier tubes. Very good pulse-shape discrimination has been demonstrated for scintillation in argon, and the detector has been designed to allow control of (alpha,n) and external neutron recoils, and surface contamination from 210Pb and radon daughters, allowing an ultimate sensitivity to spin-independent scattering of 10^{-46} cm^{2} per nucleon at 100 GeV mass. The detector is expected to begin collecting low-background data in 2016; the current status of the experiment will be presented.
        Speaker: Prof. Mark Boulay (Carleton University)
      • 13:45
        CDMSlite Run 2 Results 15m
        SuperCDMS searches for dark matter in the form of Weakly Interacting Massive Particles (WIMPs) using germanium detectors operated at a few tens of mK. Particles are detected via the change in resistance of a superconducting transition edge sensor heated by lattice vibrations (phonons) from the interaction. A bias voltage applied across the detector drifts electron-hole pairs produced in an interaction to the electrodes, producing additional phonons (Neganov-Luke effect). The CDMS low ionization threshold experiment (CDMSlite) applies a higher voltage than is normal for these detectors leading to a phonon signal which is strongly dominated by the Neganov-Luke phonons. Through this effect, a much lower energy threshold can be achieved than at lower voltages. Here, we present the results of the second run of CDMSlite which operated at 70 V for 70 kg days and reached a threshold for electron recoils as low of 56 eV. Improvements to the operation of the experiment and the analysis, particularly a fiducial volume cut, allowed for great improvement upon the results from the first CDMSlite run. The fiducial cut is needed because the electric field of this high voltage is distorted at the edges of the detector leading to a reduced Luke amplification at high radius, i.e higher energy backgrounds in this part of the detector fall into the low energy region used for WIMP search.  A radial fiducialization based on a new pulse fitting algorithm was applied to drastically reduce this background. New parameter space for the spin-independent WIMP-nucleon cross section is probed for WIMPs with mass between 1.6 and 5.5 GeV/c$^2$.
        Speaker: Mr Ryan Underwood (Queen's University)
      • 14:00
        Understanding the signal induced within a gaseous spherical detector used by the NEWS experiment 15m
        More than eighty years after its existence was originally postulated, the search for Dark Matter is still ongoing. NEWS is a direct detection experiment that aims to detect WIMPs with a metallic spherical detector with a high voltage electrode in its centre, with gas as its target mass. In the context of the NEWS experiment, our estimators of the energy of events, and their position within the detector, are based on the amplitude and risetime of our signal. We have developed an in-depth understanding of the formation process of our signal, specifically the response function of our physical detector and its electronics. Through a digital deconvolution of this response function, we recover the original electronic signal released by an energy deposition in the target volume. This allows for optimum discrimination between nuclear recoils and other pulses, and improved estimators of the energy and position of events.
        Speaker: Francisco Andres Vazquez de Sola (Queen's University)
      • 14:15
        The PICO 0.1 bubble chamber calibration 15m
        The search for dark matter calls for increasingly sensitive experiments. For several decades now, scientists have built more and more sensitive detectors in the hope to directly detect WIMPs, a type of candidate particles for dark matter. WIMPs should interact with normal matter by elastic scattering with nuclei. Experiments are typically performed underground to shield them from cosmic and atmospheric radiation. However, an important background radiation for dark matter experiments is neutrons present underground, whose response in detectors is indistinguishable form that of a WIMP. The full understanding of the neutrons’ response in dark matter detectors is, therefore, of the utmost importance. The PICO collaboration presently operates two bubble chambers in the SNOLAB underground laboratory in Sudbury, Ontario. An effort is being made by the collaboration towards the understanding of those chambers’ behavior. To this aim, multiple calibration chambers have been built. The PICO 0.1 chamber is operated at the Tandem Van de Graaff facility of the Université de Montréal where a proton beam is used to produce mono-energetic neutrons from the $^{51}V(p,n)^{51}Cr$ reaction. This chamber has shown to be one of the cleanest and most reliable chamber designed by the collaboration, which makes it the perfect detector to perform the neutron calibration. This talk will explain the goal and experimental method of the measurements. Preliminary results of the calibration will also be presented.
        Speaker: Mr Frédéric Girard (Laurentian University)
      • 14:30
        **WITHDRAWN** Characterization and mitigation of particulate sources of backgrounds in the PICO-60 experiment 15m
        The PICO experiment is a dark matter search using superheated liquid C$_3$F$_8$. The experiment operates two bubble chambers, PICO-2L and PICO-60, at the SNOLAB facility 2km underground, and is designed to be most sensitive to spin-carrying dark matter particles with a mass range of 10-10,000 GeV/$c^2$. PICO bubble chambers are threshold detectors that can be operated within a set of conditions where they are insensitive to minimally ionizing particles. Acoustic, pressure and video information is used to discriminate between nuclear recoil events and background alpha events. PICO-60 is presently being upgraded to perform dark matter searches with 60 kg of active liquid at a threshold energy of 3.2 keV. A large fraction of the background events in the previous run of PICO-60 with CF$_3$I exhibited behaviours consistent with particulates in the active volume. In this talk, an overview of the particulate contamination and background events with a possible particulate origin will be presented. The procedure developed to identify the particulates and to characterize them and their sources will be discussed, along with assay results from previous run. Strategies for mitigation of the generation mechanism and modifications to the detector to eliminate the particulate load on the detector in the next run are also presented.
        Speaker: Pitam Mitra (University of Alberta)
    • 13:15 14:45
      T2-4 Ground-based and In Situ Observations II (DASP) / Observations sur terre et in situ II (DPAE) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Martin Connors (Athabasca University)
      • 13:15
        Studying the Lower Thermosphere with Alberta’s First Cube Satellite: Ex-Alta 1 30m
        Ex-Alta 1 is the pioneer cube satellite for the AlbertaSat team at the University of Alberta and will be the first built-in-Alberta satellite. This 3U cube satellite is designed and assembled primarily by volunteer undergraduate students at the U of A, with guidance from several researchers and faculty members. In this way, AlbertaSat offers a unique opportunity to train highly qualified personnel for eventual careers in aerospace. Ex-Alta 1 is one of two Canadian satellites participating in the QB50 mission coordinated by the Von Karman Institute in Brussels, Belgium. It will be deployed from the International Space Station in the autumn of 2016. Thus, its initial orbit will be at an altitude of 400 km and inclination of 52°. Once in orbit, Ex-Alta 1 will study space weather, using a range of scientific instruments, and will act as a qualification opportunity for the first model of a new suite of open source cube satellite subsystems being developed at the University of Alberta. Ex-Alta 1 is equipped with three scientific payloads. The multi-Needle Langmuir Probe (mNLP) experiment, developed at the University of Oslo, will study variations in ion densities. These measurements can be used to better quantify how the Earth’s atmosphere expands and contracts into low Earth orbit. The mNLP will also enable the collection of information to study the effects of re-entry. A Digital Fluxgate Magnetometer (DFGM) developed and built at the U of A will be deployed at the end of a 60 cm boom and will study the Earth’s magnetic field in low Earth orbit. Finally, a radiation dosimeter onboard Ex-Alta 1 will measure variation in radiation levels in low Earth orbit, thus giving insight into average electron and proton flux during the mission. Data generated by Ex-Alta 1 will be curated by teams at the University of Alberta and the Von Karman institute and made available to the scientific community. Ex-Alta 1 will also include the Athena on-board computer. This on-board computer for cube satellites is a fully open source system designed and built by senior undergraduate students at the University of Alberta. It will be tested and qualified on the Ex-Alta 1 mission, and will then form the foundation for future cube satellite projects carried out by the AlbertaSat team.
        Speaker: Mr Charles D. A. Nokes (University of Alberta)
      • 13:45
        Statistical investigation of anisotropic ion temperature enhancements observed by the CASSIOPE/e-POP satellite 15m
        Terrestrial ion outflow and loss to space is the result of acceleration to escape speed of ionospheric ions that normally are strongly bound to earth through gravity. Previous research suggests this acceleration takes place in multiple steps. We investigate low-energy (<10 eV) ion initial energization processes in the topside ionosphere in both hemispheres using data from the SEI, MGF and RRI instruments onboard the CASSIOPE/e-POP satellite. Using the high-frame-rate (100 Hz) two-dimensional ion distribution function data measured by the SEI, we statistically investigate anisotropic ion temperature enhancements, where ion temperatures perpendicular to B rise by more than 0.4 eV relative to the background values while temperatures parallel to B decrease, and study their morphology and Kp dependence. Multiple field-aligned current (FAC) sheets are found to be always associated with these events based on magnetic data from the MGF instrument. For some events, signatures of broad-band extremely low frequency (BBELF) plasma waves, auroral hiss and chorus are detected by the RRI instrument. We study the causal relations between the anisotropic ion temperature increases and the magnitudes of the FACs and the power spectral density (PSD) of plasma waves.
        Speaker: Yangyang Shen (University of Calgary)
      • 14:00
        Field-aligned currents associated with multiple arc systems 15m
        The field-aligned current (FAC) system associated with auroral arcs provides important information regarding the generator responsible for multiple arc systems, and presumably for individual arcs themselves. We have identified two types of FAC configurations in multiple parallel arc systems using ground-based optical data from the Themis all-sky imagers (ASIs), and magnetometers onboard the Swarm satellites during the period from December 2013 to March 2015. The first type represents a collection of multiple up/down current pairs and the other is an arc system within a broad unipolar upward current sheet. We find that (1) events corresponding to the first FAC type are mainly located in the 23-0 MLT sector, and the second type between 20-22 MLT. (2) The average current intensities for upward and downward currents in the first type are similar (~0.16 A/m). However, for the second type, the upward average current intensity (~0.32 A/m) is greater than the downward current (~0.21 A/m). (3) the average current density is larger in the first type for both upward and downward currents, with the latter, however, having a larger average density than the former in both types. (4) upward currents with more arcs embedded have a larger intensity, although the intensity of upward currents and the number of arcs do not show a linear relationship.
        Speaker: Jiashu Wu (University of Calgary)
      • 14:15
        Monitoring HF transmissions with the e-POP RRI instrument on the CASSIOPE Satellite 15m
        The Radio Receiving Instrument (RRI) on e-POP payload of the CASSIOPE satellite has a relatively high sampling rate and orthogonal dipole antennas which permit the observation of continuous wave (CW), pulse and phase coded signals from transmitters on the earth. In this study, high frequency (HF) 13-bit Barker-coded binary phase shifting keying (BPSK) and CW signals are detected from a transmitter in Ottawa during satellite overpasses. The HF signal experiences several of physical effects such as ionospheric delay, Faraday rotation, Doppler shifting and mode splitting during propagation through the ionosphere. Using the BPSK pulses (of 15 msec repetition rate), independent Doppler shift estimates can be rapidly determined using amplitude and phase characteristics of the waves. During the CW transmissions, amplitude variations on the orthogonal dipoles highlight the nature of the wave propagation through the ionosphere in the HF band.
        Speaker: Donald Danskin (Natural Resources Canada)
      • 14:30
        Using the motion of Pulsating Aurora Patches to investigate the change in magnetospheric convection 15m
        Magnetospheric convection, the main process of the acceleration and injection of energetic particles into the magnetosphere, plays an important role in the study of Earth’s magnetosphere. One of our previous studies has compared the motion of Patchy Pulsating Aurora (PPA) patches with the corresponding ionospheric convection inferred from the SuperDARN radar measurements. The result shows that the motion of the PPA patches follows the convection and suggests that the motion of PPA patches could be a great new tool to remote sense the magnetospheric convection with high temporal and spatial resolution. We later have compared the patch velocities with the corresponding magnetospheric convection velocities inferred from the electric field measurements from RBSP. Although the result shows a great consistency between these two velocities, with small values of electric field measurements there might be a great uncertainty introduced into the derivation of convection velocities. In this study, we look into the PPA events with changing velocities and compare their variations with the changes of the corresponding electric field measurements from RBSP. The result not only can show us whether the motion of PPA patches follows the magnetospheric convection but also suggest the variation in convection is due to the change in large-scale or small-scale electric field.
        Speaker: Bing Yang (University of Calgary)
    • 13:15 14:45
      T2-5 Photonics I: Applications (DAMOPC-DPP) / Photonique I : applications (DPAMPC-DPP) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Paul Barclay (University of Calgary)
      • 13:15
        Generation of nonclassical states of light using photonic crystal fibers 30m
        Photonic crystal fibers (PCF) offer unique control of dispersion and nonlinearity and have revolutionized nonlinear optics. We present the possibility to use hollow-core and solid-core PCF for the generation of bright twin beams and photon triplet states. One advantage to use optical fibers is that both signal and idler can be generated in a single spatial mode. By pumping close to the zero dispersion wavelength of the fiber, such sidebands can be created through modulation instability. However, signal and idler appear in the vicinity of the pump and Raman-scattering originated from the pump deteriorates the photon correlation by increasing the background level of photons of the idler. Here we use kagomé-lattice hollow-core PCF filled with argon to generate ultrafast bright twin beams [M.A. Finger *et al*. PRL. **115**, 143602 (2015)]. Since a monatomic gas provides the nonlinearity the source does not suffer from Raman-scattering and sidebands close to the pump are generated. We measure ~35% twin beam squeezing below shot noise. Another unique advantage of this source is the tunability of the sidebands through the gas-filling pressure. Next, we address the challenging problem of generation of triplet states through spontaneous decay of one pump photon propagating in a $\chi^{(3)}$-material. This process is the reverse of third harmonic generation and phase-matching conditions are identical. Due to chromatic dispersion phase-matching cannot occur between two identical modes and this implies for the generation of triplet that the pump light has to be launched in a higher-order mode, leading to a reduced generation efficiency due to mode-mismatch between pump and triplets. Here we propose a hybrid solid-core PCF to circumvent this difficulty. The short-wavelength (~532 nm) is guided in a single-lobe mode by an all-solid photonic bandgap (PBG) while the guidance of the long-wavelengths relies on step-index. The inner PBG consists of a hexagonal array of high-refractive index glass (Schott SF6, n=1.81) embedded in a lower index host (Schott LLF1, n=1.55). The overall dispersion is strongly affected by these two distinct mechanisms and we demonstrated phase-matched third harmonic from fundamental mode at 1521 nm into the “fundamental” bandgap-guided mode ($\lambda$=507 nm), for which the field distribution is very similar to that of the LP01 mode of a step-index but with narrower mode-field diameter [A. Cavanna *et al*., in preparation].
        Speaker: Prof. Nicolas Joly (Max-Planck Institute for the Science of Light)
      • 13:45
        Integrated silicon photonics for quantum communication 30m
        The surging progress in silicon photonics over the past decade has been driven by its potential deployment in low cost, high bandwidth, wavelength-division multiplexed short reach optical interconnections in datacenters. Many device level advances have been made in recent years, and the variety of high quality components that have become available now motivate extending the application of silicon photonic integrated circuits to quantum information. In this talk, I will present my group’s recent work on silicon photonics for quantum communication. I will describe high extinction ratio microring modulators and filters, the first polarization rotator-splitters and controllers in standard silicon photonic platforms, and a prototype of an integrated quantum key distribution transmitter for the BB84 protocol.
        Speaker: Joyce Poon (University of Toronto)
      • 14:15
        Optical decoherence and spectral diffusion in an erbium-doped silica glass fiber featuring long-lived spin sublevels 15m
        Rare-earth-ion (REI) doped materials offer unique spectroscopic properties, such as narrow optical linewidths, or long-lived shelving levels that allow for spectral tailoring of their inhomogeneously broadened absorption lines. Indeed, both these properties are required simultaneously in order to implement many of the potential applications of (REI) doped materials, such as optical quantum memories. REI-doped glasses come with some advantages compared to REI-doped crystal hosts such as a larger inhomogeneous broadening, benefitting large-bandwidth applications, but also disadvantages such as coherence times limited by two level systems. Here, we study the coherence properties of a weakly doped erbium silica glass fiber, motivated by our recent observation of efficient and long-lived Zeeman level storage in this material and due to its potential for applications at telecommunication wavelengths. We present a model describing the magnetic field and temperature dependence of the coherence lifetime and determine the processes limiting the latter in different regimes. Furthermore, we investigate spectral diffusion, and find that it is magnetic field independent over long time scales. We highlight the observation of effective linewidths of the order of 1 MHz at low magnetic fields, where efficient spectral tailoring is possible.
        Speaker: Mr Mohsen Falamarzi Askarani (Department of Physics and Astronomy, University of Calgary)
      • 14:30
        Hollow-core photonic Bragg fiber for bulk and surface sensing applications 15m
        We demonstrate a hollow-core photonic Bragg fiber for bulk and surface sensing applications. The sensor operates on a resonant sensing modality. Variation in the fiber core effective refractive index modifies the bandgap guidance of the fiber, leading to a spectral shift in the fiber transmission spectrum. As a demonstration for the bulk sensing application, we apply the fiber sensor to detect refractive index of analyte filling in the fiber core, a sensitivity of 1500nm/RIU is achieved. As a demonstration for the surface sensing application, we use it to monitor the dissolution dynamic of a thin film coated on the fiber core inner surface, the obtained surface sensitivity is found to be 0.05nm/nm. The proposed sensor presents a ‘one fiber’ solution for both bulk and surface sensing applications, which is promising for the development of a new generation of the fiber-based biosensors.
        Speaker: Jingwen Li (polytechnique de montreal)
    • 13:15 14:45
      T2-6 Condensed Matter Theory (DTP-DCMMP) / Théorie de la matière condensée (DPT-DPMCM) Colonel By D207

      Colonel By D207

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Prof. Pawel Hawrylak (University of Ottawa)
      • 13:15
        Investigations of the Intermolecular Interactions between Organic Conjugated Monomers, and Conjugated Oligomers and Nanotubes Using Dispersion-Corrected DFT 30m
        This talk will focus on discussing and analyzing intermolecular interactions between organic conjugated polymers used in organic light-emitting diodes (OLEDs) and between conjugated oligomers and carbon nanotubes (CNTs) in CNT-oligomer composites. Dispersion-corrected density functional theory will be employed to study these systems. The construction of multilayered OLEDs typically involves extensive experimental searches for the combinations of polymers that give the optimum device performance. As an example, combinations of different fluorene-based conjugated polymers such as alternating triphenylamine-fluorene (TPAF)- and oxadiazole-fluorene (OxF)-based conjugated copolymers were considered as components of multilayered OLEDs. It was found that certain combination gave the best OLED performance. Our results illustrate that the best combination of polymers has monomers that have the closest intermolecular distance and the highest binding energy relative to all the other combinations. Pure CNT and CNT-oligomer/polymer composites have many useful (industry related) properties: ranging from electrical conductivity to superior strength. However the full potential of using CNTs as reinforcements (in say a polymer matrix) has been severely limited because of complications associated with the dispersion of CNTs. CNTs tend to entangle with each other forming materials that have properties that fall short of the expectations. The goal of this work is to identify the type of conjugated oligomers that are best suited for the dispersion of single walled CNT (SWCNT). We investigate the effect of intermolecular interactions on the structure, polarity and energetics of the oligomers in presence of SWCNT.
        Speaker: Jolanta Lagowski (Memorial University of Newfoundland)
      • 13:45
        The phase diagram of the Blume-Capel-Haldane-Ising spin chain 15m
        We consider the one-dimensional spin chain for arbitrary spin s on a periodic chain with N sites, H = \sum_i^N ( a (S_i^z)^2 + b S_i^z S_{i+1}^z ), the generalization of the chain that was studied by Blume and Capel. The Hamiltonian only involves the z component of the spin thus it is essentially an Ising model. The Hamiltonian also figures exactly as the anisotropic term in the famous model studied by Haldane of the large spin Heisenberg spin chain. Therefore we call the model the Blume-Capel-Haldane-Ising model. Although the Hamiltonian is trivially diagonal, it is actually not always obvious which eigenstate is the ground state. In this presentation we establish which state is the ground state for all regions of the parameter space and thus determine the phase diagram of the model. We observe the existence of massless soliton-like excitations and we show that the size of the solitons depends only on the ratio a/b and not on the number of sites N.
        Speaker: Christian Boudreault (Collège militaire royal de Saint-Jean / Université de Montréal)
      • 14:00
        The motion of spherical particles in a simple ratcheting system with AC Fields 15m
        Hanyang Wang, Gary W. Slater University of Ottawa Ratcheting systems make it possible to control the motion of particles in such a way that it becomes possible to separate mixtures of particles on the basis of various physical properties (such as charge, size, shape, etc.). The ratcheting system that we study is a standard microfluidic channel with symmetry breaking obstacles placed periodically. Zero-mean alternating electric fields are found to lead to a net ratcheting motion of the particles, whether the field is applied along the channel's axis or perpendicular to it. The resulting particle velocities depend on the particle's size and charge, thus permitting separation. We show that it is possible to make particles move in opposite directions even though their charge is of the same sign. We then explore the possibility of using rotating electric fields, with and without channel walls. In the absence of walls, i.e. with a two-dimensional distribution of obstacles, we show that it is possible to make different particles move along different directions in the plane.
        Speaker: Hanyang Wang (University of Ottawa)
      • 14:15
        Long-term behaviour of granular chains held between walls is really equilibrium. 15m
        Granular chains have been the focus of a number of studies, in part due to their numerous applications, ranging from shock absorption and vibration reduction to energy localization. Force impulses to an unloaded granular chain result in a propagating solitary wave (SW), analogous to a soliton of the Korteweg-de Vries equation. When SWs collide with a boundary or another SW, secondary solitary waves (SSWs) are produced as grains break contact. A consequence of this process is the transition from a non-ergodic, SW dominant, phase to the stable "quasi-equilibrium" (QEQ) phase, thought to be distinct from true thermodynamic equilibrium due to the absence of equipartitioning of energy. We show that, in the absence of energy dissipation, when granular systems are allowed to evolve to extremely long times, the number of SSWs becomes sufficiently large that the system actually approaches a true equilibrium phase. In this extreme-time limit, energy in fact becomes equipartitioned among all grains, and we illustrate how the specific heat and kinetic energy fluctuations can be predicted by the generalized equipartition theorem, regardless of the degree of the interaction potential. This opens up the possibility that granular systems should be treated by equilibrium statistical mechanics.
        Speaker: Michelle Przedborski (Brock University)
      • 14:30
        Critical noise parameters for fault tolerant quantum computation 15m
        Noise is imminent to a quantum computing process. With the help of quantum error correcting codes, the logical information in a qubit can be preserved by encoding it in a system of several physical qubits and by performing gates in a fault tolerant manner. However, it is crucial to know the noise model affecting the physical qubits, in order to estimate the error on the logical qubit and thereby the overhead required for fault tolerant quantum computation. For some specific types of quantum channels it is easy to identify a parameter of the physical channel that controls the logical error rate. However, for a realistic noise model, it is unclear which of the physical parameters are critical to the logical error rate. In this work, we aim to determine the parameters of a single qubit channel that can tightly bound the logical error rate of the concatenated Steane code. We do not assume any a priori structure for the physical quantum channel, except that it is a completely positive trace preserving (CPTP) map. Our method of estimating the logical error rate differs significantly from the standard and computationally expensive Monte-Carlo sampling of the error distribution. We employ a technique to compute the complete effect of a physical CPTP map, at the logical level, with just one round of error correction. By such numerical simulations on random quantum channels, we have studied the predictive power of several physical noise metrics on the logical error rate, and show that, on their own, none of the natural physical metrics lead to accurate predictions about the logical error rate. We then show how machine learning techniques help us to explore which features of a random quantum channel are important in predicting its effect at the logical level.
        Speaker: Mr Pavithran Iyer (Université de Sherbrooke)
    • 13:15 14:45
      T2-7 Gravity, Astrophysics and Cosmology (DTP) / Gravité, astrophysique et cosmologie (DPT) Colonel By B012

      Colonel By B012

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Svetlana Barkanova (Acadia University)
      • 13:15
        New exact solutions to the Einstein field equations 30m
        We present new classes of exact solutions to the five dimensional Einstein gravity with cosmological constant, coupled to the Maxwell and dilation fields. The theory has two coupling constants for dilation-Maxwell and dilation-cosmological constant terms. The solutions are non-stationary and moreover almost regular everywhere for non-zero coupling constants. The cosmological constant depends on the dilation coupling constant and can take positive, zero or negative values.
        Speaker: Masoud Ghezelbash (University of Saskatchewan)
      • 13:45
        Generating Einstein gravity, cosmological constant and Higgs mass from restricted Weyl invariance 15m
        Recently, it has been pointed out that dimensionless actions in four dimensional curved spacetime possess a symmetry which goes beyond scale invariance but is smaller than full Weyl invariance. This symmetry was dubbed *restricted Weyl invariance*. We show that starting with a restricted Weyl invariant action that includes pure $R^2$ gravity and a Higgs sector with no explicit mass, one can generate the Einstein-Hilbert action with cosmological constant and a Higgs mass. The model also contains an extra massless scalar field which couples to the Higgs field (and gravity). If the coupling of this extra scalar field to the Higgs field is negligibly small, this fixes the coefficient of the nonminimal coupling $R \Phi^2$ between the Higgs field and gravity.
        Speaker: Prof. Ariel Edery (Bishop's University)
      • 14:00
        Relativistic Geoids 15m
        In non-relativistic physics a geoid is a surface of constant gravitational potential. Here I propose, in the context of general relativity, the notion of a geoid -- a surface of constant "gravitational potential". This idea emerges as a specific choice of a previously proposed, more general and operationally useful construction called a quasilocal frame -- that is, a choice of a two-parameter family of timelike worldlines comprising the worldtube boundary of the history of a finite spatial volume. I describe the geometric properties of these geoid quasilocal frames, and construct solutions for them in some simple spacetimes. These results are then compared to their counterparts in Newtonian gravity and compute general relativistic corrections to some measurable geometric quantities. This work may have applications in applied geodesy.
        Speaker: Robert Mann (University of Waterloo)
      • 14:15
        A generalized model of repeated quantum interactions 15m
        We study the different scenarios that repeated quantum interactions between a system S and an ancillary system Sm induces on the former. These latter systems play the role of measurement devices, or meters. Distinct dynamics emerge depending on various limits that can be taken for the ancillae. Of special interest is the case where induced effective interactions between subsystems of a composite system arise due to their repeated interactions with a common set of meters, which we use to investigate the possibility of describing gravity as a classical channel, or in other words, that gravity arises as an effective force that cannot transmit quantum information.
        Speaker: Paulina Corona Ugalde (University of Waterloo)
      • 14:30
        Tunneling decay of false vortices: Gravitational effects 15m
        We consider the decay of vortices trapped in a $U(1)$-breaking false vacuum of a Einstein-Hilbert-Higgs theory in $2 + 1$ dimensions. In the true vacuum, the $U(1)$ symmetry is unbroken. The potential of the model allows the formation of metastable vortex solutions. These vortices contain the true vacuum inside in addition to a unit of magnetic flux and the appropriate topologically nontrivial false vacuum outside. The work presented extends a previous analysis by coupling the vortices to gravity. We employ numerical methods as well as analytic methods using the so-called thin-wall approximation to verify that static metastable vortices remain when gravity is turned on. In the latter case, knowledge of the metric of space-time inside and outside the core of the vortex allows one to use Israel's junction conditions and to study the dynamics of the vortex's radius. We compute an estimate for the tunneling amplitude of the vortex in the semiclassical approximation. This process of tunneling through expansion of a vortex core is of cosmological importance, as it could be much more rapid than the spontaneous decay of the false vacuum.
        Speaker: Éric Dupuis (Université de Montréal)
    • 13:15 14:45
      T2-8 Doing Physics-doing Gender: Should gender issues be of any importance in the physics community? (CEWIP) / Physique et genre : les questions de genre devraient-elles avoir de l'importance dans la communauté de physique? (CEFEP) SITE J0106

      SITE J0106

      University of Ottawa

      Convener: Shohini Ghose (Wilfrid Laurier University)
      • 13:15
        Is “interactive” teaching sufficient to promote conceptual development in physics? 30m

        Over the past few decades, systematic research has shown that many physics students express essentially the same (incorrect) ideas both before and after instruction. It is frequently assumed that these ideas can be identified by research and then addressed through “interactive” teaching approaches such as hands-on activities and small-group collaborative work. In many classrooms, incorrect ideas are elicited, their inadequacy is exposed, and students are guided in reconciling their prior knowledge with the formal concepts of the discipline. Variations of this strategy have proven fruitful in science instruction at all levels from elementary through graduate school. However, this summary greatly over-simplifies the use of students’ ideas as the basis for effective instructional strategies. Examining what students have actually learned after using research-based curriculum is essential for improving the curriculum and validating its effectiveness.

        Speaker: Prof. Paula Heron (University of Washington)
      • 13:45
        Report on the 2016 Canadian Conference for Undergraduate Women in Physics (CCUWiP) and partnership development with the American Physical Society organization 15m
        The third edition of the Canadian Conference for Undergraduate Women in Physics (CCUWiP) series was held at Dalhousie University on 8-10 January 2016. A conference report for this 2016 edition will be presented as well as statistics from the past three editions held in Canada so far. The second part of this talk will present the status of the ongoing work to develop a long-term partnership with the US American Physical Society CUWiP organization.
        Speaker: Brigitte Vachon (McGill University (CA))
      • 14:00
        My research in computational atomic physics 15m

        In atomic physics, the many-body problem is computationally challenging. When theory is well understood, accurate calculations can predict results that may be difficult to measure experimentally. For heavy elements or highly ionized systems, relativistic and quantum electrodynamic effects, not to mention nuclear effects, are less well understood and computation can assess the limitation of theory when results are compared with those from experiment.

        This talk will describe how an honours degree in mathematics and chemistry from the University of British Columbia led to research in computational atomic physics.

        Speaker: Charlotte Froese Fischer (NIST)
      • 14:15
        Advancing Women in Science and Engineering: 2016 Update of the NSERC Chair for Ontario 30m

        Chairholder Catherine Mavriplis will give an overview of the activities of the NSERC / Pratt & Whitney Canada Chair for Women in Science and Engineering for Ontario. As the Chair approaches the end of its term, we'll look back at the impact it has had in several areas including interdisciplinary research in Communications, Education, Sociology and History. Since the Chair program launch, over 5000 people have been engaged in direct programming through 75 events, over 70 Canadian companies have been contacted, 15 Ontario universities have coordinated outreach efforts, a strong online following has been developed (900 Twitter and over 100 LinkedIn followers, 1400 monthly web visitors), and the Chairholder has made 10 media appearances. Learn how you can get involved in this and other regional and national activities.

        Speaker: Prof. Catherine Mavriplis (NSERC - Pratt & Whitney Chair for Women in Science and Engineering, Department of Mechanical Engineering, University of Ottawa)
    • 15:00 15:45
      T-PLEN Bruker BioSpin Plenary Session - Russell Jacobs, Beckman Inst./Caltech / Session plénière Marion 150

      Marion 150

      University of Ottawa

      • 15:00
        Uses and abuses of μMRI and simultaneous μPET/μMRI: A Chemists talks with Physicists about Biology 45m
        Like any technology, μMRI and μPET have appropriate and inappropriate uses. I will discuss why one might bother with either; then cover a range of applications: how 3D atlas of mouse and quail can be created from high resolution MR images; delve into how lesions and brain structure changes in mouse models of multiple sclerosis are amenable to study with MRI; describe how statistical parametric mapping (SPM) of multiple MRI brain scans of transgenic mouse models provide information about neuronal circuitry alterations. Monitoring changes in tumor physiology is an important aspect of both clinical and pre-clinical imaging – ADC, DCE and cell tracking work will be discussed. Recording of μPET and μMR images simultaneously is a recent development with a host of uses and abuses – work in mouse models of atherosclerosis and oncology require the sensitivity of μPET and resolution with anatomical context of μMRI.
        Speaker: Prof. Russell Jacobs (Beckman Institute / Caltech Brain Imaging Center)
    • 15:45 16:15
      Health Break (with exhibitors) / Pause santé (avec exposants) SITE Atrium

      SITE Atrium

      University of Ottawa

    • 16:15 18:00
      T3-1 Hadronic Structure (DNP) / Structure hadronique (DPN) Colonel By B205

      Colonel By B205

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Reiner Kruecken (TRIUMF)
      • 16:15
        DNP Thesis Prize: Probing Trapped Antihydrogen: In situ diagnostics and resonant transitions 30m

        Antihydrogen is the simplest pure anti-atomic system and an excellent candidate to test the symmetry between matter and antimatter. In particular, a precise comparison of the spectrum of anytihydrogen with that of hydrogen would be an excellent test of Charge-Parity-Time symmetry. The ALPHA antihydrogen experiment is able to produce and confine antihydrogen atoms in an Ioffe-Pritchard type magnetic neutral atom trap. Once confined, resonant transitions (eg. positron spin resonance transitions, 1S - 2S transitions) in the anti-atoms can be excited. In order to determine the resonant frequencies, the magnetic field seen by the antihydrogen atoms must be measured. This presents a significant challenge because the nature of the ALPHA apparatus effectively eliminates the possibility to insert magnetic probes into the antihydrogen trapping volume. Furthermore, because of the highly inhomogeneous nature of the magnetic trapping fields, external probes will not be able to measure the relevant magnetic fields.

        To solve this problem ALPHA developed an in situ magnetometry technique based on the cyclotron resonance of an electron plasma in a Penning trap. This technique can measure the local field seen by the antihydrogen atoms and therefore determine the resonant frequency of the desired transition. With this technique ALPHA was able to perform the first ever resonant interaction with antihydrogen atoms by exciting the positron spin flip transition. This talk will present our in situ magnetometry technique, the methods used to excite and identify positron spin flip transitions in antihydrogen, and future spectroscopic measurements being pursued by ALPHA.

        Speaker: Tim Friesen (Aarhus University (DK))
      • 16:45
        Recent developments in characterization of Quark-Gluon Plasma 30m
        For the past two decades, two powerful heavy ion accelerators, the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), have ushered in a new era of high energy nuclear physics. When the temperature reaches above 200 MeV/kB, quarks and gluons are no longer confined inside hadrons. Instead, they form a plasma state. This new state of nuclear matter, Quark-Gluon Plasma (QGP), existed for about a microsecond after the Big-Bang. QGP is about a hundred thousand times hotter than the centre of a star and denser than the core of a neutron star, yet flows more freely than any known fluid. At RHIC and the LHC, collisions of heavy ions now routinely create QGP and the research is entering the precision measurement stage. To understand the properties of QGP, it is essential that we understand the many stages of relativistic heavy ion collisions theoretically which includes understanding the structure of the colliding nuclei, perturbative and non-perturbative QCD, hydrodynamics of QGP, hadronic re-scatterings and electromagnetic radiations in hot medium. In this talk, I will summarized McGill theory group's effort in exploring this extreme state of matter and what we have learned so far of its rich and often surprising properties.
        Speaker: Sangyong Jeon (McGill University)
      • 17:15
        Study the collectivity and electromagnetic emissivity in a small quark-gluon droplet 15m
        Signatures associated with collective behaviour has been observed in the hadronic measurements of high multiplicity proton+lead collisions at the Large Hadron Collider (LHC), as well as in (proton, deuteron, helium-3)+gold collisions at the Relativistic Heavy-Ion Collider (RHIC). To better understand the evolution dynamics and the strongly-coupled properties of the matter created in these small systems, we present a systematic study of the hadronic observables as well as electromagnetic radiation from these collisions using a hydrodynamic framework. The validity of the hydrodynamic description is quantified using the Knudsen and the inverse Reynold's numbers. Quantitative agreement is found between theoretical calculations and existing experimental measurements. Predictions of higher order anisotropic flow coefficients, Hanbury Brown and Twiss (HBT) radii, and signals of thermal photon enhancement are proposed. They can serve as additional signatures to hunt for the existence of a hot quark-gluon plasma (QGP) during the evolution of these small collision systems. Quantitative comparisons with future experimental measurements can further constrain the extraction of the transport properties of the QGP.
        Speaker: Dr Chun Shen (McGill University)
      • 17:30
        Exploring the Electromagnetic Structure of the Charged Pion and Kaon 15m
        In Quantum Chromodynamics (QCD), the elastic form factor of the charged pion is unique in that it can be rigorously calculated perturbatively in the limit of asymptotically large momentum transfer. However, the lack of a "free pion" target makes experimental studies of this quantity challenging, and one must make measurements using the virtual pion cloud of the nucleon via pion electroproduction. The kaon is a similar object, and experimental measurements of the ratio of the kaon and pion form factors versus $Q^2$ are of significant interest. This talk will describe the pion and kaon form factor program at Jefferson Lab, where experiments at 6 GeV have provided precise measurements of the pion form factor at moderate momentum transfers. Upcoming measurements using the upgraded 12 GeV beam and Hall C facilities will allow us to extend these measurements to even larger momentum transfer.
        Speaker: Garth Huber (University of Regina)
      • 17:45
        De-excitation of moderately excited compound nucleus for heavy-ion collisions at intermediate energies 15m
        Heavy-ion collisions at intermediate energies generate emission sources with a large distribution of excitation energies that can reach up to 10 MeV per nucleon. Evaporation models based on Weisskopf and Hauser-Feshback theories are used to de-excite these sources. Parameters used in evaporation models come from low energy experiments and must be extrapolated to de-excite high excitation energy emission sources. A better understanding of the dependence on excitation energy for these parameters is necessary. Fusion reactions give a way to study the de-excitation of emission sources with known excitation energy. The ISAC-II accelerator at TRIUMF was used to accelerate beams of 25Na, 25Mg, 20Ne and 22Ne. Experimental data was collected using the HERACLES multidetector for these reactions: 25Na+12C, 25Mg+12C at 9.2 MeV per nucleon and 20Ne+12C and 22Ne+12C at 11.7 MeV per nucleon. For nuclear reactions in this mass and energy range, reaction mechanisms include binary collisions and fusion-evaporation events. Compound nuclei produced by fusion in these reactions have an excitation energy between 2.5 and 3.3 MeV per nucleon. This excitation energy range is characteristic of emission sources produced at intermediate energies. Experimental data is compared to simulations. Antisymmetrized Molecular Dynamics (AMD) is used to simulate the dynamical phase of the collision and GEMINI++ for the de-excitation. This analysis will constrain the excitation energy dependences in evaporation models.
        Speaker: René Roy (Université Laval)
    • 16:15 17:30
      T3-2 Plasma Physics and Applications (DPP) / Applications et physique des plasmas (DPP) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Lora Ramunno (University of Ottawa)
      • 16:15
        Deflection of laser accelerated protons due to multi-megagauss magnetic fields in high-intensity laser-plasma interactions 15m
        Self-generated magnetic fields are produced in high-intensity laser-plasma experiments from several mechanisms, including relativistic electron currents and misaligned density and temperature gradients (the Biermann Battery effect). Understanding the formation and timescales of these magnetic fields is important in several high energy density regimes ranging from astrophysical jets to the fast ignition approach to laser fusion energy. Here we will present a study of the magnetic fields produced in cylindrical geometry using wire targets (10-25µm in diameter) with the Titan laser (700fs, 50 J) at the Jupiter Laser Facility. The spatial and energy distributions of the laser accelerated protons produced in the interaction are recorded using radiochromatic film (RCF) and Thomson Parabola ion spectrometers, respectively. A cylindrical RCF stack was installed around the wire target which provided a large-angle sampling of the spatial distribution. Two well-defined bands, offset ±8-15° vertically from the laser plane and surrounding the wire azimuthally, are observed for proton energies up to 7.5 MeV. We will show that the two bands observed on the RCF can be attributed to the formation of caustics in linear proton radiography theory whereby the energetic protons are deflected due to the self-generated magnetic fields. Finally, these results will be compared with 2D and 3D Particle-in-cell (PIC) simulations which qualitatively reproduce the observed bands with magnetic fields on the order of 10 MG due to the Biermann Battery effect. *This work was supported by the U.S. DOE Office of Science, Fusion Energy Science under FWP 100182 and by SLAC Laboratory Directed Research and Development. Additional support was provided by LLNL under contract DE-AC52-07NA27344 and the U.S. DOE Office of Science, Fusion Energy Science ACE HEDLP Diagnostics.*
        Speaker: Chandra Curry (SLAC National Accelerator Laboratory/University of Alberta)
      • 16:30
        Low-Frequency to High-Frequency Transition of an Atmospheric Pressure Helium Dielectric Barrier Discharge 15m
        Dielectric barrier discharge is a well-known device for its diffuse discharge capability at atmospheric pressure. In a plane parallel configuration (2 mm gas width) with solid alumina dielectrics on each electrode, a diffuse discharge will occur under proper conditions. It is the case when the driving voltage is a sinusoidal waveform oscillating at 25 kHz and the feed gas is a Penning mixture of helium with ppms of N$_2$. These conditions give rise to a glow discharge (APGD) and is typical of the low-frequency range (LF). In the same conditions, when the driving frequency is oscillating at 13.56 MHz, in the high-frequency range (HF), the discharge is no longer pulsed in nature but rather a continuous plasma fluctuating between two oscillating sheaths. This behavior is typical of capacitively coupled radio-frequency discharge (CCRF) in the $\alpha$ mode. The aim of this paper is to investigate the transition through which the discharge shifts from the LF glow discharge to the HF discharge in the RF-$\alpha$ mode. Phase-locked imaging is used as the main diagnostic. On the one hand, the discharge is no longer in a purely glow discharge mode at frequencies above 100 kHz. On the other hand, above 1 MHz, the plasma is clearly in the RF-$\alpha$ mode when the applied voltage is sufficiently high. In addition, for intermediate frequencies, in the medium frequency range (MF, defined as 0.3-3 MHz), the $\Omega$ mode can be sustained at low applied voltage. This mode, where electron heating in the bulk is the main power transfer mechanism, can only be sustained between 100 kHz and 5 MHz. Electrical measurements indicate that this discharge mode is always sustained at a power density of the order of 0.1 W/cm$^3$. Optical emission spectroscopy is used to compare the discharge modes. While the LF glow discharge and the HF discharge in the RF-$\alpha$ mode display fairly similar spectra, the spectrum of the $\Omega$ mode occurring in the MF range displays strongly different emissions. In fact, the ratio of helium emissions over impurities (mainly OH, N$_2$ and N$_2^+$) is much lower in this latter mode than in the formers. This suggests that the ratio of high-energy electrons over metastable atom density (impurities mainly depend on helium metastable atoms density) is higher in both the LF and HF discharges. In other words, the electron temperature is expected to be significantly lower in the $\Omega$ mode occurring in the MF range.
        Speaker: Jean-Sébastien Boisvert (Université de Montréal)
    • 16:15 17:30
      T3-3 Quantum Computing and Coherent Control (DAMOPC) / Calcul quantique et contrôle cohérent (DPAMPC) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Joyce Poon (University of Toronto)
      • 16:15
        Spins and photons: quantum optics with defect centers in diamond 30m
        Individual defects in crystalline materials can have electronic properties akin to those of isolated trapped atoms or ions. Recently, the nitrogen vacancy center, a type of defect in diamond, has emerged as as a particularly compelling example. Like atoms, these defect centers have spin degrees of freedom and and optical transitions that make them an attractive platform for building quantum information technologies. Their spin states might someday be used to store and manipulate quantum information, with photons connecting individual defects into a useful computational network or secure communication system. This talk will introduce the properties of nitrogen-vacancy defect centers relevant to such a vision, and present some recent results on the path toward creating a high-efficiency spin-photon interface using fiber-based optical microcavities.
        Speaker: Lilian Childress (McGill University)
      • 16:45
        Towards correcting atmospheric turbulence effects via pump beam control in a down conversion process 15m
        Quantum Communication can be done using single photons generated via spontaneous parametric down conversion (SPDC). Since these protocols only use the signals that are collected by the receiver, the system is not as negatively affected by occasional drop outs as compared to classical communication protocols. In order to collect as many photons as possible, it is necessary to have a mechanism to guide them to the receiver. The photon pairs that are created through the process of SPDC conserve their momentum and are therefore spatially correlated. The temporal and spatial modes of the photons can be adjusted according to the specific requirements of a transmission link. The correction for tip/tilt errors in pointing is usually performed on the transmitted beam itself. However, due to the correlations between the pump beam and the down converted photons, it is possible to manipulate the pump beam instead of the transmitted arm to achieve a similar effect. This technique can be very useful for Quantum Communication protocols since interfering with the transmitted arm can cause alterations to the polarisation and other properties and thus destroy the encoding in the photon. By manipulating the pump, the transmitted arm remains untouched but is guided towards the receiver for a higher collection efficiency. We have developed a theoretical model to calculate the effect of varying the pump beam angle into the nonlinear crystal on the signal photon while holding the idler photon in a fixed position. The technique we use to observe these correlations is based on an array of single photon avalanche diodes (SPAD), offering temporal and spatial resolution on a single photon level. Here we investigate the possibility to control the spatial characteristics of one of the down converted photons by altering the direction of the pump beam.
        Speaker: Mr Christopher Pugh (University of Waterloo/Institute for Quantum Computing)
      • 17:00
        The Promise of Quantum Nonlinear Optics 30m
        This presentation first reviews the historical development of the field of nonlinear optics, starting from its inception in 1961. It then reviews some of its more recent developments, including especially how nonlinear optics has become a crucial tool for the developing field of quantum technologies. Fundamental quantum processes enabled by nonlinear optics, such as the creation of squeezed and entangled light states, are reviewed. We then illustrate these concepts by means of specific applications, such as the development of secure communication systems based on the quantum states of light in the form of states that carry orbital angular momentum. Light can carry angular momentum both by means of its spin angular momentum (as manifested for example in circular polarization) and by means of its orbital angular momentum (OAM), whose origin is a helical structure of its wavefront. The orbital angular momentum of light has recently been recognized to constitute a crucial attribute for many photonic technologies, including the trapping and manipulation of small particles and for multiplexing in optical telecommunication. In this presentation we review some of the fundamental properties of OAM including its quantum features such as entanglement. We then go on to describe a secure telecommunication system in which information is encoded in OAM, and which can carry more than one bit of information per photon.
        Speaker: Robert Boyd (University of Ottawa)
    • 16:15 17:30
      T3-4 Quantum Gravity and Quantum Cosmology (DTP) / Gravité quantique et cosmologie quantique (DPT) Colonel By D103

      Colonel By D103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Prof. Ariel Edery (Bishop's University)
      • 16:15
        Cosmology from Quantum Gravity 30m
        I will explain how the large-scale cosmological dynamics can be obtained from the hydrodynamics of condensate states of quantum gravity (to be specific, isotropic group field theory condensate states in the Gross-Pitaevskii approximation). The correct Friedmann equations are recovered in the semi-classical limit for appropriate choices of the parameters in the action for the group field theory, and quantum gravity corrections arise in the high-curvature regime causing a bounce which generically resolves the big-bang and big-crunch singularities.
        Speaker: Edward Wilson-Ewing (Max Planck Institute for Gravitational Physics (Albert Einstein)
      • 16:45
        Basic elements of loop quantum gravity 30m
        The main idea of loop quantum gravity (LQG) is to develop a canonical quantum theory of general relativity (GR). In this talk, I will give a pedagogical account of LQG aimed at physicists who are unfamiliar with the field. The main focus will be on basic elements of the construction and how these relate to more familiar objects in GR and quantum field theory.
        Speaker: Jonathan Ziprick
      • 17:15
        A Non-Local Lorentz-Invariant Quantum Spacetime 15m
        From the EPR paper in 1935, to Bell’s theorem in the 1960s, to Aspect’s EPR experiment in the 1980s and its recent refinements demonstrating km range correlations, it has become increasingly clear that entangled quantum mechanical systems are inherently nonlocal. EPR experiments highlight the theoretical divergence between quantum mechanics (QM) as a theory of matter in need of a theory of spacetime and special relativity (SR), for which the converse is true. Essentially by definition, quantum nonlocality is incompatible with an interpretation of Minkowskian spacetime as a single 4D metric space, in which all relations between points are defined by a metric. *A priori*, one might expect that QFT, as a successful theory incorporating both relativistic and quantum concepts, would provide a conceptual unification of spacetime and quantum theory, but this has not proven to be the case. Also, despite the wide variety of interpretations of quantum mechanics, no consensus ontology has emerged. Quantum nonlocality demands some form of nonlocal spacetime: we consider here a spacetime consisting of multiple coexisting metric spaces. Within any one space its own metric ensures locality, but between spaces no metric is defined, so interactions between points in different spaces are inherently non-local. Following this (while honoring Lorentz invariance), we outline a new proposal in which special relativistic spacetime is reinterpreted as a superposition of multiple 4D spaces. Each space contains unique content, described by a complex-valued density function. By then postulating a coupling between spaces, quantum mechanical features such as non-locality, superposition and wave behavior naturally emerge. Remarkably, Planck’s constant is shown to govern the coupling between spaces, revealing a fundamental interdependence between spacetime and quantum concepts. The resulting picture is of a set of superposed metric spaces tightly coupled by a ‘quantum glue’ in proportion to m/h. We show that this is compatible with existing SR & QM theories, with however momentum as the fundamental physical basis of quantum superposition, and so having significant implications for the quantum ‘measurement problem’. The coexistence of multiple spaces necessitates a redundancy of physical description, providing an explanation for the origin of gauge theories.
        Speaker: Jonathan Sharp (University of Alberta)
    • 16:15 17:30
      T3-5 Cosmic Frontier: Dark Matter III (PPD) / Frontière cosmique: matière sombre III (PPD) Colonel By D207

      Colonel By D207

      University of Ottawa

      • 16:15
        SuperCDMS and CUTE at SNOLAB 15m
        The Super Cryogenic Dark Matter Search (SuperCDMS) experiment uses cryogenic semiconductor detectors to search for Weakly Interacting Massive dark matter Particles (WIMPs). After more than a decade of operations of CDMS and SuperCDMS and a sequence of world leading results, the experimental setup in the Soudan underground laboratory in Minnesota is being decommissioned and SuperCDMS will move to SNOLAB near Sudbury, ON for its next phase. In this talk I will describe the status of the preparations for the construction of the new experimental setup at SNOLAB, as well as the plans for a well shielded Cryogenic Underground TEst facility (CUTE) to be installed at SNOLAB next to SuperCDMS.
        Speaker: Dr Wolfgang Rau (Queen's University)
      • 16:30
        Upgrading the Shield of the GIOVE High-purity Germanium Detector 15m
        The GIOVE (Germanium Inner-Outer Veto) detector is a highly sensitive germanium spectrometer used to screen materials for trace amounts of radioactivity. Material screening is an important aspect of the construction rare-event experiments such as GERDA and XENON, which require extremely low background levels. GIOVE is located at the Max Planck Institute for Nuclear and Particle Physics in Heidelberg, Germany, housed in the lower level laboratory at a depth of 15$\,$m water equivalent. The extensive shield and unique passive-active veto system allows the detector to achieve sub-mBq sensitivities despite its shallow depth. A variety of new shield configurations and materials were investigated to further improve the sensitivity of the detector. Monte Carlo simulations demonstrate that substantial reductions in the neutron and gamma-ray spectrum at the diode may be possible by either rearranging the existing shield layers or making use of new materials tungsten and boron carbide. The results indicate that new materials and construction techniques may allow GIOVE to achieve higher sensitivity levels and suggest potential improvements to current material screening methods available to rare-event experiments.
        Speaker: Jennifer Mauel (Queen's University)
      • 16:45
        The NEWS-SNO project 15m
        The existence of Dark Matter in our Universe is nowadays well established, however, its exact nature still remains unknown. The goal of the NEWS-SNO (New Experiments with Spheres in SNOLAB) project is to search for particle candidates in mass regions not yet accessible by existing experiments. The planned NEWS-SNO detector consists of a spherical TPC (time-projection-chamber) out of ultrapure copper ,filled with up to 10bar of CH4 and He gas mixtures which is read out with one small central sensor set at high voltage. Thanks to the very light nuclear mass of the employed targets as well as its very low energy threshold, the detection of spin-independent interacting WIMPS down to masses of 0.1 GeV/c2 is aimed at. This mass range for Dark Matter particles is motivated in a number of models based on dark sector forces and, e.g., millicharged models. Changing the nature and/or mix of gas, the pressure, the HV, the sensor are knobs that could be used to check a possible dark matter like signal. An overview and status of the planned experiment at SNOLAB and results of the prototype detector SEDINE operated with Neon gas in the Laboratoire Souterrain de Modane underground laboratory in France will be given.
        Speaker: Dr Gilles Gerbier (Queen's University)
      • 17:00
        Spectroscopic and time-resolved measurements of the fluorescence of pyrene at low temperatures for noble liquid particle detectors 15m
        Pyrene is an interesting material because of its wavelength shifting properties. When irradiated with ultraviolet light, pyrene will emit light in the visible wavelengths. This property could be useful for experiments looking to observe scintillation light from noble gases such as argon and neon, which are popular target materials for dark matter direct detection experiments. Noble gases scintillate in the ultraviolet, and wavelength shifting materials are used to generate visible light observable with standard light detectors. These noble gas detectors are usually operated at cryogenic temperatures, so the performance of pyrene as a wavelength shifter at low temperatures is relevant to its use in such experiments. Relatively long fluorescence lifetime of pyrene provides a possibility to use pulse shape discrimination for rejection of backgrounds caused by alpha activity in regions of the detector where light collection is poor. We have studied the light emission of pyrene under ultraviolet light excitation at Queen's University using an optical cryostat down to 3.4 K. The high vapour pressure of pyrene causes thin films to evaporate when exposed to the vacuum required to achieve colder temperatures, so we have developed samples of acrylic with dissolved pyrene to prevent the loss of material. Photomultiplier tubes combined with the multiple photon-counting coincidence (MPCC) method allow us to extract the time structure of pyrene fluorescence in response to nanosecond pulses of vacuum ultraviolet light. We also use a spectrometer to measure the wavelength spectra of the emitted light at multiple temperatures to understand its performance. We present the results of both time-resolved and spectroscopic studies of pyrene dissolved in acrylic at low temperatures, including those of noble liquids.
        Speaker: Michael Clark (Queen's University)
      • 17:15
        X-ray Detectors for the Unique Third Forbidden Decay of Potassium-40 15m
        Enigmatic dark matter is responsible for 26% of the total mass-energy in the known universe. Since 1997, the DAMA/LIBRA experiment has claimed to have the first direct evidence for the observation of dark matter. One major source of background for this experiment is the 40K isotope. The chemical similarity between potassium and sodium is why trace amounts can be found in the NaI scintillators that DAMA/LIBRA uses as detectors. This contamination presents a challenging background that makes any interpretation of the dark matter signal difficult. 40K occurs in potassium (~0.0117%), which is a contaminant even in ultra-pure NaI(Tl). Two decay channels of 40K are of particular consequence. The first is the electron capture (EC*) into an excited state of 40Ar* which quickly de-excites to ground level. This releases a 2.95 keV x-ray or a 2.5 keV auger electron. A 1460 keV gamma ray is released in coincidence. There is also an electron capture (EC) directly to the ground state of 40Ar, which only releases a 2.95 keV x-ray (or 2.5 keV Auger Electron). Both decays contributes to the ~3 keV bump seen in the data by DAMA/LIBRA and are a factor in their extraordinary claim. DAMA/LIBRA is able to remove a fraction of the decays to the excited state by tagging the 1460 keV gammas. However, the branching ratio to the ground state is not known. This branching ratio will help reduce and understand the background in the dark matter signal region of the DAMA/LIBRA experiment. In addition, this will be the first observation of a unique third forbidden decay. We report on the performance of a Large Area Avalanche Photo Diode (LAAPD) for the direct measurement of the low energy x-rays and electrons. By observing multiple sources and x-ray fluorescence the LAAPD can be studied and characterised for the 40K energy range. Their viability for the use in a dedicated measurement of the EC branching ratio will then be determined.
        Speaker: Mr Matthew Stukel (Queens University)
    • 16:15 17:30
      T3-6 Panel Discussion - Women in Physics: What's in it for both men and women? (CEWIP) / Table ronde - Les femmes en physique : qu'en retirent les hommes et les femmes? (CEFEP) Colonel By C03

      Colonel By C03

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON

      Panelists: Svetlana Barkanova (Acadia University), Melanie Campbell (University of Waterloo), Charlotte Froese Fischer (NIST), Adriana Predoi-Cross (University of Lethbridge), and Michael Steinitz (St. Francis Xavier University).

      Convener: Shohini Ghose (Wilfrid Laurier University)
      • 16:15
        Women in Physics: What's in it for both men and women? / Table ronde - Les femmes en physique : qu'en retirent les hommes et les femmes? 1h 15m

        Panelists: Svetlana Barkanova (Acadia University), Melanie Campbell (University of Waterloo), Charlotte Froese Fischer (NIST), Adriana Predoi-Cross (University of Lethbridge), and Michael Steinitz (St. Francis Xavier University).

    • 16:15 17:30
      T3-7 Applied Physics in Non-Academic Environment (DIAP-DIMP) / La physique hors université (DPIA-DPIM) Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Robert Fedosejevs (University of Alberta)
      • 16:15
        Working in an applied R&D center : INO as an example 30m
        INO is an innovation house, it is home to the largest concentration of skill in the applied optics/photonics field and serves clients of all sizes from all parts of Canada and around the world. INO offers a complete range of integrated services to clients of all descriptions in every field of industrial activity. It also possesses a variety of technologies and innovative processes based on a strong IP portfolio. These assets represent unique business opportunities for companies wishing to commercialize them. Innovation is a key word nowadays and requires a good balance between creativity and realism. Being a physicist in a non-academic environment is an interesting challenge. Both the organization and the researcher point-of-view will be presented.
        Speakers: Dr Martin Bolduc (INO, Québec), Dr Pierre Galarneau (INO, Québec)
      • 16:45
        Le physicien et le génie des matériaux - Physicists in Materials Engineering 30m
        The strong basic training of physicists allows them to grasp important scientific and technological issues encountered in materials engineering. Physicists have an understanding of the fundamental mechanisms that govern the behavior and properties of materials while processing and using them in various applications. This understanding enables them to contribute effectively in multidisciplinary R&D teams by bringing a different perspective to their fellow engineers. In this presentation, we will see a series of practical examples of career opportunities facing physicists in the manufacturing industry, national laboratories and engineering departments. Several examples will be drawn from my career conducted in close interaction with Canadian industry over the past 35 years. La formation de base du physicien lui permet de saisir des enjeux scientifiques et technologiques importants rencontrés en génie des matériaux. Il a une compréhension des mécanismes fondamentaux qui régissent le comportement et les propriétés des matériaux lors de leur mise en forme et lors de leur utilisation. Cette compréhension lui permet de contribuer de façon efficace à des équipes multidisciplinaires de recherche et développement en amenant une perspective différente de ses collègues ingénieurs. Dans cette présentation, nous verrons un ensemble d’exemples illustrant de façon pratique les possibilités de carrière du physicien tant au sein de l’industrie manufacturière, de laboratoires nationaux ou de départements de génie. Plusieurs exemples seront tirés de mon parcours professionnel mené en étroite interaction avec l’industrie canadienne au cours des 35 dernières années.
        Speaker: Prof. Christian Moreau (Université Concordia)
      • 17:15
        The Canadian Atmospheric Tomography System (CATS) 15m

        C. Haley1, D. Degenstein2, R. Cooney3, and A. Bourassa2

        1 Honeywell Aerospace
        2 University of Saskatchewan
        3 Canadian Space Agency

        The Canadian Atmospheric Tomography System (CATS) is a UV/visible/near-IR spectrometer designed to measure limb-scattered sunlight to derive vertically-resolved concentrations of O3, NO2, and BrO and aerosol extinction from the Upper Troposphere through the Stratosphere. CATS is a follow-on to the Optical Spectrograph and Infrared Imager System (OSIRIS) instrument currently in operation on the Odin satellite. In addition to monitoring the stratosphere and extending the long time-series provided by OSIRIS, CATS will focus on the study of fine scale phenomena in the Upper Troposphere/Lower Stratosphere (UTLS) region. To accomplish this new goal, the current CATS design incorporates the following modifications over OSIRIS:
        1) Increased spectral range, focussed on an improved aerosol product.
        2) Better spectral resolution, aimed at improved NO2 and BrO data products.
        3) Improved vertical resolution and sampling, important for measurements in the UTLS region.
        4) Better horizontal (along-track) sampling, to allow a tomographic retrieval approach to be used.
        The current status of the CATS instrument design and development will be reviewed, highlighting the changes from the OSIRIS instrument design, the main outstanding technical risks, and the current development activities. Mission implementation options on either a dedicated microsatellite or as a payload on a small satellite will also be presented.

        Speaker: Dr Craig Haley (Honeywell Aerospace)
    • 16:15 17:30
      T3-8 Thin Films I (DSS-DCMMP) / Couches minces I (DSS-DPMCM) SITE J0106

      SITE J0106

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Mark Gallagher (Lakehead University)
      • 16:15
        Epitaxially stabilized thin films of the potentially multiferroic materials ε-Fe2O3 and ε-AlxFe2-xO3. 15m
        ε-Fe2O3 is a metastable intermediate phase of iron (III) oxide, between maghemite (γ-Fe2O3) and hematite (α-Fe2O3). Epsilon ferrite has been investigated essentially because of its ferrimagnetic ordering with a Curie temperature of circa 500 K. However, given its orthorhombic crystal structure that belongs to the non-centrosymmetric and polar space group *Pna21*, it should exhibit ferroelectric behavior along with magnetoelectric coupling of the two orders (potentially making it one of the few room temperature multiferroic materials). Moreover, the material is characterized by strong magnetic anisotropy, resulting in a ferromagnetic resonance (FMR) frequency in the THz range in the absence of magnetic field and at room temperature. This is of particular interest given its potential use in short-range wireless communications (e.g. 60GHz WiFi) and ultrafast computer non-volatile memories. Due to its metastable nature, ε-Fe2O3 needs to be stabilized at room temperature: to date such feature has been obtained mainly by synthesizing it by sol-gel as nanoparticles embedded inside a SiO2 matrix, with the stabilization mechanism being either pressure or size confinement (or both). Recently however, deposition of epitaxial thin films of ε-Fe2O3 on SrTiO3 (111) was demonstrated; in this case the stabilization is thought to be due to both epitaxial strain and interface interaction between the substrate and the film. We report the growth by Pulsed Laser Deposition of epitaxial thin films of ε-Fe2O3 and ε-AlxFe2-xO3 on different single crystal substrates, both oxides (SrTiO3, LaAlO3, LSAT, and YSZ) and non-oxides (single crystal Silicon), and discuss the influence of the chosen substrate and of aluminum doping on the structural, magnetic and dielectric properties. In particular, we focused our attention on the effect of Al inclusion inside the ε-Fe2O3 lattice, which should result (i) in the improvement of the electric properties, given the good ferroelectric properties of the isostructural AlFeO3, and (ii) in a lowering of the FMR frequency due to non-magnetic nature of Al.
        Speaker: Luca Corbellini (Institut National de la Recherche Scientifique, Centre EMT, Varennes)
      • 16:30
        **WITHDRAWN** Neutron Reflectometry: A non-destructive probe for in-situ corrosion monitoring in Cu-Ni (90/10) alloy 15m
        Neutron Reflectometry (NR) is an ideal technique to study chemical reactions at surfaces and interfaces because it is a non-destructive technique which can determine in-situ the chemical profile in a film with nanometre resolution. Therefore, NR can provide information on the metal and oxide layer thickness and the changing interfaces between metal and oxide layer as well as oxide layer and an aqueous environment, thereby investigating the corrosion process on the atomic scale. The Cu-Ni (90/10) alloy is an interesting material from its corrosion resistance property and is being used in many industries including marine and nuclear applications. The accelerated corrosion of this alloy in seawater under certain conditions has been attributed to the breaking and removal of the passive Cu2O/CuO layer. According to this picture, the density of the Cu2O/CuO passive layer, as well as the film thickness, should start changing at the onset of the corrosion process. To date, this phenomenon has not been observed directly and in situ. In this study, we used NR to monitor the surface corrosion to get insight into the passive layer modification during the very early stages of corrosion. We prepared 60 nm thick Cu90Ni10 films on Si wafers using DC magnetron sputtering and exposed them to simulated seawater and to a similar seawater but contaminated with sulphur, and measured neutron reflectivity as a function of time. The first experiment (i.e. without sulphur) showed that the reaction at the surface starts after a few minutes and progresses slowly. In contrast, in sulphur polluted seawater (10 ppm S) the reaction was much faster.
        Speaker: Syed Bukhari (Candian Nuclear Laboratories (CNL))
      • 16:45
        **WITHDRAWN** Growth of Cu-Ni (90/10) films by DC magnetron sputtering 15m
        It is a common fact about alloys that surface chemical composition varies from the bulk in terms of elemental ratio and chemical state of the elements which can affect their material performances. That’s why deposition of alloy films is very challenging. We prepared CuNi (90/10) alloy thin films by D.C. magnetron sputtering on Si(111) substrates and studied the effect of deposition times and sputtering powers on their surface and bulk chemical compositions and microstructures. According to XRD studies, all deposited films were composed of single phase CuNi (90/10) alloy and predominantly (111) textured. Crystallite sizes increased linearly with the increase in deposition times and sputtering powers. SEM studies revealed that sputtering powers have relatively stronger influence on the surface roughness and island formation as compared to the deposition times. Our XPS analysis showed slight Ni enrichment on the surface and presence of Ni2O3 along with NiO strongly which strongly suggested existence of a surface defect in all films. Furthermore, there was a clear evidence of presence of CuO along with Cu2O as Cu2p core level had a strong satellite peak. Neutron Reflectometry measurements, indicated that the film thickness increases linearly both with deposition times and sputtering times.
        Speaker: Dr Syed Bukhari (Canadian Nuclear Laboratories)
      • 17:00
        Plasmonic colouring of noble metals via picosecond laser pulses 15m
        We report the creation of angle independent colors on silver due to plasmonic effects arising from random nanoparticle distributions induced by picosecond laser exposure. The color is determined by the total accumulated fluence on the surface. This is valid for all combinations of laser parameters producing the same total accumulated fluence. Both spectral and extra-spectral colors can be obtained. Finite-difference time-domain computations carried out on a high-performance computing system identify the role of each geometrical parameter leading to understanding of color formation. Absorptive plasmonic resonances in heterogeneous nanoclusters are found to be key in the color formation. We also simultaneously report the angle-independent coloring of pure gold with colors covering the entire spectral and extra-spectral region. To our knowledge this represents a world first in the laser coloring of metals.
        Speaker: Jean-Michel Guay (University of Ottawa)
      • 17:15
        Novel Phases of High-Tc Cuprates in Superoxygenated and Heterostructured Thin Films* 15m
        Thin films of transition-metal oxides, by virtue of their high surface-to-volume ratio, tend to have very different thermodynamic phase stability than in bulk form. When these films are grown epitaxially on perovskite substrates, the heteroepitaxial mismatch can also induce strong interfacial strains resulting in intergrowths of novel lattice defects [1]. We apply these two concepts of nanoscale materials synthesis to the Y-Ba-Cu-O family of cuprates, in an effort to stabilize novel cuprate phases with very high superconducting critical temperature (Tc). Pulsed laser-ablated deposition is used to grow thin layers of YBa2Cu3O7 (YBCO) epitaxially on and between various cubic perovskites, ranging from insulating titanates to half-metallic maganites. The thin films and heterostructures are also subjected to superoxygenation by annealing under 500 atm of O2 pressure. Atomic-scale transmission electron microscopy and electron energy loss spectroscopy revealed unambiguous evidence for three novel phases of Y-Ba-Cu-O in the nominally YBCO layers. These phases are characterized by either triple-CuO chains, BaO layers within double-CuO chains or extra Y-O layers within the CuO2-Y-CuO2 bilayer; their formation can be attributed to the superoxygenation and heteroepitaxial strain. We discuss the likelihood that these novel cuprate phases have enhanced Tc, in light of a recent pump-probe spectroscopy study [2] of YBCO showing pairing enhancement by dynamic increase of the CuO2 bilayer thickness. [1] H. Zhang, N. Gauquelin, G. A. Botton, J. Y.T. Wei, Appl. Phys. Lett. 103, 052606 (2013). [2] W. Hu, S. Kaiser, D. Nicoletti, C. R. Hunt, I. Gierz, M. C. Ho mann, M. Le Tacon, T. Loew, B. Keimer and A. Cavalleri, Nature Materials 13, 705 (2014). *Work supported by NSERC, CFI-OIT, and the Canadian Institute for Advanced Research.
        Speaker: John Wei (University of Toronto)
    • 16:15 17:30
      T3-9 Atmospheric and Space Physics (DASP) / Physique atmosphérique et de l'espace II (DPAE) SITE H0104

      SITE H0104

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: james Drummond (Dalhousie University)
      • 16:15
        New Observation of the Polar Wind in the Topside Ionosphere 15m
        The theoretical prediction of the “classical” polar wind dates back to the works of Banks et al., Lemaire et al., Marubashi, Nishida, and other authors in the late sixties and early seventies. Since then, direct in-situ observations of the polar wind have been made on a number of satellites above the topside ionosphere, notably ISIS-2, Akebono, and DE-1, at altitudes of 1400–50,000 km. In this paper, we present the first in-situ observation of the polar wind inside the topside ionosphere on the Enhanced Polar Outflow Probe (e-POP) down to 600 km, and we compare our low-altitude observation with earlier observations at higher altitudes as well as theoretical predictions.
        Speaker: Andrew Yau (University of Calgary)
      • 16:30
        On the validation of Swarm TII and LP data 15m
        The Thermal Ion Imagers (TII) on the Swarm satellites measure ion distribution functions which carry information about ion temperature in the topside ionosphere. Ion temperature, which is obtained from the second moments of the imaged ion distribution, requires validation. One way to evaluate the accuracy of the TII ion temperature, as well as electron temperatures and densities measured by the Langmuir probes (LP), is to study their consistency with a physics-based model of energy exchange between electrons, ions, and neutrals. We first assess the validity and accuracy of the method of topside ion temperature estimation from the energy balance equation using a physics-based ionosphere model at low and middle latitudes. Next, since the method depends on the LP data, the measurements of electron density and temperature are compared with corresponding measurements from incoherent scatter radars. In addition, the electron density data are compared with those obtained from COSMIC GPS radio occultation globally. Possible adjustments to the data are proposed.
        Speaker: Levan Lomidze (University of Calgary)
      • 16:45
        Dynamic analysis of the polar ionosphere during scintillation: towards an optimization of the detrending frequency 15m
        In the context of scintillation, the chaotic behavior of the ionospheric plasma in the high latitude region is investigated using the GPS (Global Positioning System). The study is carried out with the use of the data from the Canadian High Arctic Ionospheric Network (CHAIN). The L1 GPS signal, sampled at 50 Hz, is characterized and analyzed. The statistical analysis is performed on both components of the signal, namely the amplitude and the phase. The Tsalis entropy is constructed for the signal, and along a multiscale analysis, criteria for the determination of the optimum detrending frequency, delimiting the scintillation components from the background variations, are defined. I will present the method used in this study and discuss the importance of the detrending frequency in the mitigation process of the effect of the ionospheric scintillation on the Global Navigational Satellite System (GNSS).
        Speaker: Hichem Mezaoui (University of New Brunswick)
    • 17:30 18:45
      CAP Past Presidents' Meeting / Réunion des anciens présidents de l'ACP Colonel By B202

      Colonel By B202

      University of Ottawa

      Convener: Robert Fedosejevs (University of Alberta)
    • 17:30 18:45
      Carl Zeiss Canada Student-Industry Meet & Mingle / Session de réseautage industrie-étudiants SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Kirk Michaelian (Natural Resources Canada)
      • 17:30
        A Journey to the Dark Side ... Some alternate uses of your physics degree 30m

        Bio
        Neil Rowlands obtained his B.Sc (Engineering Physics) from the University of Alberta in 1985 and his Ph.D. (Astronomy) from Cornell University in 1991. At Cornell, he participated in the construction and use of infrared instrumentation for the Kuiper Airborne Observatory and the 5m Hale telescope at Mt. Palomar. After post-doctoral fellowships at the Université de Montréal, and at the Canada Centre for Remote Sensing where he worked with infrared instrumentation, he joined CAL Corporation (Ottawa, ON), now Honeywell Aerospace, as an electro-optical engineer. Since 1995 he has been developing space-borne scientific instrumentation for the space physics, atmospheric sciences and astronomy communities. He is currently a Staff Scientist at Honeywell in Ottawa. He has been working on the Canadian contribution to the James Webb Space Telescope (JWST) project, the Fine Guidance Sensor (FGS/NIRISS), since 1997.

        Speaker: Dr Neil Rowlands (Honeywell Aerospace)
    • 17:30 18:45
      Department Leaders Business Meeting / Réunion d'affaires des directeurs de départements Desmarais 12th Floor- 12-102

      Desmarais 12th Floor- 12-102

      University of Ottawa

      Convener: Donna Strickland (University of Waterloo)
    • 19:00 21:30
      CJP Editorial Board Meeting / Réunion du comité de rédaction de la RCP Mamma Teresa Ristorante

      Mamma Teresa Ristorante

      300 Somerset St W, Ottawa, ON K2P 2C2 Phone:+1 613-236-3023 Menu: mammateresa.com
      Convener: Michael O. Steinitz (St. Francis-Xavier University)
    • 19:00 22:00
      DAMOPC Poster Session with beer / Session d'affiches avec bière DPAMPC SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Matt Reid (University of northern british columbia)
      • 19:00
        A Fine Pointing System Suitable for Quantum Communications on a Satellite 2m
        In order to perform quantum key distribution (QKD) to a moving satellite, a fine pointing system is needed to ensure the collection of as many photons as possible. Since QKD only relies on the number of detected photons, any lost signal will not reduce security but will decrease the amount of key generated. A dedicated fine pointing system would help reduce the amount of photons that are lost within the satellite after collection by the primary optics. We have designed a novel fine pointing apparatus, along with the Institute national d’optique and Neptec Design Group, to assist photon coupling into multimode fibres after the photons undergo polarisation analysis on a QKD receiver. This system keeps in mind weight and volume restrictions imposed by future space applications. It also mitigates polarisation error through the design of custom mirror coatings. Pointing accuracy of the APT is sufficient to allow QKD to be performed even with angular disturbances to the receiver telescope and fluctuations of the laser beacon. This presentation will outline the APT design concept, summarize the fine pointing performance of the unit as demonstrated through various laboratory tests, and discuss plans to use the device to perform outdoor QKD trials with receivers aboard trucks, boats or aircraft.
        Speaker: Christopher Pugh (University of Waterloo)
      • 19:02
        On a minimal set of separable measurements for a pure state determination in a two-qubit system. 2m
        **On a minimal set of separable measurements for a pure state determination in a two-qubit system.** I.D. Ivanovic, Department of Physics, Carleton University In this note I will address the problem of minimum set of separable measurements necessary to determine a pure state of a two-qubit system. A set of measurements for a complete state determination of a 2x2 system was given in[1], later it was expanded to arbitrary 2^(⊗n) in [2], and 2x2 was experimentally confirmed in [3]. Besides, a question of determining an unknown pure state was always present, and as recently as this year, it was discussed e.g. in [4] and [5]. In [5] a set of measurements was suggested aiming at determining an unknown pure state P,({P≥0,tr(P)=1,P^2=P }) of a two-qubit system. The set of nine operators allows pure state determination. The set of seven expected values for operators σ_i⊗σ_j ,tr(Pσ_i⊗σ_j ), plus normalization, where σ_i∈{I,σ_x,σ_y,σ_z } are Pauli matrices, { σ_x⊗I,σ_y⊗σ_x ,σ_y⊗σ_y ,σ_y⊗σ_z ,σ_z⊗σ_x ,σ_z⊗σ_y ,σ_z⊗σ_z } does not. It is shown, by construction, that this particular choice of operators is inadequate. Some other possible solutions are discussed. Email: igor@physics.carleton.ca References: [1] I.D. Ivanovic , in CISM Courses and lectures No.294 Proceedings of “Information complexity and control in quantum physics”, Editors Blaquiere et al –Udine,1985, Springer Verlag 1987, p 67-76. [2] W. K. Wooters and B. D. Fields, Ann. Phys (NY) 191 (189) p.363 [3] Adamson R.B.A and A.M. Steinberg arxiv: 0808.0944v4[quant-ph] [4] Chapman R. J. et al arxiv:1602.04194v1[quant-ph] [5] Xian Ma, et al arXiv: 1601.05379v1 [quant-ph]
        Speaker: Dr Igor Ivanovic (Carleton University)
      • 19:04
        Detection of Metastable Particles Using Solid N2 at 10K 2m
        Metastable particles produced in the interaction of electrons of carefully controlled energy with thermal gaseous target beams in a crossed beam set-up have been studied in the energy range from threshold to 300 eV. The e-beam is pulsed and the metastables produced drift to a solid nitrogen detector held at 10 K. Here they transfer their energy to states which radiate. The resultant photons are detected using a photomultiplier-filter combination. Time-of-flight techniques are used to separate these photons from prompt photons produced in the initial electron collision. With N2 as both target and detection matrix, the emission is strongest in the green but still significant in the red spectral region. Excitation functions will be presented together with threshold measurements. These help to identify the metastable states being observed and the excitation mechanisms which are responsible. The authors thank NSERC and CFI, (Canada), for financial support.
        Speaker: Dr Wladek Kedzierski (University of Windsor)
      • 19:06
        Modelling seeded stimulated Brillouin scattering (SBS) and dispersion 2m
        The dominant nonlinear effect within standard telecommunication fibers is stimulated Brillouin scattering (SBS). SBS can grow from a spontaneous process or it can be seeded for applications such as fiber amplifiers or fiber sensors. The spontaneous process occurs when a pump signal is scattered by thermal fluctuations within the fiber, resulting in a frequency downshifted Stokes signal. The seeded process involves injecting the counterpropagating pump and Stokes signals into their respective ends of the fiber and not relying on the random scattering from thermal noise for initiation. In applications that implement a seeded configuration, spontaneous generation is usually irrelevant and therefore SBS occurs primarily when the pump and Stokes overlap and drive stimulated scattering. Numerical models typically only incorporate attenuation and SBS within their equations while neglecting dispersion and other nonlinear effects. Under specific conditions it is possible for both pump and Stokes waves to travel significant distances, during which they may experience dispersion, before overlapping and interacting. We are presenting a hybrid numerical method that separates the propagation and interaction regimes within the fiber. The propagation of the pump and Stokes up to the interaction region is accomplished using a split step method which allows attenuation, dispersion, and nonlinear effects other than SBS to be included. Within the interaction region dispersion, SBS, and other nonlinear effects are evaluated through an implicit Runga-Kutta integration. This method is uniquely suited to evaluate situations with large propagations with relatively short interaction regions, allowing the pump and Stokes pulses to be altered by dispersive effects before coupling and transferring energy through SBS.
        Speaker: Scott Newman (Univeristy of Ottawa)
      • 19:08
        The Effect of Electrolyte Additives on Crystallite Orientation in Galvanic Cu Deposits on ⟨111⟩, ⟨100⟩ and ⟨110⟩ Cu Surfaces 2m
        Copper films for applications in printed circuit boards usually have to be fine-grained to achieve even filling of microvias. When galvanically plating Cu films on roll-annealed Cu substrates, unacceptably large epitaxial crystals were found for certain conditions. Here galvanic Cu films were plated on oriented single-crystal Cu substrates from an additive-free electrolyte and from a commercial electrolyte designed for DC plating. The crystallite distribution in the films was mapped with XRD. For the additive-free bath, the transition to a polycrystalline film occurs more readily on ⟨111⟩ and ⟨100⟩ oriented surfaces, whereas films on ⟨110⟩ substrates are persistently epitaxial. A sequence of recursive twinning steps is the main mechanism for the transition to polycrystalline texture. The bath additives promote fine-grained films and they deliver, for the same plating conditions, remarkably improved results.
        Speaker: Ralf Bruening (Mount Allison University)
      • 19:10
        Peak Intensity and Energy Confinement Enhancement of Airy Bullets 2m
        Over the last few years, Airy beams have attracted an increasing interest due to their peculiar characteristics, such as accelerating propagation trajectories featuring non-dispersion along with self-healing properties. Beside their relevance for fundamental optics research, these beams have found numerous applications in several fields including, among others, the generation of curved plasma channels and optical trapping. An Airy beam propagates following a curved trajectory without diffracting along one or two spatial dimensions. Similarly, an optical pulse featured by an Airy temporal profile is not affected by dispersion during its propagation (i.e. its temporal shape remains unchanged). Thus, by combining such confinements both in time and space, it is possible to generate a 3D-confined accelerating optical beam, which does not diffract/disperse along any coordinate, named Airy Bullet (AB). Herein, we present a numerical study of these AB dynamics, providing a technique capable of optimizing the power features associated to the spatio-temporal confinement of such a bullet. In particular, we show that by reshaping the initial spatio-temporal spectrum of the AB in order to obtain a maximal overlap with the spectral content associated with the main lobe, one is able to readily contain the spatio-temporal expansion of such a bullet.
        Speaker: domenico bongiovanni (INRS)
      • 19:12
        Entangled photon pair source towards quantum spectroscopy 2m
        In nonlinear spectroscopy, measuring weak nonlinear signals generated from feeble signal and probe fields in a nonlinear material can be quite difficult, especially with photosensitive materials. The field of quantum spectroscopy has long theorised applications of photon pairs from Spontaneous Parametric Down-Conversion sources for enhancing two-photon nonlinear spectroscopy through the utilization of quantum properties. Using the high frequency correlations between photons in a pair as well as the tight pair creation times, it has been shown that two-photon frequency conversion processes such as two-photon absorption and sum-frequency generation are linear in input flux rather than quadratic, as with classical laser light. Building off of the established experimental foundation of entangled two-photon absorption and entangled photon pair up-conversion, I present a source of entangled photon pairs based off of periodically-poled magnesium oxide-doped lithium niobate capable of single-photon-level frequency conversion. This source is optimized for high photon fluxes and low chromatic dispersion which can be verified through sum-frequency generation in an identical, second crystal. This is a first step towards demonstrating time-domain quantum spectroscopy in biological media.
        Speaker: Mrs Aimee Gunther (Institute for Quantum Computing, University of Waterloo)
      • 19:14
        3D Printed Hollow-Core Terahertz Optical Waveguides With Hyperuniform Disordered Dielectric Reflectors 2m
        Novel hollow-core THz waveguides featuring hyperuniform disordered reflectors are proposed, fabricated, and characterized. Our main motivation is to explore the possibility of designing hollow core waveguides that feature spectrally broad bandgaps that are potentially superior to those attainable with purely periodic structures. Particularly, we demonstrated theoretically that using resin/air material combination that offers relatively low refractive index contrast of 1.67/1, one can design a hollow core waveguide featuring a 90GHz (~21%) bandgap centered at 0.43THz. In such a waveguide, a highly porous PBG reflector comprised ~113μm radius cylinders connected with ~35μm thick bridges. We then attempted fabrication of such waveguides using 3D stereolithography. The diameter of the resultant waveguides (reflector size) is ~20mm, while the diameter of the hollow core is ~5mm. Due to limitations of 3D printer used in our work, the resolution was limited to 100µm which allowed us to print structures with bridges thicker than 200µm. As we demonstrated both theoretically and experimentally, thicker bridges lead to the overall reduction in the bandgap spectral size. Nevertheless, the fabricated waveguides featured relative wide bandgaps (up to ~15%), and low transmission losses (<0.10cm-1) within their PBGs.
        Speaker: Mr Tian Ma (Ecole Polytechnique de Montreal)
      • 19:16
        Lasing in the nitrogen molecular ion 2m

        Lasing in the nitrogen molecular ion
        Mathew Britton, Patrick Laferriere, Ladan Arissian, Michael Spanner and P. B. Corkum
        Joint Attosecond Science Laboratory, National Research Council and University of Ottawa, Ottawa, Canada

        Intense light-matter interaction beyond a unimolecular limit faces unique challenges. In this regime, light and matter both have a non-negligible effect on each other. It is in this complex environment that lasing has been discovered on a nitrogen molecular ion transition [1].
        We investigate the gain dynamics in nitrogen ions created from a neutral gas by an intense ultrashort laser pulse. To isolate the phenomenon, we use a one atmosphere pure-nitrogen 200 µm thick gas jet in a vacuum chamber. The gain is initiated by an 800 nm pump pulse with intensity in the range of 2-4 x10^14 W/cm^2 and pulse duration of 27 fs. A weak second harmonic probe pulse monitors the time dependence of the gain on the B (v=0) to X (v=0) transition.
        We observe a peak gain of approximately 2 over a distance of about 200 µm and we measure gain as a function of nitrogen concentration, density, and intensity of the pump and probe. While the gain is present immediately (i.e. within the duration of the 27 femtosecond pump pulse) we observe two time-scales of decay: population inversion decay and rotational wave packet decay.

        [1] see for example, G. Point, Y. Liu, Y. Brelet, S. Mitryukovskiy, P. Ding, A. Houard, and A. Mysyrowicz, “Lasing of ambient air with microjoule pulse energy pumped by a multi-terawatt infrared femtosecond laser”, OPTICS LETTERS, 29, 1725, (2014)

        Speakers: Mathew Britton (Joint Attosecond Science Laboratory, National Research Council and University of Ottawa, Ottawa, Canada), Patrick Laferriere (Joint Attosecond Science Laboratory, National Research Council and University of Ottawa, Ottawa, Canada)
      • 19:18
        Experiment friendly entanglement witness for multipartite entanglement in atomic frequency combs 2m

        Atomic frequency comb, an atomic ensemble with comb shaped optical transition, is useful for multimode photonic quantum memory where a photon is absorbed collectively over the teeth of the comb resulting in a multipartite entangled state. The teeth of the comb constitute the individual subsystems participating in the entanglement. Since each tooth of the comb consists of a macroscopic number of atoms (typically several thousand), the atomic frequency comb (AFC) system presents an entirely different class of entangled state, which we call the colossal entangled state, i.e., multipartite entanglement between macroscopic systems.

        In this work we propose an experimentally realizable witness and entanglement measure for the colossal entanglement in the AFC systems which is the entanglement between the teeth of the AFC. The witness is achieved in two steps. First we determine the minimum number of teeth coherently absorbing the photon, i.e., the coherence depth, from the signal to noise ratio of the light coming out of the AFC system. We argue that coherence depth is synonymous to entanglement depth, i.e., the minimum number of provably entangled systems, for the case when exactly one photon is present in the system. However, higher photon number component in the photonic states can cause differences between the coherence depth and the entanglement depth. We rectify this problem by estimating the probabilities P0 of no photon and P1 of having exactly one photon in the AFC system and using the bound on P1 for a given P0 and entanglement depth derived in [Hass et al. 2014]. Our method requires no prior knowledge of the number of teeth and is scalable. Furthermore, the method uses only macroscopic quantities to estimate the entanglement in the system, hence, is a suitable choice for the experimental demonstration of genuine multipartite entanglement. We have numerical and experimental results to support our entanglement witness.

        Speaker: Parisa Zarkeshian (University of Calgary)
      • 19:20
        Field synthesis at 1.8 microns for isolated attosecond pulses 2m

        Attaining an isolated attosecond pulse via high harmonic generation requires a temporal gate that can act within one half cycle of the driving field. Here, we use the interplay of nonlinear optics and spatio-temporal coupling to synthesize a half-cycle pulse. The half cycle pulse is centered at 1.8 microns, the idler of an optical parametric amplifier, and is intense enough to generate isolated attosecond pulses, tuneable over an octave in the extreme ultraviolet. I will also discuss this tool to study attosecond dynamics in the condensed phase.

        Speaker: TJ Hammond (University of Ottawa/NRC)
      • 19:22
        Anomalous magnetic moment (AMM) effect on some $2s^2 2p$ $^2P_{3/2}$ lifetimes 2m

        An experimental lifetime of exceptional accuracy [9.573(4)(5) (stat)(sys)] has been reported by Lapierre et al. [1] for the $2p$ $^2P_{3/2}$ state of Ar$^{13+}$. This result is in good agreement with theory [2] when neglecting the effect of the anomalous magnetic moment (AMM), namely 9.582(2) ms, whereas the lifetime with the AMM correction is 9.538(2) ms, well outside the experimental error bar.

        The theory method used by Tupisyn et al. started with the non-relativistic operator for the line strength of the $2p$ $^2P_{1/2}$ - $^2P_{3/2}$ transition and applied relativistic perturbation theory to the calculation of the lifetime as the inverse of the transition probability between these two fine-structure levels.

        The General Relativistic Atomic Structure Package (GRASP2K) [3] is different. It relies on a variational method for determining wave functions for the initial and final states and then a matrix element for a transition operator which, in the Gordon form, can determine the lifetime both with and without the AMM correction, using the observed transition energy. Our lifetimes, 9.5804(16) ms and 9.536(16) ms, respectively are in excellent agreement with the Tupystin et al. values. In GRASP2K calculations, a check on the accuracy of the wave function is the prediction of the transition energy and this is the basis for our error estimate. Thus the discrepancy with experiment for Ar$^{13+}$ remains unresolved.

        Data will be presented for other ions of the isoelectronic sequence. For K$^{14+}$ a measured value [4] is closer to the value with the AMM correction but the uncertainty in the experimental lifetime is so large that it includes both values.

        REFERENCES

        [1] A. Lapierre et al., Phys, Rev. Letters, 95, 183001 (2005)

        [2] I.I. Tupitsyn et al., Phys. Rev. A, 72, 062503 (2005)

        [3] P. Jonsson et al., Comp. Phys. Commun., 184, 2197 (2013)

        [4] E. Trabert et al., Phys. REv. A, **64"", 034501 (2001)

        Speaker: Charlotte Froese Fischer (NIST)
      • 19:24
        Achieving super-resolution through nonlinear structured illumination 2m

        Conventional imaging systems are limited in their optical resolution by diffraction. Thus, super-resolution techniques are required to overcome this limit. Many super-resolution techniques, such as structured illumination (SIM) [1,2], have been developed. However, these techniques often take advantage of linear optical processes and only a few techniques applicable to nonlinear optical processes exist [3, 4]. Here, we propose a scheme similar traditional SIM compatible with coherent nonlinear processes such as second- and third-harmonic generation and predict a resolution improvement of up to ~4 fold.

        In traditional SIM the resolution is doubled by capturing and utilizing spatial frequencies that would otherwise not be received by the imaging system [1]. This may be further enhanced if the saturable absorption of the fluorescent molecules can be utilized to collect even higher harmonics of the spatial frequencies [5]. Since coherent imaging systems are linear with respect to the electric field, the concepts of structured illumination may be generalized to nonlinear widefield microscopy modalities where field amplitudes instead of field intensities are measured [6]. We show that this is possible through the use of second-harmonic and third-harmonic widefield microscopy and show a resolution improvement of three- and four-fold, respectively. Our results suggest that a spatial resolution smaller than 100 nm may be achievable.

        References:

        1. M.G.L Gustafsson. Journal of microscopy 198, 82-87 (2000).
        2. E. Betzig et al. Science 313, 1642-1645 (2006).
        3. C. Heinrich et al. Applied physics letters. 84, 816-818 (2004).
        4. K.M Hajek et al. Optics express 18, 19263-19272 (2010).
        5. M.G.L Gustafsson. Proceedings of the National Academy of Sciences of the United States of America 102, 13081-13086 (2005).
        6. O. Masihzadeh et al. Optics express 18, 9840-9851 (2010).
        Speaker: Aazad Abbas (University of Ottawa - Quantum Photonics Group)
      • 19:26
        Hyperbolic Metamaterial Nano-Resonators Make Poor Single Photon Sources 2m

        We study field and radiation attributes of photonic nano-resonators composed of alternating metal and dielectric layers, known as hyperbolic metamaterials (HMMs). HMMs offer the ability to confine light in ultra-small volumes and enhance its interaction with matter, thereby increasing the spontaneous emission rates of nearby photon emitters through the Purcell effect. It has been suggested that one of the first applications of HMM nanophotonics is in the domain of single photon sources for use in quantum cryptography and quantum plasmonics. Here we describe the physics of HMM nano-resonators in terms of open cavity resonant modes known as quasinormal modes (QNMs). Using an analytical expansion of the photon Green function in terms of QNMs, we introduce a modelling technique that is orders of magnitude faster that direct dipole solutions of Maxwell's equations and offers considerable insight into the HMM coupling effects. We show how coupling to HMM nano-resonators can substantially increase spontaneous emission rates of quantum emitters by an order of magnitude more than pure metal resonators. However, in contrast to recent claims, we also show that most of this emission increase is lost to Ohmic heating. We demonstrate that, counter-intuitively, less metal present in the HMM resonator results in larger non-radiative losses. Using our semi-analytical QNM theory, we describe how this increase in photon quenching originates from an increased overlap between the metal and dielectric, which allows fields to leak or tunnel into the lossy metallic regions. We thus conclude that HMM nano-resonators likely make poor single photon sources, and that pure metallic resonators are preferred for single photon applications.

        Speaker: Simon Axelrod (Queen's University)
      • 19:28
        Generation of vortex beam superpositions using angular gratings 2m

        Vortex beams form a class of beams carrying orbital angular momentum (OAM). A single photon carries OAM where l represents the OAM state and a beam with non-zero OAM state has a zero intensity at its centre and a helical phase wavefront.

        Vortex beams have gained interest for their applications in optical manipulation, optical communication and quantum information [1-3]. In particular, they can enhance communication security by improving the quantum key distribution (QKD) procedure [4]. The original proposal uses the photon polarization degree of freedom, resulting in each photon carrying a single bit. Since OAM states are unbounded and mutually orthogonal, using instead the OAM degree of freedom as a basis enables far greater channel capacity. As QKD requires superpositions of states, this improved version of QKD requires superpositions of different OAM values.

        There are many ways to generate vortex beams with bulk optics, such as spiral phase plates, spatial light modulators, q-plates and cylindrical lens mode converters [5-8]. However, an integrated photonic approach has advantages over bulk optics because of its scalability, stability and small size. It turns out that ring resonators with lateral grating elements, called angular gratings, radiates a vortex above the structure when on resonance [9,10]. To generate a superposition of vortex beams, we expand this idea to a single ring with two sets of gratings, one on the inside wall and one on the outside. We then show with simulations that, after post-selecting on one of the circular polarizations, we can generate OAM superposition states based on the number of grating elements for each grating.

        1. J. E. Curtis, D. G. Grier Phys. Rev. Lett. 90, 133901 (2003).
        2. G. Gibson et al. Optics Express 12, 5448-5456 (2004).
        3. R. W. Boyd et al. Proc. Of SPIE, 7948, 79480L (2011).
        4. A. Mair et al. Nature 412, 313-316 (2001).
        5. M. W. Beijersbergen et al. Opt. Commun. 112, 321 (1994).
        6. V. Y. Bazhenov et al. J. Mod. Opt. 39, 985 (1992).
        7. L. Marrucci et al. Phys. Rev. Lett. 96, 163905 (2006).
        8. L. Allen et al. Phys. Rev. A 45, 8185 (1992)
        9. Y. F. Yu et al. Optics Express 18, 21651-21662 (2010).
        10. X. Cai et al. Science 338, 363-366 (2012).
        Speaker: Ms Marie-Claude Dicaire (University of Ottawa)
    • 19:00 22:00
      DASP Poster Session with beer / Session d'affiches avec bière DPAE SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Prof. Richard Marchand (University of Alberta)
      • 19:02
        Miniature Plasma Imager: A new tool for in situ ionospheric and auroral investigations from nanosatellites 2m
        Development has commenced at the University of Calgary on a prototype next-generation ion imager called the Miniature Plasma Imager (MPI). The work is being performed under contract to the Canadian Space Agency as part of its Space Technology Development Program. The Miniature Plasma Imager is designed to be an smaller Thermal Ion Imager, which is the sensor used on the Swarm Electric Field Instrument to measure ion drift and temperature in the F region ionosphere. Having similar ion focusing optics, MPI replaces the high-voltage (5 kV to 8 kV) TII electro-optical detector with an ion-sensing IonCCD(TM) running at 24 V. We present an overview of the new instrument, describe its anticipated measurement performance (velocity resolution and accuracy), and discuss its application to multi-point ionospheric and auroral physics studies using nanosatellite (<10 kg) orbital platforms.
        Speaker: Johnathan Burchill (University of Calgary)
    • 19:00 22:00
      DCMMP Poster Session with beer / Session d'affiches, avec bière DPMCM SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Giovanni Fanchini (The University of Western Ontario)
      • 19:00
        Structure and Dynamics with Ultrafast Electron Microscopes: Watching nano-microstructural evolution during complex crystallization in a-Ge 2m
        The crystallization of amorphous semiconductors is a strongly exothermic process. Once initiated, the release of latent heat can be sufficient to drive a self-sustaining crystallization front through the material in a manner that has been described as explosive. Using Dynamic Transmission Electron Microscope (DTEM), we have obtained time-resolved snap shots of three distinct microstructural zones as they are formed following pulsed laser excitation. This allows the direct observation of a rich variety of physical processes occurring at nanosecond time scales, including nanocrystallite nucelation and grain growth, crystallization front faceting and self-diffusion at the interface as well as the onset of complex layered microstructure far from initially illuminated zone. This work reveals new insights into the mechanisms governing this complex crystallization process and provides a dramatic demonstration of the power of DETM for studying time-dependent material processes far from equilibrium.
        Speaker: Mark Stern (McGill University)
      • 19:02
        Photoinduced phase transition in vanadium dioxide: visualizing the time-dependent crystal potential using ultrafast electron diffraction data 2m
        Vanadium dioxide is notable for exhibiting several low-temperature insulating phases and having a very well studied insulator-metal transition at ~68$^{\circ}C$ that is associated with a crystallographic change from monoclinic semiconductor to rutile metal. Using a combination of ultrafast electron diffraction (UED) and broadband spectroscopy, we have recently demonstrated that photoexcitation of monoclinic vanadium dioxide crystals below a threshold fluence induces a transition to a metastable state with monoclinic crystallography, but metal-like optical/electronic properties. This long-lived metallic phase appears to have no equilibrium analog. A detailed structural characterization of this phase, using a 3D visualization of electron scattering potential, is the subject of this poster. This visualization techniques confirms previous suspicions and offers more dynamical information than radial pair-correlation functions.
        Speaker: Laurent René de Cotret (McGill University)
      • 19:04
        A Phononic Crystal Waveguide for Surface Acoustic Waves 2m
        Surface acoustic waves (SAWs) on semiconductors, such as gallium arsenide (GaAs), are able to control quantum processes. SAW devices are augmented with phononic crystal waveguides to have fine control of the acoustic path. A phononic crystal in a GaAs substrate is produced by wet etching a square lattice array of void inclusions with an L1 defect. GaAs by its piezoelectricity, is suited for SAW generation via interdigitated transducers (IDTs). Initially, an IDT design must allow for determination of the phononic crystal mode frequency which is difficult to predict exactly. IDTs with uniform adjacent electrode overlap produce a narrow SAW bandwidth, which is even narrower with additional electrodes. Such low bandwidth is not practical for probing the mode frequency since it is unlikely to coincide. However, adjacent electrode overlap and a large number of electrodes are necessary to achieve appreciable SAW amplitude on GaAs; hence an optimized IDT is necessary for sufficient bandwidth and amplitude. Apodized IDTs with varying electrode overlap are developed for large SAW bandwidth and amplitude to probe the waveguide mode frequency. Once the mode is determined, focusing, narrowband IDTs on GaAs are then utilized for high power excitation of the phononic crystal mode frequency. The SAW vertical displacement amplitude is measured with surface scanning Sagnac interferometry as the SAW interacts with the phononic crystal. Spatial and frequency mapping of the SAW vertical displacement amplitude is analyzed to determine transmission and modal qualities of the phononic crystal waveguide.
        Speaker: Mr Edward Muzar (Queen's University)
      • 19:06
        Phonon Dynamics of Lead Scandium Tantalate 2m
        Brillouin light scattering experiments were performed on lead scandium tantalate ceramics using a 180˚ backscattering geometry. Spectral peaks due to longitudinal bulk acoustic modes were observed and their frequencies were used to determine the corresponding phonon velocities and elastic constant c¬11. Temperature dependence of longitudinal bulk mode frequencies, and subsequently velocities, was characterized in the high temperature regime. Experiments performed on a sample of lead scandium tantalate ceramic coated with a thin film of aluminium failed to yield Brillouin peaks due to surface acoustic modes. Complementary Raman scattering experiments were performed on lead scandium tantalate at room temperature and high temperatures.
        Speaker: Mr Stephen Spencer (Memorial University of Newfoundland)
      • 19:08
        Monte Carlo studies of the pseudogap regime in the cuprate superconductors 2m
        We present a theory that describes the pseudogap regime of the hole-doped cuprate superconductors by incorporating the competing effects of superconducting and charge density wave orders into six-dimensional degrees of freedom on a two-dimensional lattice [Science 343, 1336 (2014)]. Using Monte Carlo simulations, we calculate the charge order correlations and diamagnetic susceptibility [PRB 90, 094515 (2014)] associated with this O(6) model. We demonstrate that the structure factors calculated using our theory agree qualitatively with recent X-ray scattering experiments on hole-doped YBa$_2$Cu$_3$O$_{6+x}$ for a wide range of temperatures about the superconducting transition. We also study the effects of incorporating into our model interlayer coupling and disorder [PRB 92, 174505 (2015)]. In the presence of disorder, we find that our theory can reproduce experimental structure factors in the zero temperature limit.
        Speaker: Lauren Hayward Sierens (University of Waterloo)
      • 19:12
        Intrinsic instability of metal-trihalide perovskite solar cell 2m
        Metal-trihalide perovskite is a new promising third generation active material for solar cell applications. The material is crystallized in a perovskite structure ABX3, where A is an organic cation (e.g. formamidinium), B is the metal cation (lead) and X is the halide anion (iodine). Perovskites exhibit the power conversion efficiency, which is comparable to silicon photovoltaic devices. Perovskite material can be synthesized using low-temperature and low-cost method, combined with the ability to be made flexible, tunable band gap, broad range of absorption spectrum, and high carrier mobility required for solar cells. Although the properties are promising, there are challenges to overcome before perovskite solar cells can be viewed as a competitor to silicon technology. It is commonly assumed that the reaction with water or oxygen in the external environment leads to a poor stability of hybrid halide materials. Its instability appears like a spontaneous phase separation into the formamidinium iodide and lead(II) iodide. Here, we aim to use first-principles calculations to capture energies of the material degradation. Our calculations suggest that the decomposition is exothermic, independent of the water or oxygen in the external environment. It means that the poor chemical stability is intrinsic to metal-trihalide perovskite structure. Now we are working on understanding of the instability mechanism in virtue of electrostatic potential energy of the metal-trihalide perovskite structure. The result will guide the search for materials with improved stability.
        Speaker: Mr Chao Zheng (McMaster University)
      • 19:14
        Electron Localization in Group III-V Semiconductor Compound Alloys 2m
        We explore the band structures of new III-V material zinc blende alloys composed of B, N, Ga, As, In, Sb, and Bi for 1.55 μm wavelength telecommunication lasers and their corresponding electron localization at atomic sites from first principles. Engineering III-V semiconductors by mixing modifies their electronic properties including band gaps and lattice constants that are typically a blend of the original compounds and elements. Isoelectronic elements often result in undesirable effects. Electron localization in the vicinity of band edges affects the efficiency of carrier transport and recombination in lasers and solar cells. A new method has been developed to determine the electron localization from muffin tin radii (atomic sites) using the scheme of outlier detection with quartiles of electron probabilities. The advantage of this method is the ability to distinguish a strongly localized electron within the atomic muffin tin radius from a baseline of delocalized electrons. Comparing the results with the unfolded band structures’ Bloch character; the outlier method is in general agreement. The industry standard of InGaAs for 1.55 μm is shown to have the least amount of localized electronic states near the band edges. Alternatively, we find that the electron localization is increased, noticeably with the addition of B and Bi, which affects both radiative and non-radiative recombination rates. To accommodate future Group III-V semiconductor band engineering, we suggest design criteria to facilitate the prediction of localization in new alloys.
        Speaker: Christopher Pashartis (McMaster)
      • 19:16
        Real-space renormalization group approach to the Anderson model 2m
        Real-space renormalization group approach to the Anderson model Many of the most interesting electronic behaviors currently being studied are associated with strong correlations. In addition, many of these materials are disordered either intrinsically or due to doping. Solving interacting systems exactly is extremely computationally expensive, and moreover approximate techniques developed for strongly correlated systems do not adapt to the inclusion of disorder easily. However a real-space renormalization group (RSRG) approach seems ideally suited for strongly disordered systems. While this approach has been successfully applied to many systems, few applications have been specific to the Anderson model. We present a RSRG study of the Anderson model, benchmarking density of states and inverse participation ratio results against exact diagonalization. Our approach points to the possibility of a RSRG approach to strongly disordered and interacting systems of significantly greater size than currently possible with exact diagonalization
        Speaker: Eamonn Campbell (Trent University)
      • 19:18
        Is SmB6 the topological insulator or not ? 2m
        We theoretically examined whether samarium hexaboride (SmB$_6$) is topological insulator, or not. Despite the fact that the SmB$_6$ has long been known as a topological Kondo insulator, with strong correlations and band hybridization, it is still of a great interest because of low-temperature transport anomalies which have recently been interpreted as evidence that SmB$_6 $ is a topological insulator. SmB$_6 $ behaves electronically at high temperatures like an insulator, and at low temperature its resistance mysteriously saturates. We studies de Haas van-Alphen quantum oscillation results to resolve the Fermi surface topology in this material. Although dHvA measurement may be consistent with two-dimensional conducting electronic states, we find an elongated 3D ellipsoidal Fermi surface . Furthermore, resistance measurement also can give some evidence of SmB$_6$ topological surface states, by study different geometries to determine whether the conduction is dominated by the surface or the bulk. Another measurement is Scanning Tunneling Microscopy (STM) which use to discover the properties of the surface states with atomic spatial resolution.Finally, Angle-resolved photo-emission spectroscopy (ARPES), is another useful surface state probe directly the electronic structure of the (SmB$_6$).
        Speaker: Mrs Khawla Elfied (Memorial University of Newfoundland)
      • 19:20
        Indirect internuclear coupling in topological insulator Bi2Se3 2m
        Topological insulators constitute a new class of material with an energy gap in the bulk and unusual metallic states on the surface. To date, most experiments have focused on probing the surface properties of these materials and suppressing the often inevitable contribution from bulk states. However, the bulk states in topological materials are of interest on their own and contain useful information that can be extracted with a local probe like nuclear magnetic resonance (NMR). Recently, 77Se NMR experiments on Bi2Se3 single crystals have reported unusual field-independent linewidths and short spin-echo decays [1]. It is likely that an unexpectedly strong indirect internuclear coupling, characteristic of inverted band structures in topological materials, is the probable cause of these peculiar results. The main objective of our research project is to provide a theory that explains the experiment of Ref. [1]. Starting from a microscopic tight-binding model for Bi2Se3, we calculate the Ruderman-Kittel-Kasuya-Yoshida (RKKY) and Bloembergen-Rowland (BR) couplings between nuclear spins, as well as the T1 relaxation time. We will compare our results to the experimentally available data. [1] N. Georgieva, D. Rybicki, R. Guhne, G. Williams, S. Chong, I. Garate and J. Haase (arXiv: 1511.01727; manuscript submitted).
        Speaker: Chloé Gauvin-Ndiaye (Université de Sherbrooke)
      • 19:22
        Can gravity stabilize a topological quantum memory at finite temperature? 2m
        We study the existence of stable topological quantum memory at finite temperature. This aids in tackling the fundamental problematic of storing quantum information for macroscopically significant times without the use of external intervention in the form of error correction. It has been argued before that a gravitational attraction could confine the anyonic excitations in a topological material, thus preventing them from altering the topological information stored in the system. This idea has led Hamma et al. (2009) to propose a model in which the toric code qubits are coupled to a bosonic bath materializing the gravitational force. Although this confinement is well established for ordinary matter, it has not been observed before for Z2-type excitations, i.e., particles whose mass is preserved only modulo 2. We study this question using numerical simulations wich are performed on a continuous lattice in which the thermal processes were limited to creation, annihilation, and diffusion, with the latter being constrained by an additional energy cost. While preliminary data does not indicate the presence of a defect density threshold in the topological phase below which open strings are confined and the topological order remains intact, our results do not dismiss its existence conclusively and warrant further inquiry.
        Speaker: Thomas Gobeil (University of Sherbrooke)
      • 19:24
        Quantum Model for Machine Learning Applications 2m
        The field of machine learning has been revolutionized by the recent improvements in the training of deep networks. Their architecture is based on a set of stacked layers of simpler modules. One of the most successful building blocks, known as a restricted Boltzmann machine, is an energetic model based on the classical Ising Hamiltonian. In our work, we investigate the benefits of quantum effects on the learning capacity of Boltzmann machines by extending its underlying Hamiltonian with a transverse field. For this purpose, we employ exact and stochastic training procedures on data sets with physical origins.
        Speaker: Bohdan Kulchytskyy (University of Waterloo)
      • 19:26
        Hydrogen storage properties of TiFe + x%ZrMn2 (x = 2, 4, 8, 12) alloys 2m
        Hydrogen is considered to be a good candidate to replace oil as an energy vector for mobile and stationary applications. Presently, the main ways to store hydrogen are in the liquid form at very low temperature or in gaseous state in high pressure tanks. However, these two techniques have serious limitations due to the low temperature and high pressure involved. There is thus the need to develop other means of hydrogen storage. Metal hydrides are considered to be good candidates to replace liquid and gaseous storage in many applications because the hydrogen could be stored in a compact way at low temperature and pressure. In a metal hydride the hydrogen is chemically bonded to metal atoms. We present here the effects of ZrMn2 on hydrogen storage properties of TiFe alloys prepared by arc melting. Compositions of the form TiFe+x%ZrMn2 (x = 2, 4, 8, 12) were studied. Each alloy is made of two phases: a primary phase with small amount of zirconium and manganese, and a secondary phase which has a higher proportion of zirconium and manganese than the primary phase. For both primary and secondary phases, when x increases there is substitution of iron by manganese and zirconium. We found that when x increases, the first hydrogenation is much faster and the alloy is getting more stable. Moreover, for x = 12, air exposure had a minimal impact on hydrogen sorption behavior. We can conclude that addition of ZrMn2 to TiFe greatly improves the first hydrogenation kinetics and improves the air resistance of the alloy.
        Speaker: PENG LV (UQTR)
      • 19:30
        Investigation of effect of ball milling on hydrogen storage properties of 52Ti-12V-36Cr. 2m
        Hydrogen is a promising renewable energy vector that could be used in chemistry or to produce electricity via a fuel cell. Hydrogen can be stored in various forms such as gaseous, liquid, and metal hydrides. Metal hydrides are particularly attractive because of their low operation pressure and high volumetric capacities. In this communication we report the effect of ball milling on the hydrogen storage properties of a titanium based alloy having a body centred cubic (BCC) crystal structure. It is known that Ti-V-Cr based BCC solid solutions alloys are performing well at room temperature and atmospheric pressure. But one problem is the slow first hydrogenation. However, the first hydrogenation can be improved by high energy ball milling. In the present investigation, a BCC alloy of composition 52Ti-12V-36Cr was synthesized by arc melting and afterward subjected to high energy milling for various durations (15 min, 30 min, 1 hr, 2 hrs, 5 hrs, 10 hrs, and 20 hrs). The microstructure was studied by scanning electron microscopy (SEM) and composition of the various phases measured by Energy-dispersive X-ray spectroscopy (EDX). The crystal structure was investigated by X-ray diffraction. The activation and hydrogen storage properties were measured using a homemade hydrogen titration system. The correlation between milling time and hydrogen storage properties will be reported.
        Speaker: Mr Amol Kamble (Queen Elizabeth Scholar, UQTR)
      • 19:32
        Hydrogen storage properties of TiFe + Zr alloys 2m
        Economic and environmental considerations are pushing the society to replace oil by renewable energies. In this perspective, hydrogen is considered to be a good candidate as an energy vector for mobile and stationary applications. The conventional ways to store hydrogen are in the liquid form at very low temperature or in gaseous state in high pressure tanks. However, these two techniques have serious limitations due to the low temperature and high pressure involved. There is thus the need to develop other means of hydrogen storage. One good candidate is metal hydride where the hydrogen is chemically bonded to metal atoms.In metal hydrides the hydrogen could be stored in a compact way at low temperature and pressure thus making this technique particularly safe. However, in order to be used commercially, the cost of metal hydrides has to be reduced. The aim of this study is to understand the comparative effect of Zr and V on hydrogenation characteristics of TiFe alloy, using industrial grade Fe (ASTM 10005) and Ti (ASTM B265 grade 1) as a raw material. Materials were synthesized by arc melting and studied without further heat treatments. X-ray diffraction patterns were taken to find out the crystal structures of pure TiFe and doped TiFe alloys. Morphology and compositional analysis were studied by Scanning electron microscopy (SEM) image and energy dispersive x-ray spectroscopy (EDX).We found that TiFe alloy doped with 4 wt% of Zr leads to a remarkable improvement of the first hydrogenation behavior of TiFe alloy.
        Speaker: Mr Abhishek Kumar Patel (UQTR)
      • 19:34
        Investigation of Entropy-Enthalpy Compensation Effect on the Ti-V-Cr system 2m
        Hydrogen has attracted a permanent interest as a future energy carrier because of its high ignition power and pollution free nature. One problem facing the widespread of hydrogen as an energy carrier is storage. Presently the main ways to store hydrogen are in liquid form or as a high pressure gas. Both techniques have their drawbacks and new ways to store hydrogen at room temperature and low pressure should be found. One possible candidate is to store hydrogen in metal hydrides where hydrogen is chemically bonded to the metal atoms. Among various materials body centered cubic (BCC) solid solutions and alloys are found very promising due to their high volumetric storage capacity and relatively high gravimetric capacity. We have recently found that in Ti-V-Cr BCC solid solutions the enthalpy of hydrogenation is linearly related to the entropy change. This is the so-called enthalpy-entropy compensation. The aim of the present work is to investigate the entropy-enthalpy compensation effect by varying the elemental concentration of the Ti-V-Cr system. For this purpose, sample with different elemental concentration doped with 4wt.% of Zr7Ni10 have been synthesized by arc melting. The XRD patterns of as-cast samples confirm their BCC crystal structure. Lattice parameter and crystallite size were calculated by Rietveld analysis and hydrogenation studies were carried-out using a home-made hydrogen titration system. We found that for compositions Ti60V3Cr37, Ti52V12Cr36, Ti48V15Cr37, Ti42V21Cr37, and Ti33V30Cr37 the entropies and enthalpies are linearly correlated. The slope (Compensation temperature) was calculated to be 617 K. Possible explanations of this phenomenon will be discussed.
        Speaker: Ms Viney Dixit (UQTR)
      • 19:36
        **WITHDRAWN** Study of Mesoporous Silica Hybrid Nanoparticles and their Biocompatibility 2m
        Mesoporous silica nanoparticles (MSNs) have attracted a lot of attention recently due to their versatile applications in biomedical field. The origin of this is related to the nature of nanometer size pores which create a huge surface area to harbor drug molecules and act as potential carriers in biological systems. The charged surface of MSNs is also highly instrumental in inviting the other inorganic or organic species to produce inorganic – or organic – silica hybrid nanomaterials with even better drug delivery functionalities than MSNs. In the present work we have synthesized hybrid MSN with incorporation of Au and Ag nanoparticles and investigated their structure and properties using microscopy and dynamic light scattering. Biocompatibility of the hybrid nanoparticles has been investigated by performing hemolysis.
        Speakers: Dr Gurinder Kaur Ahluwalia (College of The North Atlantic), Dr Mandeep Singh Bakshi (Wlfred laurier University)
      • 19:38
        A Computational Analysis of the Application of Skewness and Kurtosis to Corrugated and Abraded Surfaces 2m
        In this poster, we describe the results of our investigation into the relevance of skewness and kurtosis as measures of surface roughness. Two types of surfaces are computationally generated: abraded surfaces consisting of surface scratches, and corrugated surfaces, consisting of hemispherical features. It was found that abraded surfaces could be well described by the skewness and kurtosis, exhibiting a large variation in these parameters over the range of surfaces sampled. The RMS roughness, RMS slope, and surface area ratio did not change significantly by comparison. A monotonic relationship was also found to exist between the skewness and kurtosis for abraded surfaces. For corrugated surfaces, the skewness and kurtosis were nearly constant for surfaces with RMS roughness values differing by a factor of 5, while the RMS roughness, RMS slope, and surface area ratio changed significantly in comparison, indicating that these surfaces are best characterized by the latter three parameters. No monotonic relationship was found to exist between skewness and kurtosis for corrugated surfaces.
        Speaker: Mr Tyler Downey (Memorial University of Newfoundland)
      • 19:40
        Investigating the Binding Capabilities of Triazole-Calix[4]arene Functionalized Microcantilever Sensors Towards Heavy Metals in Aqueous Solution 2m
        The main objective of this work was to investigate the binding capabilities of the newly synthesized bimodal triazole-calix[4]arene functionalized microcantilevers towards selected heavy metals in aqueous solution. Gold-coated microcantilever sensors were first modified with a self-assembled monolayer of a calix[4]arene modified at both its upper- and lower-rims. Selected target metal ions (e.g. Hg2+, Fe3+, Ni2+, Zn2+, and Pb2+) were then introduced into a cell containing the functionalized microcantilevers. The interactions between the calix[4]arene-functionalized microcantilevers and the target analytes resulted in the formation of differential surface stresses which, in turn, resulted in a mechanical deflection of the microcantilever. Results showed that microcantilever arrays modified with triazole-calix[4]arene were capable of detecting trace concentrations of Hg2+ions as low as 10-11 M, which is sufficiently low for most applications. Results also showed that triazole-calix[4]arene functionalized microcantilevers were capable of detecting the presence of different heavy metal ions with high sensitivity and selectivity. A functionalization unit was also constructed in order to allow for the simultaneous functionalization of all eight microcantilevers in an array. By using this unit, it was possible to functionalize all microcantilevers with different sensing layers at the same time thus increasing the accuracy and reliability of the experimental results.
        Speaker: Ms Mona Braim (Memorial University)
      • 19:42
        Surface vacancy mediated pinning of the magnetisation in $\gamma$-Fe2O3 nanoparticles: A micromagnetic simulation study$^*$ 2m
        Results from finite temperature stochastic LLG simulations of an atomistic core-shell model of $\gamma$-Fe$_2$O$_3$ spherical nanoparticles are presented. The radial surface anisotropy gives rise to a surface magnetisation with a Neel-like domain wall separating the magnetic poles. It is shown that the pinning of the domain wall by the oxygen anion sites plays an important role in the low temperature relaxation processes [1]. The core-shell model shows qualitative agreement with experimental results. A super-spin model with temperature-dependent anisotropy is a promising model to simulate complex hierarchical structures and the long time scale dynamics of such nanoparticles[2]. [1] T. N. Shendruk, R. D. Desautels, B. W. Southern, and J. van Lierop, Nanotechnology, vol. 18, p. 455704, 2007. [2] M. A. Kostiainen, P. Ceci, M. Fornara, P. Hiekkataipale, O. Kasyutich, R. J. M. Nolte, J. J. L. M. Cornelissen, R. D. Desautels, and J. van Lierop, ACS Nano, vol. 5, pp. 6394–6402, 2011 $^*$ Supported by NSERC
        Speaker: Mr Bassel Alkadour (Department of Physics and Physical Oceanography, Memorial University)
      • 19:44
        Electron spin resonance spectra of strontium aluminate at high microwave fields and strong illumination 2m
        Strontium aluminate co-doped with europium and dysprosium [SrAl2O4(Eu2+,Dy3+)] is a popular long-lasting (~10 hrs) phosphor for security signs, medical diagnostics, and other applications. Although it has been 20 years since the discovery of persistent luminescence (PL) in SrAl2O4(Eu2+,Dy3+), the associated physical mechanism is still unclear. Electron spin resonance (ESR) is a powerful technique to investigate the excitation of paramagnetic centers in solids, and the associated energy transfer processes. It was previously observed [1] that the intensity of the ESR signal of SrAl2O4(Eu2+,Dy3+) decreases under illumination and is restored upon remission of light during PL, a phenomenon that has been taken as evidence of the transformation of ESR-active Eu2+ centers into diamagnetic Eu3+ under illumination, and their recovery upon PL remission. Here, we present the ESR spectra of SrAl2O4(Eu2+,Dy3+) in the X microwave band, in the dark and under illumination by violet (405 nm) light. At high enough microwave field or sufficiently long and intense illumination, a "negative" ESR signal is observed, which, clearly, cannot be associated to negative concentrations of Eu2+ centers. Our findings put in question the validity of the current interpretation of the ESR spectra and PL mechanism in SrAl2O4 (Eu2+,Dy3+). We propose that the transformation of the ESR spectra at high microwave power and under illumination is due to dephasing of the ESR signal as a consequence of extremely long spin-lattice relaxation times in (Eu2+,Dy3+)SrAl2O4, a phenomenon that may also be responsible to persistent luminescence. [1] Clabau, Frédéric, et al. Chemistry of materials 17.15 (2005): 3904-3912.
        Speaker: ye li (uwo)
      • 19:46
        Colossal Permittivity in In + Nb co-doped TiO2 2m
        In $+$ Nb co-doped TiO$_2$ has been previously investigated and shown to display colossal permittivity ($\epsilon_1 >10^3$) for frequencies less than or equal to 1 MHz using impedance spectroscopy. In this work the lattice vibrational contribution to the low frequency dielectric function is studied in ceramic samples at the 0\%,5\%, and 10\% doping level using temperature-dependent reflectance spectroscopy. It is found that the soft mode behaviour exhibited by the lowest frequency infrared ibrational mode in pure TiO$_2$ is not strongly affected by the co-doping. There is a large discrepancy between the $\epsilon_1$ measured at the lowest far infrared frequencies in this reflectance spectroscopy study ($\approx 1.5$ THz) and the value measured below 1 MHz.
        Speaker: Susan Yee
      • 19:48
        Spin Correlation Functions on Pyrochlore Lattice 2m
        Pyrochlores have the chemical formula A$_2$B$_2$O$_7$ with A, B or both magnetic. It has corner-sharing tetrahedra in the structure, therefore, frustration phenomena naturally occurs in these systems. Because of the frustration, pyrochlore have many interesting properties, including the spin glass in Y$_2$Mo$_2$O$_7$, spin liquid in Tb$_2$Ti$_2$O$_7$, disordered spin ice in Ho$_2$Ti$_2$O$_7$, and ordered spin ice in Tb$_2$Sn$_2$O$_7$. I will focus on Tb$_2$Ti$_2$O$_7$ particularly, use perturbation theory to find the spin correlation function between the nearest neighbour for the spin $1/2$ system.
        Speaker: chen wei (Memorial University of Newfoundland)
      • 19:50
        New room-temperature multiferroic thin films of Ba2LnFeNb4O15 (Ln = Eu and Sm) deposited by pulsed laser deposition 2m
        The study of Ba2LnFeNb4O15 (TTB-Ln) bulk ceramics revealed that they have a tetragonal tungsten bronze crystal structure, are ferroelectric and that a magnetic phase of barium hexaferrite BaFe12O19 (BaFO) spontaneously forms within the TTB-Ln phase during the ceramic processing, resulting in a novel multiferroic composite material at room temperature. Our goal is to investigate new room-temperature multiferroic thin films grown by pulsed laser deposition (PLD), namely thin films of the spontaneously forming composite BaFO/TTB-Ln (Ln = Eu and Sm). c-oriented thin films of TTB-Ln have been successfully grown on Nb doped SrTiO3(100) substrates by PLD. In specific and optimized growth conditions, the structural study of the BaFO/TTB-Ln thin films shows an epitaxial growth perpendicularly to the substrate plan and parallel to the c-axis of tetragonal crystal structure. Further structural analysis reveals two kinds of azimuthal orientation of the c-axis oriented grains of TTB-Ln onto the cubic substrate, with the a and b axes of TTB-Ln aligned at 18° with respect to the a-axis of the cubic substrate. Ferroelectric macroscopic hysteresis loops demonstrate the existence of a spontaneous polarization at room temperature. An enhancement of the ferroelectricity due to the epitaxial growth has been evidenced. To further study the ferroelectricity in TTB-Ln thin films, local electromechanical properties were studied using piezoelectric force microscopy. These experiments allowed determining the piezoelectric coefficient and confirming that the ferroelectric nature of the studied thin films is conserved down to the nanoscale. Finally, the magnetic properties of BaFO/TTB-Ln thin films were studied which reveals that the PLD grown BaFO/TTB-Ln composite films exhibit a ferromagnetic behavior at room temperature, confirming their multiferroic nature at room temperature.
        Speaker: Mr Thameur Hajlaoui (INSTITUT NATIONAL DE LA RECHERCHE SCIENTIFIQUE (INRS))
      • 19:52
        Four state ferroelectric memory devices at room temperature 2m
        We report the four step ferroelectric polarization switching in BiFeO3(BFO)/SrRuO3 (SRO)/BiMnO3(BMO) heterostructure thin films. All crystalline films are grown on (100) oriented Niobium doped SrTiO3 (NSTO) single crystal substrates by pulsed laser deposition. We found a novel four step ferroelectric polarization switching dynamics that clearly differs from that of individual layers. The binary states of ferroelectric polarization in ferroelectrics are considered for digital data storage applications. Multiple energy states of ferroelectric polarization are essential to shrinking the dimension down of the memory devices. No clear experimental evidences have been reported until now towards multi state ferroelectric polarization switching in multiferroic perovskites at room temperature. Our results show a promising device concept that can enhance the data storage capacity in heterostucture capacitor devices.
        Speaker: Mr Joyprokash Chakrabartty (University of Quebec, INRS-EMT)
      • 19:54
        ** WITHDRAWN** Photocarrier Dynamics in Si and SiGe Nanowires Studied Using Optical-Pump Terahertz-Probe Measurements 2m
        CONTENT For this work, Si and SiGe nanowires (NWs) were grown in a hot-wall reduced pressure chemical vapor deposition system via the vapor-liquid-solid mechanism on both silicon and sapphire substrates using gold as a catalyst. These NW samples were characterized using optical-pump terahertz-probe (OPTP) transmission experiments. The influence of the experimental conditions on the photocarrier dynamics has been investigated by studying the impact of the substrate, the Ge content, the excitation wavelength, the pump fluence and the sample temperature on the time-resolved photoconductivity measurements. In all cases, the data curves show a rapid rise of the OPTP signal followed by a bi-exponential decay behavior with an initial decay time of ∼ 6 ps and a longer decay time of few tens of picoseconds up to 140 ps. Our results show that the capture and recombination of photocarriers by the traps present on the surface of the NWs play an important role in the observed photoconductivity dynamics.
        Speaker: Denis Morris (Unniversité de sherbrooke)
      • 19:56
        Dynamical polarizability of the pseudospin-1 dice lattice 2m
        The two-dimensional dice lattice is the pseudospin-1 analogue the pseudospin-1/2 Dirac material graphene. The dice-lattice low-energy excitation spectrum consists of the Dirac cone dispersion found also in graphene, with an additional dispersionless flat band intersecting the Dirac point. We present theoretical results for the electronic dynamical polarization function in the material. This fundamental entity in many-body physics renormalizes the Coulomb interaction by accounting for the screening of charges. From the polarizability, many interesting phenomena can be described, such as plasmonic excitations or Friedel oscillations. The flat band in the dice lattice provides distinct alteration of the typical physics seen in graphene.
        Speaker: John Malcolm (University of Guelph)
      • 19:58
        Floquet many-body localization transition in the thermodynamic limit 2m
        Generic ergodic quantum many-body systems under periodic driving, in the long-time limit, are described by an infinite temperature canonical ensemble. In the presence of disorder, heating can be prevented in a certain regime (e.g. high frequency), and many-body localized (MBL) systems are stable under periodic driving. The precise value of the transition has relied on exact diagonalization and finite size scaling studies of different quantities such as level statistics and entanglement entropy. Here we show that the numerical linked cluster expansion applied to the entanglement entropy of eigenstates is significantly more precise in determining the transition and conforming to the static case we find that the exact diagonalization methods overestimate the MBL regime.
        Speaker: Mr Pedro Ponte (University of Waterloo / Perimeter Institute)
      • 20:00
        Raman and Infrared Study of Phonons in a Pyrochlore Superconductor 2m

        Cd$_2$Re$_2$O$_7$ is a pyrochlore superconductor with a transition temperature (T$_C$) near 2 K. The results of Raman scattering and far-infrared reflectance measurements will be presented. The temperature dependence of optical phonons has been investigated above and below T$_C$ via IR spectroscopy, and as a function of Oxygen and Cadmium isotope substitution in the normal state via Raman scattering. The dominant presence of lattice vibrational modes in the optical spectra suggests that electron-phonon interaction plays an important role in the normal and superconducting state properties.

        Speaker: Maureen Reedyk (Brock University)
      • 20:02
        InGaN/GaN Nanostructures for High Efficiency Solar Cells 2m

        The InGaN/GaN material system is a promising candidate for the growth of highly efficient solar cells. With direct nanowire growth on silicon, superior light trapping properties at low costs are possible. With the introduction of quantum well superlattices, intermediate states well below the bandgap of GaN enable the absorption of lower energy photons that would otherwise pass through the structure. In this work, we investigate the potential of InGaN/GaN nanowire heterostructures as candidates for novel solar cell designs on silicon via a combination of optical/electrical characterization and computer-aided device simulation.

        The InGaN/GaN nanowire heterostructures were grown via radio frequency plasma-assisted molecular beam epitaxy (MBE) on Si (111) [1]. Nanowires were grown as axially oriented p-i-n junctions with p-GaN and n-GaN regions as the emitter and base, respectively. Ten InGaN/GaN QD/s form the intrinsic region.

        The device is modelled as a bulk structure with ten quantum wells as the nanowire dimensions approach 100 nm. The large diameter of the QDs (~50 nm) permits the treatment of the quantum dots as quantum wells, since confinement is primarily along the growth axis. Confined states are solved via the Schrödinger equation for ten coupled quantum wells using Crosslight Apsys for various coupling regimes.

        Current-voltage measurements, photoluminescence and electroluminescence spectroscopy of the nanowire solar cells were performed. External quantum efficiency (EQE) was measured as a function of increasing beam intensity and wavelength. The presence of non-negligible current generated at wavelengths below the bandgap of GaN, suggest photons are sequentially absorbed in the InGaN QDs and into the GaN conduction band for collection. This fulfills one of the requirements of an intermediate band solar cell. Future directions and design possibilities are discussed.

        Speaker: Ross Cheriton (University of Ottawa)
    • 19:00 22:00
      DHP Poster Session with beer / Session d'affiches, avec bière DHP SITE Atrium (University of Ottatwa)

      SITE Atrium

      University of Ottatwa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Louis Marchildon (Universite du Quebec a Trois-Rivieres)
    • 19:00 22:00
      DIAP Poster Session with beer / Session d'affiches, avec bière DPIA SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: René Roy (Université Laval)
      • 19:00
        Measurement of Curium Fluoride Anions by Accelerator Mass Spectrometry 2m
        Radiotoxic actinides including $^{236}$U, $^{239/240}$Pu, $^{241}$Am, and $^{244}$Cm are found in spent nuclear fuels and high-level radioactive waste. In particular $^{244}$Cm (half-life 18.1 y) is a useful tracer of exposure to radioactive materials, but dose assessments typically require measuring atto- to femtogram levels of curium in biological and environmental media. Accelerator mass spectrometry (AMS) is the only technique able to measure such ultra-low level abundances, but suffers from relatively poor ionization efficiencies for curium oxides made in sputter-ion sources used by AMS. In our work (i.e. Cornett et al [NIMB 2015]) we have experimented with a variety of sample chemistries and target matrices in an ongoing effort to boost anion currents for AMS actinide measurements of U, Am and Pu. To-date, the addition of PbF2 is shown to boost specific fluoride anions for actinides, and the addition of Si and Ta appears to form the most promising matrix for UO– current enhancement, resulting in a 3x increase of anion currents (Kazi et al [this meeting]). The situation for Cm remains unknown. Here we present the first AMS spectrum of curium fluoride anions generated during sputtering. We use samples spiked with $^{244}$Cm, and assess whether curium fluorides, with the assistance of PbF2, give an improvement in beam current compared to curium oxides, and whether Si/Ta matrices further boost curium oxide anion currents. The ability to increase curium currents may allow lower-level measurements of $^{244}$Cm in natural samples, and may be useful for studies of even rarer heaver elements including Bk, Cf and others by AMS.
        Speaker: Christopher Charles (University of Ottawa)
      • 19:02
        Muon Tomography applications to nuclear non-proliferation and waste management 2m
        Muon Scattering Tomography (MST) exploits the naturally occurring flux of high energy cosmic ray muons at the surface of the Earth to non-destructively assay the distributions of dense materials in a region of interest. The Cosmic Ray Inspection and Passive Tomography (CRIPT) detector was designed and built for this application. CRIPT is a unique MST apparatus using extruded plastic scintillating strips coupled with wavelength shifting fiber optics to reconstruct muon tracks. This information is used to extrapolate spatial points where muons have scattered off high density/high-Z materials therefore allowing for the reconstruction of 2D and 3D images. This is of particular relevance in the fields of nuclear non-proliferation, spent fuel verification, and reactor imaging. The former two fields are being explored in detail by research activities underway at Canadian Nuclear Laboratories’ Chalk River site. Using the CRIPT detector, fresh PHWR fuel, shielding materials, and storage containers have been successfully imaged. The characterization of these materials and geometries serves as a demonstration of the applicability of MST to current issues in nuclear materials management and nuclear non-proliferation.
        Speaker: Dr Oleg Kamaev (Canadian Nuclear Laboratories)
      • 19:06
        Metal Colorization and its application: using picosecond pulses 2m
        World mints compete year after year to produce new technologies that will revolutionize the field, increase revenue and make these new technologies unique and attractive to the Market place. New technologies developed in this project is to use nanoparticles and laser induced gratings to create fixed colors and holograms on metallic surfaces. The use of nanoparticles (NPs) as the colorizing agent dates back to the Roman Empire. When exposed to electro-magnetic radiations, NPs exhibit unique optical properties that depend on their shape, volume fraction, hosting medium and permittivity, a feature that has drawn considerable attention in fields such as sensing, jewel making and solar cells. We present the angle-independent coloring of silver and gold. The coloring of pure gold (from violet to red) is a world first. We also present the direct writing and transfer of holograms on silver, gold and steel for a new product line at the Royal Canadian Mint.
        Speaker: Mr Guillaume Cote (University of Ottawa)
      • 19:08
        Comovement of Unrelated Equities with Similar Ticker Symbols 2m

        Correlation is used to analyze the daily returns of pairs of unrelated stocks with similar ticker symbols. By encoding the relationship between two Chinese ticker symbols by three digits, we found that, in contrast to the developed Western markets, comovement of stocks with similar ticker symbols is relatively common in the Taiwanese market. When the last two characters are identical, comovement influences the daily return of ~40% of stock pairs. These results suggest that investor confusion has a important role to play in the return of stocks in developing markets.

        Speaker: Jonathon David White (Yuan Ze University)
    • 19:00 22:00
      DIMP Poster Session with beer / Session d'affiches, avec bière DPIM SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 19:00
        Cloud Point Extraction of Plutonium in Fish Tissues Coupled to Alpha Spectrometry 2m
        A cloud point extraction procedure was developed to quantify the plutonium in environmental samples. This procedure uses a selective ligand within micelle which will complex with the element to be extracted. The extraction is effective in highly acidic solution with the addition of bromine in the system thereby forming a shield around the micelles. In this study, this procedure is used to preconcentrate the plutonium in samples of fish. The selected ligand is P,P di-(2-ethylhexyl) methanediphosphonic acid (H2DEH[MDP]) because it has a high potential of extraction for actinides and especially for the plutonium. The cloud point extraction is coupled with an alpha spectrometer for plutonium quantification. But first, the flesh fish is treated to remove water and organic matter before doing cloud point extraction. The samples were dried at 105 °C for 24 hours followed by dry ashing at 450 °C for 5 hours in an oven. The resultant ashes are then treated by wet digestion with dilute nitric acid. These steps are repeated until complete removal of organic matter. The step of dry ashing is critical since a temperature exceeding 450 °C reduces the yield of plutonium because of the formation of refractory species.
        Speaker: Ms Alexa Leblanc (Chemistry Department, Laval University)
      • 19:02
        Towards sequential and automated CPE methods to pre-concentrate and extract radionuclides from environmental matrices 2m
        It can be challenging to measure the concentration of radionuclides using mass spectrometry when these concentrations are in the “parts per trillion” range. Yet, radionuclides can cause health problems even at these low concentrations, especially alpha-emitting radionuclides with a short half-life. This is why we are developing a methods to rapidly extract and pre-concentrate radionuclides at the ultra-trace level in environmental matrices to be able to measure their concentration. The method consists of a cloud point extraction (CPE) of target radionuclides coupled with an ICP-MS. The CPE system developed is composed of a mixture of non-ionic (Triton X-114, Triton X-100) and ionic (cetyltrimethylammonium bromide) surfactants. Targeted radionuclides are extracted by forming stable complexes with chelating agents chosen for their selective behavior towards one or a few radionuclides. The complexes formed are electronically neutral and tend to go inside the micelles, in the hydrophobic environment. By separating the micelles from the aqueous phase of the solution, we achieve the pre-concentration and the extraction of the targeted radionuclides. In this work we will present our progress regarding the use of sequential CPE for the separation and preconcentration of uranium and fission products (lanthanides). The automation of the CPE system to extract two or more target elements from the same sample using two different cloud point extraction systems will also be discussed.
        Speaker: Mr Anthony Tremblay (Chemistry Department, Laval University)
      • 19:04
        A Primary Cold-Atom Based Vacuum Pressure Standard 2m
        Laser cooling and trapping of atoms has created a revolution in physics and technology. For example, the GPS network used for global navigation relies on cold atoms for time keeping. This poster will review the recent advances of our research program which is aimed at creating a cold-atom based primary pressure standard for the high-, and ultra-high vacuum regimes. Cold, trapped atoms can act as very sensitive flux detectors owing to the fact that they form an ensemble of non-interacting particles whose momenta, positions, and quantum states are well-controlled. A particle in the vacuum environment which passes through the cold atom’s collision cross-section imparts momentum to the trapped particle. The collision is detected when the momentum gain is large enough to eject the cold atom from the trap, observed as a decrease in the light scattered from the trapped ensemble. The loss rate of trapped particles, detected optically, transduces the particle flux (pressure) into a timing signal. The loss rate is sensitive to both the type of collision and collision partner, as well as to the state of the trapped atom and the trap depth in which it is confined [1]. Thus, this provides an opportunity to study collisions and collisions physics in different types of traps, their dependence on trapped atom electronic state, and the spectroscopy of trap loss as a function of trap depth, all while working towards a new standard. The advantages of a cold atom standard include the fact the sensor relies on immutable, long-range interaction properties of atomic matter and that it will be a primary pressure standard, tied directly to the base SI unit of the second. [1] D. Fagnan, J. Wang, C. Zhu, P. Djuricanin, B. G. Klappauf, J. L. Booth and K. W. Madison, Phys. Rev. A 80, 022712, 2009.
        Speaker: Mr Kais Jooya (University of British Columbia)
      • 19:06
        RF-Compressed Ultrafast Electron Diffraction: Long-Term Sub-50 fs Phase Stabilization in High-Brightness Instruments 2m
        Ultrafast electron diffraction is a powerful table-top technique to characterize structural dynamics in condensed matter. We present an analysis of the phase stability of a 3 GHz radio-frequency electron pulse compression cavity. We implement low-noise microwave phase detection electronics to measure the slow drift (greater than 1 s) of the cavity resonance, allowing for continuous feedback and stabilization during an experiment. By optimally tuning the parameters of the feedback system, the additive drift of the cavity phase is reduced from ~ 1 ps to ~ 50 fs, yielding a significant improvement in the time resolution of the instrument.
        Speaker: Martin Otto (McGill University)
      • 19:08
        Gas Source Development for Accelerator Mass Spectrometry 2m
        Caesium sputtered ion sources when used on solid graphite powdered samples have been thus far - capable of generating a peak negative (_6^12)C-beam current of around 200-400 µA (~〖10〗^15 ions/s). However, when using CO2 gas directly as the carbon source – less of the sample is lost during the graphitization process, which is of vital importance when one has a limited amount of the material they want to analyze. Middleton (1984) tested a Cs sputtering ion source to form C - – ions directly from CO2 gas on titanium targets. At which time he produced a 10 µA beam current by using a very low CO2 flow rate of <4 µL/min. (STP) (<2 µg/min. carbon) that was shown to be the best for high sputtering efficiencies of ~10%. Accordingly, the runtime was longer – but more of the carbon ions were measured. In comparison, when using TiH2 & other solid hydride samples were used to create a negative hydrogen beam (using a similar source as mentioned above), an 80-90 µA peak current was the maximum ever achieved (while 20-30 µA is typical). This report describes the development of novel gas source AMS - to ideally be able to measure tritium ions & other rare isotopes using µg sample sizes.
        Speaker: Ryan Bolen (University of Ottawa)
    • 19:00 22:00
      DNP Poster Session with beer / Session d'affiches, avec bière DPN SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Reiner Kruecken (TRIUMF)
      • 19:00
        Installation of EMMA, a Recoil Mass Spectrometer for TRIUMF's ISAC-II Facility 2m
        EMMA is a recoil mass spectrometer designed to separate the recoils of nuclear reactions from the beams that produce them. It is being installed in the ISAC-II experimental hall of TRIUMF, where it will be used with heavy radioactive ion beams accelerated to energies close to the Coulomb barrier on a variety of targets. An update on its installation will be given.
        Speaker: Barry Davids (TRIUMF)
      • 19:02
        45$^{\circ}$ Ion Motion in an RFQ: a Study of SIMION 8.1 for Modeling Isobar Separator Beam Dynamics in AMS 2m
        Radiofrequency multipoles (RFM’s) are a promising new technology in accelerator mass spectrometry (AMS) for contributing to the removal of atomic and molecular isobars when combined with appropriate gases. The motion of charged particles in vacuo through the hyperbolic RFQ version are governed by the Mathieu functions for which convenient algebraic solutions exist for direct, continuous calculation of position, velocity and energy of a particle over a range of initial conditions and RF inputs for the continuous RFQ. Though the Mathieu solutions for the RFQ are well known, the ability to model reliably cation and anion trajectories in a general isobar separator column for AMS remains incompletely explored. This difficulty is due to issues inherent to matching an RFM to particle beams from AMS sputter-ion sources, i.e.: (1) large time-dependent phase-space variations of the beams into the RFQ, (2) space-charge effects, (3) the effect of (residual) gas collisions during deceleration, reactions and final re-acceleration, and (4) geometric impedances associated with an RFM column. A key reason for using the software SIMION extensively is to assist the designs of such devices, thus it is highly desirable to ensure SIMION results are reliable by comparing it to purely algebraic solutions. Here we report one such comparable case: the study of the ion motion in an RFQ for the extreme 45$^{\circ}$-limit between the hyperbolic poles under vacuum conditions. Particle positions, trajectories and energies for the RFQ ions initially at $\pm$45$^{\circ}$ are compared with the “direct” Mathematica calculations and those obtained by SIMION “simulations”. We confirm that SIMION results are trustworthy for assisting RFM device designs.
        Speaker: Christopher Charles (University of Ottawa)
      • 19:04
        An absolute neutron flux measurement of the $^{51}V(p,n)^{51}Cr$ reaction for PICO bubble chambers calibration 2m
        The PICO collaboration presently operates two bubbles chambers for the search of dark matter in the SNOLAB underground laboratory in Sudbury, Ontario. Multiple calibration chambers were created to understand the detectors’ behavior when exposed to different background radiation. The PICO 0.1 bubble chamber is used to perform neutron calibration at the Tandem Van de Graaff facility of the Université de Montréal. The electrostatic accelerator uses a 1.6 MeV proton beam to produce mono-energetic neutrons from the $^{51}V(p,n)^{51}Cr$ reaction off a 14 nm thick vanadium target. Only the relative neutron flux had been measured with either one or two $^3He$ neutron counters since the beginning of the previous PICASSO experiment as a mean to normalize the chamber’s count rate. A measurement of the absolute neutron flux was therefore made by Proton Activation Analysis (PAA). $^{51}Cr$ produced by the nuclear reaction always decays by beta decay, characterized by a half-life of 27.7 days, with the emission of a 320 keV gamma roughly 10% of the time. The activation of a new Vanadium target, followed by a gamma emission analysis with a calibrated High Purity Germanium detector (HPGe) enabled us to calculate the total amount of nuclear reactions triggered during the activation. The $^3He$ counters’ efficiencies and absolute neutron flux where thereafter determined. This poster presentation describes the experimental setup and present the results of the measurement.
        Speaker: Frédéric Girard (Laurentian University)
      • 19:06
        Progress on TITAN's Cooler PEnning Trap 2m
        The masses of radioisotopes is a fundamental property which is critical to a number of fields of study, and Penning traps have proven to be an important tool in measuring these masses to high precision. The TITAN facility at TRIUMF has achieved many successes in this field including a successful measurement of the mass of 11Li, the shortest-lived nuclide to ever be measured in such a trap. There is always a trade-off between half-life and precision, and masses off short-lived isotopes are necessary inputs for fields ranging from tests of the unitarity of the CKM matrix, to studies of r-process nucleosynthesis. The precision of these measurements can be maximized by charge-breeding the isotopes to highly ionized states by utilizing the high-energy electron beam of an Electron Beam Ion Trap (EBIT). The EBIT has been found to increase the energy spread of the ion bunch sent to the measurement Penning trap for mass measurement. However, the improvement due to charge-breeding will be greatest if we limit this energy spread to $\sim$1eV/q. For this reason, TITAN is developing a Cooler PEnning Trap (CPET), which will trap the charge-bred ions with a large acceptance, and cool them to appropriate energies prior to mass measurement. Since highly charged ions would charge exchange with a buffer gas, cooling will be accomplished by trapping the ions in the same region as a simultaneously trapped plasma of electrons. Recent steps toward implementing this trap in the radioactive beam-line will be discussed.
        Speaker: Brian Kootte
      • 19:08
        Alpha-gamma Angular Correlation in 209Po Using TIGRESS Integrated Plunger 2m
        Alpha decay provides a powerful tool to study structure of heavy nuclei with Z>83 (above Pb and Bi). When a gamma ray is emitted following the alpha decay, the alpha-gamma angular correlation can be used to assess the height of Coulomb and centrifugal barriers, which determine the rate of the alpha-particle tunnelling. This correlation, through the selection rules for the decays, can also be used as a tool for spin and parity assignments for the nuclear states involved in the decay. In addition, studies of alpha-gamma correlation provide a test for parity conservation in the decay processes governed by the strong and electromagnetic forces. For that reason, an apparatus to study alpha-gamma correlation has been set up at TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, through coupling of the CsI wall of the Tigress Integrated Plunger (TIP) device and TRIUMF-ISAC Gamma-Ray Escape Suppressed Spectrometer (TIGRESS). Alpha-gamma sources can be positioned at the centre of the TIP chamber, which is installed within the centre of TIGRESS. The identification of the alpha-decay is achieved through the pulse-shape sensitivity of the CsI scintillators. In this study, the sensitivity of the setup is investigated from a comparison of measured and predicted, as well as previously reported, alpha-gamma angular distribution from $^{209}$Po decay. So far, time correlation of alpha and gamma decay has been imposed, and alpha identification has been applied from CsI pulse shape sensitivity. Around 8000 events with extremely high signal-to-noise ratio have been identified for further analysis under the imposed condition. Optimal angular grouping between different TIP and TIGRESS detector pairs is currently investigated. Analysis and results will be presented and discussed.
        Speaker: Frank(Tongan) Wu (Simon Fraser University)
    • 19:00 22:00
      DPE Poster Session with beer / Session d'affiches avec bière DPE SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Martin Williams (University of Guelph)
      • 19:00
        Optical trapping of micrometer sized latex spheres in the undergraduate advanced lab: learning goals and outcomes 2m
        The all-optical manipulation of 1 to 4 µm latex spheres with a 20 mW He-Ne laser has been used to demonstrate the concepts of single beam optical trapping in the case when the particle size is comparable to the laser wavelength. Drag coefficient, particle diameter, laser beam waist and trap strength are some of the calculated parameters for the calibration of the optical trap. A CCD camera with high sampling rate is used to video capture the Brownian motion of the spheres in the optical trap as is periodically switched on and off. Students are tested on optics building set-ups and alignment skills. To expand learning outcomes, students conduct analyses on large sets of digitized images for the interpretation of the optical trap properties.
        Speaker: Penka Matanska (Carleton Univesity)
      • 19:02
        La vulgarisation au sujet des aurores boréales dans le projet AUTUMNX 2m
        Le projet AUTUMNX, soutenu par l’Agence Spatiale Canadienne (ASC), a installé une dixaine de magnétomètres haut de gamme au Québec. On y étudie le champs magnétique dû aux aurores boréales avec le but de mieux comprendre la magnétosphère et aussi de déterminer les effets de ses changements (loi de Faraday) sur le réseau électrique. Comme on travaille dans des communautés partout au Québec, mais surtout petites et éloignées des grands centres, on fait de la vulgarisation quand possible. À cette fin, on a développé une affiche/poster en français, qu’on présente ici. Cette affiche, basée sur celle du projet américain THEMIS, est disponible sous forme PDF à ceux qui aimeraient se joindre à notre projet de vulgarisation.
        Speaker: Martin Connors (Athabasca University)
    • 19:00 22:00
      DPMB Poster session, with beer / Session d'affiches DPMB, avec bière SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Melanie Martin (University of Winnipeg)
      • 19:00
        Development of synchrotron-based x-ray scatter projection imaging 2m
        In medical x-ray imaging a major challenge is to obtain adequate soft tissue contrast. The goal of our research is to develop a high soft-tissue contrast x-ray technique based on the detection of low-angle scattered photons. Scattered photons comprise up to 90% of the radiation downstream of the patient and can provide information in addition to that of the transmitted primary x rays. In particular, the cross section for coherent x-ray scattering, the basis of x-ray diffraction, varies with angle and photon energy in a material-specific manner, even for amorphous materials, and thus it can provide good soft tissue contrast. At the photon energies of medical radiology coherent scatter is a minority of all photon interactions, but its forward nature at these energies makes it relatively easy to detect. For example, in abdominal radiography coherent single scatter is 10% of the total scatter and 26% of the primary fluence. We are developing x-ray scatter imaging at the BioMedical Imaging & Therapy (BMIT) facility of the Canadian Light Source (CLS) synchrotron in Saskatoon, Canada. The BMIT facility provides an excellent development environment with the availability of monoenergetic x-ray beams, flat-panel x-ray imagers and automated sample positioning stages. The best images are obtained using step-and-shoot scanning with a pencil beam and area detector to capture sequentially the scatter pattern for each primary beam location on the sample. Primary x-ray transmission is recorded simultaneously using photodiodes. Our beam energy is 33.2 keV and the pencil beam area is about 2.5 mm2. The technological challenge is to acquire the scatter data in a reasonable time. Our aim is to acquire images on a time scale similar to that of nuclear medicine, e.g., under 15 minutes. Geometries using multiple pencil beams producing partially-overlapping scatter patterns reduce acquisition time but increase the complexity due to the need for a disentangling algorithm to extract the data. Continuous sample motion, rather than step-and-shoot, also reduces acquisition time at the expense of introducing motion blur and is the subject of our latest investigation. Our recent work with plastic phantoms and animal tissues is described.
        Speaker: Christopher Dydula (Carleton University)
      • 19:02
        Multi-modality Bone Mineral Density Measurements in the Presence of Bone Seeking Elements Accumulated in Bone 2m
        Dual-energy X-ray Absorptiometry (DXA) is currently the “gold standard” for measuring bone mineral density (BMD). Due to dependency of DXA on the atomic composition of bone, deposition of bone seeking elements that differ in atomic numbers from calcium (Ca, Z=20) can cause inaccurate estimation of BMD. One of the most notable elements of concern is strontium (Sr, Z=38), which is used to treat osteoporosis in the form of strontium ranelate. Because the atomic number of Sr is higher than that of Ca, Sr has higher attenuation coefficients than Ca for the photon energy range relevant to DXA. Therefore the BMD value of Sr can be overestimated. Other elements of interests are lead (Pb, Z=82) that accumulates in bone due to chronic occupational exposure or poisoning, and aluminum (Al, Z=13) which accumulates in human bone due to dialysis or administration of aluminum-containing medications. Although the accumulation of these elements occurs in relatively small concentrations, it is known to have adverse effects on bone health. Because Pb has higher atomic number and Al has lower atomic number in comparison to Ca, overestimation of BMD due to Pb and underestimation of BMD due to Al are of potential concern. Quantitative Ultrasound (QUS) offers an alternative method of assessing bone health by measuring speed of sound (SOS), broadband ultrasound attenuation (BUA), and a derived quantity called the stiffness index (SI). Because QUS depends on the macroscopic acoustic properties and is not influenced by the microscopic changes in the atomic composition of bone, we are hypothesizing that the QUS should not be subjected to inaccurate estimation of the BMD measurement in the presence of these bone seeking elements. In this study, hydroxyapatite that mimics bone mineral was synthesized with partial substitution of calcium with individual bone mimicking element (Sr, Pb and Al). The synthesized minerals were mixed homogeneously with gelatin to produce trabecular bone-mimicking phantoms that are compatible with both BUA and QUS, with volumetric BMD of 200 mg/$cm^{3}$ and varying analyte concentrations. The phantoms were then measured with a Hologic Discovery® DXA system, a Hologic Sahara® QUS system and an in-house research QUS system. The relationship between the concentration of the bone seeking elements and BMD as assessed by each modality will be presented.
        Speaker: Mr Deok Hyun Jang (Department of Physics, Ryerson University, Toronto, Ontario, Canada)
      • 19:04
        Vérification de l'équation de la friction visqueuse 2m
        Selon l'équation de la friction visqueuse, la force de friction entre deux surfaces séparées par une couche de fluide newtonien augmente proportionnellement avec la viscosité, l'aire de la surface de contact et la vitesse de déplacement relatif. La force de friction décroit avec l'épaisseur de la couche de fluide. L'expérience présentée vise à vérifier facilement (et avec un matériel limité) la relation entre l'aire de la surface de contact et la vitesse de déplacement, en gardant la force exercée, la viscosité et l'épaisseur de la couche de fluide constantes. L'hypothèse posée est que la vitesse de déplacement sera inversement proportionnelle à l'aire de la surface de contact, ce qui est le comportement prévu par l'équation de la friction visqueuse.
        Speaker: Michaël Smith (Cégep de Rivière-du-Loup)
      • 19:06
        Vérification de la loi de Poiseuille 2m
        Selon la loi de Poiseuille, le débit d'écoulement d'un fluide dans une conduite cylindrique est proportionnel au gradient de pression et au rayon de la conduite élevé à la puissance quatre. Il est aussi inversement proportionnel à la viscosité du fluide. La loi de Poiseuille fut d'abord établie en lien avec l'étude de l'écoulement du sang dans les veines et les artères. L'expérience présentée vise à vérifier facilement (et avec un matériel limité) la relation entre le débit d'écoulement et la longueur de la conduite, en gardant la différence de pression, le rayon de la conduite et la viscosité constantes. L'hypothèse posée est que le débit d'écoulement sera inversement proportionnel à la longueur de la conduite, ce qui est le comportement prévu par la loi de Poiseuille.
        Speaker: Frédéric Lirette (Cégep de Rivière-du-Loup)
      • 19:08
        Alteration of Bacterial Cell Elemental Concentrations by Environmental Influences as Determined by Laser-Induced Breakdown Spectroscopy 2m
        There is an urgent demand from many sectors (health, environmental safety, security, and food-processing) for a diagnostic test to rapidly and accurately identify bacterial pathogens. In recent years, it has been shown that laser-induced breakdown spectroscopy (LIBS) can provide a real-time bacterial cell elemental assay. On the basis of this assay, sensitive and specific discrimination between bacterial specimens at both the species and strain levels is possible. In this work we investigated the impact of the elemental content of the growth environment on the LIBS spectral signature obtained from bacterial cells with a focus on three specific variables. Growth media used for cultures of *E. coli* were intentionally doped with zinc, magnesium, and glucose in varying concentrations prior to cell growth. The range of concentrations was chosen to allow both an investigation of extreme environments and also an investigation of fairly low-concentration environments that would typically be encountered in physiological (i.e. in the human body) and environmental settings. The spectra obtained from doped cells were compared to those of the same species grown in an unaltered tryptic soy agar medium to assess potential cell alteration. This study is highly relevant for the use of LIBS on cells obtained from a medical specimen for infection diagnosis as well on cells obtained from an environmental setting for use as a diagnostic of water or soil contamination.
        Speaker: Dylan Malenfant (University of Windsor)
      • 19:10
        Stacking of Red Blood Cells due to Depletion Effects 2m
        The aggregation of red blood cells into coin-like stacks called rouleaux is associated with a number of underlying causes including infections and diseases such as cancer. Rouleaux formation occurs when the protein concentration in blood plasma is high. Hence, one possible cause for rouleaux formation is red blood cells clumping together due to depletion forces. In the case of several large objects suspended in a bath of small objects (the depletants), it is globally entropically favourable at high depletant concentration for the large objects to remain in contact since this gives more free space to the smaller objects. The depth of the resulting depletant potential is directly related to the density of the depletants. In this presentation I will present results from coarse-grained simulations investigating depletant induced rouleaux formation. Simulations are performed for different depletant and red blood cell densities. Rouleaux formation is observed to happen relatively suddenly at a critical depletant density. The rouleaux stacks are characterized in terms of the cluster size and the number of aligned red blood cells with the stack. Results indicate that the stacks form with a central, orderly aligned stack that has a maximum size after which additional red blood cells adhere to the sides of the stack yielding a more disordered morphology. The dependency of these results on the red blood density is also explored. Large scale systems that yield multiple rouleaux formation are investigated within the context of network formation via nucleation processes.
        Speaker: Austin Nehring
      • 19:12
        Relaxation of a Simulated Lipid Bilayer Vesicle Compressed by an AFM 2m
        The Atomic Force Microscope (AFM) lets us reach out and touch cells, on force and length scales native to them. But what *physically* happens when the AFM's tip touches a cell? The membrane is a first point of contact, and that is why we begin by studying vesicles —cell membranes laid bare. Using Coarse-Grained Molecular Dynamics simulations, we study the relaxation of uniaxially compressed bilayer vesicles. The relaxation time exhibits a strong force-dependence. This suggests that the results of the widely used AFM probe are greatly dependent on the manner in which the tip is applied to a vesicle. We explain the strong force dependence of the relaxation time in terms of the undulations present in lipid bilayers, and can fit our simulations with the results of an attractive theory developed by Helfrich and Servuss. Force-compression curves are very similar to recent experiments wherein giant unilamellar vesicles were compressed in a nearly identical manner.
        Speaker: Benjamin MacPherson Barlow (University of Ottawa)
      • 19:14
        Plasma-Based Coatings in Biomaterial Engineering 2m
        Plasma-based processes are increasingly finding applications in a variety of fields, including biomaterial engineering and medicine. This proliferation, in part, is due to the fact that the plasma state of matter not only allows surface modifications with monoatomic layer precision, but also offers the opportunity of synthesizing new materials and nanostructures that could influence the cell response, or could be used as treatment delivery vehicles. The quality of implants for the recipients of medical prosthetics determines the quality of their lives. These implants in addition to their bio- and haemocompatibility characteristics must also possess the required mechanical, electrical or tribological properties. Designing materials that could simultaneously fulfil all these characteristics constitutes a significant challenge to the biomaterial engineering community. The application of plasma-based thin film coatings or synthesized layers offers the possibility of surface engineering of medical implants and medical tools. In this presentation we will give a brief highlight of plasma-based technologies commonly in use, along with some examples of their applications for biomaterial surface engineering.
        Speaker: Sean Wolfe (Plasmionique Inc.)
      • 19:18
        ** WITHDRAWN** Adaptive endoscopic imaging of brain 2m
        With the continued miniaturization of endoscopic imaging tools, the use of mechanical adaptation (focusing, etc.) becomes difficult. This is particularly true for the "mobile" or portable implants, including the freely behaving animals. In the current presentation we shall describe the concept of a motion less adaptive imaging on the example of a stationary (still large) system using liquid crystal micro lenses. Fixed gradient index and electrically tunable liquid crystal lenses (TLCL) were used to build the imaging optical probe. A focal shift of approximately 74 ± 3um was achieved by electrically controlling the lens TLCL. The potential of the system was tested by imaging neurons and spines in thick adult mouse brain sections and in vivo, in the adult mouse brain at different focal planes. Our results indicate that we can further modify our imaging system and obtain its miniaturized version for mobile applications
        Speaker: Prof. Tigran Galstian (University Laval)
      • 19:20
        Towards measurements on intramolecular velocity fluctuations during DNA transport through nanopores 2m

        Despite considerable technical progress in recent years, DNA sequencing is still a time and resource consuming procedure. Finding inexpensive, easy, and reliable alternative DNA sequencing strategies is a tall task. As recently demonstrated on biological pores, a promising approach to this challenge is the use of nanopores to characterize single strands of DNA. The advantages of nanopore technology for the characterization of DNA are manifold. The ability to directly interrogate single molecules electrically in the nanopore makes this approach very competitive over conventional DNA sequencing techniques, by sample preparation, reducing cost, and enabling point-of-need sequencing. However before solid-state nanopore devices can also be used to sequence DNA some challenges need to be overcome. The transport dynamics of DNA through solid-state nanopores have been intensively studied for a few years but the control of motion and speed proves to be very difficult on solid-state devices. In this poster, branched DNA molecules specifically designed to measure intra-molecular translocation velocities of DNA polymers through solid-state nanopores fabricated by controlled breakdown (CBD) will be described. Finally, preliminary results of the building blocks of these branched DNA molecules will be presented. The ultimate goal is to develop a better understanding of the kinetics of DNA transport in these pores, which is one of the crucial steps towards implementing solid-state nanopore based DNA sequencing.

        Speaker: Philipp Karau (University of Ottawa)
      • 19:22
        ZMW Nanopore Fabrication by Controlled Breakdown for Single-Molecule Sensing 2m

        The last decade has seen significant advancements in nanofluidic devices to study transport processes at the single-molecule level. In particular, exciting results have been obtained through the study of passage of nucleic acids through solid-state nanopores (ssNP). ssNP are nanometer-sized holes in thin dielectric membranes, which have emerged as a versatile tool to investigate a wide range of phenomena involving DNA and proteins. Controlled breakdown (CBD) is a technique for fabricating such ssNP involving sustained high electric fields that was recently developed by our group as a low-cost, high-yield alternative to traditional focused ion-beam/TEM drilling methods. We have characterized the ability of CBD to create pores in substrates of increasing complexity. Devices incorporating different materials and advanced functionalization represent a crucial step toward refining the capabilities of ssNP as single-molecule sensors of electrophoretically-driven biomolecules, and increasing their range of potential applications. To this end, we demonstrate pore fabrication by CBD through multilayer dielectric membranes equipped with an embedded metal electrode. A thin gold layer was deposited on 10/30 nm SiNx membranes by thermal evaporation, followed by the addition of a second dielectric (HfO2) to both sides using atomic layer deposition. After pore fabrication, conductance-based models are used to extract an effective nanopore diameter, which can be compared to values obtained from TEM imaging and by using passing, voltage-driven DNA as a molecular-sized ruler through its effect on ionic current. Applied to these membranes, the CBD process resulted in structures consisting of a nanopore surrounded by a concentric area of removed metal 100s of nm in diameter. By using laser-excited Ca2+ fluorescent dyes, the ability of these structures to act as zero-mode waveguides, attenuating the fluorescence signal away from the pore and enabling high-contrast optical detection of single-molecules, can be characterized.

        Speaker: Mr Zachary Roelen (University of Ottawa)
      • 19:24
        Optimizing Nanopores for Single-Molecule Counting and Target Quantification 2m

        Nanopores have proven to be useful single-molecule sensing tools in the past two decades. One of the many promising applications of these electrical nano-sensors is to act as molecular counting devices with single-molecule sensitivity, essentially determining concentrations of specific molecular species. To achieve this, it is essential to develop a better understanding of the nanopore capture process and the factors affecting the reliability and accuracy of such nano-devices.
        This poster will present our investigation of the mechanisms controlling the nanopore capture process and the factors affecting its reliability for nanopores specifically fabricated using the recently developed controlled dielectric breakdown (CBD) technique. Using 50bp dsDNA to translocate through the nano-sensors, the energy barrier and system resolution limit of pores of different sizes are studied and are used to determine what parameters are optimal for efficiently counting this type of molecule.

        Speaker: Martin Charron (University of Ottawa)
      • 19:26
        Personalized Treatment Planning for Targeted Radionuclide Therapy: A Monte Carlo Model 2m

        Patients who receive targeted radionuclide therapy (TRT) for cancer treatment suffer from damaging unwanted healthy body tissues and may receive unexpected dose to healthy organs as an inadvertent consequence of their treatment. In particular, they risk significant dose to critical and secondary organs, e.g. bone marrow, gonads, uterus etc., which may cause long- or short- term damage for entire life. The unintended dose to organs varies widely depending on the types and energy of the emitted radiation and their decay scheme. Royal University Hospital at University of Saskatchewan recently started Yitrium-90 (Yt-90) treatment available for the liver patients in a drug name TheraSphere. Several other radionuclide treatments, e.g. Radium-223, Strontium-89 will be available in coming months. Till now, MIRD principle is the only methodology that is being widely used for TRT dosimetry and there is no commercial program available that can be fitted over wide varieties of radionuclide treatments. Medical Imaging team at Royal hospital is currently building a customized virtual treatment planning system that is capable to combine personalized CT images to advanced particle transport framework. This presentation showcases design features and initial results of this planning system.

        The proposed virtual planning system consists of series of 2-D DICOM images of the patient captured by CT scanner. The 2-D data set are transformed to 3-D object (composed of thousands of voxels (volume of the pixels) that is readable to a particle transport framework. This framework is capable for dose modeling to specific organs. Initially, this system will be used in planning Yt-90 for liver-treatment and Strontium-90 for treatment of bone. In the long run, the system will be upgraded for treatment of alpha emitters with substantial improvements in particle transport data framework. This customized user friendly tool can be used by the clinicians in parallel to existing commercial planning system in order to cross-validate diagnosis and treatment plan for individual patient.
        The initial design is completed and been tested for several radionuclides. The presentation will include the results and future challenges.

        Speaker: Dr Josef Daka (Health Canada)
    • 19:00 22:00
      DPP Poster Session with beer / Session d'affiches, avec bière DPP SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Lora Ramunno (University of Ottawa)
      • 19:00
        Filamentation and multiple filamentation in in fused silica 2m
        Propagation of high-power femtosecond laser pulses in transparent materials can lead to filamentation. Filamentation occurs due to the Kerr-focusing of the laser pulses in nonlinear medium. Plasma defocusing effect prevent the colapse of the laser pulse and the balance between Kerr nonlinearity and plasma defocusing leads to filamentation. For the first time, we observed multiple filamentation in fused silicaa in interaction of short laser pulses (50 fs-100 fs) using high-resolution three-dimensional FDTD simulations. We show a map of our simulation results in terms of laser energy and laser waist size (NA). Our investigations show that for NA (<0.65) multiple filamentation can occur when the power is above(3.3p_{cr}) the critical power for self-focusing; for tighter focusing conditions only one filament forms. For laser pulses with lower NA, the laser pulse focuses due to nonlinear Kerr effect and ionizes the medium.and the first filament appear. When the plasma is produced, it changes the refractive index of the medium and as a result the trailing part of the laser pulse defocuses. The intensity in front of the laser pulse drops and the ionization process stops. As the pulse propagtes farther, it focuses for the second time, the intensity becomes above the ionization threshold and the second filament appear. Increasing NA results in void shape structure formation in the bulk of fused silica. Our results agrees well with experimental results of (Sudrie et. al. PRL 2002, Yamada et. al. Courier et. al. PRB 2005).
        Speaker: Mr Gabriel Dupras (University of Ottawa)
    • 19:00 22:00
      DSS Poster Session, with beer / Session d'affiches DSS, avec bière SITE Atrium (University of Ottatwa)

      SITE Atrium

      University of Ottatwa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Steve Patitsas (University of Lethbridge)
    • 19:00 22:00
      DTP Poster Session with beer / Session d'affiches, avec bière DPT SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Svetlana Barkanova (Acadia University)
      • 19:00
        Gravitationally induced quantum transitions 2m
        Abstract 1. Introduction 2. ULTRA-COLD NEUTRONS IN A GRAVITATIONAL FIELD 3. GRAVITATIONAL PERTURBATION 4. NUMERICAL VALUES AND EXPERIMENTAL POSSIBILITIES 5. Conclusion 6. Acknowledgements 7. References
        Speaker: Mr Alexandre Landry (Université de Montréal)
      • 19:02
        Spacetime in Everett's interpretation of quantum mechanics 2m
        Sixty years ago, Hugh Everett III suggested that when a quantum observable is measured by an apparatus, all possible results of the measurement exist. Many different ways to understand this statement have later been proposed, which roughly fall under the headings of many worlds, many minds and decohering sectors of the wave function. Understanding multiplicity is, in my view, a pressing problem in making sense of Everett's approach. Related to this is the problem of the nature of space, or spacetime. It turns out that interpreters of Everett view spacetime in different ways. Some believe, for instance, that all worlds exist in a single spacetime, others that spacetime itself splits, others still that the spacetime of quantum mechanics and quantum field theory is not the same as the macroscopic spacetime. I intend to analyse some consequences of such views, and will argue that much remains to be done for this approach to be defined adequately.
        Speaker: Prof. Louis Marchildon (Université du Québec à Trois-Rivières)
      • 19:04
        Scalar fields in a shell: the response of an Unruh-Dewitt detector inside, and what it means for us outside 2m
        We show that a particle detector can distinguish the interior of a hollow shell from at space for switching times much shorter than the light-crossing time of the shell, even though the local metrics are indistinguishable. This shows that a particle detector can read out information about the non-local structure of spacetime even when switched on for scales much shorter than the characteristic scale of the non-locality.
        Speaker: Keith Ng (University of Waterloo)
      • 19:06
        Super-Entropic Black Holes 2m
        Black Hole Chemistry is a new perspective on black hole thermodynamics, one that indicates that once vacuum energy is taken into account, black holes behave more like chemical systems. As a consequence mass becomes chemical enthalpy, the notion of a thermodynamic volume appears, and black holes exhibit a broad range of chemical phenomena, including liquid/gas phase transitions similar to a Van der Waals fluid, triple points similar to that of water, and re-entrant phase transitions that appear in gels. One conjecture to follow from this program is that the entropy of an AdS black hole is bounded above by a function of its thermodynamic volume via a relation known as the Reverse Isoperimetric Inequality. Here I construct a new new class of rotating AdS black holes that provide counterexamples to this conjecture. They are formed by taking a new ultraspinning limit to the Kerr-AdS class of black holes, yielding objects whose event horizons are non-compact but have finite area. The structure of the spacetime is qualitatively changed since it is no longer possible to return to a frame that does not rotate at infinity. I shall present both the construction of these “super-entropic” black holes and their implications for black hole thermodynamics.
        Speaker: Robert Mann (University of Waterloo)
      • 19:08
        First and second order Viriel coefficients for a gas of anyons 2m
        In this work, we study, using numerical -Monte Carlo- simulations, quantum properties of a gas of anyons with a topological-type interaction in finite three dimensional space-time. This model is an effective description of the Abelian Higgs model with the Chern-Simons theories. The effective anyon gas with topological-type interaction is already constructed and developped in the lattice in [1;2]. In the present work, we add two anyons travelling the time direction of the lattice and compute the first and second order Viriel coefficients of the model. We present our numerical computations and analyse the Data. References: [1] R. MacKenzie, F. Nebia-Rahal, and M.B. Paranjape, Phys. Rev. D 81,114505 (2010). [2] R. MacKenzie, F. Nebia-Rahal, M. B. Paranjape, J. Richer, Phys. Rev. D 82, 074506 (2010).
        Speaker: Faïza Nebia (Cégep du Vieux Montréal)
      • 19:10
        Incompatibility of Determinism, Independence, and Objectivity 2m
        Quantum mechanics is often described as "weird" and "strange" because it abandons many of the intuitive traits of classical physics. Specifically, the notion that the world is objective, is deterministic, and exists independent of measurement are basic features of classical theory, but do not always hold up in quantum theory. I point out that these intuitive ideas are actually not genuine features of classical physics. Instead, these three apparently reasonable classical assumptions —objectivity, determinism, and independence—are mutually incompatible with any theory, not only with quantum mechanics. While any two of these three assumptions are compatible, all three are not. Hence our seemingly reasonable classical assumptions may not be so reasonable after all.
        Speaker: Robert Mann (University of Waterloo)
      • 19:12
        Random Matrices Approach to Neutrino Masses 2m
        The origin of neutrinos masses is one of the great mysteries of modern physic. As it turns out, the Standard Model of particle physics cannot account for massive neutrinos. They can only be described as massless Weyl spinors (left handed) due to symmetry constraints. On the other hand, experiments on neutrinos oscillations have provided strong evidence for a non-zero mass, which indicate the presence of a mechanism or phenomenon beyond the current limit of our understanding. To generate the neutrino masses, we choose to work in a minimal extension of the standard model in which three right handed (sterile) neutrinos are added to the particle content in order to use the type I seesaw mechanism. However, due to the lack of knowledge about the underlying theory of neutrino masses and mixing, the parameters and couplings of the two mass matrices allowed by gauge invariance (i.e. the Dirac and Majorana mass matrices $M^{D}\ $ and $M^{R}\ $ respectively) cannot be predicted. In order to overcome this obstacle, we choose to adopt the anarchy scenario proposed by Murayama et al., which allow us to randomly generate these matrices and study the resulting spectrum (for the eigenvalues) with the tools develop in the study of random matrix theory. In this work, we propose to compute the joint probability distribution for the mass matrix eigenvalues (of arbitrary dimensions) using the seesaw mechanism and extract information on neutrinos masses from the resulting spectrum. This statistical analysis allows determining among other things, the hierarchy of the mass spectrum and the mass gap between generations.
        Speaker: Nicolas Giasson (Université Laval)
      • 19:16
        Paczynski-Wiita-like potential for any static spherical black hole in metric theories of gravity 2m
        We present a Paczynski-Wiita-like pseudo-Newtonian potential describing the orbits of particles in arbitrary static and spherically symmetric spacetimes, including black hole solutions of alternative theories of gravity. This general prescription differs substantially from a previous one, showing that the association of pseudo-potentials with black hole spacetimes is not unique. [Based on V. Faraoni, S. Belknap-Keet & M. Lapierre-Leonard 2016, Phys. Rev. D 93, 044042]
        Speaker: Valerio Faraoni (Bishop's University)
      • 19:18
        A Holographic Model for Quantum Critical Responses 2m
        In this talk we construct a self-consistent holographic model that is used to analyze the dynamical response functions for strongly interacting quantum critical systems described by conformal field theories (CFTs). A relevant scalar operator is incorporated in order to drive a quantum critical phase transition and we study the effect that our model parameters have on the finite temperature conductivity, most notably, the scaling dimension of the relevant operator. We find that the conductivity is well-approximated by a simple ansatz proposed by Katz et al [Physical Review B 90 (24), 245109]. At large frequencies, we expand the conductivity using the operator product expansion to reveal the spectrum of our model CFT. Finally, our model can be used to analyze the conductivity as we tune away from the quantum critical point, allowing for a comprehensive analysis of the phase diagram.
        Speaker: Todd Sierens (Perimeter Institute)
      • 19:20
        Gravitational Screens as Quasi-local Observers 2m

        The anti-de Sitter/conformal field theory correspondence and the membrane paradigm have illuminated many aspects of string and field theory, giving key insights into what a quantum theory of gravity might look like, while also providing tools to study a wide range of strongly coupled systems. In essence, these ideas are a statement of the holographic principle: a fundamental observation about our universe which states that all of the information contained in a bulk region of space-time can be encoded on the boundary of that region. However, these approaches are generally restricted to situations where knowledge of the boundary of space or the entire future history of the universe is required. From a practical point of view this is unsatisfactory. As local observers, we are not generally able to access these types of boundaries.

        In an attempt to address these issues we use `gravitational screens' as quasi-local observers. A gravitational screen is a two dimensional space-like hypersurface surrounding an arbitrary region of space-time. Projecting Einstein's equations onto the screen results in the equations of non-equilibrium thermodynamics for a viscous fluid, which encode all of the information present inside the screen in terms of the holographic fluid on the surface, without being restricted to the event horizon of a black hole or to spatial infinity. In this project we study the dynamics and equations of state for screens in various space-times. Of particular interest are screens/geometries which have fluids obeying the second law of thermodynamics, since it is not obvious that an arbitrarily chosen screen will behave physically. We determine the properties of the fluids that arise from different background geometries, discuss their interpretation, and clarify the relationship between the gravitational degrees of freedom in the bulk, and the thermodynamic degrees of freedom on the screen.

        Speaker: Mr Filip Simovic (University of Waterloo)
    • 19:00 22:00
      PPD Poster Session with beer / Session d'affiches, avec bière PPD SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Christine Kraus
      • 19:00
        Search for single production of a vector-like quark via a heavy gluon in the $4b$ final state with the ATLAS detector in $pp$ collisions at $\sqrt{s} = 8$ TeV 2m
        A search is performed for the process $pp \to G^* \to B_H\bar b/\bar B_H b \to H b \bar b \to b\bar bb\bar b$, predicted in composite Higgs scenarios, where $G^*$ is a heavy colour octet vector resonance and $B_H$ a vector-like quark of charge $-1/3$. The data were obtained from $pp$ collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of $19.5 \text{ fb}^{-1}$, recorded by the ATLAS detector at the LHC. The largest background, multijet production, is estimated using a data-driven method. No significant excess of events with respect to Standard Model predictions is observed, and upper limits on the production cross section times branching ratio are set. Comparisons to the predictions from a specific benchmark model are made, resulting in lower mass limits in the two-dimensional mass plane of $m_{G^*}$ vs. $m_{B_H}$.
        Speaker: Frederick Dallaire (Universite de Montreal (CA))
      • 19:02
        Cryogenic Underground TEst facility (CUTE) at SNOLAB 2m
        A well shielded Cryogenic Underground TEst facility (CUTE) will be installed at SNOLAB with the goal to do performance tests, calibrations and background measurements with cryogenic dark matter detectors in support and preparation of the search for Weakly Interacting Massive Particles (WIMPs) with SuperCDMS at SNOLAB. This facility will also offer the opportunity for the European Underground Rare Event Calorimeter Array (EURECA), a collaboration including the European cryogenic dark matter search experiments EDELWEISS and CRESST, to demonstrate the compatibility of their detector design with the SuperCDMS infrastructure. This in turn opens the door for bringing EURECA detectors as additional payload into SuperCDMS to increase the physics reach of the experiment. The primary component of CUTE will be a cryogen-free dilution refrigerator mounted within a drywell in the centre of a water tank shielding. In addition, lead and polyethylene shielding will be installed in two phases to further reduce the radioactive background level at the detectors. Meanwhile, in order to minimise microphonics noise in the signal, special care will be taken to measure and suppress the level of micro-vibrations within the cryostat.
        Speaker: Xiaohe Zhang (Queen's University)
      • 19:04
        Bubbles: A Model And Formation Process Within Superheated Liquid Bubble Chambers 2m
        The PICO experiment uses superheated liquid bubble chambers with different freons, presently $C_3F_8$, as the active fluid to search directly for dark matter. When a particle deposits energy in the active fluid, within a certain critical length, a local phase transition might occur if this energy is greater than a certain critical energy. This phase transition is explosive in nature and will be followed by an emission of an acoustic signal. This signal carries enough information that allows for the discrimination the main background particles, alphas and neutrons. A more complete model of the formation of the bubble, the explosive bubble growth and the generation of the acoustic signal can help to improve the background discrimination techniques. This work summarizes the progress we have made in the understanding of those issues.
        Speaker: Mr Alexandre Le Blanc (Laurentian University)
      • 19:08
        Cover gas board for the SNO+ Universal Interface 2m
        The SNO+ experiment is a large-scale liquid scintillator detector with a focus on investigating neutrinoless double beta decay. In order to fully calibrate the experiment, human access is required to within the detector region and therefore careful consideration is needed to prevent radon ingress from the mine air, a significant source of background. A cover gas system is being developed to pump on specific volumes located on the Universal Interface (UI), used to introduce calibration sources into the detector volume, where there is potential for contact with mine air and purge it with inert nitrogen gas. The development of the cover gas board used to control the pump/purge system will be discussed here.
        Speaker: Mr Zachariah Barnard (Laurentian University)
      • 19:10
        Present and Future Lead-based Supernova Detectors 2m

        Lead is an interesting target material for a supernova detector. The neutron excess in lead nuclei leads to Pauli-blocking of the charged-current $\overline{\nu_e}$ interaction, and the high atomic number of lead Coulomb enhances $\nu_e$ over $\overline{\nu_e}$ giving a large $\nu_e$ CC neutrino interaction cross-section. This leaves a lead-based SN detector dominantly sensitive to $\nu_e$ through CC channels and to a lesser extent to $\nu_x$ through NC channels. Therefore, such a detector complements the dominantly $\overline{\nu_e}$ sensitivity of current water Cherenkov and liquid scintillator detectors worldwide. Supernova neutrinos, which undergo CC or NC interactions with the lead nuclei, eject one or two neutrons; so instrumenting lead with neutron detectors can be a cost efficient approach to robust supernova detector. The HALO detector at SNOLAB, running since May 2012, was designed to be a high live-time, low-maintenance, and low-cost dedicated supernova detector. HALO consists of a core of 79 tonnes of lead instrumented with 376 m of $^3{\rm He}$ neutron detectors and surrounded by a layer of water shielding. The measurement of the ratio of two detected neutrons to one neutron has been shown to provide a measure of the temperature of the neutrinos, due to the distinct thresholds for one and two neutron emission in neutrino-lead interactions. Since October 2015 HALO has been a part of the network of SN neutrino sensitive detectors participating in the Supernova Early Warning System (SNEWS). The decommissioning of the OPERA detector at LNGS has potentially made available 1.3 kilo-tonnes of lead for future experiments. Efforts are currently underway to explore neutron detection technologies that could be used to instrument this sixteen-fold increase in mass for a more sensitive version of HALO at LNGS. The status of HALO at SNOLAB and plans for HALO at LNGS are reported.

        Speaker: Clarence Virtue (Laurentian University)
    • 07:30 08:30
      PiC Editorial Board Meeting / Réunion du Comité de rédaction de La Physique au Canada SITE 5084

      SITE 5084

      University of Ottawa

      Convener: Bela Joos (University of Ottawa)
    • 08:30 16:00
      Exhibit booths open 08:30-16:00 / Salle d'exposition ouverte de 08h30 à 16h00 SITE Atrium

      SITE Atrium

      University of Ottawa

    • 08:30 10:30
      W1-1 Superconductivity (DCMMP) / Supraconductivité (DPMCM) SITE G0103

      SITE G0103

      University of Ottawa

      Convener: Oleg Rubel (McMaster University)
      • 08:30
        CJP Best Paper Award: The effect of quasiparticle-self-energy on Cd$_2$Re$_2$O$_7$ superconductor 30m

        The magnitude and the temperature dependence of the superconducting order parameter $\Delta(T)$ of
        single-crystals of Cd$_2$Re$_2$O$_7$ ($T_c$ = 1.02~K) was measured using point-contact
        spectroscopy. In order to fit the conductance spectra and to extract the order parameter
        at different temperatures we generalized
        the Blonder-Tinkham-Klapwijk theory by including the self-energy of the quasiparticles into the Bogoliubov equations.
        This modification enabled excellent fits of the conductance spectra.
        $\Delta (T)$ increases steeply below the superconducting transition temperature of 1.02 K
        and levels off below $\sim$0.8 K
        at a value of 0.22(1) meV, $\approx $40 \% larger than the BCS value.
        Our results indicate the presence of a strong electron-phonon interaction and an enhanced quasiparticle damping
        and may be related to a possible phase transition within the superconducting region at $\sim$0.8 K.

        Speaker: Prof. Bozidar Mitrovic (Department of Physics, Brock University)
      • 09:00
        Emergent charge order in cuprate high temperature superconductors 15m
        Charge ordered phases are now found in a wide range of underdoped cuprate high temperature superconductors. The relationship between these phases and nearby antiferromagnetic, superconducting, and pseudogap phases is not well established. However, the close proximity of the different phases suggests the possibility of nontrivial mixed states comprising multiple coexisting phases. In this talk, I will review our recent theoretical calculations to understand charge order and, in particular, its relationship to the pseudogap.
        Speaker: Prof. Bill Atkinson (Trent University)
      • 09:15
        Gapless superconductivity on the surface of a 3D topological insulator 15m
        Recent angle-resolved photoemission experiments have observed a proximity-induced superconducting gap in the helical surface states of the 3D topological insulator Bi$_2$Se$_3$, when a thin film of the latter is grown on a superconducting NbSe$_2$ substrate. The superconducting coherence peaks are strongly suppressed when the topological insulator thin film is doped with magnetic Mn impurities, which was interpreted as a destruction of superconductivity in the topological surface states. Motivated by these experiments, we explore a different possibility: gapless superconductivity, where a gapless electronic density of states coexists with a nonzero superconducting order parameter. We study a model of superconducting Dirac fermions coupled to random magnetic impurities within the Abrikosov-Gor'kov framework, and find finite regions of gapless superconductivity in the phase diagram of the system for both proximity-induced and intrinsic superconductivity.
        Speaker: isil ozfidan (University of Alberta)
      • 09:30
        Temperature-Dependent Band Structure of LaAlO$_3$/SrTiO$_3$ Interfaces 15m
        In recent years, the two dimensional electron gases ($2$DEG) that form at some oxide interfaces have attracted worldwide attention due to their fascinating properties such as conductivity, superconductivity, and magnetic order. Here, we build a theoretical model for exploring the electronic properties of the $2$DEG at LaAlO$_3$/SrTiO$_3$ interfaces considering the strong dependence of the dielectric constant of SrTiO$_3$ on temperature, electric field, and wave vector. We model the SrTiO$_3$ dielectric properties using Landau-Ginzburg theory for the polarization. By solving a set of self-consistent Hartree equations for the charge density and lattice displacement, we obtain the band structure and charge density profile for the SrTiO$_3$ film at different temperatures and different doping. We find that the charge density is less confined to the interface at low temperatures and low doping.
        Speaker: Mrs Amany Raslan (Trent University)
      • 09:45
        Gradient Flow in the Ginzburg-Landau Model of Superconductivity 15m
        The Ginzburg-Landau model for superconductivity provides a phenomenological description of superconductors near the critical temperature where a phase transition between superconducting and regular states occurs. The model has a single dimensionless free parameter, $\kappa$, that has a critical value separating type I and type II superconductors. Of particular interest are the vortex solutions (which are known to occur in type II superconductors) where we have some quantized magnetic flux through the material. We study the dynamics of the vortices using the gradient flow of the free energy. The gradient flow gives a system of coupled partial differential equations whose stationary points are given by the solutions to the Ginzburg-Landau equations. Far from equilibrium, the flow equations provide a description of the dynamics of a configuration with multiple vortices that evolves as quickly as possible to minimize the energy. Close to equilibrium the flow equations tell us about the stability of the vortices. We solve the equations numerically to study the interactions between vortices as well as the decay of larger vortices into multiple smaller ones. We find two different time-scales, a short time-scale where vortices form, and a longer time-scale where the vortices interact with eachother.
        Speaker: Paul Mikula (University of Manitoba)
      • 10:00
        Muon Spin Rotation/Relaxation as a Probe of Unconventional Superconductivity 30m
        There has been a resurgence of interest in superconductivity since the discovery of high temperature superconductivity in the cuprates. As a result, a variety of new superconductors with high transition temperatures and other interesting properties have been discovered. The muon spin rotation/relaxation ($\mu$SR) technique is an extremely sensitive probe of magnetic fields in materials and has been used to determine electronic/magnetic phase diagrams and measure the London penetration depth. Measurements in zero magnetic field ZF-$\mu$SR allowed us to identify a broken time reversal symmetry superconducting state in Sr$_2$RuO$_4$. The most likely superconducting state in this system is the chiral p-wave state which could potentially be employed for quantum computation. I will describe our transverse field TF-$\mu$SR measurements of the vortex lattice in Sr$_2$RuO$_4$ determining the magnetic field penetration depth to further characterize its superconducting state. I will also describe some of our recent measurements of other novel superconductors including iron pnictides, the non-centrosymmetric CaIrSi$_3$ and the strong spin-orbit coupled Pt$_{0.05}$Ir$_{0.95}$Te$_2$.
        Speaker: Graeme Luke (McMaster University)
    • 08:30 10:30
      W1-2 Energy Frontier: Standard Model and Higgs Boson (PPD) / Frontière d'énergie: modèle standard et boson de Higgs (PPD) Colonel By B205

      Colonel By B205

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Richard Ford (SNOLAB)
      • 08:30
        Standard Model and Higgs boson studies with the ATLAS detector 30m
        After about two years of operation, the excellent performance of the LHC and the ATLAS detector made possible, a number of important experimental results, including precision test of the Standard Model and the discovery of a new scalar particle compatible with the Higgs boson. The ATLAS experiment has been enthusiastically analyzing the LHC data recorded a centre of mass energy of 8 TeV and 13 TeV. This talk will explore some of these recent results that are pushing our understanding of the Standard Model and might open the door to more intriguing questions.
        Speaker: Joany Manjarres (York University (CA))
      • 09:00
        Production of Silicon Strip Modules for the ATLAS Phase-II Upgrade of the Inner Detector 15m
        The Phase-II upgrade of the Large Hadron Collider (HL-LHC) will increase the luminosity of the machine by a factor of 10, providing an additional integrated luminosity of 3000 fb-1 over the course of 10 years. The present ATLAS inner detector must therefore be completely replaced in order to cope with the high pileup and radiation environment of the HL-LHC. The new all-silicon tracker (ITk) will be composed of pixel and strip layers, an extensive undertaking which will involve the coordinated effort of many groups around the world. After the development of a dedicated lab and clean room, the University of Toronto, in partnership with industry, successfully fabricated and tested the first ITk silicon strip modules produced entirely in Canada. The readout boards ("hybrids") of individual strip modules are wire-bonded to the silicon, and as such the success and reliability of these bonds are crucial for the functioning and longevity of the detector. Optimization of the wire-bonding process is therefore very important, in addition to ensuring even and precise glue heights between the hybrids, silicon, and other surface-mounted components. As the next phase of prototype fabrication begins, studies of wire-bonding optimization and metrology are performed. In addition, we are investigating the possibility of industrializing the production process of the hybrids in anticipation of mass-production. Finally, we are implementing a beta test set-up for the characterization and testing of electrical modules.
        Speaker: Laurelle Maria Veloce (University of Toronto (CA))
      • 09:15
        ATLAS New Small Wheel (NSW) small-strip Thin Gap Chamber (sTGC) simulation in Athena 15m
        The muon detector subsystem known as the small wheel of the ATLAS experiment will be completely replaced during the long shut down of the LHC starting in 2019. The replacement New Small Wheel (NSW) will have 16 sensitive layers, these layers are comprised of 2 different detector technologies: 2 quadruplet layers of small-strip Thin Gap Chambers (sTGC) and 2 quadruplet layers of MicroMegas detectors (MM). The NSW is built from trapezoidal segments being constructed at institutions around the world including Carleton University. The NSW will be situated in a background radiation dense region (up to 15 kHz/cm$^2$) where it will have to provide Level-1 online trigger information as well as accurately reconstructing muons. The required performance criteria are substantial, particularly a single hit resolution of roughly 100 $\mu$m and providing track segments reconstructed online with an angular resolution of roughly 1 mrad. These requirements are motivated by the need to reconstruct muons in the very forward region of ATLAS with high efficiency and high background rejection. The NSW will enable the ATLAS collaboration to study the standard model, in particular the decay of the Higgs Boson into 4 muons, throughout future LHC upgrades beyond 2022. The task of simulating the response of these sTGC chambers in the ATLAS Athena framework and the validation of the simulation is the focus of the research. The sTGC chambers consist of a gas gap with anode wires (1.8 mm pitch) and 2 distinct cathode planes: one with large area pads to serve as a fast trigger ($<$25 ns) and the other with 2.7 mm wide strips for precise tracking. The research involves simulating the behavior of the chamber due to energy deposition by ionizing radiation. This simulation includes the drifting of ionization electrons towards the anode wires, an analytic model of the charge dispersion on the cathode strips through a resistive graphite layer, the electronic response of the VMM readout chip, cross talk of neighboring channels and statistical response of the detector as a function of incident muon angle and energy. The simulation is used to perform detailed timing studies of the VMM reading chips including the effects of threshold, noise level and dead time. The simulation results are also used to perform a study of trigger efficiency from minimum ionizing muons, an efficiency of 96% was observed.
        Speaker: Stephen Weber (Carleton University (CA))
      • 09:30
        Search for direct top squark pair production in events with two tau leptons with the ATLAS detector 15m
        A search for direct pair production of the supersymmetric partner of the top quark in events with two tau leptons has been performed using proton-proton collision data. The 20 fb$^{-1}$ of $\sqrt{s}=8$ TeV data were collected in 2012 by the ATLAS experiment at the LHC. The search is optimised for a model where both top squarks decay via a scalar tau to a nearly massless gravitino. No significant excesses from the Standard Model expectations are found. Exclusion limits at the $95\%$ confidence level are set as a function of the top squark and scalar tau masses. Depending on the scalar tau mass, lower limits between 490 GeV and 650 GeV are placed on the top squark mass within the model considered.
        Speaker: Ewan Chin Hill (University of Victoria (CA))
      • 09:45
        Search for supersymmetric partners of gluons and third generation quarks in events with b-jets and large missing transverse momentum in 13 TeV proton-proton collisions at the LHC using the ATLAS detector. 15m
        Supersymmetry, a generalisation of the space-time symmetries which associates a new boson to each Standard Model fermion and vice-versa, must be obervable near the weak scale in order to solve the hierarchy problem. If the lepton and baryon numbers are conserved, the lightest supersymmetric particle is stable and interacts only weakly providing a viable dark matter candidate. Searches for supersymmetry at the LHC are thus highly motivated. A search for strong production of pairs of gluinos, the supersymmetric partner of the gluon, decaying via sbottom and stop quarks, the supersymmetric partners of the bottom and top quarks, is reported. A 3.3 fb-1 13 TeV proton-proton LHC dataset, recorded by the ATLAS detector, is used. This sample is probed for events containing several high transverse momentum jets, of which at least 3 must be identified as originating from b-quarks, large missing transverse momentum, and potentially isolated charged leptons. Massive large-radius jets, indicating the presence of highly boosted top quarks, are also used. No significant deviation from the Standard Model prediction is observed and limits are set in the gluino-neutralino mass plane in the framework of simplified models of gluinos decaying via sbottom and stop quarks. Large increase in cross-sections for gluino pair-production with respect to the 8 TeV LHC and the recent installation of the Insertable B-Layer at the center of the ATLAS detector, which appreciably improves the b-jet identification performance, allows the previous limits to be significantly increased using the relatively small 2015 LHC dataset. For neutralino masses below approximately 700 GeV, gluino masses of less than approximately 1.8 TeV are excluded at the 95% CL in both models, constituting the current world-wide best limits in these frameworks and some of the biggest improvements with respect to LHC run 1 searches so far.
        Speaker: Louis-Guillaume Gagnon (Universite de Montreal (CA))
      • 10:00
        Towards First Physics At Belle II 30m
        The next-generation B-factory Belle II at the upgraded KEKB accelerator, SuperKEKB, is aiming to start physics data taking in 2018. It is an asymmetric e+e- collider that will operate with 40x the instantaneous luminosity of KEKB/Belle. The broad physics program will cover physics with B and D mesons, muon and tau leptons as well as measurements using the method of radiative returns and direct searches for New Physics. This talk will summarize the current status of the accelerator and the detector with emphasis on the electromagnetic calorimeter. This talk will furthermore give an overview about physics topics for the first data with a focus on direct searches for Dark Photons decaying into standard model particles or light dark matter.
        Speaker: Torben Ferber (University Of British Columbia)
    • 08:30 10:30
      W1-3 Testing Fundamental Symmetries I (DNP-PPD-DTP) / Tests de symétries fondamentales I (DPN-PPD-DPT) Colonel By D207

      Colonel By D207

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Dr Gerald Gwinner (University of Manitoba)
      • 08:30
        Tests of the electroweak interaction from studies of the beta decay of trapped 8Li ions 30m
        Detailed studies of nuclear beta decay can provide stringent tests of the Standard Model of particle physics. In the beta decay of $^{8}$Li, the nucleus emits an electron and an antineutrino, and the daughter $^{8}$Be nucleus is left in an excited state which breaks up into two alpha particles. The angular correlations between these decay products are sensitive to any possible tensor contribution to the pure “vector minus axial-vector” structure of the electroweak interaction. The Beta-decay Paul Trap (BPT), an open-geometry radiofrequency-quadrupole ion trap which is instrumented with an array of double-sided silicon strip detectors, has been used to precisely study these angular correlations. The BPT is used to suspend the $^{8}$Li nuclei in vacuum so that the energy and momentum of the two alpha particles and the direction of the electron can be precisely determined. From this information, the energy and direction of each emitted antineutrino, despite them being virtually undetectable, could be inferred from energy and momentum considerations and the angular distribution of the neutrinos from the decay was precisely determined. For the first time in over half a century, the tensor-interaction limits obtained from electron-neutrino angular measurements have been improved. In addition, data of similar quality on the decay of $^{8}$B has been obtained, which, when combined with the data from the $^{8}$Li decay, will provide additional tests of fundamental symmetries.
        Speaker: Nicholas Scielzo (Lawrence Livermore National Laboratory)
      • 09:00
        Search for a permanent electric dipole moment of the Ra-225 atom 30m
        The observation of a permanent electric dipole moment (EDM) in a non-degenerate system would indicate violation of time reversal symmetry (T violation) or, equivalently, C(charge)P(parity) violation due to the CPT theorem. The diamagnetic Ra-225 atom is a favorable system in the search for a permanent EDM. This is because the experimental sensitivity to CP violation in radium is enhanced due to its high atomic mass and its octupole deformed nucleus. Ra-225 has nuclear spin I=1/2 and a half-life of 14.9 days. Due to radium’s low vapor pressure and its relative scarcity, we use techniques of laser cooling and trapping to enhance our sensitivity to small number of atoms. The experiment involves collecting laser cooled radium atoms in a magneto-optical trap (MOT), transporting them 1 meter with a far off-resonant optical dipole trap (ODT) and then transferring the atoms to a second standing-wave ODT in an experimental chamber. In this talk I will discuss the recent results from the experiment and plans for future improvements.
        Speaker: Mukut Kalita (Triumf)
      • 09:30
        The Ultra-Cold Neutron Facility at TRIUMF 15m
        Construction of an Ultra-Cold Neutron (UCN) facility is nearing completion in the TRIUMF Meson Hall. The new 500 MeV proton beamline (BL1U) and neutron spallation target, which feeds the superthermal UCN source, will be completed and transition over to the commissioning phase in Spring 2016. As well, the front end of the UCN source will be installed and also undergoing commissioning tests. Installation of the full UCN source is scheduled for completion during the second half of 2016, with UCN production expected in late 2016. A first experiment searching for the neutron electric dipole moment (nEDM) is currently being planned. The design and construction highlights, as well future plans for the UCN facility, will be presented.
        Speaker: Larry Lee (TRIUMF)
      • 09:45
        Design of the first neutron production experiment using the new TRIUMF UCN beamline 15m
        Our final goal is the measurement of the neutron electric dipole moment with ultracold neutrons (UCN). A new proton beamline for the UCN experiment was recently constructed at TRIUMF. UCNs will be produced by the superfluid He-II UCN source shipped from Japan. For the beam operation, sufficient radiation shields are necessary. We optimized the design of the shields and the layout of the UCN guide pipe to minimize the UCN loss as well as the radiation leakage. This year, we will start the first beam commissioning. In the commissioning, we aim to precisely measure the cold neutron flux since it is important to gain a better understanding of the UCN production. In this presentation, we will report the design of the radiation shields and the first beam commissioning in the TRIUMF UCN beamline.
        Speaker: Dr Tatsuya Kikawa (TRIUMF)
      • 10:00
        Custodial symmetry violation in the Georgi-Machacek model 15m
        We study the effects of custodial symmetry violation in the most general scalar potential of the Georgi-Machacek model (GM). The GM model, which adds isospin triplet scalars to the Standard Model, preserves SU(2) custodial symmetry at tree level by imposing a global SU(2)$_L\times$SU(2)$_R$ symmetry and produces a degenerate fiveplet, a degenerate triplet and two singlet states. Custodial symmetry violation is induced by hypercharge gauge interactions when the model is run down to the weak scale from a higher scale at which the exact SU(2)$_L \times$SU(2)$_R$ global symmetry is imposed on the scalar potential. The magnitude of the running is heavily constrained by the $\rho$ parameter. The effect of this small custodial violating running is quantified using a linearized approximation to solve the renormalization group equations (RGE) of the custodial violating parameters while the RGE of the custodial preserving parameters is solved numerically. We compute the resulting custodial-violating mass splittings and mixings among the original states and study the consequences for the Higgs couplings to fermions and gauge bosons. Numerical scans over the allowable parameter space are also performed.
        Speaker: Ben Keeshan (Carleton University)
      • 10:15
        Using dressed fields to extract gauge invariant information. 15m
        The existence of unexpected states (states not predicted by the conventional quark model) in heavy Quarkonia, specifically Charmonium and Bottomonium like states, is of great interest to modern particle physics. States like X(3872), \(Y_{b}\)(10890), \(Z^{\pm}_{b}\)(10610), and \(Z^{\pm}_{b}\)(10650) have proven difficult to reconcile with the conventional quark model. However, analysis of diquark constituent masses has pointed towards tetraquark configurations being responsible for many of these exotic states. Thus far, the diquark correlations required for a tetraquark configuration of X(3872) have been primarily examined through the use of diquark correlation functions where the Schwinger string is introduced to ensure the gauge invariance of the diquark correlator. Here, research is presented on the use of dressed fields for diquark currents. Results for doubly light, light-heavy, and doubly heavy diquark systems have been obtained, and all results have shown this dressed field method to be an effective means of extracting gauge invariant results from diquark correlation functions.
        Speaker: Mr Paul Smith (University of Saskatchewan)
    • 08:30 10:30
      W1-4 Radiation Therapy (DPMB-DNP) / Thérapie par rayonnement (DPMB-DPN) Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Melanie Martin (University of Winnipeg)
      • 08:30
        The role of advanced dose calculation methods in modern brachytherapy techniques 30m
        Radiation therapy is used in the treatment of almost 50% of all cancers in industrialized countries. Over the years, advances in engineering, computer technology, material sciences and biology has enabled medical physicists to devise more accurate radiation delivery systems. One of the oldest forms of radiation therapy is brachytherapy, or originally called Curiethérapie in honor of Marie Curie. In brachytherapy one or more radiation sources are placed within or in close proximity of the tumor mass, thus spearing more easily normal tissues and limiting irradiation to a small area of the body. While medical imaging has been central to the new generation of brachytherapy systems currently available, it is but one of many enablers. In this presentation, we will underline the increasing role that advanced dose calculation methods, in particular the Monte Carlo, are playing in developing the next generation of treatments for cancer patients. This includes the design of new sources, the extraction of their dosimetric characteristics, the development of new applicators and better treatment planning and dose optimization algorithms. Looking forward, the Monte Carlo method will likely be central to the safe and accurate deployment of targeted therapies based on a combination of radioisotopes and nanomaterials. It could further play an important role in modeling the interaction physics, and ensuing chemical processes, of radiation with DNA and other cellular structures.
        Speaker: Luc Beaulieu (Université Laval)
      • 09:00
        Comparison of quantum and classical trajectory Monte Carlo simulations of low energy electron transport in water and biological tissues 15m
        Monte Carlo simulations are increasingly applied in medical physics to understand radiation interactions and energy deposition on sub-micron length scales within biological targets, e.g. DNA. These classical trajectory Monte Carlo simulations neglect the quantum wave nature of electrons, however, quantum effects may become non-negligible at sub-1 keV energies. In this work, quantum mechanical (QM) and classical trajectory Monte Carlo (MC) simulations are compared within a simplified model of electron transport in small droplets of condensed media. In QM simulations, water droplets are modeled as collections of $>10^3$ point scatterers (molecules) from which electrons may be isotropically scattered. Scatterer positions are random or constrained by a minimum scatterer-to-scatterer separation, $d_{min}$. Elastic and inelastic (absorption) cross sections are varied. For QM calculations, the system of $>10^3$ coupled equations for the electron wavefield incident on each scatterer is solved numerically for each droplet; results are then averaged over $>10^5$ droplets each with different scatterer positions but otherwise same parameters. Average QM water droplet incoherent differential cross section and scattering event density are compared with MC analogues; relative errors on MC results are computed. Relative errors on MC results are sensitive to electron wavelength, droplet shape and structure, scatterer number density, and interaction cross sections; relative errors on droplet differential cross section generally differ from errors on scattering event density. The inclusion of structure ($d_{min}\ne0$) enhances differences between QM and MC results: relative errors increase with $d_{min}$. Introducing inelastic scatter while maintaining the same elastic scatter cross section generally increases relative errors with some exceptions (e.g. longer wavelengths and large inelastic cross section). The quantum wave nature of electrons should not be neglected for accurate simulations of radiation interactions and energy deposition on short length scales within biological targets. Ongoing work involves the development of more realistic models of electron transport in condensed media.
        Speaker: Prof. Rowan Thomson (Carleton University)
      • 09:15
        Characterization of radioresistance in human ovarian cancer cells 15m
        The development of a radiosensitivity predictive assay is an attractive goal in radiation oncology. Since there is a high degree of inter-patient variability in the inherent sensitivity or resistance to therapy, it is crucial to have the ability to identify molecular markers that correlate with sensitivity or resistance to radiation treatment. We have applied Raman micro-spectroscopy (RMS) in vitro to discriminate between the ovarian carcinoma cell lines A2780s (parental wild type) and A2780cp (cisplatin cross radio-resistant variant). These two cell lines represent a good model of tumor tissues of similar origin but with different intrinsic chemo- and radio-sensitivities. Moreover, their radiobiological behavior has been extensively studied and their survival curves under different irradiation schemes are known. The Raman spectra collected from individual cells undergo initial preprocessing (background subtraction, normalization and noise reduction) to yield true Raman spectra representative of the cells. The mean of these spectra are analysed with Principal Component Analysis (PCA) followed by Linear Discriminant Analysis (LDA) to yield a strong separation between the cell lines. The objective of this ongoing work is to characterize the spectral differences between the two cell types in order to determine the underlying biochemical basis for this separation. The multivariate classification model constructed using such Raman spectra of ovarian cancer cells could potentially be utilized for early prediction of tumor response.
        Speaker: Mr Hamid Moradi (Dept. of Physics, Carleton University)
      • 09:30
        Energy-cascaded Upconversion Nanoparticles for 800 nm Activated Photodynamic Therapy 15m
        Photodynamic therapy (PDT) is emerging as a novel clinical approach that uses light (including laser sources) and photoactivatable compounds (photosensitizers) for the treatment of various tumors and other non-malignant conditions. PDT has potential advantages over surgery and other therapies, being minimally invasive, with accurate targeting and few side effects. However, most clinical PDT agents are activated at wavelengths of 630-690 nm, at which the tissue penetration and effective depth of treatment are limited. Hence, one focus of current PDT research is to develop compounds sensitive to light at near-infrared (NIR) wavelengths. Upconversion nanoparticles (UCNPs) have been extensively explored for NIR-activated PDT due to their large anti-Stokes shifts, excellent bio-compatibility and photochemical stability. In order to overcome the heat effect from 980 nm excitation lasers in conventional UCNP-based PDT, we developed an energy-cascaded upconversion nanoplatform excited with 800 nm continuous lasers for PDT. NaYF4:Yb,Er,Nd@NaYF4:Nd core-shell nanoparticles were coupled with carboxylic acid-functionalized IR780 and rose bengal via direct electrostatic interactions and exhibited a large production of cytotoxic singlet oxygen under 800 nm laser excitation. Due to a close contact between each component, high energy transfer efficiencies of the energy-cascaded pathway (dye → upconversion nanoparticles→rose bengal) were achieved. With antenna effects contributed by near-infrared dyes attached to the nanoparticle surface, the photon harvesting ability of the UCNPs were dramatically improved (∼ 30-fold) with low excitation power density being required for singlet oxygen production. Our nanoplatform has potential to achieve 800 nm laser-activated photodynamic therapy for treatment of challenging deep tumors.
        Speaker: Mr Yang Hu (Department of Chemistry, University of Waterloo)
      • 09:45
        Inductively coupled plasma mass spectrometry of photocorroding GaAs/AlGaAs nano-heterostructures in aqueous environments 15m
        Photonic biosensors based on photocorrosion of GaAs/AlGaAs nano-heterostructures have been investigated as an attractive platform for low-cost and rapid detection of bacteria in aqueous environments.1, 2 Both GaAs and Al0.35Ga0.65As layers are unstable in an aqueous surrounding when illuminated with photons of energy exceeding bandgap of either of these materials. Among elements released to a biochip-containing cell, arsenic is of particular importance as the presence of this element could affect metabolism of some bacteria. 3, 4 To investigate the rate of photocorrosion, we have employed an inductively coupled plasma mass spectrometry (ICP-MS) technique. For this purpose, a series of samples were prepared with small volumes of the product of photocorrosion collected from GaAs/Al0.35Ga0.65As nanoheterostructures photocorroding for the same periods of time, for up to 14 hours. The nanoheterostructures were excited with an LED light source operating at 660 nm wavelength and delivering ~ 20 mW/cm2 of uniform radiation on the surface of investigated samples. For comparison, a series of liquid samples were also analysed for GaAs/Al0.35Ga0.65As nanoheterostructures kept under dark conditions. The results indicate that the maximum amount of As released during biosensing photocorrosion is less than 20 ppb. We discuss dynamics of the photocorrosion process and the influence of the products of photocorrosion on the performance of GaAs/Al0.35Ga0.65As biosensing devices. 1. E. Nazemi, S. Aithal, W. M. Hassen, E. H. Frost and J. J. Dubowski, Sensors and Actuators B: Chemical 207, Part A, 556-562 (2015). 2. M. R. Aziziyan, W. M. Hassen, D. Morris, E. H. Frost and J. J. Dubowski, Biointerphases 11 (1), 019301 (2016). 3. P. I. Harvey and F. K. Crundwell, Minerals Engineering 9 (10), 1059-1068 (1996). 4. V. I. Podol'skaia, T. G. Gruzina, Z. P. Ul'berg, A. S. Sokolovskaia and N. I. Grishchenko, Prikl Biokhim Mikrobiol 38 (1), 57-62 (2002).
        Speaker: Mohammad Reza Aziziyan (Université de Sherbrooke)
      • 10:00
        Electron-Transfer-Based Combination Therapy of Cisplatin with a Molecular Promoter for Cancer Treatment 15m
        Cisplatin is a very widely used platinum-based chemotherapy drug and is the cornerstone agent in treating a variety of cancers, including ovarian cancer, testicular cancer, cervical cancer, bladder cancer, lung cancer, head and neck cancer, lymphoma, and brain tumors. It is one of the few curative anticancer agents. However, its clinical application is often limited by severe toxic side effects and resistance possessed by various cancers. Our group has recently, through the femtomedicine approach, unraveled a new molecular mechanism of cisplatin. We found that cisplatin is extremely effective for the dissociative electron transfer (DET) reaction [1,2] to produce a reactive radical that causes DNA strand breaks, apoptosis and final clonogenic cell kill. Based on this DET mechanism, it is proposed that cisplatin may be administered in combination with a biological electron donor PM to enhance the chemotherapeutic efficacy. We have obtained promising results in in vitro tests of a few combinations. Through cell survival experiments, MTT assays and clonogenic assays, it has been shown that our proposed combinations significantly enhance the cell-killing on cancer cells, but surprisingly, not on normal cells. Besides, γ-H2AX staining on treated cells indicates that more double strand breaks can be induced using our combination. In addition, measurements on caspase 3/7 activity clearly show an enhancement in the population of apoptotic cells using our combination. Xenograft mouse models have also proved the anti-cancer effect of our combination. Furthermore, spectroscopic measurement has confirmed the electron transfer reaction between cisplatin and PM. These results show great potential of the DET mechanism to improve the therapy of cancer using cisplatin. [1] Lu, Q.-B., Kalantari, S., and Wang, C.-R. (2007) Electron transfer reaction mechanism of cisplatin with DNA at the molecular level. Mol. Pharm. 4, 624–8. [2] Lu, Q.-B. (2007) Molecular reaction mechanisms of combination treatments of low-dose cisplatin with radiotherapy and photodynamic therapy. J. Med. Chem. 50, 2601–4.
        Speaker: Qinrong Zhang (University of Waterloo)
      • 10:15
        Red Blood Cell Ghosts for biomedical applications: Blood on a Chip 15m
        The preparation of Red Blood Cell (RBC) Ghosts is a well-known protocol in biological and medical research. It describes the extraction of the membranes from RBCs. Another well-known protocol is the preparation of highly ordered stacks of artificial lipid bilayers on silicon wafers. This technique is useful for analyzing the molecular structure and dynamical properties of these bilayers via X-Ray and neutron scattering experiments, and other biophysical techniques. Such experiments in particular allow the study of the interaction between cell membranes and drugs, small molecules, and bacteria. There are various attempts to adapt this protocol to a native cell membrane. For the first time we were able to combine both described protocols and to prepare highly ordered stacks of RBC membranes on silicon wafers. These systems can now be used as inexpensive and safe platforms for testing the effect of drugs and bacteria on RBC membranes in-vitro using biophysical techniques, such as X-ray and neutron diffraction, optical spectroscopy and AFM. We present the preparation and characterization of “Blood on a Chip” from molecular structure to the morphology of the membrane assemblies. Aspirin, which is commonly used in the “low-dose-aspirin therapy” was found to have a drastic effect on our human blood membranes and leads to a significant softening and fluidification of the membranes.
        Speaker: Sebastian Himbert (Mcmaster University)
    • 08:30 10:30
      W1-5 Solar Energy Materials and Solar Cells (DCMMP-DAMOPC) / Matériaux pour l'énergie solaire et piles solaires (DPMCM-DPAMPC) SITE A0150

      SITE A0150

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Ayse Turak (McMaster University)
      • 08:30
        Paths for High-Efficiency Low-Cost Photovoltaics 30m
        Over the last couple of decades, the field of photovoltaics has experienced dramatic advances both scientifically and technologically. Critical elements playing into these advances have been the development of novel solar materials, innovative light trapping approaches, and innovative device integrations and enhancements. This talk will provide an introductory overview of the advances in incumbent technologies of silicon and III-V multijunction crystalline semiconductors as well as highlight the nascent and rapidly progressing perovskite solar cells – considering that the focus of all technologies is to continuously advance both high-efficiency and low-cost. Thereafter, the talk will speak to molding the flow of light and passivation as critical aspects to the attainment of high-efficiency solar cells, and in particular with regard to thin Si solar cells. Photonic crystals, periodic nanostructures that exhibit optical bandgaps and various propagation modes, provide an opportunity for control over reflection, transmission and trapping of light in a given device construct. Potential paths for photonic crystal integration in silicon solar cells will be discussed. Specifically, successful integration of recently developed selectively transparent and conducting photonic crystal as an intermediate reflector in a multi-junction thin film silicon photovoltaic cell will be presented. Further, possible patterning of silicon into a photonic crystal absorber itself will be considered. In this context, the importance of surface passivation will be highlighted and in particular recent development of low temperature optically transparent passivation material and their integration in silicon devices will be given.
        Speaker: Prof. Nazir P. Kherani (University of Toronto)
      • 09:00
        Lateral silicon structures for light-trapping enhancement in solar cells 15m
        Si wires vertically grown by the vapor-liquid-solid (VLS) method have been frequently reported in literature, and has been considered as the long-standing symbolic image of this method. The efforts have been focused on studying the vertical Si wires-based solar cells in the last decades. In this study, the lateral or horizontal growth of Si wires recently reported by our group has been incorporated into Si-based solar cell devices. The reduction of optical losses is one of the important factors in obtaining high-efficiency solar cells. In order to achieve this, the top surface of the solar cells are often texturized or covered with antireflection coating. Lateral Si wires and Si film with various morphologies are on the solar cell devices fabricated on Si(001) substrates by the molecular beam epitaxy (MBE). Enhancement of light trapping in the presence of top epitaxial layer was demonstrated. We analyzed the surface morphology and size distribution of Si wires and alternative morphological features by scanning electron microscopy (SEM). Our results show that the lateral growth of silicon wires has been only initiated around the carbon-contaminated Au catalyst particles covered surface areas. The performance of lateral Si wire-based solar cells has been tested and correlated with topmost Si layer morphology. Efficiency enhancement by 1.5 to 2.5 times was observed for highly corrugated surfaces. Notably, the best efficiencies are achieved for Si overlayer structures (Si wires, ridges and films), where significant area on the surface becomes covered with rough epitaxial Si structures, and the magnitude of the surface roughness exceeds 200-500nm. Different mechanisms contributing to this enhancement will be discussed.
        Speaker: Lyudmila Goncharova (The University of Western Ontario)
      • 09:15
        Nighttime solar cells 15m
        Energy demand from the electrical grid is substantially higher during evening times when solar panels cannot contribute to electrical power generation. The fact that solar cells only produce energy during daytime necessitates their costly integration with expensive storage components. At the present cost levels, even a solar panel operating at the theoretical maximum of 70% power conversion efficiency would not be competitive with fossil fuels due to the cost of batteries used to dispatch solar power at night. Here we introduce a new family of photovoltaics capable of generating power in the dark by exploiting the afterglow redox properties of strontium aluminate, a persistently luminescent (PL) material, in a way that, even after 9 hours operation in the dark, our photovoltaics still produce an afterglow short-circuit current that is 75% of the amount generated immediately after illumination. We demonstrate that our "nighttime" photogeneration system can be integrated into dye-sensitized solar cells, and, potentially, other types of photovoltaics for optimized power generation during daytime and nighttime. our work offers unique advances in the photo-physics of PL materials through the invention and operation of nighttime solar cells. Although 1-sun power conversion efficiency from our devices is apparently low (1%), overnight electrical power generation from afterglow currents make them uniquely competitive on the energy market, because low efficiency under illumination is at least partially compensated by power storage and release in the afterglow.
        Speaker: ye li (uwo)
      • 09:30
        In-situ investigation of charge transport/recombination dynamics in organic semiconductors over wide time range at microscopic scale 15m
        Organic semiconductors have garnered a lot of interest in the recent years owing to their easy processibility, tunability to required optical and electrical properties, and of course to their cost-effectiveness. Their use in the organic light-emitting diodes and photovoltaics is already quite promising. However, the charge mobility in these materials is strongly affected by their structural disorder and the energetic disorder introduced by the defects that act as traps to the charge carriers. Depending upon their physical location, be it interfacial or the bulk of the material; and distribution of energetically favoured level, these traps significantly affect the carrier current flow. In this work, the dynamics of injected/photogenerated charge carriers' recombination and transportation are studied over wide range of time scales. The charged carrier current relaxation dynamics, post pulsed electrical/optical excitation, is studied using time-resolved fluorecence(TRF) in the time range of few tens of picoseconds to few microseconds, while higher time-range dynamics of upto many milliseconds is investigated using the technique called Charge extraction by linearly increasing voltage(CELIV). Polythiophene based polymer P3HT, and the same blend-doped with Phenyl-C61 -Butyric acid Methyl ester(PCBM) molecules and Zinc Oxide nanoparticles are studied at microscopic scale under optical microscopy.
        Speaker: Mr Sanyasi Rao Bobbara (Department of Physics, Engineering Physics & Astronomy, Queen's University, ON, Canada)
      • 09:45
        Interfacial degradation in organic thin films for optoelectronic and photovoltaic applications: challenges and opportunities 30m

        After efficiency, lifetime is the second most important parameter for molecular photovoltaic devices. In organic solar cells (OPVs), heterojunctions play a defining in device stability. They also control the major processes: charge separation relies on effective organic/organic interfaces; charge transport is critically determined by the structure of the thin film, controlled by the organic/inorganic interfaces with substrates; and charge extraction can only occur at high quality inorganic/organic interfaces at the electrodes.
        This contribution reviews the current state of the art with regards to interfacial stability of electrode/active layer interfaces to understand the performance of OPVs. From examples relating to interfacial chemical reactions, interfacial morphological changes, and interfacial electronic level modification, a comprehensive picture of the role of the organic-electrode interfaces in device stability can be formed. Beginning with a brief overview of general degradation in organic devices, including definitions and measurement approaches, this contribution then focuses on two key interfaces within the device architecture. The first is the bottom contact (substrate) interface, where chemical reactions and dewetting are the two main mechanisms of device degradation. The second is the top contact interface, which is prone to oxidation, interdiffusion, blistering and delamination, and inhomogeneous loss of performance (dark spots). For both bottom and top contact interface degradation, various approaches to overcoming device instabilities are given, with special attention to the various interlayers that have been introduced for improved stability. Examples are given where degradation mechanisms are used advantageously to produce novel devices and surprising solutions to device degradation.

        Speaker: Ayse Turak (McMaster University)
      • 10:15
        Ultrafast dynamics of a charge density wave in non-equilibrium in 1T-TiSe2 15m
        Spontaneously broken symmetries in solids often result from many-body interactions that fall outside the scope of conventional solid-state models. As a consequence, some of the most fascinating phase transitions such as stripe formation, unconventional superconductivity or colossal magnetoresistance are still not fully understood. Time-resolved multi-terahertz spectroscopy is an ideal optical technique to resolve the microscopic interactions in complex materials and to trace their dynamics on an ultrafast time scale. We apply this optical technique to investigate the non-equilibrium dynamics of a charge density wave (CDW), an intriguing phase characterized by a static modulation of the electronic charge distribution accompanied by a periodic lattice distortion (PLD). In the transition metal dichalcogenide 1T-TiSe2, the CDW occurs at temperatures below 200 K and has been studied with several experimental techniques such as x-ray diffraction and photoemission experiments. These experiments have highlighted two potential driving mechanisms of the phase transition: excitonic correlations and a Jahn-Teller lattice distortion. Despite intense efforts, both in experiments and theory, no consensus could be reached on which one of these interaction mechanisms is the actual driving force of the CDW and which one is simply a consequence of it. Here we perturb the CDW in a 80 nm thin film of single crystalline TiSe2 and monitor the subsequent ultrafast dynamics of the two constituent orders via PLD induced phonons resonances and characteristic terahertz fingerprints of excitonic order [1]. Our experiment reveals a new transient phase in which the PLD persists in a coherently oscillating state while the excitonic order is entirely quenched. These results prove that the CDW transition in 1T-TiSe2 is not solely driven by excitonic correlations, but also by a Jahn-Teller distortion in a cooperative process. Our low-energy spectroscopic technique of ultrafast dynamics associated to a complex long-range order provides a new benchmark for exploring this fascinating class of quantum phenomena in strongly correlated materials. [1] M. Porer et al. Non-thermal separation of electronic and structural orders in a persisting charge density wave. Nature Materials 13, 857 (2014)
        Speaker: Prof. Jean-Michel Ménard (University of Ottawa, University of Regensburg)
    • 08:30 10:30
      W1-6 Instrumentation for the Detection of Low-Level Radioactivity (DIMP) / Appareillage de détection de radioactivité de faible intensité (DPIM) Colonel By D103

      Colonel By D103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Kirk Michaelian (Natural Resources Canada)
      • 08:30
        The New Research Injection Line at the André E. Lalonde AMS Laboratory, University of Ottawa 15m
        In Accelerator Mass Spectrometry (AMS), research into new analytical technologies, the development of new applications, as well as the improvement of existing techniques frequently requires extensive experimental time using ion sources and their associated low energy analytical equipment. To support our research and development program at the André E. Lalonde AMS Laboratory, we are completing a second injection line, which can be connected through to the accelerator and the high energy analysis and detector systems when required. However, it can also be used on a stand-alone basis for low energy experimental work while production analytical work continues on the original injection line. The new line will incorporate two ion sources: one a duplicate of the source on the original line and a second, an upgrade of the SIMS (secondary ion mass spectrometry) source that was used at IsoTrace in Toronto. Either of the sources can be switched into the remainder of the injection line through an electric analyzer with plates that can be rotated, without breaking vacuum, to accept the beam from either source. This analyzer is followed by a 90° magnet with the ability to use electric switching to select nearby isotopes of the element of interest. The magnet is followed by a beam diagnostic box and space for the integration of a pre-commercial version of the Isobar Separator for Anions (ISA)[1]. The ISA[2] uses ion-gas collisions to preferentially remove unwanted isobars while transmitting the isotope of interest; the eV level energies necessary for these interactions require the use of radio-frequency quadrupole ion guides to reduce the effects of scattering and space charge. Following the ISA location are further beam conditioning elements and a 45° magnet for beam analysis during stand-alone operation. In addition to the development work on the ISA, this line will be used for research into improved and new ion source technology. As an example of work that will be done on this line, data obtained using an earlier version of the ISA to separate the isobars Yttrium and Zirconium for the analysis of Strontium will be discussed. More recent work on the development of suitable ion source materials for the analysis of 90Sr will also be presented. 1. Designed and built by Isobarex Corp, Bolton, Ontario - J-F Alary, G. Javahery, W. Kieser, X-L Zhao, A.E. Litherland L. Cousins, C. Charles Isobar Separator for Anions: Current Status, Nuclear Instruments and Methods B 361 (2015) 197-200 2. A.E. Litherland, I. Tomski, X.-L. Zhao, L. M. Cousins, J.P. Doupé, G. Javahery, W.E. Kieser, Isobar separation at very low energy for AMS, Nuclear Instruments and Methods B 259 (2007) 230-235
        Speaker: Prof. William Kieser (Lalonde AMS Lab, Dept of Physics, uOttawa)
      • 08:45
        The Measurement of Actinides by Accelerator Mass Spectrometry 15m
        We developed a simple method to separate Pu and Am isotopes from the sample matrix using a single extraction chromatography column and to measure the concentrations of the isotopes by isotope dilution accelerator mass spectrometry (AMS). Pu and Am in the extraction chromatography column eluent were coprecipitated with NdF3 or Fe(OH)3 and the precipitates were analyzed by AMS at the University of Ottawa, A.E. Lalonde AMS Laboratory. The advantages of each precipitation method were assessed by studying the sensitivity, detection limits, and precision of the Am and Pu isotope measurements. The strongest AMS beams of Pu and Am were produced when there was a large excess of fluoride donor atoms in the target and the NdF3 precipitates were diluted with PbF2. The measured concentrations of Pu-239,240 and Am-241 agreed with the concentrations in standards of known activity and with IAEA certified reference materials. This work demonstrated that both oxide and fluoride targets produce reliable beams of actinide anions and that the measurement of actinides using fluorides agrees with measurements made using oxide precipitates and with the values in certified reference materials.
        Speaker: Jack Cornett (University of Ottawa)
      • 09:00
        The Accurate Determination of Radionuclides without Prior Chemical Separation of Interferences using an Agilent 8800 ICP-MS/MS 15m
        This paper summarizes the accomplishments-to-date of the Agilent 8800 ICP-MS/MS in the direct determination of the radionuclides, 90Sr+, 129I+, 137Cs+, 238Pu+, 239Pu+, and 236U+/238U+ ratios by tandem mass spectrometry with chemical resolution using gas-phase ion chemistry. The ICP-MS/MS configuration consists of a collision reaction cell (CRC) between two quadrupole mass filters, Q1 and Q2. The abundance sensitivity afforded by tandem MS is better than 10E-10, eliminating wing overlaps of 127IH+ on 129I+ and 238U+ on 237Np+ and 239Pu+. The CRC is filled with a gas that reacts with the analyte and its interferences at different rates. When the reaction kinetics favor the analyte, the analyte is converted to a molecular ion which is then measured in “mass-shift” mode. The interference from 235UH+ on 236U+ was circumvented by oxidizing U with O2. The 236U+/238U+ ratio was determined as a 236U16O+/238U16O+ ratio. When the reaction kinetics favor the interferent, the interferent is converted to another form and the analyte is measured at its elemental mass (the “on-mass” mode). Differences in the oxidizing efficiencies of N2O, O2, CO2 were used to discriminate interferences Ba+ from Cs+, 90Zr+ from 90Sr+, and 239U+ from 239Pu+, respectively. The 238U+ interference on 238Pu+ was removed by reacting U+ to amine cluster ions by a blend of 10% NH3/90% He. The 129Xe+ interference on 129I+ was removed by charge transfer reaction with O2. Q1 is unique to the Agilent 8800x ICP-MS/MS: it is a unit mass resolution mass spectrometer, operated under vacuum, and precedes the reaction cell. This configuration is vital for the successful and simple implementation of chemical resolution in ICP-MS. Results from the efforts of many scientists will be presented.
        Speaker: Ms Pamela Wee (Agilent Technologies Canada Inc)
      • 09:15
        CaF3-/KF3- on-line separation methods and the present 41Ca/Ca sensitivity at AEL-AMS 15m
        The use of 41Ca as a sensitive long-period tracer for osteoporosis diagnoses is made possible by accelerator mass spectrometry (AMS), with which CaF3- ions are produced and the resulting MeV positive 41Ca ions are counted. When the ion energy is sufficiently high, 41Ca and its interfering isobar 41K can be well separated by their dE/dx differences in the final ionization detector. Such applications to the populace at large, however, still await the creation of efficient small (<1MV) AMS systems that can still have a sufficiently high abundance sensitivity (41Ca/Ca~1e-13 or better). At present, small AMS systems do not have effective means to separate 41Ca from 41K on-line. Two potential methods have been explored in Canada, one exploits the molecular binding differences in CaF3- and KF3-, and the other exploits the yield differences when CaF3- and KF3- are partially fragmented into CaF+ and KF+. While these are being further developed at Lalonde AMS of uOttawa, its existing capability for 41Ca analysis using the AMS system as is, has also been determined. The 41Ca/Ca abundance sensitivity using the straightforward fast sequential injection technique between 41CaF3- and 40CaF3-, is found to be ≤5e-13 with the 3MV tandem accelerator running at its designed upper voltage limit. This is already adequate for supporting 41Ca medical research at the new and presently the only AMS facility in Canada.
        Speaker: Xiaolei Zhao (University of Ottawa)
      • 09:30
        Separation and analysis of Sr-90 and Zr-90 for nuclear forensic applications 15m
        In this work, a technological development to determine the age of radioactive strontium sources through the [Zr-90]/[Sr-90] ratio using mass spectrometry and liquid scintillation to quantify both isotopes is presented. Because Sr-90 and Zr-90 are isobaric interferences in mass spectrometry, a radiochemical separation to isolate Zr-90 has been shown to be mandatory prior to analysis. Four commercial resins (AG50W-X9, Dowex1-X8, Sr and DGA resins) were tested to isolate Zr-90 from Sr-90. Best performance was observed for the DGA resin, including recoveries higher than 99% for Zr-90. DGA has also demonstrated to be the faster approach and the most efficient not only to eliminate isobaric interferences from Sr-90, but also from Y-90, potentially present in samples containing high levels of radioactivity. The use of ICP-MS/MS using oxygen as a reaction gas in the Octopole Reaction system (ORS) was also evaluated as a potential approach to reduce isobaric interferences at *m/z* 90. While some level of decontamination was achieved, the coupling of this instrumental configuration with a pre-plasma separation was deemed necessary.
        Speaker: Prof. Dominic Lariviere (Chemistry Department, Laval University)
      • 09:45
        Semiconductor nanocrystals as detector of ionizing radiation in liquid scintillation counting 15m
        The understanding of the health impact of low dose exposition to ionizing radiation is one of the scientific challenges of this century. To insure a proper assessment of the exposition to radioactivity, different methods of detection have been investigated. One of the most common detection methods is liquid scintillation counting, which convert the radiation energy into a light signal with the use of fluorophores. In our study, semiconductors nanocrystals (NCs) were optimized to detect ionizing radiation through liquid scintillation counting.[1] Few experiments have been reported on the detection of actinides with NCs and they were performed exclusively with nanocomposite materials embedding NCs.[2,3] Because radionuclides standards are mostly available in acidic matrices and NCs are not stable in this condition, the elaboration of a scintillation cocktail was explored to validate the potential of NCs as scintillators. In a commercial scintillation cocktail, the addition of acidic water will quench part of the organic fluorophore but in the case of NCs there is a total dissolution of the fluorophore. Therefore, the acidic standard must be neutralized before it is added to the scintillation cocktail and the latter must be stable with the addition of this neutralized standard. This contribution highlights our recent progress concerning the optimization of the scintillation cocktail and the counting efficiency with different radionuclide and NCs.
        Speaker: Ms Marie-Eve Lecavalier (Chemistry department, Laval university)
      • 10:00
        Determination of Pb-210 in water samples by ICP-MS after cloud point extraction using crown ethers. 15m
        Isotopes such as Sr-90, Cs-137 Pb-210 and Po-210 are often the most important contributors to human radiation exposure due to their short half-life. The radiotoxicity of Pb-210 originates from its relatively long half-life compared with time of fulfillment of environmental processes and the high energy associated with the decay of its progeny, such as Po-210.[1] For these reasons, Pb-210 has the lowest maximum acceptable concentration in drinking water, which has been set at 0.1 Bq/L.[2] Furthermore, this radionuclide is chemically similar to alkaline earth elements making its separation challenging for complex environmental matrices. The objective of this project will be to investigate an effective way to specifically extract lead-210 and achieve interesting preconcentration factor after cloud point extraction (CPE). The increase in temperature of a micellar system allows to separate the solution in two distinct phases by dehydration of non-ionic surfactants. The use of a binding agent which has great affinity with a metal ion of interest, into the system, provides the ability to recover this complexed ion in a very small surfactant rich phase with a great preconcentration factor. Crown ethers have already demonstrated their great affinity for Pb with other kinds of extraction such as solid phase extraction (SPE) and surely can be transposed to CPE.[3] Another challenge will be to couple this extraction technique with Inductively Coupled Plasma Mass Spectrometry (ICP-MS-MS) to achieve the necessary sensitivity for analysis of Pb-210 in environmental samples and to have a rapid sample throughput. The limits of detection reach by ICP-MS-MS technique will allow the quantification of Pb-210 at ultra-trace. [1] Larivière, D.; Reiber, K.M.; Evans, R.D.; Cornett, R.J. Anal. Chim. Acta. 2005, 549, 188-196. [2] Federal-Provincial Subcommittee on Drinking Water, Guideline for Canadian Drinking Water Quality, Environment Canada, 2001. [3] Horwitz, E.P.; Chiarizia, R.; Dietz, M.L. Solvent Extr. Ion Exc. 2007, 10 (2), 313-336.
        Speaker: Mr Guillaume Blanchet-Chouinard (Chemistry department, Laval University)
      • 10:15
        Development of a fast and robust sequential method for uranium and thorium decay series quantification in environmental samples 15m
        Easily determine the radioactive behavior of a sample becomes one of the challenge of the industrialized world. Due to the enhancement of nuclear and mining activities, it is relevant to quantify the radioactivity effect of these activities and especially for nuclear disaster such as Fukushima within a short time. It currently exists a lot of method to analyse the most impact radionuclides of the uranium and thorium decay series,[1] however they are not sequenced or they are time consuming[2] and not reliable with less of 70% recovery[3]. Moreover, most currently used methods are only relevant for water samples and cannot afford to analyse all environmental matrices due to high salt concentration and heterogeneity. In order to do so, we propose to develop an easy, fast, reliable and robust method to fractionate and analyse, in a raw material, impact radionuclides of uranium and thorium decay series which are uranium, thorium, polonium, radium and lead. [1] Porcelli, D. & Swarzenski, P. W. The Behavior of U- and Th-series Nuclides in Groundwater. Rev. Mineral. Geochemistry 52, 317–361 (2003).[2] Lozano, J. C., Tomé, F. V., Rodriguez, P. B. & Prieto, C. A sequential method for the determination of 210Pb, 226Ra, and uranium and thorium radioisotopes by LSC and alpha-spectrometry. Appl. Radiat. Isot. 68, 828–831 (2010) [3] Oliveira, J. M. & Carvalho, F. P. Sequential extraction procedure for determination of uranium, thorium, radium, lead and polonium radionuclides by alpha spectrometry in environmental samples. Czechoslov. J. Phys. 56, 545–555 (2006).
        Speaker: Ms Claire Dalencourt (Chemistry Department, Laval University)
    • 08:30 10:30
      W1-7 History of Physics (DHP) / Histoire de la physique (DHP) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Louis Marchildon (Universite du Quebec a Trois-Rivieres)
      • 08:30
        Documenting the Magnetic Crusade in Canada and Beyond 30m
        Canada has a long history related to the history of the study and measurement of geomagnetism. In 1840, the observatory at Toronto was part of a world-wide network for magnetic measurements; in the 19th century, explorers and scientists were active in collecting magnetic data in field surveys throughout our territories; in the 20th century, Canadian scientists did pioneering oceanographic and airborne studies; and today Canadian physicists are part of the SWARM project from space. In this paper, I describe this history, in particular some of the key instruments used by scientists in these diverse studies. The Canada Science and Technology Museum is presently documenting and collecting instruments and records from this history. In addition, we are combining our findings with British colleagues to create a larger, global picture of the magnetic crusade.
        Speaker: David Pantalony (Canada Science and Technology Museum)
      • 09:00
        Enrico Fermi’s group at La Sapienza included Franco Rasetti : de Rome à Québec ce Rasetti fonde le département de physique il y a 75 ans 30m
        Il a fallu qu’un chimiste décide de ne plus enseigner la physique pour que les autorités de l’Université Laval acceptent d’engager un physicien de renom afin de fonder le département de physique. On est en 1939. C‘est Franco Rasetti qui est engagé ; il arrive en septembre 1939 et le département démarra l’année suivante. Le nouveau directeur met sur pied un réel programme de formation en physique, mais les premières années sont difficiles. The first graduation took place in 1944. Three graduate students were in place : Harold Feeney coming from McGill, Paul Koenig and Larkin Kerwin from MIT. Kerwin will develop the atomic physics locally and optics and nuclear physics will be established by Albéric Boivin and Claude Geoffrion respectively, two former students from Laval. Rasetti left Laval in 1947 to accept an offer from Johns Hopkins University, Enrico Persico took over for less than 3 years and Koenig, Geoffrion, Kerwin, etc. will follow as chairs… À la fin des années 50 s’est préparé le grand déménagement de toute la faculté des sciences et de génie pour aménager sur le campus actuel dans des locaux nouveaux et luxueux où les activités de recherche ont réellement pu prendre leur envol, surtout dans les secteurs de l’optique, de la physique atomique et de la physique nucléaire. Ce n’est qu’en 1976 que l’on verra débuter les activités en astrophysique. Dans la présentation, on revivra les moments forts des premières 75 années du département. Details of particular events will be remembered…
        Speaker: René Roy (Université Laval)
    • 08:30 10:30
      W1-8 Observations In Situ and Remote Sensing I (DASP) / Observations in situ et détection à distance II (DPAE) SITE J0106

      SITE J0106

      University of Ottawa

      Convener: Wayne Hocking (University of Western Ontario)
      • 08:30
        Studying the carbon cycle with atmospheric remote sensing measurements of carbon dioxide 30m
        The carbon cycle describes the flow of carbon, typically in the form of carbon dioxide, between the atmosphere, oceans and land. It is influenced by changes in the sources and sinks of carbon: from anthropogenic releases (fossil fuel burning), changes in land use, the respiration and photosynthesis of plants, and the uptake and release by oceans. Atmospheric measurements of carbon dioxide are required to quantify the sources and sinks and monitor their long-term trends. With the establishment of several sources of high-quality remote sensing measurements of carbon dioxide from the ground-based Total Carbon Column Observing Network (TCCON), and the space-based Greenhouse Gases Observing Satellite (GOSAT, 2009) and the Orbiting Carbon Observatory (OCO-2, 2014), we are now entering an exciting, data-rich era in carbon cycle science.
        Speaker: Debra Wunch (University of Toronto)
      • 09:00
        Longitudinal perturbations in thermospheric atomic oxygen concentrations observed at mid-latitudes by the Wind Imaging Interferometer compared with the Canadian Ionosphere and Atmosphere Model 15m
        The Canada/France WIND Imaging Interferometer (WINDII) made measurements from NASA’s Upper Atmosphere Research Satellite from 1991 to 2003. The observations were of upper atmospheric winds in the altitude range 80 to 300 km from Doppler shifts of the visible region emissions from a number of species. Altogether the atomic oxygen O(1S) 557.7 nm and O(1D) 630.0 nm emissions along with lines in the OH (8,3) band, and O2 Atmospheric band at 760 nm were observed. As well, emission from the O+(2P) emission at 732 nm was included. This excited ion is produced by solar photoionization from the ground state atomic oxygen and so from the observed emission the concentration of atomic oxygen [O] can be retrieved, but it is only recently that this has been accomplished. In plots of [O] at 250 km versus latitude and longitude acquired during March 1993, a region of depleted [O] near 40 S latitude and 100 W longitude was evident. The GUVI (Global Ultra Violet Imager) far ultraviolet observations of [O] taken ten years later, in March 2003, showed the same feature, but it is not seen in the Canadian Ionosphere and Atmosphere Model. Further preliminary investigations showed that this depletion was the negative portion of a wave 1 in longitude, at that latitude, stationary in local time, and further that this feature appears to have an annual variation. It has also been observed in mass density variations with the CHAMP (CHAllenging Minisatellite Payload). Further investigations are in progress, including the possibility of coupling associated with the “springtime transition” observed with WINDII in the O(1S) 557.7 nm night airglow emission near 100 km and in ground-based observations. One plausible origin is the change in winter to summer circulation. The presentation will include a review of the observations, and possible interpretations.
        Speaker: Prof. Gordon Shepherd (York University)
      • 09:15
        Spectroscopic measurements of marine atmospheric boundary layer composition in Halifax 15m
        As part of a new research program dedicated to understanding atmospheric composition, we have initiated measurements of marine boundary layer trace gases using the technique of Open-Path Fourier Transform Infrared Spectroscopy (OP-FTIR) deployed in monostatic mode (collocated source and detector) in 2015. The recently acquired system significantly expands the measurement capability of atmospheric trace gases in Halifax and in Atlantic Canada. To date, we have conducted field campaigns in traffic conditions, as well as coastal forest and indoor environments. Trace gas concentrations are derived from atmospheric absorption spectra recorded over one-way atmospheric open paths ranging from 100-400 m. The retrieval process is being optimized to target greenhouse gases (CO2, CH4, N2O), ozone and its precursors (CO, NOx and many VOCs), trace gases implicated in particle formation (SO2, HNO3, NH3), and other IR-active species permanently imprinted in stored absorption spectra. Details of retrievals and detection limits under variable atmospheric conditions (primarily driven by absolute water vapour amounts) will be presented, along with first results from field measurements to date. Progress on long-term plans for incorporating the active-source OP-FTIR system into a diurnal/nocturnal observatory at Saint Mary’s University will be discussed. Finally, as the system is planned to remain mobile, planned direct measurements of marine shipping sector emissions in Halifax Harbour will be presented.
        Speaker: Prof. Aldona Wiacek (Saint Mary's University)
      • 09:30
        Trace Gas Measurements in the Canadian High Arctic using Infrared Emission Spectroscopy 15m
        The High Arctic experiences prolonged periods of total darkness in the winter and continuous daylight in the summer, influencing the atmosphere and its composition in ways that are still not fully understood. Conducting atmospheric measurements in this remote region is challenging, particularly during polar night when solar-viewing instruments are not operational. By using infrared emission spectroscopy, which is independent of sunlight, we are able to document year-round the total column abundances of carbon monoxide (CO), methane (CH4), nitrous oxide (N2O), and ozone (O3). Measurements are made at the Polar Environment Atmospheric Research Laboratory (PEARL, Eureka, Nunavut, Canada, 80.05 N, 86.42 W) using Atmospheric Emitted Radiance Interferometers (AERIs) to measure the absolute downwelling infrared emission from the atmosphere between 500 and 3000 cm-1. The instruments have a moderate resolution of 1 cm-1 and provide total column trace gas measurements with high sensitivity to the lower troposphere. The University of Idaho’s Polar AERI (P-AERI) was installed at PEARL from March 2006 to February 2009 while the second instrument, the E-AERI (Extended-range AERI from 400 cm-1), was installed in October 2008 and is still operating today. The combined measurements allow us to investigate the total column densities of CO, CH4, N2O and O3 at PEARL from 2006 to 2015. These two datasets are compared and validated, during sunlit hours, with measurements made by a high-resolution solar-viewing infrared spectrometer (Bruker 125HR) on-site. Preliminary results indicate that the AERI and Bruker 125HR O3 and CO measurements are highly correlated, with a correlation coefficient of 0.95 and 0.83 respectively (unsmoothed). We present the annual, seasonal and diurnal variability of trace gases in the high Arctic, highlighting ozone depletion events as well as biomass burning events that were observed between 2006 and 2015.
        Speaker: Sophie Tran (Department of Physics, University of Toronto, Toronto, ON, Canada)
      • 09:45
        Dynamical perturbations of the thermosphere inferred from satellite observations of O(1D) nightglow 15m
        Manifestations of thermospheric dynamics have been observed in the variations of the upper atmosphere density, temperature, neutral winds and F-region plasma over a wide time range. These fields are influenced by perturbations propagating vertically from the lower and middle atmosphere (e.g. tides) and from above through variations in the solar and geomagnetic activity. The Wind Imaging Interferometer (WINDII) flown on the Upper Atmosphere Research Satellite provides multiyear observations of O(1D) nightglow volume emission rates, Doppler temperatures and neutral winds over the altitude range of 150 − 300 km with continuous latitude coverage of 42°N − 42°S. These data are employed in the study of the global and seasonal extent and variability of the thermospheric midnight temperature (MTM), a large scale neutral temperature anomaly with wide-range effect on the nighttime thermospheric dynamics at low latitudes. It is found that the MTM extends well into midlatitudes and coincides in local time with the appearance of a wave 4 signature, observed in the vertical and zonal variability of the O(1D) volume emission rates, Doppler temperatures and neutral winds (zonal and meridional). The current understanding is that the wave 4 is associated with non-migrating tides propagating upward from the lower atmosphere. The vertical and global extend of the wave 4 as the source of the MTM will be discussed.
        Speaker: Marianna Shepherd (York University, Lassonde School of Engineering)
      • 10:00
        Electron temperature anisotropies measured by CHAMP 15m
        CHAMP (CHAllenging Minisatellite Payload), a low Earth orbit minisatellite launched by the German Space Agency (DLR), was operated between July 2000 and September 2010. Its primary mission was to provide high accuracy measurements of Earth gravity and magnetic fields, but it was also equipped with other instruments to monitor its near ionospheric environment, including a large area planar Langmuir probe (PLP) used to measure local electron density and temperature. Over the ten years of operation of the satellite, it was observed that, at given latitudes, there were a small but systematic difference between electron temperatures obtained when the satellite was Southbound compared to those when it was Northbound [1]. The largest relative differences of order 10%, were observed at mid latitudes in both hemispheres. In this work we show that a possible explanation for these differences can be attributed to the geometry of the planar Langmuir probe, and the varying “magnetic connection” between the probe and the boom of the satellite. With the boom and the attached magnetometer in the upstream direction, and under normal CHAMP flying attitude, magnetic field lines passing through the PLP will intersect the boom when the satellite is Northbound in the southern hemisphere, or when it is Southbound in the Northern hemisphere. Otherwise, magnetic field field lines passing trough the LPL do not intersect the boom or any other satellite structure. Given thermal electron gyroradii of order 2 cm at CHAMP altitude, the fact that electrons essentially trapped in magnetic flux tubes of radius of order of a gyroradius, and the dimensions of the boom and LPL, it follows that when the probe is “magnetically connected” to the boom, the latter effectively obstructs the flow of electrons to the probe and hence the number and velocity distribution of collected electrons. This hypothesis is tested with Particle in Cell (PIC) simulations of the CHAMP PLP characteristics measured under representative ionospheric plasma parameters assuming a simplified satellite geometry. Characteristics obtained from computed collected currents as a function of probe bias voltage are then fitted using the probe response function derived by Rother, et al. and shown to be consistent qualitatively and quantitatively with observation. In particular, it is found that, using the same plasma density and temperatures in the simulations, the electron temperature is lower by approximately 10% when magnetic lines at the PLP intersect the boom, than when they don't. [1] Rother, et al., Radio Science, Vol. 45, RS6020, doi:10.1029/2010RS004445, 2010
        Speaker: Richard Marchand (University of Alberta)
    • 08:30 10:30
      W1-9 Nonlinear Optics and High Field Physics (DAMOPC) / Optique non linéaire et physique en champs intenses (DPAMPC) SITE H0104

      SITE H0104

      University of Ottawa

      Convener: Tsuneyuki Ozaki (INRS-EMT)
      • 08:30
        Towards efficient second-order nonlinear optical processes in hollow-core photonic crystal fibres 30m
        Second-order solid-state nonlinear crystals are used for a wide variety of parametric frequency-conversion processes including the generation of second harmonic, degenerate entangled photon pairs and phase-locked terahertz transients. These crystals can have a high χ$^{(2)}$ coefficient enabling efficient nonlinear effects, but their spectral range of operation is limited because of their strong linear dispersion properties and their relatively narrow transmission window. Gas-filled hollow-core photonic crystal fibres (PCFs) are efficient nonlinear optical platforms featuring low-loss broadband guidance and tunable dispersion (via an adjustable gas pressure) [1]. However, both the gas and the glass are amorphous materials with a vanishingly small χ$^{(2)}$. Here we rely on a strong dc electric field E$_{dc}$, which breaks the centrosymmetry of the gas inside the fibre and induces an effective χ$^{(2)}$ $\propto$ χ$^{(3)}$E$_{dc}$, to enable a new design of second-order nonlinear medium with highly tunable linear properties [2]. We demonstrate the concept by monitoring the electric-field-induced second harmonic generation (EFISH) when pumping a xenon-filled kagomé PCF with nanosecond and femtosecond pulses at $\lambda$ $\sim$ 1 µm. A second harmonic (SH) signal is detected at Xe pressures where intermodal phase-matching is satisfied. For example, SH can be generated in the LP02 mode when the Xe pressure is 3.85 bar and the pump beam is launched into the fundamental LP01 mode. Also, by means of quasi-phase-matching (QPM) using a periodic electrode, we demonstrate generation of SH in the low-loss LP01 mode. We observe a maximum conversion efficiency of 2.5 $\times$ 10$^{-3}$ % with a non-optimized electrode configuration and we discuss modified designs that will lead to larger electric-field-induced optical nonlinearities. [1] P. St.J. Russell et al. Hollow-core photonic crystal fibres for gas-based nonlinear optics. Nature Photonics 8, 278 (2014). [2] J.-M. Ménard and P. St.J. Russell. Phase-matched electric-field-induced second-harmonic generation in Xe-filled hollow-core photonic crystal fiber. Optics Letters 40, 3679 (2015).
        Speaker: Prof. Jean-Michel Ménard (University of Ottawa, Max Planck Institute for the Science of Light)
      • 09:00
        Near-field Effects on SHG Imaging 15m
        Collagen fibrils can be found in a wide array of biological tissues such as bones, tendons, arteries, cornea. They give most of the biological tissues its mechanical properties and as such are an important area of research. Second Harmonic Generation (SHG) is a non-linear optical process that is particularly strong in collagen fibrils due to their unique chiral molecular structure, enabling label-free imaging. Furthermore, the radiation pattern correlates with the fibril sizes and orientations in collagen tissue[1], allowing one to study the underlying structure through careful modelling[2], even though the fibril diameters are usually smaller than the SHG wavelength. One key property that is often used for this is the ratio between the far-field signals in the forward and the backward directions, the F/B ratio[3], as that is linked to fibril size. Our calculations show that the presence of small differences in the refractive index, as commonly found in biological tissue, can have a profound effect on the measured signal of a single fibril. Near-field enhancements cause the SHG signal to come from an area with a smaller radius than the fibril's geometric radius, significantly altering phase matching conditions for the backward scattered signals. This may skew diameter measurements such as in [3]. It also affects imaging of collagen tissue where a entire distribution of fibrils is in the laser focus. The signal of the smaller fibrils will not change significantly, but of large fibrils it will and those can be present in large numbers in collagen tissue. Therefore SHG experiments concerning the direct measurement of fibril diameters need to take these effects into consideration. **References** 1. J. Mertz et al., **Optics Communications** 196, 325 – 330 (2001). 2. C. P. Brown at al., **Biomed. Opt. Express** 5, 233–243 (2014). 3. S. Bancelin et al., **Nat Commun** 5 (2014).
        Speaker: Jarno Nicolaas van der Kolk (University of Ottawa)
      • 09:15
        Photon pair generation in fiber microcouplers for quantum information 15m
        Due to its inherent stability and compactness, integrated photonics can allow for experimental complexity not currently achievable with bulk optics. This opens up the possibility for large-scale quantum technological applications, such as quantum communication networks and quantum information processing. Most demonstrations so far have featured the on-chip manipulation of photon states using a free-space bulk-optic source of photons [1, 2]. This has the drawback that it introduces loss due to mismatch between the diverse spatial modes of the produced photons and the chip’s waveguide modes. In this way loss limits the number of photons that are simultaneously in the integrated optical device, and thus limits the number of qubits. One way to avoid this loss is to generate the photons in another waveguide device. This can be done through, for example, spontaneous four-wave mixing (SFWM) [3]. In this work, we experimentally and theoretically investigate the SFWM generation of photons in a waveguide coupler comprised of two touching tapered optical fibres, which we call a microcoupler. The two silica tapered fibers are 1 micron in diameter and 10 cm long. The device has three advantages over a standard telecom 2x2 fiber coupler. 1. The small mode area enhances the photon generation rates. 2. Since the coupler exhibits both birefringence and has two output fibres, in principle the device should be able to produce polarization-entangled photon pairs. 3. The strong waveguide-waveguide coupling and waveguide dispersion (due to the tapering) forces the photons to be far in wavelength from the background light around the pump. We present experimental characterizations of the produced photons. References: [1]. Matthews, J. C. F. et al. Nat. Photon. 3, 346–350 (2009). [2]. Silverstone, J. et al. Nat. Photon. 8, 104–108 (2014). [3]. Smith, B. et al. Opt. Express 17, 23589-23602 (2009).
        Speaker: Xinru Cheng (University of Ottawa)
      • 09:30
        Nanoscale enhancement in quantum state preparation 15m
        The use of nanoscale structures to enhance local electric fields has seen much recent use in improving the effectiveness of numerous, optically-driven systems. As such, we investigate how these nanoscale enhancements can be used to improve the operation of quantum control systems. These nanoscale systems have various different effects on quantum systems, but in most cases are able to increase the local electric field and the spontaneous decay experienced by transitions in the system. The most noticeable property of these enhancements is that are strongly dependant on the position and quantization axis of the system relative to the arrangement of materials in the nanostructure. With this in mind we investigate how this directional dependance can be exploited to improve the overall operation of quantum informations systems. We take advantage of non-symmetric structures and different driving field directions in order to selectively tune the environment of a quantum system. We also show that simple noble metal nanoparticles can arranged and used to rapidly prepare pure state qubits from arbitrary mixed states while retaining low decoherence during regular operations.
        Speaker: Christopher DiLoreto (University of Windsor)
      • 09:45
        High-dimensional quantum cloning of photons 15m
        Optimal quantum cloning machines are realized in linear optical systems by means of the symmetrization method, a method involving the two-photon interference effect at a beam splitter. Optimal quantum cloning has been realized with two-dimensional quantum states, qubits, and four-dimensional quantum system comprised of polarization and orbital angular momentum qubits. Nonetheless, no experimental demonstration of high-dimensional quantum cloning has hitherto been realized. Here, we perform optimal quantum cloning of photonic orbital angular momentum states belonging to Hilbert spaces with dimensions ranging from two to seven. Moreover, we perform full quantum state tomography of high-dimensional cloned states and a cloning attack on a high-dimensional quantum cryptography protocol.
        Speaker: Mr Frédéric Bouchard (University of Ottawa)
      • 10:00
        Plasmonic metasurface to enhance difference frequency generation for THz radiation 15m
        Plasmonic nanostructures have been extensively investigated in recent years for their ability to concentrate light to sub-wavelength scales. Plasmonics allows us to overcome the diffraction limit and confine an intense field to spatial dimensions that are not achievable with a laser or dielectrics, which are typically used in nonlinear optics. The strong fields created by arrays of nanoantennas and metasurfaces can be used to locally enhance nonlinear optical processes, such as surface enhanced Raman scattering (SERS) or second harmonic and difference frequency generation (SHG and DFG), opening new opportunities in, ${\it e.g.}$, nonlinear spectroscopy, nonlinear microscopy, near-field sensing, and bio-sensing. Plasmonic nanostructures also alter the local density of optical states (LDOS), impacting radiative processes of nearby nano-scale emitters (${\it e.g.}$, molecules, quantum dots). Our plasmonic metasurfaces are modelled using the finite-difference time-domain (FDTD) method, exploiting the most powerful supercomputer accessible in Canada (an IBM BlueGene/Q, Southern Ontario Smart Computing Innovation Platform), which allows us to perform simulations of complex problems with high resolution and accuracy in a short time, speeding-up the design process. We show a plasmonic metasurface which can enhance perpendicularly polarized incident beams in the same volume. This can be exploited to generate THz radiation by DFG in $\bar{4}$3m crystal class materials, such as GaAs.
        Speaker: Dr Antonino Calà Lesina (University of Ottawa, Department of Physics)
      • 10:15
        Formation of an all–optical extreme–ultraviolet Fresnel zone plate by perturbative high harmonic wavefront control 15m
        High harmonic generation is a non-perturbative nonlinear optical process [1], quite different from conventional perturbative nonlinear optics [2]. These two regimes are bridged by the nonlinear wave mixing process in high harmonic generation [3], in which a harmonic extreme ultraviolet (XUV) photon with frequency Ω is a combination of n1 driving photons with frequency ω1 and n2 perturbing photons with frequency ω2 (Ω=n1ω1+n2ω2) and its intensity scales as I2^n2, where I2 is the perturbing beam intensity. Here we demonstrate a perturbative control scheme to the high harmonic XUV wavefront. To generate an all-optical Fresnel zone plate that focuses the XUV radiation, we intersect the intense driving laser pulse for high harmonic generation, with a tightly focused, weak, control pulse. We use both experiment and simulation to demonstrate the all-optical zone plate. Experimentally, we probe and correct the intrinsic XUV divergence due to the intensity gradient of the driving beam. In addition, SWORD (Spectral Wavefront Optical Reconstruction by Diffraction) [4] measurements quantitatively characterized the zone plate focal spot positions and sizes. Extending beyond our current experiment, simulations predict that by increasing the driving beam size and focusing the perturbing beam more tightly, the zone plate focal spot sizes can reach sub-micrometer dimension resulting in an increase in intensity of 4-6 orders-of-magnitude. The intensity increase that we predict will allow applications such as XUV pump-XUV probe experiments, XUV light monochromation, and XUV nonlinear optics. In addition, the perturbative control concept can be generalized for other versatile all-optical XUV optics besides a zone plate. 1. P. B. Corkum, Phys. Rev. Lett. 71, 1994–1997 (1993). 2. R. W. Boyd, Nonlinear Optics (Academic, New York, 2008), 3rd ed. 3. J. B. Bertrand, et al., Phys. Rev. Lett. 106, 023001 (2011). 4. E. Frumker, et al., Opt. Lett. 34, 3026–3028 (2009).
        Speaker: Zhengyan Li (JASLab, National Research Council and University of Ottawa)
    • 10:30 11:00
      Health Break (with exhibitors) / Pause santé (avec exposants) SITE Atrium

      SITE Atrium

      University of Ottawa

    • 11:00 11:30
      W-MEDAL1 CAP Medal Talk - Carlos Silva, U. de Montréal (Brockhouse Medal Recipient / Récipiendaire de la médaille Brockhouse) Marion 150

      Marion 150

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 11:00
        Excitonic Correlations and Their Relationship to Solid-State Microstructure in Polymeric Semiconductors 30m

        This presentation will summarise a body of work emanating from our research group over the past five years. It focuses on correlating the properties of excitons with the complex solid-state microstructure in macromolecular semiconductors. In general, the optical properties of polymeric semiconductors are governed fundamentally by the interplay of electronic interactions occurring within a given polymer chain and those occurring between chains that constitute crystalline motifs. The competition between through-bond (intrachain) and through-space (interchain) electronic coupling determines two-dimensional spatial extent of excitons. The balance of these competing interactions depends very sensitively on solid-state microstructure of the polymer film (e.g. polycrystalline, semicrystalline with amorphous domains, etc.) Via analysis of absorption and photoluminescence spectral lineshapes, we have developed a protocol by which the spatial coherence of excitons, the degree to which the disordered landscape is correlated, and the interplay of intra- and interchain excitonic coupling in disordered polymeric semiconductors can be predicted when processing thin films within devices. 
I will outline novel ultrafast optical probes developed to probe in more detail the spectral correlations arising from excitonic properties of this class of materials.

        Speaker: Carlos Silva (Université de Montréal)
    • 11:30 12:00
      W-MEDAL2 CAP Medal Talk - Gilles Fontaine, U. de Montréal (Achievement Medal Recipient / Récipiendaire de la médaille pour contributions exceptionnelles) Marion 150

      Marion 150

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 11:30
        Measuring the Total Angular Momentum of Stars through Asteroseismology 30m

        Have stars that end up as isolated white dwarfs lost their initial angular momentum as suggested by the relatively long rotation periods measured at their surfaces through spectroscopy? Could it be instead that a large fraction of that angular momentum is bound in a fast rotating core, hidden from direct observations, as proposed by some theories favouring a weak rotational coupling between the radiative core and the convective envelope in the previous red giant phase of stellar evolution? To answer these questions, we need to map the internal rotation pro?files of representative white dwarfs.

        In the last few years, we have devised a way to exploit the signature that rotation imprints on the pulsation properties of white dwarfs in order to carry out such a mapping. The technique is particularly useful for pulsating white dwarfs of the so-called GW Vir type, for which the mapping can be done over essentially the full mass of the star, thus allowing a determination of the total angular momentum.

        Est-ce que les ?étoiles qui terminent leur vie stellaire sous la forme de naines blanches isol?ées ont perdu l'essentiel de leur moment cinétique comme semblent le sugg?érer les mesures de périodes de rotation de leurs couches superficielles obtenues par spectroscopie? Se pourrait-t-il, au contraire, qu'une grande fraction du moment cinétique initial soit contenue dans les r?égions internes inacessibles ?à l'observation directe comme le proposent certaines th?éories de transfert (inefficace) de moment cinétique entre le noyau radiatif et l'enveloppe convective dans la phase ?évolutive des g?éantes rouges qui pr?écède celle des naines blanches? Pour répondre ?à ces questions, il est nécessaire de cartographier le pro?fil de rotation interne de naines blanches représentatives.

        Au cours des récentes années, nous avons d?éeloppé une méthode pour exploiter la signature de la rotation sur les propri?étés de pulsation des naines blanches et de déterminer ainsi ce profil de rotation interne. La technique est particulièrement utile pour les ?étoiles pulsantes de type GW Vir, pour lesquelles essentiellement toute la masse peut être ?échantillonnée, ce qui permet de calculer le moment cinétique total.

        Speaker: Prof. Gilles Fontaine (Université de Montréal)
    • 12:00 13:00
      DCMMP Annual Meeting / Assemblée annuelle DPMCM SITE G0103

      SITE G0103

      University of Ottawa

      Convener: Giovanni Fanchini (The University of Western Ontario)
    • 12:00 13:00
      DIMP-DIAP Annual Meeting / Assemblée annuelle DPIM-DPIA
      Conveners: Kirk Michaelian (Natural Resources Canada), René Roy (Université Laval)
    • 12:00 13:00
      DPE Annual Meetings / Assemblée annuelle DEP SITE A0150

      SITE A0150

      University of Ottawa

      Convener: Martin Williams (University of Guelph)
    • 12:00 13:00
      Lunch / Dîner
    • 12:30 13:00
      Asia-Pacific Centre for Theoretical Physics-CAP MOU Signing Ceremony and Information Session / Cérémonie de signature du PE de l'APCTP-ACP et séance d'information: APCTP Signing Ceremony/Information Session / Cérémonie de signature et séance d'information de l'APCTP SITE J0106

      SITE J0106

      University of Ottawa

      Convener: Richard MacKenzie (U. Montréal)
    • 13:15 14:45
      W2-1 Biomechanics and Fluid Dynamics (DPMB) / Biomécanique et dynamique des fluides (DPMB) Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Christopher Bergevin (York University)
      • 13:15
        On-chip evaluation and manipulation of directed cell migration 15m
        Directed cell migration is a complex cellular function that critically mediates a broad range of physiological and pathological processes. Chemical concentration gradient and electric field are two important guidance cues for many cell types such as immune cells, metastatic cancer cells, adult stem cells and neurons. Microfluidic devices can precisely configure cellular microenvironments and therefore have been increasingly employed to investigate the mechanism of directed cell migration and to manipulate migratory cells. In this short talk, I will briefly discuss our recent work in on-chip evaluation and manipulation of cell migration in response to chemical and electrical cues including 1) application of microfluidic systems for studying the molecular mechanisms of chemotaxis; 2) development of an all-on-chip method for rapid chemotaxis analysis; 3) microfluidic selection of therapeutic stem cells; 4) on-chip characterizations of immune-cancer cell migratory interactions.
        Speaker: Prof. Francis Lin (University of Manitoba)
      • 13:30
        Effect of temperature on the generation of acoustic harmonics in a tissue-mimicking liquid 15m
        In this study, the temperature dependence of acoustic harmonics generated by nonlinear ultrasound beam propagation in a mixture of 90% glycerol and 10% water (by volume) used as a tissue-mimicking liquid, was studied as a function of temperature from 26°C to 46°C at two different frequencies. Simulations were performed with a temperature-dependent Khokhlov–Zabolotskaya–Kuznetsov (KZK) nonlinear acoustic beam propagation model. Two single-element focused transducers with center frequencies of 5 and 13 MHz were used to transmit high pressure ultrasound signals. The ultrasound signals along the acoustic axis of each transducer were recorded using a needle hydrophone. The axial components of the fundamental (p1), the second (p2) and the third (p3) harmonics where calculated from the measured and simulated signals at temperatures of 26, 31, 36, 41 and 46°C for both transmit frequencies. At the transmit frequency of 5 MHz, the peak values of the harmonics p1, p2, and p3, and their ratios p2/p1, p3/p1 increased by 35%, 189%, 573%, 113% and 396%, respectively in simulations and by 35% ± 2.5%, 223% ± 17%, 797% ± 38%, 138% ± 9% and 576% ± 31%, respectively in measurements as the temperature elevated from 26°C to 46°C. The peak values of p1, p2, and p2/p1 increased by 256%, 1773% and 426%, respectively in simulations and by 205% ± 15%, 1411% ± 103%, and 394% ± 17%, respectively in measurements at 13 MHz for the same temperature range. Moreover, the p3 and p3/p1 increased by 597% and 311%, respectively in simulations and by 387% ± 31% and 204% ± 37%, respectively in measurements at 13 MHz as the temperature was increased from 36 to 46°C. The significant increase in the rate of generation of harmonics with temperature is due to the combined effects of increase in the nonlinearity parameter (B/A) and reduction in both the attenuation coefficient and the speed of sound with temperature in the medium.
        Speakers: Mr Borna Maraghechi (Department of Physics, Ryerson University, 350 Victoria Street, Toronto, Ontario, M5B 2K3, Canada), Mr Elyas Shaswary (Dept. of Physics, Ryerson University)
      • 13:45
        The Translocation Time through a Nanopore with an Internal Cavity is Minimal for Polymers of Intermediate Length 15m
        Nanopores are of great interest in the study of biological systems and in the development of new scientific and industrial tools. Synthetic nanopores, constructed from silicon wafers or similar materials, show great potential for detecting, sorting, and manipulating polymers rapidly and efficienctly. Traditional nanopores are short cylindrical holes in a membrane, whose radii and lengths are comparable. The average translocation time of polymer electrically forced to pass through such pores is a monotonic function of polymer length. In the present work, we conceive of a novel nanopore design, in which a relatively large hollow cavity is included between two traditional nanopores. Using numerical simulations of a model system, the average polymer translocation time through this new geometry is found to be a complicated function of length and driving force. For moderate driving forces, translocation time is minimal for some critical polymer length, with shorter chains slowed by entropic trapping, and longer chains slowed by virtue of their length. For larger driving forces, the effects of entropic trapping are suppressed as the chain is forced against the far side of the cavity. As such, translocation time is almost constant below the critical polymer length. Furthermore, the rich dynamics of this system can be explained by a simple free energy description. This model accurately predicts the relationship between the critical polymer length of the system and the strength of the driving force with no free parameters. These results suggest that the new pore geometry could be used as a highly selective filter for extracting polymers from a solution, behaving as a band-pass filter for moderate driving forces and a low-pass filter for strong driving forces. Further, the filter threshold can be tuned dynamically using the relation predicted by the free energy model. Thus, this device opens up new applications for nanopores within nanofluidic devices.
        Speaker: Mr Martin Magill (University of Ontario Institute of Technology)
      • 14:00
        Flow-induced beta-sheet formation in silk fibroin solutions 15m
        Silk fibres from the Bombyx Mori silkworm are well known for their impressive strength and toughness. They have mechanical properties that are comparable to the best synthetic fibres available, and consequently have numerous applications as structural materials in biomedicine and engineering. Despite their importance as high performance materials, a comprehensive understanding of the how the sequence of the structural protein, fibroin, impacts the fibre formation during the spinning process is still lacking. In this talk, we present experimental studies of reconstituted silk fibroin proteins and supporting computer simulations of silk-mimetic peptide fragments that suggest two important mechanisms in the fibre formation process: (1) tyrosine residues in the fibroin sequence template the inter-molecular association chains in solution, and (2) flow-induced chain tension acts to nucleate the formation of inter-molecular beta sheet content in an orientational dependent manner. Moreover, we show that covalent cross-linking of tyrosine side chains results in spontaneous beta-sheet formation upon removal of water, even in the absence of shear, while non-crosslinked samples require post treatment to induce similar levels of crystallinity. The implications of these findings for ex vivo fabrication of high-strength silk fibres will be discussed.
        Speaker: Mehran Bagheri (University of Ottawa)
      • 14:15
        Differential dynamic microscopy studies of collective cell dynamics 30m
        We discuss the use of a recently developed microscopy technique, differential dynamic microscopy (DDM), for studying the collective dynamics of two dimensional assemblies of living cells. DDM is a Fourier-space image analysis method that allows one to obtain the equivalent of multi-angle dynamic light scattering data using an ordinary white-light microscopy set-up and a digital video camera. The dynamical information obtained in a DMM experiment is a direct probe of collective cell motion on a range of length and time scales. As such, DMM measurements of cell dynamics are complimentary to direct cell tracking and PIV methods. We illustrate this approach with examples of motile populations of cell at different densities on model substrates.
        Speaker: James L. Harden (University of Ottawa)
    • 13:15 14:45
      W2-2 Curriculum Development and Revitalization (DPE) / Développement et revitalisation des programmes (DEP) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Patricia Mitchler (Balmoral Hall School)
      • 13:15
        The evolution of the undergraduate physics curriculum at the University of Guelph 30m
        Over the past decade we have made many changes to our undergraduate physics offerings, both for majors and non-majors alike. Throughout this process our goal has been to implement best practices from the Physics Education Research community, in such a way that we are mindful of resource implications. I will highlight some of the more significant changes we have made, such as designing and delivering an integrated course in first year that combines physics and calculus in a coordinated way, introducing gaming elements into our online course content for non-majors, and overhauling the full suite of undergraduate laboratory courses for our majors to provide more opportunities for guided inquiry. The presentation will also include a discussion of what we have learned along the way, as well as plans for the future.
        Speaker: Joanne O'Meara (University of Guelph)
      • 13:45
        Authentic Assessment in Physics: A case study 15m
        Authentic assessment [1,2], or assessment of real-world tasks that demonstrate the student's acquisition of skills and knowledge, is a paradigm that is growing in importance in higher education. In Ontario, this form of assessment is taking on greater relevance as the Province aims to connect the funding of higher education programs to the graduates' demonstrated achievement of gaining job and career-ready skills [3]. How should we do so in Physics, where the philosophy is to create abstract models of reduced complexity? At the University of Windsor, retired Writing Instructor Ron Dumouchelle and I have developed a course entitled 'Technical Communication Skills' that is a multi-genre course with several authentic assessment tasks, where students demonstrate their achievement of multiple program-level learning goals. In this talk, I will present the course design for this fourth year course that enables students to produce multimedia instructional modules [4] on several topics of Physics Instruction. [1] Stiggins, R. J. (1987). The design and development of performance assessments. Educational Measurement: Issues and Practice, 6, 33-42. [2] Wiggins, G. P., & McTighe, J. (1998). Understanding by design. Alexandria, VA: Association for Supervision and Curriculum Development. [3] https://www.tcu.gov.on.ca/pepg/audiences/universities/uff/UniversityFundingFormulaConsultationReport_2015.pdf [4] http://www1.uwindsor.ca/physics/student-projects
        Speaker: Chitra Rangan (University of Windsor)
      • 14:00
        GRASP: a free app to manage group work and active learning classrooms 15m
        In teacher-centered classrooms, instructors know in advance what will happen in 5, 10 or 20 minutes time. In an active learning classroom, students control the learning sequence. Hence, many instructors have trouble managing many groups working simultaneously. This is known as the "Orchestration load” problem in learning sciences. A simple case is that of a problem session with N groups working on the a given number of problems. It is possible that one group is very efficient and can solve 3 or 4 problems quickly before they request help from the instructor. Suppose that a noticeably small moment later, another group requests help too. However, this second group is still struggling with the very first question. Typically, instructors will help the group that requested help first. This creates an even greater lag before the second group completes their first question. We developed a free mobile application called GRASP (Group Response and Ambient Student Participation system) to avoid these issues and provide useful data for real time classroom management as well as exportable data to analyze your active learning classrooms. We will demonstrate the ease of use of GRASP, some data collected and the process that any attendee can use to adopt the app in their courses.
        Speaker: Nathaniel Lasry (John Abbott College)
      • 14:15
        The Physics Educator: Findings and Insights 15m
        The focus of this talk will be on the findings and insights of mentoring and editing a text which focused on the essence of ‘story’, as it relates to the experiences of physicists and physics educators at the tertiary level. The original call for chapters indicated, that each author who is either a physicist and/or a physics educator address their career path to their current role as a physicist or physics educator, or they could address their present situation including what each does as a physicist or physics educator, possibly including a discussion of the courses taught and strategies which they have found effective in their teaching environment, the issues faced, and lastly their vision for the future of physics as a discipline – a science and the trajectory of physics education research. The contributors present their perspectives and research findings both within and outside the lines of traditional frameworks whereby they infuse context, events, and experience; our intention is to present a number of perspectives of the work roles of physicists and physics educators and researchers within post-secondary education (PSE). The views of the experienced instructor include first-hand insights and details of practice that are instructive, and somewhat unique. This unique post-secondary perspective, with its diversity, provides a rich source of authenticity.
        Speaker: Dr Katarin MacLeod (St. Francis Xavier University)
    • 13:15 14:45
      W2-3 Remote Sensing (DASP) / Détection à distance (DPAE) SITE J0106

      SITE J0106

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Richard Marchand (University of Alberta)
      • 13:15
        Canada's Triad of Atmospheric Space Instruments: A 21st Century Success Story 30m
        18th December, 1999, February 20th, 2001 and 12th August, 2003 marked the launch dates of three Canadian atmospheric experiments: MOPITT, Odin/OSIRIS and SciSat/ACE. These three satellites, launched in the space of less than four years share another enviable characteristic: They are all still working after 13-16 years and between them they have accumulated over 45 years of on-orbit operating time. Not bad for missions whose planned lifetime ranged from 2-5 years! The instruments of these missions all operate by sensing electromagnetic radiation, but differ in the instrumentation used to analyse the radiation. MOPITT uses correlation radiometry, OSIRIS uses a grating spectrometer and the ACE instruments use a Fourier transform spectrometer and a grating spectrometer. The differing techniques are suited to the atmospheric components and altitude ranges targeted by these instruments. These global space-based measurements tackle some of the most significant atmospheric issues facing humanity today: ozone and atmospheric pollution, but also provide measurements relevant to climate change. After their several decades of operation each of them has a story to tell of atmospheric discoveries and new science. MOPITT has given us a global picture of lower atmosphere pollution transport showing how carbon monoxide is changing over the planet and is influenced by El Nino, industrialisation and perhaps even the state of the world economy. Over the past fifteen years OSIRIS has provided international climate scientists with a high resolution view of both the changing vertical distribution of ozone and the increase of stratospheric sulphate particles that result from volcanic eruptions and that cause noticeable surface cooling. ACE has provided the most comprehensive view of composition of the Earth's atmosphere including measurements of more than 50 trace gases and isotopologues. It was designed to monitor the recovery of the ozone layer and was the first to measure CFC-113, HCFC-142b, HFC-134a, COClF, COCl2, and HFC-23 from orbit. Financing for these instruments was provided by the Canadian Space Agency but many other agencies and organisations have also provided funding and support. We also acknowledge that the success of these instruments is due to the dedication and hard work of many people over several decades.
        Speaker: james Drummond (Dalhousie University)
      • 13:45
        Improved techniques for monitoring and investigating polar cap absorption 15m
        Shock waves produced in front of coronal mass ejections can accelerate solar energetic protons Earthward where they are guided by the Earth’s magnetic field into the high-latitude polar cap region. Energetic >10 MeV protons can penetrate into the ionosphere increasing ionization in the D-region causing a polar cap absorption (PCA) event potentially blocking out high frequency (HF) radio communications at high latitudes. This is of direct importance to the safety of transpolar flights which communicate using the affected radio signals. Riometer instruments are able to monitor variations in ionospheric absorption by observing background cosmic radio noise. This presentation introduces the development of a new two-dimensional visualization tool for viewing riometer-derived absorption on a Canada-wide scale. Such a visualization tool will greatly enhance the monitoring and investigation of ionospheric effects on HF radio communication allowing system operators to optimize system performance thereby contributing to the reduction of economic losses during PCA events.
        Speaker: Dr Robyn Fiori (Natural Resources Canada)
      • 14:00
        GPS phase scintillation during the geomagnetic storm of March 17, 2015: The relation to auroral electrojet currents 15m
        Ionospheric irregularities cause rapid fluctuations of radio wave amplitude and phase that can degrade GPS positional accuracy and affect performance of radio communication and navigation systems. The ionosphere becomes particularly disturbed during geomagnetic storms caused by impacts of coronal mass ejections compounded by high-speed plasma streams from coronal holes. Geomagnetic storm of March 17, 2015 was the largest in the current solar cycle. The high-latitude ionosphere dynamics is studied using arrays of ground-based instruments including Global Navigation Satellite System (GNSS) receivers, HF radars, ionosondes, riometers and magnetometers. The phase scintillation index is computed for L1 signal sampled at the rate of up to 100 Hz by specialized GNSS scintillation receivers of the Expanded Canadian High Arctic Ionospheric Network (ECHAIN) and the Norwegian Mapping Authority network supplemented by additional GNSS receivers operated by other institutions. To further extend the geographic coverage, the phase scintillation proxy index is obtained from geodetic-quality GPS data sampled at 1 Hz. In the context of solar wind coupling to the magnetosphere-ionosphere system, it has been demonstrated that GPS phase scintillation is primarily enhanced in the cusp, tongue of ionization (TOI) broken into patches drawn into the polar cap from the dayside storm-enhanced plasma density (SED) and in the auroral oval during energetic particle precipitation events, substorms and pseudo-breakups in particular. In this paper we examine the relation to auroral electrojet currents observed by arrays of ground-based magnetometers and energetic particle precipitation observed by DMSP satellites. Equivalent ionospheric currents (EICs) are obtained from ground magnetometer data using the spherical elementary currents systems (SECS) technique (Amm and Viljanen, Earth Planets Space, 51, 431–440, 1999) that has been applied over the entire North American ground magnetometer network (Weygand et al., J. Geophys. Res., 116, A03305, 2011).
        Speaker: P. Prikryl (Physics Department, University of New Brunswick, Fredericton, NB; Geomagnetic Laboratory, Natural Resources Canada, Ottawa, ON, Canada)
      • 14:15
        Evening and nighttime features of equatorial ionospheric F2 layer 15m
        Oyedemi S. Oyekola Etobicoke, ON M8V 3C8, Canada Email:ooyekola@gmail.com Abstract. We have used ionosonde observations recorded at Ibadan (7.4 degree North, 3.9 degree East) during the International Geophysical year (1957-58) to investigate evening and nighttime characteristic features of equatorial ionosphere during high solar flux and quiet magnetic conditions. We have also used International Reference Ionosphere model (IRI-2012) data. Our results show that the base of the ionosphere descends at a rate of -27.5 km/hr between 2000 LT and 0400 LT, whereas the observed bottomside peak of the ionosphere move down at a rate of -29.3 km/hr between 1900 and 0500 LT, while IRI2012 bottomside peak show -29.8 km/hr between 2000 LT and 0500 LT. The downward flow rate of plasma concentration between 1900 LT and 0500 LT and between 1800 LT and 0400 LT is approximately 0.040 electron per cubic metre per hour and 0.081 electron per cubic metre per hour, respectively for observed and for modeled NmF2. Month-by-month averaged altitudes (h’F, hmF2, and modeled hmF2) indicate significant local time variation. In addition, the month-by month variation indicates nighttime double crest of averaged peak height (hmF2) in the ionosonde measurements and in the IRI-2012 empirical model with a trough in June-August for data and In July for model. The monthly mean downward vertical drift velocities derived from local time variation of h’F and hmF2 together with global drift model essentially demonstrate much fluctuation. We found a “domed shaped” in modeled drift velocity, indicating equatorward plasma between April and September.
        Speaker: Dr Oyedemi Oyekola (Private)
      • 14:30
        RISR-C incoherent scatter radar operations 15m
        The Canadian face of the Resolute Bay Incoherent Scatter Radar (RISR-C) saw first light in August of 2015. To date, several different experiments measuring the polar ionosphere have been performed with RISR-C. These experiments are often complemented with data from the co-located northward facing RISR-N radar operated by SRI International. Like other Advanced Modular Incoherent Scatter (AMISR) radars, RISR-C (and RISR-N) use electronic beam steering to sample multiple look directions effectively simultaneously. Measurements of electron density, electron temperature, ion temperature, and line-of-sight velocity are made at various ranges along each of these beams in (typically) 1-minute intervals. Manipulation of the data from multiple beams and ranges allows a reasonable 3-D estimate of ionospheric parameters to be made within the field-of-view of the radar. Initial analysis of data taken by RISR-C shows that the radar is operating well and providing high quality ionospheric measurements. Further, the interesting first results from the radar demonstrate the potential for collaborations with existing ground- and space-based polar instruments.
        Speaker: Rob Gillies (University of Calgary)
    • 13:15 14:45
      W2-4 Neutrino Physics (PPD-DNP-DTP) / Physique des neutrinos (PPD-DPN-DPT) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Christine Kraus
      • 13:15
        T2K 30m
        T2K is a accelerator-based neutrino oscillation experiment operating in Japan, sending a muon (anti)neutrino beam produced at J-PARC to the Super-Kamiokande detector 295 km away. The neutrino oscillation process along the way, which results in some fraction of these muon neutrinos being detected as neutrinos of different flavors. T2K has reached several important milestones recently, including the definitive observation of muon neutrino to electron neutrino oscillation, the most precise measurement of the muon neutrino disappearance parameters, a joint analysis of these two modes towards the first constraint on the CP violating phase delta, and the first results from the experiment using an antineutrino beam. In this talk, we will report on the latest results from T2K and discuss the future prospects for T2K and beyond, including Hyper-Kamiokande
        Speaker: Blair Jamieson (University of Winnipeg)
      • 13:45
        Calibration of HALO for Long-Term Supernova Monitoring 15m
        Supernovae are the only location where the effects of neutrino-neutrino scattering could plausibly be observed, and they are also the favored location in the universe for certain processes necessary for the formation of heavy elements. This makes supernovae mechanics relevant to the fields of both particle physics and nuclear astrophysics. A core collapse supernova can be detected by the immense burst of neutrinos it produces. For this reason, HALO (Helium And Lead Observatory) was built to detect supernova neutrinos by detecting neutrons released from lead nuclei when struck by neutrinos. The use of lead as a target material gives the detector a unique sensitivity to electron neutrinos, where as other detectors predominantly see electron anti-neutrinos. The comparison of the spectra of different neutrino flavours could provide more information about the structure and mechanics of the core-collapse and the resulting neutrino interactions. HALO has been connected to SNEWS (SuperNova Early Warning System) since Oct 9, 2015. SNEWS is a network of neutrino detectors around the world that will send an alarm to the astronomy community when a galactic supernova is detected. The surface of a supernova progenitor star does not explode until the shock wave from the core collapse reaches it, allowing the neutrino pulse to lead the light by a few hours. Because of this delay, SNEWS can inform astronomers of a supernova before it is visible, which will hopefully allow for a supernova to be observed from its very beginning for the first time. HALO is expected to run continuously for decades in order to detect a supernova. This is important because most other detectors in the SNEWS network are not primarily focused on supernovae, and as such may be shut down for refurbishments aimed at other physics goals when a supernova occurs. An “always on” detector removes the possibility that SNEWS misses a galactic supernova. The calibration of HALO will be done during March 2016 with a Californium neutron source. Knowledge of the multiplicity of the neutrons emitted will be used to make measurements independent of the listed source strength and to mitigate statistical errors. The calibration will determine the neutron drift lengths, drift times, and capture efficiencies, which will be compared to simulations and to existing muon-induced spallation event data.
        Speaker: Mr Colin Bruulsema (Laurentian University)
      • 14:00
        T2K Phase II: towards initial discovery of CP violation in neutrino oscillations 15m
        The recent discovery of muon neutrino to electron neutrino conversion arising from neutrino oscillations has opened the door to the possibility for CP violation in neutrino oscillations. Such CP violation will be an important clue to how our universe came to our matter dominated state and for understanding the mass and mixing structure of neutrinos, a question left unanswered by the Standard Model. Furthermore, the currently measured parameters weakly suggest a potentially large CP violation effect in neutrino oscillations that may be accessible to the current generation of experiments. In this talk, we will discuss T2K Phase II, a possible extension to the T2K program with higher beam power and three times the data that may allow the first definitive look at CP violation in neutrino oscillations.
        Speaker: Tom Feusels (UBC)
      • 14:15
        Intermediate near detector NuPRISM for T2K extension and HyperK 15m
        CP violation in the lepton sector is the next major milestone in neutrino physics. Recent T2K and NOvA results show some preference for a large CP violation. In the next several years, the statistical sensitivity will start to reach the sensitive region if the systematic uncertainties are suppressed down to a few percent level, in particular for nuclear uncertainties in the neutrino cross sections. NuPRISM is a proposed water Cherenkov detector as a T2K and Hyper-K intermediate near detector. It locates at around 1km from the production target, covering off-axis angles of 1-4 degrees which provides ranges of well predicted neutrino spectra at each off-axis positions. By taking a linear combination of neutrino interaction events at different off-axis positions, neutrino cross sections, including lepton kinematics, in the water Cherenkov detector can be measured for a given neutrino energy spectrum, e.g. monochromatic neutrino spectrum. NuPRISM thus provides an elegant solution to experimentally constrain the systematic uncertainties of neutrino cross sections for the CP violation measurement. NuPRISM can also measure neutron tagging efficiencies for atmospheric neutrino interactions in the coming Gd loaded phase of Super-K (SK-Gd), which would suppress backgrounds for proton decay search and enable anti-neutrino tagging for atmospheric neutrino oscillation studies. NuPRISM is also sensitive to the LSND/MiniBooNE sterile neutrino oscillation with an additional information of varying neutrino energy spectrum to test oscillation hypotheses. An overview and status of NuPRISM will be presented in this talk.
        Speaker: Mark Scott (TRIUMF)
      • 14:30
        Photon detection in nEXO 15m
        The nEXO experiment is being designed to achieve unprecedented sensitivity to the neutrino-less double beta decay of 136Xenon. nEXO background rejection strategy includes in particular self-shielding, interaction site counting and energy resolution. Efficient light detection is critical for achieving the desired energy resolution of 2% (FHWM) or better. Simulations show that such an energy resolution can be achieved if at least 5% of the scintillation photons are detected, which requires mirroring most inactive surface and at least 4m2 of single photon detectors. So-called silicon photo-multipliers (SiPMs) are the only viable option as Photo-multiplier tubes are too radioactive and Avalanche Photo-Diodes yield too much electronics noise due to their low gain and are difficult to produce in mass quantity. The development of SiPMs for nEXO has already produced promising results: 1) measured limits for the radio-isotope content of SiPMs (produced by Foundation Bruno Kessler, FBK) are consistent with requirements, 2) the photo-detection efficiency exceeds 15% for FBK and Hamamatsu Photonics SiPMs at the liquid Xenon scintillation wavelength, 3) dark noise and correlated avalanche rates are within specifications. The nEXO collaboration is continuing to work with the SiPM vendors to further improve performances. The nEXO collaboration is also investigating solutions for reading out m2 of SiPMs, which has not been done before. In addition to conventional analog electronics solutions, the nEXO collaboration is investigating using the 3-dimensionally integrated technology (3D-SiPMs) that completely avoid any analog electronics and provide a mean of tagging every photon with minimum power dissipation. In this poster we will report the development of solutions for light detection in nEXO highlighting the technology that are pioneered by the collaboration, for example VUV sensitive SiPMs and 3D-SiPMs.
        Speaker: Fabrice Retiere (TRIUMF)
    • 13:15 14:45
      W2-5 Thin Films II (DCMMP-DSS) / Couches minces II (DPMCM-DSS) Colonel By B205

      Colonel By B205

      University of Ottawa

      Convener: Fabio Variola (University of Ottawa)
      • 13:15
        Exploring Silicene mono- and multilayers of Silicene and their oxidation with soft X-ray spectroscopy and DFT calculations 30m

        2012 brought the first reports of a new member of the 2D material family: a hexagonal honeycomb of Si atoms deposited on the Ag(111) surface called “silicene”[1]. The characteristics and stability of freestanding silicene had previously been theoretically explored [2], and there was a strong push to determine if the epitaxial sheets possessed the promising qualities of their hypothetical freestanding counterparts. Initially, ARPES experiments were thought to indicate that epitaxial silicene had a gapped Dirac cone in its electronic structure [1], as would be expected of freestanding silicene with a broken inversion symmetry. This enticing result, however, would be later overturned through a combination of experimental and theoretical techniques [3-5], and it would eventually be concluded that the epitaxial silicene sheet was in fact metallic with a strong cohesion to the underlying Ag(111) face. However, this conclusion would prove controversial [6,7], as the ambiguity of the ARPES data left some room for interpretation as to whether specific electronic features belonged to the epitaxial Si, the Ag substrate, or represented a hybridization between the two.
        Soft X-ray emission and absorption spectroscopy (XES and XAS) are synchrotron-based experimental techniques for directly probing the (element-specific) partial density of electronic states (PDOS) in the valence and conduction bands of a material. When performed at the Si L2,3 emission and Si 2p absorption edges, XES and XAS allowed us to unambiguously show that the Si valence and conduction states were continuous across the Fermi energy; i.e. that the silicene overlayer was indeed metallic [3]. However, for the material to be of use, it must be isolated from the substrate. One suggested way of achieving these characteristics is to produce a multilayer of silicene on the Ag(111) surface. However, other reports insist that bilayers and multilayers are inherently unstable, collapsing into bulk Si nanocrystals shortly after the monolayer deposition is complete [8].
        Our DFT calculations [9] predict a stable, AA-stacked silicene bilayer on Ag(111) that corresponds nicely to the scanning tunnelling microscopy (STM) bilayer observations. Unfortunately, these same DFT calculations predict a similar electronic structure as that of the monolayers, namely metallic and bound to the Ag(111). However, our XES and XAS measurements indicate a transition to bulk, sp3-hybridized Si beginning shortly after the completion of a monolayer, supporting the low-energy electron microscopy study that first suggested the nucleation of the silicene sheets to bulk crystals [9]. Finally, we will discuss our recent study in which we explore how Silicene oxidizes [10].

        References:

        [1] P. Vogt, P. De Padova, C. Quaresima, J. Avila, E. Frantzeskakis, M.C. Asesnsio, A. Resta, B. Ealet and G. Le Lay. Phys. Rev. Lett. 108, 155501 (2012).

        [2] S. Cahangirov, M. Topsakal, E. Aktürk, H. Şahin and S. Ciraci. Phys. Rev. Lett. 102, 236804 (2009).

        [3] N.W. Johnson, P. Vogt, A. Resta, P. De Padova, I. Perez, D. Muir, E. Z. Kurmaev, G. Le Lay and A. Moewes. Adv. Funct. Mater. 24, 5253 (2014)

        [4] S. Cahangirov, M. Audiffred, P. Tang, A. Iacomino, W. Duan, G. Merino and A. Rubio. Phys. Rev. B 88, 035432 (2013).

        [5] D. Tsoutsou, E. Xenogiannopoulou, E. Golias, P. Tsipas and A. Dimoulas. Appl. Phys. Lett. 103, 231604 (2013).

        [6] S. Huang, W. Kang and L. Yang. Appl. Phys. Lett. 102, 133106 (2013).

        [7] J. Avila, P. De Padova, S. Cho, I. Colambo, S. Lorcy, C. Quaresima, P. Vogt, A. Resta, G. Le Lay, M. C. Asensio. J. Phys.: Condens. Matter 25, 262001 (2013).

        [8] P. De Padova, P. Vogt, A. Resta, J. Avila, I. Razado-Colambo, C. Quaresima, C. Ottaviani, B. Olivieri, T. Bruhn, T. Hirahara, T. Shirai, S. Hasegawa, M. C. Asensio and G. Le Lay. Appl. Phys. Lett. 102, 163106 (2013).

        [9] N.W. Johnson, D. Muir, E.Z. Kurmaev, and A. Moewes, Adv. Funct. Mat. 25, 4083(2015).

        [10] N.W. Johnson, D. Muir, A. Moewes, Sci. Rep. 6, 22510 (2016).

        Speaker: Prof. Alexander Moewes (University of Saskatchewan)
      • 13:45
        Microstructure and hydrogen storage properties of FeTi + x wt% Hf alloys (x = 0, 2, 4 and 8) 15m
        In the perspective of widespread utilization of hydrogen, safe and low cost ways to store hydrogen are needed. Two common ways to store hydrogen are in the liquid and gaseous forms. However, both of these technique present serious drawbacks for many practical applications because they necessitate either a very low temperature (20 K) or a high pressure (700 bar). Another way to store hydrogen is to use metal hydrides. In metal hydride the hydrogen is chemically bonded to metal atoms. Metal hydrides are a safe and compact way to store hydrogen but, in order to be widely used by the industry, the cost should be reduced. A big part of the cost of FeTi is the first hydrogenation (activation) which has to be performed at high temperature and pressure. In order to reduce the activation time and conditions of operation, we investigated the addition of hafnium to FeTi. Alloys of compositions FeTi + x wt% Hf , with x=0, 2, 4 and 8 were synthesized using an induction furnace. The microstructure of the as-cast alloys were investigated by scanning electron microscopy and electron microprobe analysis. We found that the alloys are multiphase: one phase corresponding to the matrix FeTi, with about 1 at% of Hf irrespective of the amount of doping. Another phase is hafnium-rich of approximate composition Ti1.1Fe0.74Hf0.16. The effect of Hf doping on activation kinetics will be reported and possible mechanism discussed.
        Speaker: VOLATIANA RAZAFINDRAMANANA
      • 14:00
        Adsorption d’hydrogène dans des adsorbants microporeux : Étude numérique des propriétés thermodynamiques 15m
        En raison de sa faible densité ambiante, le stockage de l'hydrogène à l'état pur (comme dans l'état gaz ou liquide) nécessite des conditions thermodynamiques difficiles. Le stockage d'hydrogène basé sur les matériaux constitue un moyen efficace de réduire les exigences thermodynamiques afin d'atteindre des densités de stockage importantes pour les systèmes énergétiques. Par exemple, la physisorption d'hydrogène sur des adsorbants fortement microporeux a été largement étudiée pour les applications de véhicules. Puisque les adsorbants courants donnent des résultats d'adsorption intéressants seulement à température cryogénique (~100 K) et que les processus d'adsorption peuvent causer des changements thermiques significatifs, la modélisation de système de stockage basé sur l'adsorption nécessite la connaissance des équations d'états du phénomène d'adsorption sur une grande plage de conditions thermodynamique. La simulation informatique de la physique statistique basée sur la méthode Monte Carlo permet de calculer les isothermes d'adsorption pour un adsorbant cristallin idéal dont les paramètres des interactions adsorbat-adsorbant sont correctement paramétrés. En raison de leur surface accessible élevée, de leur forte microporosité et de leurs propriétés poreuses modulables, les structures métallo-organique ont été largement étudiées comme matériaux pour le stockage d'hydrogène par cryosorption. Dans ce travail, nous examinons la limite de densité des isothermes d'adsorption de l'hydrogène sur le MOF-5 et le CuBTC afin de guider les critères nécessaires à l’optimisation du stockage par physisorption. Différentes propriétés physiques et thermodynamiques de ces adsorbants sont étudiées comme le volume poreux, la surface spécifique, les fonctions de distributions radiales, les sites d'adsorptions et les isothermes d'adsorptions et de densité à l'intérieur des pores de l'adsorbant. Les propriétés thermodynamiques sont calculées en utilisant des simulations Grand Canonique Monte Carlo basées sur les intégrales de parcours pour la plage de pression 0-150 atm dans les états sous-critiques et super-critiques à 30, 50, 77, 113, 196 et 296 K.
        Speaker: Mr David Durette (UQTR)
      • 14:15
        Detection of hydrogen in steel with an N-15 nuclear resonance 15m
        We have used a 6.38 MeV N-15 nuclear resonance to detect hydrogen in steel that had been electroplated with a protective Cd surface coating. With the sample maintained at room temperature, we observed a rapid decline in hydrogen concentration during the measurement, indicative of beam-induced hydrogen detrapping and mobility. It appears that the hydrogen concentration falls off as a simple exponential decay with ion fluence, however it settles at a finite hydrogen concentration different from 0. In spite of the hydrogen loss, we have been able to detect small concentrations of hydrogen which has diffused into the bulk of the steel sample. We also studied in more detail the temperature dependence and aysmptotic behaviour of the hydrogen loss and will report on these studies.
        Speaker: Jean-Simon Larochelle (Université de Montréal)
      • 14:30
        Orienting an ensemble of dipoles near a dielectric interface 15m

        Fluorescence of single dipole emitters near a dielectric interface are studied. A 15 nm thick layer of polystyrene lightly doped with Rhodamine 6G was spin-cast onto cleaned glass and PMMA coated glass slides. Flourescence lifetime was found to increase by a factor of three as the PMMA spacer layer thickness was increased. This lifetime increase is accounted for by a change in the ensemble averaged distribution of the dipole orientation from isotropic to perpendicular to the interface as the spacer layer thickness increases. This reorientation occurs proceeds takes place over a 200nm range (from 100 to 300nm) of buffer layer thicknesses. The ability to tune dipole orientation and hence charge injection into 2D materials.

        Speaker: Jonathon David White (Yuan Ze University)
    • 13:15 14:45
      W2-6 DCMMP PhD Thesis Award Competition / Compétition du Prix de thèse doctorale DPMCM Colonel By D207

      Colonel By D207

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Giovanni Fanchini (The University of Western Ontario)
      • 13:15
        Ultrasonic waves in strongly scattering disordered media: understanding complex systems through statistics and correlations of multiply scattered acoustic and elastic waves. 30m
        The study of classical wave transport in strongly scattering, disordered media is a field rich with potential for understanding new fundamental wave physics phenomena, understanding the physical properties of amorphous materials, and probing the characteristics of complex, real-world systems. In this thesis, ultrasonic wave transport in complex media is investigated via analysis of the multiply-scattered transmitted field. In the strong-scattering regime, wave interference effects give rise to interesting physical phenomena, such as Anderson localization, which for electron transport was awarded the Nobel prize, and infinite-range $C_0$ correlations. The results presented provide the first experimental determination of the mobility edge and critical exponent $\nu$ that characterize the Anderson transition for classical waves. Additionally, infinite-range $C_0$ correlations have for the first time been directly observed [1], and found to grow dramatically near the mobility edge, along with the $C_2$ and $C_3$ correlations. Measurements of the multifractal exponent $\Delta_2$ demonstrated the link between $C_0$ correlations and Anderson localization. The density of states and level-spacing statistics are two underlying properties that affect wave transport in amorphous materials. Direct measurements of these quantities were obtained using small samples, allowing individual vibrational modes to be resolved [2]. The density of states showed a plateau extending well into the expected Debye regime, and evidence of a Boson peak was observed at low frequencies. The level-spacing statistics indicated that transport in the frequency ranges measured was on the diffusive side of the mobility edge, providing experimental evidence that the Boson peak need not result from localized modes. Multiply scattered classical waves also provide a useful tool for characterizing disordered systems. In this work, the dynamics of a suspension of bubbles were investigated using phase-based Diffusing Acoustic Wave Spectroscopy, where a new approach using phase correlations was shown to give additional information beyond that obtainable from traditional methods. [1] W.K. Hildebrand, A. Strybulevych, S.E. Skipetrov, B.A. van Tiggelen, and J.H. Page, Phys. Rev. Lett. **112**, 073902 (2014). [2] W.K. Hildebrand, L.A. Cobus, and J.H. Page, J. Acoust. Soc. Am. **127**, 2819 (2010).
        Speaker: Dr William Hildebrand
      • 13:45
        Electron-Electron Interactions in Optical Properties of Graphene Quantum Dots 30m
        In this thesis, I present a theory of electron-electron interactions in optical properties of graphene and transition metal dichalcogenides (TMDCs), two dimensional nanostructures with a hexagonal lattice. We start our discussion with electron-electron interactions in artificial rings for which the strength of interactions can be varied and exact results can be obtained. The artificial rings are described by the extended Hubbard model and solved using an exact diagonalization method in real and Fourier space of configurations. Exact and analytical results for charged rings are obtained in the limit of very strong interactions. For the quadruple quantum dot ring and the artificial benzene ring, we find that chirality leads to the appearance of a topological phase and an effective gauge field that determines the ground state character with varied interaction strength. For the charged artificial benzene ring, our numerical results show a transition from a degenerate to a non degenerate ground state with increasing strength of Coulomb interactions. We show that the artificial gauge and the transition in the ground state can be detected as changes in the optical absorption spectrum. In the second part of the thesis, the electronic and optical properties of colloidal graphene quantum dots (CGQD) consisting of many benzene rings are determined. The CGQDs are described by the combination of tight binding, mean field Hartree Fock (HF) and Configuration Interaction methods. The single particle properties are described through the tight binding method based on the pz carbon orbitals. Screened Coulomb interactions between electrons, including direct, exchange, and scattering matrix elements, are calculated using Slater pz orbitals. HF ground states corresponding to semiconductor, Mott-insulator, and spin-polarized phases are obtained as a function of the strength of the screened interaction versus the tunnelling matrix element. The many-body ground and excited states in the semiconducting phase are constructed as a linear combination of a finite number of electron-hole pair excitations from the HF ground state (GS). The Hamiltonian is constructed in the subspace of multi-pair HF excitations to obtain the low energy, many body states by exact diagonalization using the Lanczos method. The degeneracy of the valence- and conduction-band edges of 3-fold rotationally symmetric CGQDs is shown to lead to a characteristic exciton and bi-exciton spectrum. The low-energy exciton spectrum is predicted to consist of two bright-singlet exciton states corresponding to two circular polarizations of light and a lower-energy band of dark singlets and dark triplets. The robustness of the bright degenerate singlet pair against correlations in the many-body state is demonstrated as well as the breaking of the degeneracy by the lowering of symmetry of the CGQD. Band edge biexciton energies and binding energies are predicted, and two degenerate exciton (X) states and a corresponding biexciton (XX) state are identified for the generation of an XX-X cascade. The Auger coupling of XX and excited X states is determined and our theoretical results are compared with experimental absorption and non-linear transient absorption spectra. In the third and final part of the thesis, we replace the two non-equivalent carbon atoms of the graphene hexagonal lattice with a heavy transition-metal atom M, (e.g. Mo or W) and a dimer X2 (e.g. S). The bandstructure of a monolayer MX2 is calculated using density functional theory (DFT). It is shown that a direct gap opens up at all K points of the Brillouin zone and strong spin orbit coupling leads to spin splitting of the valence and conduction bands and emergence of valley dependent optical selection rules. Finally, the magnetoluminescence experiments on a monolayer WS2 emitting circularly polarized light upon its excitation by unpolarized light are described. The emission of polarized light in zero magnetic field is explained by the possibility of formation of a valley polarized 2D electron gas in unintentionally doped WS2.
        Speaker: isil ozfidan (University of Alberta)
      • 14:15
        Band Engineering of Graphene using Metal Mediated Oxidation 30m
        In the study of materials for electronic devices, there is a continuous search for new materials with useful properties such as grapheme and grapheme-based materials. Research on these materials is widespread for many applications such as manipulation the band structure of grapheme to induce a semiconducting band gap. The focus of this study is a cobalt nanoparticle-graphene system investigated for the manipulation of the graphene electronic structure. The properties of this system were investigated using various X-ray spectroscopy and surface science techniques. At a low concentration of cobalt, the metal is completely oxidized into primarily CoO, and the graphene is not heavily damaged. Oxide groups form on the graphene surface but are found to be proportional to the cobalt concentration at thicknesses below 1 nm. Using X-ray spectroscopy, an electronic band gap of up to 0.30 eV is observed in graphene 2p states when cobalt nucleates into nanooparticle islands on the graphene surface. The mechanism of band gap opening is interpreted using electronic structure calculations, showing a contribution from both the oxidation of the graphene itself and the presence of CoO that acts to localize electron charge. These results have implications for graphene electronics and spintronics where magnetic metals can be used to induce a band gap in graphene that is stable at room temperature and under atmospheric exposure. [1] Paul F. Bazylewski, Van Luan Nguyen, Robert P.C. Bauer, Adrian H. Hunt, Eamon J. G. McDermott, Brett D. Leedahl, Andrey I. Kukharenko, Seif O. Cholakh, Ernst Z. Kurmaev, Peter Blaha, Alexander Moewes, Young Hee Lee, and Gap Soo Chang. Sci Rep. 2015, 5, 15380. [2] P. Bazylewski, D. W. Boukhvalov, A. I. Kukharenko, E. Z. Kurmaev, A. Hunt, A. Moewes, Y. H. Lee, S. O. Cholakh and G. S. Chang. RSC Adv., 2015, 5, 75600-75606.
        Speaker: Dr Paul Bazylewski (University of Saskatchewan)
    • 13:15 14:45
      W2-7 Terahertz Science and Applications (DAMOPC) / Sciences et applications des Terahertz (DPAMPC) SITE A0150

      SITE A0150

      University of Ottawa

      Convener: Denis Morris (Unniversité de sherbrooke)
      • 13:15
        Ultrahigh Vacuum Terahertz Scanning Tunneling Microscope 30m
        The terahertz scanning tunneling microscope (THz-STM) is a new system for ultrafast imaging of surfaces at the nanoscale. Previous experiments have shown a spatial resolution of 2 nm and temporal resolution of 500 fs under ambient conditions. Currently, the THz-STM is being developed for operation in ultrahigh vacuum. The challenges involved with operating in a vacuum environment, simulations of a terahertz pulse coupling to an STM tip, and progress towards atomic resolution with THz-STM will be discussed.
        Speaker: Vedran Jelic (University of Alberta)
      • 13:45
        Silk Foam Terahertz Waveguides for Biomedical and Agri-Food Applications 15m
        Silk is a unique kind of nature protein. In recent years this ancient material has been introduced into biomedical field as a promising biomaterial which opened a new era in the development of optical interfaces and sensors for biomedical applications. In this work, we present biocompatible THz waveguides made from silk foam. To our knowledge, this is the first time when biocompatible waveguides are demonstrated in the mid-THz frequency range. Silk foams were obtained from a purified aqueous silk fibroin solution and lyophilised in a vertical freezer at -80 °C for several hours. Density measurements show a porosity (air fraction by volume) higher than 94%. Fiber silk foams are investigated with a THz Time-Domain Spectroscopy setup. We measure the THz transmission through different lengths of samples. We extract both the refractive index and the extinction coefficient in the THz virtually constant with a value of 1.0654, close to that of air. The losses follow a square law (0.3 cm^-1 at 0.3 THz). Because of its high porosity, the absorption losses are reduces by one order of magnitude compared to solid silk. Its main advantage compared to other waveguides is that it is biocompatible, biodegradable and it could be biofunctionalized. Moreover the foam porous structure can be useful for sampling of biofluids using capillary effect for applications in biosensing. This cannot be done with usual THz polymer waveguides.
        Speaker: Hichem Guerboukha (École Polytechnique de Montréal)
      • 14:00
        Dynamic measurements at THz frequencies with a fast rotary optical delay line 15m
        For several years, THz spectroscopy and imaging have been applied to many different fields. However, some burdens still remain in its commercial generalization, particularly for the industry sector. One of these difficulties lies in the acquisition time. In a typical THz time-domain spectroscopy system (THz-TDS), the THz pulse is sampled in time by the means of a micrometer linear delay line. This operation is highly time-consuming, often on the minute scale. We design and fabricate a fast rotary optical delay line (FRODL) consisting of two curvilinear reflectors directly connected to a rotating motor. The optical delay is linear with the rotation angle of the FRODL. The optical input and output are separate and stable to avoid the use of other moving components. We present an experimental implementation of such FRODL. The FRODL surface is made with a CNC machine. We fabricated four blades on the same disk to increase by four the total scan rate. We tested the FRLODL with speeds up to 48 Hz (192 Hz maximum). The motor and the electronics were limiting this speed. The total delay was experimentally evaluated to 100 ps. As a first application, we present contactless monitoring of spray painting process and thickness real-time evaluation of the thickness of the paint layer. As a second application, we present the simultaneous detection and thickness characterization of fast moving objects.
        Speaker: Hichem Guerboukha (Ecole Polytechnique de Montreal)
      • 14:15
        Intense Terahertz Sources and their Applications at the Advanced Laser Light Source 30m
        Tabletop sources of high-field terahertz (THz) pulses are currently a hot topic, which is being pursued by many groups around the world. While the favourite method for intense THz generation is optical rectification in nonlinear crystals, research on using other novel methods have shown promising results, including those using air-plasmas, relativistic laser-solid interactions, and large aperture photoconductive antennas. At the Canadian Advanced Laser Light Source, we have built an array of intense THz sources with different central frequencies, with peak THz electric fields ranging from few 100 kV/cm to few MV/cm. In parallel, we have used these sources to study the nonlinear THz response of various materials. In this talk, I will first quickly review the various components of the “intense THz rainbow” at ALLS. I will then describe more in detail our recent results on intense THz sources based on relativistic laser-solid interactions, and the use of nanorod targets to increase the THz conversion efficiency by 28 times. This provides us with an excellent opportunity for multi-mJ THz sources, which when focused could reach peak intensities of $10^{14} Wcm^{-2}$. Finally, I will present our recent results on the nonlinear THz spectroscopy of monolayer graphene. By using gated graphene samples to control their Fermi level energy, we show that their nonlinear response in the THz regime changes drastically when the Fermi level is at or away from the charge neutral point. Comparison with simulations reveals the mechanism involved in such changes.
        Speaker: Tsuneyuki Ozaki (INRS-EMT)
    • 13:15 14:45
      W2-8 Cosmic Frontier: Dark Matter IV (PPD) / Frontière cosmique: matière sombre IV (PPD) Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Darren Grant (University of Alberta)
      • 13:15
        Pulse Finding and Single Photon Counting for the DEAP-3600 Experiment 15m
        DEAP-3600, comprised of a 1 tonne fiducial mass of ultra-pure liquid argon, is designed to achieve world-leading sensitivity for spin-independent dark matter interactions. DEAP-3600 uses an array of photomultiplier tubes (PMTs) to measure the time distribution of scintillation light arising from the de-excitation of argon dimers. This measurement allows background events from Ar-39 decays to be rejected at a high level using pulse shape discrimination. The performance of this analysis relies critically on DEAP’s ability to identify pulses in the PMT waveforms and accurately assess the number of photo-electrons contributing to each pulse. This talk will present an algorithm developed for finding pulses and identifying the number of photo-electrons, as well as removing pulses from unwanted PMT artifacts. A method for quickly identifying single-photoelectron-like pulses and its use to provide a high level of data compression will also be discussed.
        Speaker: Thomas McElroy (University of Alberta)
      • 13:30
        Dark matter with Vector-like Fermions 15m
        In this work we analyze the effects of introducing vectorlike leptons in the Higgs triplet model to provide a scenario that can explain both neutrino masses and provide a Dark Matter candidate, two essential shortcomings of the Standard Model. We investigate constraints, including the invisible decay width of the Higgs boson and the electroweak precision variables, and impose restrictions on model parameters. We analyze the effect of the relic density constraint on the mass and Yukawa coupling of dark matter. We also calculate the cross sections for indirect and direct dark matter detection and show our model predictions for the neutrino and muon fluxes from the Sun, and the restrictions they impose on the parameter space. With the addition of vectorlike leptons, the model is completely consistent with dark matter constraints, in addition to improving electroweak precision and doubly charged mass restrictions, which are rendered consistent with present experimental data.
        Speaker: SAHAR BAHRAMI (CONCORDIA UNIVERSITY)
      • 13:45
        **WITHDRAWN** Delayed Coincidence Analysis to Tag Alpha Decays from Radon in The DEAP-3600 Experiment 15m
        The DEAP-3600 experiment, located 6800 feet underground at the SNOLAB facility, uses 3.6 tons of liquid argon for a direct detection search for weakly-interacting massive particle (WIMP) dark matter. The target sensitivity to the spin-independent WIMP-nucleon cross section is 10$^{-46}$ cm$^{2}$ at 100 GeV/c$^{2}$ WIMP mass. The success of dark matter experiments depends critically on understanding and reducing any possible sources of background. In the DEAP-3600 experiment radon (Rn) daughters decaying on the surface of the detector and in the argon may mimic the expected dark matter signal. Here we will present an analysis using time and energy to identify and tag such radioactive decays. This talk will discuss the results from this analysis method, applied to various stages of the DEAP-3600 experiment, to determine the Rn activity and to perform basic calibrations.
        Speaker: Mr Pietro Giampa (Queen's University)
      • 14:00
        Phenomenological constraints on a model with a Higgs-like dilaton and singlet scalar dark matter 15m
        We consider a variant of the Standard Model with a Higgs-like dilaton, extended to include a singlet scalar dark matter candidate. In this model, the properties of the dilaton are constrained by the observed Higgs properties, dark matter relic abundance, and dark matter direct detection limits, as well as the latest collider limits. We place constraints on the free parameters of the model: the scale of conformal symmetry breaking f, the mass of the dark matter, and the ultraviolet contribution to the running of the dilaton-photon and dilaton-gluon couplings at a scale above conformal symmetry breaking, b$_{UV}$. The latter we treat as a free parameter to reflect our ignorance of the high-energy behavior of the underlying conformally invariant theory. We explore how the model can be further probed by future measurements.
        Speaker: Robyn Campbell (Carleton University)
      • 14:15
        A Study of Alpha Particle Backgrounds in the Neck of the DEAP-3600 Detector 15m
        The DEAP-3600 experiment searches for spin-independent interactions of weakly interacting massive particle (WIMP) dark matter candidates. The detector utilizes a 3600 kg mass of liquid argon as the dark matter target, which is contained in a spherical acrylic vessel. There is an opening at the top of the acrylic vessel where the cooling system is located, in the ‘neck’ of the detector. The decay of alpha particles from components in this region can potentially mimic a WIMP signal, and so it is critically important to understand and mitigate this source of alpha backgrounds. Monte Carlo simulation is used to estimate the rate of such neck background events, employing material radioactivities that were carefully measured and constrained in the construction of DEAP-3600. A likelihood ratio method has been developed to identify and remove alpha particle backgrounds originating in the neck region. This talk will present the results of the Monte Carlo simulation and a preliminary analysis of neck alphas from data taken during DEAP-3600 commissioning with gaseous argon.
        Speaker: Courtney Mielnichuk (for the DEAP Collaboration, University of Alberta, Department of Physics)
      • 14:30
        Search for New Physics: Dark Vector Boson 15m
        Based on the simple U’(1) extension of Standard Model (SM), we have used Dark Vector boson kinetic and mass mixings to generate the new beyond the SM extension: dark photon and Z’ bosons. Both dark photon and Z’ have different masses and couplings to the original SM particles defined by the set of mixing parameters. In addition, Z’ boson have parity -violating nature and could be used as candidate for physics beyond the SM in precision electroweak searches. Comparing the theoretical predictions and the experimental data, we made exclusion plots to determine possible allowed region of masses and mixing parameters for these new particles. Our calculations have been completed up to one-loop level with dark photon or Z’ participating in Moller scattering or electron-positron collisions. We also plan to include a discussion of possible SU(2)’ SM extension in order to study strong CP violation in electron-positron collisions. The talk will give detailed analysis of the impact of dark photon and Z’ on the observables of the proposed Moller and Belle II experiments.
        Speaker: Mr Shihao Wu (Memorial University Grenfell Campus)
    • 14:45 15:15
      Health Break (with exhibitors) / Pause santé (avec exposants) SITE Atrium

      SITE Atrium

      University of Ottawa

    • 15:15 16:30
      W3-1 Nuclear Structure III (DNP) / Structure nucléaire III (DPN) Colonel By B205

      Colonel By B205

      University of Ottawa

      Convener: Rituparna Kanungo (Saint Mary's University)
      • 15:15
        Mass Measurements with TITAN: Capabilities and Progress 30m
        Nuclear and atomic masses factor into almost every branch of physics. In nuclear physics and nuclear astrophysics, masses contribute to our understanding of fundamental symmetries and explosive nucleosynthesis, just to name a few applications. TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) has been built to study exotic, short-lived nuclei. The TITAN facility consists of three main ion traps: a gas-filled RadioFrequency Quadrupole (RFQ) trap that cools and bunches continuous beam from TRIUMF’s ISAC facility, an Electron Beam Ion Trap (EBIT) which charge breeds ions in advance of their mass measurement, and a Measurement PEnning Trap (MPET) which makes precision mass measurements via the Time-of-Flight ion cyclotron resonance method. In addition to the ion traps currently in operation, TITAN is commissioning two additional ion traps to assist in the goal of precision mass measurements. The energy spread of the charge bred ion bunch coming from the EBIT adversely affects the precision of mass measurements in MPET. A new Cooler PEnning Trap (CPET) seeks to cool highly charged ion bunches via the Coulomb interaction with a simultaneously trapped electron plasma. The cooled iopn bunch can then be sent to MPET for precision mass measurement. TITAN’s other trap is a Multi-Reflection Time-of-Flight mass spectrometer (MR-ToF) which is designed to provide a mass resolving power of greater than 1 part in $10^5$ (an improvement of more than an order of magnitude over ISAC’s mass separator). Both CPET and the TITAN MR-ToF are currently being tested offline before being integrated into the TITAN beamline. Recent upgrades to TITANs capabilities, such as the ability of the EBIT to be used for isobaric separation, status of the MR-ToF and CPET, as well as updates on the state of mass measurements with TITAN will be discussed.
        Speaker: Dr Daniel Lascar (TRIUMF)
      • 15:45
        Probing Nuclear Shell Evolution using Radioactive Ion Beams at ISOLDE, CERN 30m
        The science of stellar nucleosynthesis aims at understanding how the elements in the universe are formed in stars. On a microscopic scale, the formation of elements is dictated by the properties of atomic nuclei and their interactions. Of special importance for r-process nucleosynthesis is a fundamental understanding of shell evolution towards neutron-rich nuclei. The finding of a soft N=2 harmonic oscillator shell in the “Island of Inversion” was one of the first discoveries of changing shell structure in exotic nuclei and triggered a renaissance in our field thanks to the availability of intense beams of unstable ions. Recent experiments at the RIKEN Nishina Center (Japan) indicate that also the N=3 harmonic oscillator shell is softened for extremely neutron-rich nuclei, which would effect the r-process flow in a dramatic way. I will discuss the underlying physics and will report on our recent experiments at the radioactive ion beam facility ISOLDE at CERN using the high-granularity MINIBALL array. In a series of studies we probed the N=3 Neutorn harmonic oscillator shell gap around 68Ni. Specially, using a multiple coulomb excitation experiment a clear indication for an onset of deformation beyond N=40 can be observed, indicating the pivotal role of subshell structure on the evolution of collevtice nuclear properties.
        Speaker: Dennis Muecher (University of Guelph)
      • 16:15
        Chiral basis for particle-rotor model for triaxial nuclei 15m
        In the last decade nuclear chirality resulting from an orthogonal coupling of angular momentum vectors in triaxial nuclei has been a subject of numerous experimental and theoretical studies. Three perpendicular angular momenta can form two systems of the opposite handedness, the right-handed and the left-handed system; the time-reversal operator, which reverses orientation of each of the components, relates these two systems. The underlying mechanism for generating chiral geometry of angular momentum coupling emphasizes the interplay between single-particle and collective degrees of freedom in nuclear structure physics. In the simplest case of odd- odd nuclei, two out of three mutually orthogonal angular momenta are provided by the high-$j$ valence proton and neutron quasiparticles, which are of particle and hole character as defined by the respective position of the Fermi level within a unique-parity sub-shell. The single-particle contribution to the total energy is minimised when the angular momenta of the particles and holes align along the short and the long axis of the core, respectively. The third angular momentum component is provided by the collective core rotation and aligns along the axis of the largest moment of inertia; this is the intermediate axis for irrotational flow-like moments of inertia for a triaxial body. This simple picture leads to prediction of distinct observables manifesting chirality in rotational structures, most notably to the doubling of states. All these effects can be demonstrated using particle-rotor model for triaxial nuclei, and are especially transparent when a newly developed chiral basis is used in calculations. The model, the basis, numerical results, and comparison to the data will be presented and discussed.
        Speaker: Prof. Krzysztof Starosta (Simon Fraser University)
    • 15:15 16:30
      W3-2 Teaching Physics to a Wider Audience (DPE) / Enseigner la physique à un auditoire plus vaste (DEP) SITE J0106

      SITE J0106

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Daria Ahrensmeier (Simon Fraser University)
      • 15:15
        An Asynchronous Peer Instruction Platform 15m
        Few pedagogical approaches have been as well documented in physics education research as Peer Instruction as developed by Eric Mazur at Harvard University 25 years ago. Peer instruction is an interactive process that takes place in real-time between students in a classroom. However, could Peer Instruction be used asychronously? The utility of asynchronous Peer Instruction is evident for blended and e-learning approaches (MOOCs in particular). Furthermore, as instructors shift more of their classroom content to preparatory activities given to students before class (as with Just in Time Teaching and flipped classroom) asynchronous Peer Instruction platforms also provide an effective way to prepare students for class. We describe the development in three Montreal-based Cegeps of a Peer Instruction platform called DALITE. We also describe its migration onto the Open edX platform with use cases from an MITx physics MOOC and a HarvardX course called Justice.
        Speaker: Nathaniel Lasry (John Abbott College)
      • 15:30
        Can learning about History of Science and Nature of Science in a student-centred classroom change science students' conception of science? 30m
        Learning about the Nature of Science (NOS) and the History of Science (HOS) has been shown to be highly beneficial to both the study and the practice of science. In particular, students’ conception of science can be improved by including NOS and HOS in the curriculum. However, teaching of NOS and HOS is not always effective: simplistic or erroneous conceptions of science sometimes persist. Innovative, student-centered teaching methods may circumvent this problem. That is why a course focused on NOS and HOS taught using two innovative pedagogical methods is offered as part of a multidisciplinary minor in Science, at Concordia University. The present study aims to investigate the changes in conception of science experienced by students in this course. In-depth interviews with eight students and in-class observation were carried out throughout the semester, and written products of students’ reflection on NOS and HOS was analyzed using a rubric from previous research. Results indicate that students react positively to this form of teaching NOS and HOS. In addition, all interviewed students report having developed a more elaborate and more nuanced conception of science.
        Speaker: Calvin Kalman (Concordia University)
      • 16:00
        Twenty Years of Innovative Physics Distance Education at Athabasca University 15m
        Although Athabasca University has offered distance education courses in many subjects for over a quarter century, twenty years ago Physics was taught by mailing out printed course materials while requiring students to physically attend onsite labs, some coming from as far away as Texas. A major increase in Physics enrollment took place after we switched to mail-out course material, with home labs using lab kits borrowed from the university library. We have progressed to a mail-out textbook with online Study Guide and Home Lab Manual, and reduced the cost of lab kits as we use modern technologies to serve nearly 500 students per year. Our latest endeavor is to move to an open source e-textbook (OpenStax College Physics) with improved online lab materials. The ubiquitous use of cellphones and the measurement capabilities they now provide allow us to envisage using only materials available in students’ homes to provide a meaningful lab experience. Many of our advances have implications for campus-based institutions.
        Speaker: Martin Connors (Athabasca University)
      • 16:15
        The online preparatory course on basic mechanics for first year life-science students without HS background in physics. 15m

        Under current admission conditions for the Faculty of Science at the University of Ottawa, students entering our faculty need to have equivalents of two advanced math courses (Advanced Functions, and Calculus and Vectors), as well as two of the three 4U science courses (Chemistry, Biology and Physics). At present time, roughly 30% of all admitted students are missing one of them, and it is invariably a physics course. Altogether, they make up more than half (nearly 350 in fall of 2015) of the students taking introductory life-science physics course (PHY1321).
        To address this issue within the program’s current credit constraints, we created a course known as PHY1331, in which students are offered an extra 80 minutes lecture time every week to be spent on basic mechanics concepts.
        Over the last ten years, this approach has been used with some success, when measured by the grade gaps between two groups of students at the start of the semester and at the end. In the fall of 2015, the online component of the course has been offered to students as a way to foster their familiarity with fundamental concepts of mechanics.
        It was offered as an option rewarded with extra credit against the final exam.
        By scoring the maximum points, students would be able to lower their final exam weight by 25%. Roughly 50 students participated in this exercise.
        In the presentation, the participants’ results on three identical tests will be compared with the results of non-participants, as well as with the scores of the students from PHY1321. The correlations and effectiveness of the proposed approach will be discussed, together with the specifics of the online course component’s structure. The conclusions and the resulting modifications for the future mandatory, blended course of this type will also be presented.

        Speaker: Prof. Andrzej Czajkowski (University of Ottawa)
    • 15:15 16:30
      W3-3 Quantum Transport (DCMMP) / Transport quantique (DPMCM) SITE A0150

      SITE A0150

      University of Ottawa

      Convener: An-Chang Shi (McMaster University)
      • 15:15
        Dynamique ultra-rapide de polaritons excitoniques: de leur création à leur condensation dans un état macroscopique quantique 30m
        Récents progrès dans les techniques de fabrication de microcavités à semi-conducteurs ont permis d’observer des nouveaux états propres issus du couplage fort entre un champ photonique fortement confiné et des excitons de puits quantiques. Ces états, appelés exciton-polaritons, ont un caractère mixte lumière-matière qui leur confère des propriétés très particulières. Notamment, leur faible masse leur permet de former, à des températures relativement élevées (au-delà de 4 K), un état quantique macroscopique similaire aux condensats de Bose-Einstein (CBE). Depuis, de nombreux travaux de recherche se sont basés sur la détection de la photoluminescence émise par la microcavité pour caractériser et analyser le CBE. Toutefois, ces expériences ne permettent que de sonder la composante photonique des polaritons sans possibilité d’adresser directement la partie matière. De par sa structure semi-conductrice similaire à un autre système cohérent, le laser en microcavité, un doute s’est d’ailleurs installé sur la nature exacte du CBE et de ses propriétés qui le démarquent du laser. Notre approche expérimentale se base sur l’utilisation de la spectroscopie térahertz (THz) résolue en temps pour sonder la formation du CBE à partir de ses interactions microscopiques. Cette technique nous permet non seulement d’accéder directement à la composante matière des polaritons, mais elle donne aussi accès à une dynamique ultra-rapide très riche qui comprend la formation d’exciton-polaritons à partir de porteurs de charges libres et le processus complet de condensation qui s’en suit [1]. Nos résultats démontrent directement l’existence de la composante matière de l’état quantique macroscopique établissant ainsi une différence fondamentale entre le CBE et le laser en microcavité. [1] Ménard, J.-M. et al. Revealing the dark side of a bright exciton-polariton condensate. Nature Communications 5, 4648 (2014).
        Speaker: Prof. Jean-Michel Ménard (University of Ottawa, University of Regensburg)
      • 15:45
        Electrode effects in dielectric spectroscopy measurements on (Nb$+$In) co-doped TiO$_2$ 15m
        Recently, several papers reported the discovery of giant permittivity and low dielectric loss in (Nb+In) co-doped TiO$_2$. A series of tests was performed which included the measurement of the frequency dependence of the dielectric permittivity and ac conductivity of co-doped (Nb+In)TiO$_2$ as a function of electrode type, sample thickness and temperature. The data suggest that the measurements are strongly affected by the electrodes. The consistency between four contact van der Pauw dc conductivity measurements and bulk conductivity values extracted from two contact ac conductivity measurements suggest that the values of colossal permittivity are, at least in part, a result of Schottky barrier depletion widths that depend on electrode type and temperature.
        Speaker: David Crandles (Brock University)
      • 16:00
        Fingerprints of the axion in the phonon properties of topological semimetals 15m
        Weyl semimetals are three dimensional crystals that contain topologically protected Dirac fermions in the electronic band structure. These materials display an array of unusual transport and optical properties, which can be traced to the emergence of an axion term in Maxwell's equations. Predicted four decades ago in the context of high energy physics, the axion has remained experimentally elusive until its recent discovery in topological materials. Following this discovery, the impact of the axion in the electronic properties has been extensively studied. However, little is known about the interplay between the axion and the lattice vibrations. In this talk, I will present a theory which describes the coupling between the axion and the polar optical phonons in Weyl semimetals. I will thereafter show how this coupling modifies the dynamical properties of the lattice and the electron-phonon interactions.
        Speaker: pierre rinkel (Université de Sherbrooke)
      • 16:15
        Chiral spin liquid from magnetic Wannier states 15m
        We present a mapping of a two-dimensional system of interacting bosons in a strong perpendicular magnetic eld to an equivalent system of interacting bosons on the square lattice in the absence of the eld. The mapping utilizes a magnetic Bloch and the corresponding magnetic Wannier singleparticle basis in the lowest Landau level. By construction, the ground states of the resulting model of interacting bosons on the square lattice are gapped fractionalized liquids or gapless Bose metal states with broken time reversal symmetry at specic rational lling fractions.
        Speaker: Ivan Panfilov
    • 15:15 16:30
      W3-4 Technical Exploits (DIAP-DIMP) / Prouesses techniques (DPIA-DPIM) Colonel By B012

      Colonel By B012

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: René Roy (Université Laval)
      • 15:15
        Optique pour téléphone cellulaire : Pouvons-nous miniaturiser davantage? - Consumer electronic optics : How small a lens can be? 30m
        En 2016, on trouve des modules de caméra miniature dans une variété de produits, comme les webcams, les cellulaires, le véhicules, les endoscopes, les tablettes, les ordinateurs portables et bien d’autres. Les caméras de téléphones cellulaires présentent peut-être les plus grands défis puisque le marché exige des dispositifs toujours plus minces et des algorithmes intégrés de traitement d’image optimisés. À mesure que la technologie évolue, pour répondre aux besoins du marché, de nouvelles capacités devront être développées pour atteindre une meilleure résolution et une meilleure qualité d’image. Par conséquent, le système de lentilles deviendra plus complexe et comprendra plus d’éléments optiques et/ou de nouveaux éléments optiques. Y a-t-il une limite? Nous aborderons le sujet du point de vue des contraintes de fabrication et aussi de la limite théorique des principes de physique derrière la conception de lentille de si faibles dimensions. In 2016, miniature camera modules can be found in a variety of products such as webcams, mobile phones, vehicles, endoscopes, tablets, portable computers and many others. Mobile phone cameras are probably one of the most challenging because of the requirement for ever smaller total track length (TTL) and optimized embedded image processing algorithms. As the technology is developing, new capabilities in terms of higher resolution and higher image quality are required to fulfil market needs. Consequently, the lens system becomes more complex and requires more optical elements and/or new optical elements. What is the limit? We will discuss this topic in terms of manufacturing constraints but also in terms of the theoretical limit of the physics behind the lens design of such miniature optical components
        Speaker: Dr Simon Thibault (Université Laval)
      • 15:45
        Non stick coatings from thin air 30m
        Non stick coatings are everywhere in nature and these have stimulated numerous applications in industry. For example leaf surfaces have been the inspiration for novel waterproof textile coatings. Insect wings may hold the key to strategies for antifouling on marine vessels and the associated energy savings that go hand in hand with such developments. The latest “green” nanotechnology approach to fabricating extremely non-stick surfaces involves self-organized and chemically cross linked nanoparticles. These generate exceptionally rough multi scale hierarchical (ultra rough) interfaces that simultaneously possess a unique ability to self-clean. But what is behind such an effect? Why does a lotus leaf stay clean in nature but when freshly cut it rapidly contaminates? Rinsing inert “dirt” from textiles is enhanced if the surface has multi scale roughness yet biological (live) contaminants “sense” subtle nanoscale features and may “hold on” despite such washing. This talk will discuss investigation of immersed interfaces using synchrotron X ray scattering and phase contract imaging at Australian and Canadian Lightsources respectively. Results suggest that ultra rough surfaces that are visibly soaked are not necessarily completely wet and this can have major implications with respect to optimizing, for instance, antifouling behavior. It all about what is trapped in the interface. Similarly, fine tuning bulk mixtures of nanoparticle cluster sizes and variable surface architectures can have a major impact on film optical properties and not surprisingly non stick surface properties.
        Speaker: Robert Lamb (Canadian Light Source Inc.)
    • 15:15 16:30
      W3-5 Cosmology and Astrophysics (DTP-DIMP-PPD) / Cosmologie et astrophysique (DPT-DPIM-PPD) Colonel By D207

      Colonel By D207

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Mohammad Ahmady (Mount Allison University)
      • 15:15
        The Conformal Standard Model, Higgs Portal Extensions, and Dark Matter 30m
        One of the possible custodial symmetries responsible for naturalness in the Standard Model is conformal (scale invariance) symmetry of the Lagrangian. After a brief review of the Higgs mechanism in the classically-conformal Standard Model, Higgs-portal singlet extensions as a model for dark matter are introduced. Results for the dark matter mass and cosmological abundance predictions in these Higgs-portal models will be presented.
        Speaker: Tom Steele (U of Saskatchewan)
      • 15:45
        Turnaround radius in an accelerated universe for Einstein and for modified gravity 15m
        In an accelerating universe there is a maximum radius above which a shell of test particles cannot collapse and is dispersed by the cosmic expansion. This radius could be used in conjunction with observations of large structures to constrain the equation of state of the universe. We express the turnaround radius in general relativity in terms of the Hawking quasilocal mass and we extend the concept to modified theories of gravity for which the gravitational slip is non-vanishing. [Based on V. Faraoni, M. Lapierre-Leonard & A. Prain 2015, JCAP 10, 013; V. Faraoni 2016, Phys. Dark Universe 11, 11]
        Speaker: Valerio Faraoni (Bishop's University)
      • 16:00
        Secular Increase of the Astronomical Unit: A Hubble-like Expansion? 15m
        This paper analyses the outcome of a new metric [1] that describes the space-time geometry of a static symmetric massive celestial object. It is based on an *erfc* potential that characterizes the gravitation field emerging from this model. The metric relies on an intrinsic physical constant σ, a star-specific proper length that scales measurements in its surroundings. Although σ must be evaluated experimentally, we propose a heuristic to estimate its value and call attention to the resultant numerical predictions regarding the Hubble constant and the secular increase of the Astronomical Unit (AU). In this context, the Hubble constant provides an experimental backing to the new metric. As a corollary, the metric conveys theoretical support to the Hubble methodology for standardizing the various extragalactic distance measurements. However, the definition of the Hubble constant is star specific; its value in the solar system is derived from the Sun *erfc* metric. To support this specificity hypothesis, we show that the secular increase of the AU is the result of a similar space-time expansion effect. Indeed, the AU spread out rate is predicted with the same paradigm, using the Earth *erfc* metric in this case. These accurate numerical estimates support the concept of a specific proper length σ associated to a massive object, at the expense of challenging our understanding of the space-time expansion. [1]Plamondon, R., Ouellet-Plamondon, (2015), **Emergence of a quasi-Newtonian law of gravitation: a geometrical impact study** in Rosquist, K., Jantzen, R.T., Ruffini, R., Eds., On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics, and Relativistic Field Theories, World Scientific, Singapore, 1301.
        Speaker: Réjean Plamondon (École Polytechnique de Montréal)
      • 16:15
        Formation and Evaporation of Nonsingular Black Holes in New 2d Gravity 15m
        I will first briefly review the key features of the black hole information loss paradox and the famous “firewall” resolution of Almheiri, Marolf, Polchinski and Susskind. I will then go on to describe work on a different, considerably more mundane solution to the problem based on the observation that the singularity at the center of all black holes lies at the heart of the information loss conundrum. Specifically, I will present a new class of 2D effective actions that can be used to describe the formation and evaporation of non-singular black holes. We are currently completing numerical calculations that will hopefully show that the usual event horizon of the black holes in these theories is replaced by a compact trapping horizon that allows the information to emerge gradually as the black hole evaporates, thereby potentially solving the information loss conundrum.
        Speaker: Gabor Kunstatter (University of Winnipeg)
    • 15:15 16:30
      W3-6 Cold and Trapped Atoms, Molecules and Ions (DAMOPC) / Atomes, molécules et ions froids et piégés (DPAMPC) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Adriana Predoi-Cross (University of Lethbridge)
      • 15:15
        Spatio-temporal correlations after a quantum quench in the Bose-Hubbard model 15m
        The Bose Hubbard model (BHM) is a minimal model that describes interacting ultracold bosons in an optical lattice, allowing the opportunity for experiments to probe quench dynamics of the model. Theoretically, it has proven challenging to study spatio-temporal correlations in the BHM in dimensions higher than one. We use the Schwinger-Keldysh technique and a strong-coupling expansion to develop a two-particle irreducible formalism that allows the study of spatio-temporal correlations in both the superfluid (SF) and Mott-insulating (MI) regimes during a quantum quench for dimensions higher than one. We obtain equations of motion for the superfluid order parameter and two-time correlation functions and present numerical results for the evolution of these functions. We relate our results to recent cold-atom experiments.
        Speaker: Matthew Fitzpatrick (Simon Fraser University)
      • 15:30
        Nonclassical diffusion in a nondegenerate ultracold gas 30m
        We study the crossover from classical to quantum diffusion by studying the equilibration of longitudinal spin domains in a trapped 87Rb sample just above quantum degeneracy. By controlling the degree of spin coherence in the domain wall, we can dramatically alter the relaxation dynamics of the system. Coherence in the domain wall leads to transverse-spin-mediated longitudinal spin diffusion that is slower than classical predictions, as well as altering the domains' oscillation frequency. We also investigate an instability in the longitudinal spin dynamics as the longitudinal and transverse spin components couple, and a conversion of longitudinal spin to transverse spin is observed, leading to longer lived coherent spin oscillations.
        Speaker: Jeffrey McGuirk (Simon Fraser University)
      • 16:00
        Calibration of a Larmor Clock for Tunneling Time Experiments 15m
        How much time does it take for a particle to tunnel? This has been a controversial question for nearly a century because of the inability to make a direct measurement of time. One operational definition for the tunnelling time is the Larmor clock, in which the spin degree of freedom of a tunneling particle is used as a clock that ticks only inside the forbidden region due to the presence of a magnetic field localized to within the barrier. Here, we report the calibration of a Larmor clock to measure tunneling times. Our system is a 87 Rb Bose Einstein condensate in the F=2 ground state manifold, traversing an optical waveguide. We use the Zeeman sublevels (a spin-2 system) and Raman beams for the implementation of the Larmor clock. Experimental progress towards measuring the tunneling time and the challenges involved in this measurement will also be discussed.
        Speaker: Mr David Spierings (University of Toronto)
      • 16:15
        Vortex formation in spin-orbit coupled Bose-Einstein condensates 15m
        Using techniques that exploit the high precision atomic physics, we have exquisite control over several degrees of freedom in an ultracold atomic system, with which we can create analogues to a broader class of physical systems through the principle of quantum simulation. Raman transitions give us the ability to effect a "spin-orbit coupling" in our ultracold gas, by facilitating the transfer of momentum to the atoms from light in a controlled way. In this system, vortices may arise when the spin-orbit coupling is designed with a spatial dependence that simulates a magnetic field in one direction for one spin, and the opposite direction for another. With numerical tools, we investigate the formation and interaction of vortices created in such as system as a means of probing the superfluidity of the spin-orbit coupled sample. Finally, we discuss our experimental progress in realizing such a system.
        Speaker: Lindsay LeBlanc (University of Alberta)
    • 16:40 17:00
      CAP President's report / Rapport du président de l'ACP SITE G0103

      SITE G0103

      University of Ottawa

      Convener: Richard MacKenzie (U. Montréal)
    • 17:00 18:30
      CAP Annual General Meeting with election of Board and Advisory Council members/ Assemblée générale annuelle de l'ACP avec election des membres du c.a. et du conseil consultatif SITE G0103

      SITE G0103

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
    • 18:45 20:00
      "Friends of CAP" Dinner and Meeting / Souper et réunion des "Ami(e)s de l'ACP" FSS 4004

      FSS 4004

      University of Ottawa

      Convener: Steven Rehse (University of Windsor)
    • 18:45 20:00
      CEWIP Annual Meeting & Reception / Assemblée annuelle CEFEP et réception Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Shohini Ghose (urn:Facebook)
    • 18:45 20:00
      Outreach "Tête-à-tête Liaisons externes SITE 5084

      SITE 5084

      University of Ottawa

      Convener: Francine Ford (Canadian Association of Physicists)
    • 18:45 20:00
      Professional Practice Development / Développement d'exercice professionnel SITE A0150 (University of Ottatwa)

      SITE A0150

      University of Ottatwa

      Convener: Mike O'Neill
      • 18:45
        P.Phys. Professional Practice Session / Séance sur la désignation d'exercice professionnel phys. 1h 15m

        In this session we will discuss recent developments related to the P.Phys. designation and a review of the ongoing efforts to improve the P.Phys. model. We will focus on professional development programs typically in place for other professional designations and potential improvements in this area for P.Phys.

        Dans cette séance, nous allons discuter des développements récents liés à la désignation phys. et un examen des efforts continus pour améliorer le modèle de phys. Nous allons nous concentrer sur les programmes de perfectionnement professionnel généralement en place pour d'autres désignations professionnelles et les améliorations possibles dans ce domaine pour la désignation phys.

    • 19:30 21:30
      100 Years in 100 Minutes: A Century of Physics at the National Research Council of Canada / 100 ans en 100 minutes : Un siècle de physique au Conseil national de recherche du Canada Marion 150 (University of Ottatwa)

      Marion 150

      University of Ottatwa

      • 19:30
        NRC's 100th Anniversary Public Session 2h

        MC – Richard Bourgeois-Doyle from NRC

        Basic and applied physics and standards
        Dr. Nelson Rowell
        NRC Photometry and Spectrophotometry

        Chemical physics
        Dr. Albert Stolow
        Canada Research Chair in Molecular Photonics, University of Ottawa

        Astrophysics
        Dr. Gregory Fahlman
        NRC General Manager, NRC Herzberg

        Biological physics
        Dr. Linda Johnston
        NRC Nanoscale Measurement

        Physics for industrial applications
        Dr. Sylvain Charbonneau
        Associate Vice-President, Research, University of Ottawa

    • 07:30 08:30
      CNILC Breakfast Meeting / Réunion du comité de liaison national canadien de l'UIPPA SITE 5084

      SITE 5084

      University of Ottawa

      Convener: Jens Dilling (triumf/UBC)
    • 08:15 10:30
      R1-7 Cosmic Frontier: Dark Matter V (PPD) / Frontière cosmique: matière sombre V (PPD) Colonel By D207

      Colonel By D207

      University of Ottawa

      Convener: Gilles Gerbier (Queen's Univesrity)
      • 08:15
        PICO-60-RSU: A buffer liquid free bubble chamber to search for dark matter 15m
        The PICO collaboration uses superheated liquid detectors, or "bubble chambers", to search for dark matter. Recent operation of the PICO-2L and PICO-60 detectors at SNOLAB allows the most stringent constraints for WIMP dark matter interaction in the spin-dependent sector despite the presence of an anomalous background attributed to the presence of dust particulates in the superheated fluid. I this talk I will present the design of a 60kg bubble chamber in a new "Right-Side-Up" (RSU) configuration that eliminates the need for a buffer fluid and places the particulate generating materials in an inactive region of the detector.
        Speaker: Guillaume Giroux (Queen's University)
      • 08:30
        Backgrounds involved in dark matter signal extraction for DEAP-3600 15m
        Astrophysical lines of evidence point towards dark matter constituting 27\% of the energy density of the Universe and 85\% of all matter. DEAP-3600, located at SNOLAB in Sudbury Canada, is a single phase liquid argon direct detection dark matter experiment. The light produced by nuclear recoil within liquid argon has considerable light yield and is characteristic of the interaction type allowing for powerful pulse shape discrimination. The discovery potential is a combination of the radio purity of construction materials and the success of active rejection and identification criteria. This talk will report on preliminary results of these background reduction efforts.
        Speaker: Dr Christian Ouellet (Carleton University)
      • 08:45
        A Study of Optical Calibration for the DEAP-3600 Dark Matter Search 15m
        Rashid Mehdiyev, for the DEAP Collaboration, Carleton University, Department of Physics DEAP-3600 is a direct dark matter search experiment at SNOLAB. The optical system for DEAP-3600 consists of 255 high quantum efficiency photomultipier tubes (PMTs), which detect and monitor the scintillation light produced by particle interactions in the liquid argon target of the detector. The PMT response is calibrated with two kinds of optical calibration sources: an LED-fed fiber array located at the positions of 20 PMTs, and a central laser source. This talk will discuss the optical calibration of the PMTs, present a method to determine relative PMT efficiency values in-situ using the optical calibration sources, and discuss PMT calibration results from commissioning data.
        Speaker: Dr Rashid Mehdiyev (Carleton Unversity, Department of Physics)
      • 09:00
        *WITHDRAWN** Status of the upgraded PICO-60 experiment 15m
        The PICO collaboration searches for dark matter particles with superheated fluid detectors operated under conditions in which they are insensitive to the electron recoils that constitute the traditionally dominant background for direct detection searches. By measuring the acoustic energy emitted during bubble formation, these detectors are also able to discriminate against alpha particle backgrounds. The current target fluid, C$_3$F$_8$, allows for excellent sensitivity to the spin-dependent WIMP-proton cross section due to its high density of $^{19}$F. The chamber can be operated with other target fluids with relatively minor changes to detector operations, allowing study of the coupling of dark matter to ordinary matter in the case of a positive signal. The PICO-60 experiment has been upgraded since the completion of the previous run in May 2014. The original 20 L CF$_3$I target fluid has been exchanged for 40 L of C$_3$F$_8$. There have been corresponding upgrades to the stereoscopic camera system to allow imaging of the doubled volume and detailed studies of bubble growth, as well as many hardware improvements focused on eliminating the particulate contamination that was one source of backgrounds in the detector. This talk presents the status of the experiment and these upgrades.
        Speaker: Scott Fallows (University of Alberta)
      • 09:15
        Status of the DAMIC Dark Matter Experiment 15m
        The DAMIC detector, currently taking data at SNOLAB, is a Dark Matter search experiment that employs scientific grade CCDs made of silicon as target material. The low readout noise of the CCDs yield to a ionization energy threshold below 60 eVee and provides optimal sensitivity for low mass WIMPs (< 20 GeV). The pixelization (15 microns) and superb energy resolution of the detectors allow for unique background rejection and identification techniques. We present here an overview of the DAMIC experiment together with a summary of the latest results produced using data acquired at SNOLAB since its installation in December 2012. We also discuss the commissioning schedule and reach of DAMIC100, a 100 g silicon target detector currently being installed at SNOLAB.
        Speaker: Dr Ian Lawson (SNOLAB)
      • 09:30
        Characterization of the NEWS spherical gas detectors 15m
        The NEWS (New Experiments with Spheres) project employs novel spherical gas detectors that are very sensitive to very low energy deposition. Each detector consists of a spherical gas volume with a small central electrode forming a radial electric field. At Queen's University we are currently working with a few prototype detectors for their characterization under different working conditions such as gas, pressure, high voltage and sensor. We proved that sub-keV energy threshold with good energy resolution can be achieved and demonstrated that the detectors can be used to measure particle energy loss functions along their tracks in the gas. The testing of data acquisition system, electronics, gas handling system and studies of noise reduction are proven useful for designing the larger scale low-mass dark matter detector to be located underground at SNOLAB, the NEWS-SNO experiment.
        Speaker: Bei Cai (Queen's University)
      • 09:45
        NEWS experiment: results from a 60 cm prototype run with Neon 15m
        Modern precision astronomy strongly suggests the presence of Dark Matter particles whose hunt is among the forefront activities in particle physics nowadays. The NEWS-SNO project (News Experiment With Spheres in SNOLAB) is setting up to probe very low mass Dark Matter particles using a large spherical gaseous detector and very light target nuclei such as H, He and Ne. A 60 cm diameter prototype filled with neon gas was installed and operated in Modane (Laboratoire Souterrain de Modane) with a very low threshold which allowed to investigate less than 10 GeV WIMP (Weakly Interacting Massive Particle) Dark Matter. The analysis of the collected data to extract a Dark Matter signal will be presented and discussed. The attained performance paves the way forward for the larger scale detector to be installed at SNOLAB.
        Speaker: Dr Alvine Kamaha (Queen's University)
      • 10:00
        Muon Veto for the PICO Dark Matter Search Experiment 15m
        The PICO (PICASSO+COUPP) experiment searches for cold dark matter through the direct detection of weakly interacting massive particles (WIMPs) via their spin-dependent interactions with fluorine at SNOLAB, Sudbury - ON. The detection principle is based on the bubble chamber technique. The muon veto for PICO-60 experiment has been developed to reject the signals from muons. Muons interaction can produce neutrons which can mimic the signals from WIMPs. In this talk the model, software and hardware of muon veto will be discussed.
        Speaker: Dr RUSLAN PODVIIANIUK (Laurentian University)
      • 10:15
        Photoneutron calibration of SuperCDMS cryogenic dark matter detectors 15m
        A compelling set of diverse astrophysical observations points to the existence of dark matter, motivating the quest for its direct detection. The most widely accepted dark matter candidates are weakly interacting massive particles (WIMPs). SuperCDMS, the advanced successor of the Cryogenic Dark Matter Search, is designed to directly observe galactic WIMPs via keV-scale nuclear recoils in semiconductor detectors. The sensitivity to WIMPs depends on understanding the nuclear recoil energy scale. This understanding can be achieved by calibrating the detectors with photoneutron sources that emit quasi monoenergetic neutrons of known energy after nuclear excitation by hard gamma radiation. After a short introduction to the detection principle of SuperCDMS, I will describe the Sb/Be and Y/Be calibration sources and method applied to the Ge detectors. I will also present SuperCDMS photoneutron data taken at Soudan and summarize the status and plans for the photoneutron calibration efforts.
        Speaker: Dr Belina von Krosigk (University of British Columbia)
    • 08:30 10:30
      R1-1 Interactive Teaching: Teaching with Technology (DPE) / Enseignement interactif et à l'aide de la technologie (DEP) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Don Mathewson (Division of Physics Education, CAP)
      • 08:30
        OpenPhys: a Responsive Website Platform for Interactive Physics Education 15m
        We have developed an open source web-based platform (‘OpenMap’) and website (‘OpenPhys’) to present interactive self-guided multi-level learning resources. Content is designed for viewing on any device (phone, tablet, laptop) using mobile web technologies. **OpenMap Format:** The OpenMap format is crudely: ‘a 2D interactive PowerPoint for the web’. Content is organized as a series of lessons (or ‘learning objects’). Each lesson consists of a 2D concept map and a set of content pages. The clickable map shows the 2D arrangement of the content pages, which may contain any combination of text, images, animations etc. The learner can navigate between pages by arrow key or swipe, or may return to the map for overview. Pages are arranged left-to-right as a progression through lesson topics, and up/down to present topics at a gradation of difficulty levels. A key objective of this design is to allow learners to progress through lessons at their own level. This multipath approach is a key advantage of a digital medium, and is well suited to self-guided study. The 2D map grid encourages authors to convey the logical structure of the lesson by design of the map shape. The platform is adaptable to any type of material. All the development tools, packages and developed software are open source. The software uses standard web technologies (HTML5, CSS, Javascript, CreateJS) with no plug-ins or downloads required. **OpenPhys Radiation Physics Site:** The first OpenMap site is ‘OpenPhys’. This makes use of text, images, graphics, equations and interactive animations to present a series of radiation physics concepts. Web software and device graphic display capabilities have advanced sufficiently that quite complex simulations are feasible on the mobile web platform. In atomic and nuclear physics, many key physical processes, such as radioactivity and X-ray interactions, are invisible and physically hazardous, rendering hands-on experimental interaction difficult, and interactive simulations particularly useful. The OpenPhys website currently contains lessons such as: The electronic structure of the atom, Radioactivity; Compton X-ray Scattering, and the Photo-electric effect. The OpenPhys website is available at: https://openphys.med.ualberta.ca/ . Source code and documentation is at: https://github.com/OpenPhysProject/OpenPhys.
        Speaker: Dr Jonathan Sharp (University of Alberta)
      • 08:45
        Online versus paper homework – how does it affect student experience, attitudes, and learning? 15m
        In many first-year physics courses, students use publisher-created online homework systems that provide student learning supports including hints to address specific mistakes and additional resources such as tutorials, videos, or simulations. Compared to traditional paper-based homework, these online systems have advantages (e.g. 24/7 hint access, problems often Physics Education Research-informed) as well as disadvantages (e.g. very expensive, potential privacy or technical issues). To learn more about how students use and perceive different homework formats, as well as the realized effects of their advantages/disadvantages, we provided students in an introductory physics class with both an e-textbook with publisher-created online homework problems and equivalent paper homework problems. Each student was randomly assigned to a group that was graded on either the online or the written homework to separate students into two groups. Students were provided access to both forms of homework for equitability purposes, but we found the vast majority of students exclusively used the form of homework they were graded on. Using surveys at the beginning and at the end of the term, we studied the students’ attitudes towards online vs paper homework, how they used it, their satisfaction with the format, the relative effect on their grades, as well as other questions related to course behavior and preferences. We will report our findings from these surveys, including changes between the beginning and the end of the term, as well as the educational implications of our findings.
        Speaker: Daria Ahrensmeier (Simon Fraser University)
      • 09:00
        Integrated Testlets: Multiple-Choice Testing 2.0 30m
        Multiple-choice (MC) exams are becoming more prevalent in physics courses as student populations rise and instructional resources dwindle. Particularly in STEM disciplines we would like to find ways to test deeper levels of understanding or knowledge integrations than are typically afforded by multiple-choice tests. With simple immediate-feedback tools we can construct new types of multiple-choice assessment structures that test both higher-level thinking, and knowledge integration. Such “Integrated Testlets” (ITs) also add the benefits of simple and valid granting of partial credit, as well as turning a final exam into a formative assessment opportunity. In this talk, I will touch on the antagonism between constructed-response and multiple-choice testing in physics, I will outline how ITs resolve some of this antagonism, I will summarize recent data on the validity of partial credit in MC testing, and I will briefly review the development and current usage of ITs.
        Speaker: Aaron Slepkov (Trent University)
      • 09:30
        Innovative use of collaborative video annotation system in physics teacher education 15m
        At the University of British Columbia (UBC) we educate 8-14 future physics teachers annually. Most of them already have B.Sc. degrees in physics or related fields, while some are a completing the B.Sc. concurrently. As part of their secondary teacher education program, teacher-candidates participate in a 3-credit physics methods course taught by the author. Its goal is to help teacher-candidates to acquire Pedagogical Content Knowledge (the knowledge about physics teaching). In order to practice its implementation in a classroom-like situations, teacher-candidates teach four 10-15 minute long mini-lessons during the course. This practice is especially important, as in order to complete the teacher education program, they have to complete successfully a school-based 13-week practicum where they teach real students (under teacher’s supervision). To achieve this goal, we started using Collaborative Learning Annotation System (CLAS) (http://ets.educ.ubc.ca/clas/) developed by our UBC colleagues and freely available to the students. CLAS allows physics teacher-candidates to upload videos of their mini-lessons and collaboratively comment and reflect on them. As a result, every teacher-candidate received multiple feedback about their lessons from their peers, the course Teaching Assistant, and the course instructor. During the feedback stage, all of us commented on mini-lessons emphasizing their strengths and suggesting areas for improvement. Then teacher-candidates were asked to incorporate relevant suggestions and reteach the lessons. From teacher-candidates’ feedback and our observations, we found CLAS to be extremely useful for preparing future physics teachers. It is especially valuable considering English is not the first language for many of our teacher-candidates. We hope that other faculty members involved in physics (and in general mathematics and science) teacher education will consider incorporating CLAS in their courses.
        Speaker: Marina Milner-Bolotin (The University of British Columbia)
      • 09:45
        High quality online content for Blended/Flipped Physics classrooms, Successes and Challenges 15m
        The availability of high quality online material that was developed in house for an online course provided the impetus to do a complete Flipping of an introductory physics class for non-majors, and create a blended version for majors. We overview the material and the technology used and highlight the chosen selections for the pre-class component. We also discuss the effectiveness of the in class activities used and comment on how the experience can be enriched in light of extensive student feedback. We comment on the potential pitfalls in flipping a classroom, in the pre class material, the in class activities as well as student push back. We also comment on the effect of demographic diversity on the reception and applicability of the flipped classroom.
        Speaker: firas mansour (university of waterloo)
    • 08:30 10:30
      R1-2 Strongly Correlated Systems (DCMMP) / Systèmes fortement corrélés (DPMCM) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Graeme Luke (McMaster University)
      • 08:30
        **WITHDRAWN** Nanoengineering materials: a bottom-up approach towards understanding long outstanding challenges in condensed matter science 15m
        Chemists have made tremendous advances in synthesizing a variety of nanostructures with control over their size, shape, and chemical composition. Plus, it is possible to control their assembly and to make macroscopic materials. Combined, these advances suggest an opportunity to “nanoengineer” materials ie controllably fabricate materials from the nanoscale up with a wide range of controlled and potentially even new behaviours. Our group has been exploring this opportunity, and has found a rich range of material electronic behaviours that even simple nano-building blocks can generate, e.g. single electron effects, metal-insulator transitions, semiconductor transistor-like conductance gating, and, most recently, strongly correlated electronic behaviour. The latter is particularly exciting. Strongly correlated electrons are known to lie at the heart of some of the most exotic, widely studied and still outstanding challenges in condensed matter science (e.g. high Tc superconductivity in the cuprates and others). The talk will survey both new insights and new opportunities that arise as a result of using this nanoengineering approach. The talk will also outline how such materials have provided inspiration for new technologies.
        Speaker: Prof. Al-Amin Dhirani (University of Toronto)
      • 08:45
        Antagonistic effects of nearest-neighbor repulsion on the pairing dynamics of the extended Hubbard model 15m
        While most experimental and theoretical clues lean towards a magnetic origin for the pairing mechanism of cuprates, the question of its degree of retardation in the strong correlation regime remains highly controversial.[1,2] The answer to this question lies partly in the frequency dependence of the anomalous spectral function of doped Mott insulators, extracted at finite temperature via the MaxEntAux method [3] for analytic continuation. Using Cellular Dynamical Mean-Field Theory for the Hubbard model with nearest-neighbor repulsion $V$, we show that this repulsion has antagonistic effects on the critical temperature $T_c$ as it boosts $T_c$ at low doping but diminishes it at large doping. The study of pair-breaking and pair-forming contributions to superconductivity clarifies the nature of these effects. They emerge from a compromise between the trivial Coulomb pair-breaking effect of $V$ and a more subtle pair-forming effect of $V$. The latter arises from the strengthening of short-ranged antiferromagnetism through the coupling constant $J=4t^2/(U-V)$ where $U$ is the on-site Hubbard interaction, and $t$ the hopping amplitude. [1] P.W. Anderson, Science **316**, 1705 (2007). [2] D.J. Scalapino, e-letter response to Science **316**, 1705 (2007). [3] A. Reymbaut, D. Bergeron and A.-M.S. Tremblay, Phys. Rev. B **92**, 060509(R) (2015)
        Speaker: Dr Alexis Reymbaut (Université de Sherbrooke)
      • 09:00
        Pseudospin representation of the two-site Anderson-Hubbard model 15m
        The state of an Anderson localized system can be described in terms of the occupation of a set of single-particle wave functions which are localized in space. When interactions are added, single-particle wave functions are no longer well defined, so what is a useful description of the state of a many-body localized system and what about it is localized? Given that any system with Hilbert-space dimension 2$^N$ may be described by an Ising-type Hamiltonian, it has been proposed that in a fully many-body localized system the Ising pseudospins in this representation may be chosen to be local. Actually constructing these spins is non-trivial. While a number of approaches have been proposed, few explicit examples exist and almost all work has been on spin systems. Here we present the Hamiltonian of a two-site Hubbard model with disorder and nearest-neighbor interactions written in terms of pseudospins, and we explore the form of these pseudospins and their evolution as a function of hopping amplitude.
        Speaker: Rachel Wortis (Trent University)
      • 09:15
        Metallization of a neutral organic radical by pressure 15m
        We have measured resistivity vs. temperature and pressure on the fluoro-substituted oxobenzene-bridged bisdithiazolyl radical, FBBO. This is a layered, single component organic compound that is a Mott insulator at ambient pressure, due to the singly occupied molecular orbitals and an intrinsically high inter-molecular charge transfer energy barrier. Previous room temperature infrared absorption and conductivity measurements suggest that the charge gap of 0.1eV closes and the sample may become metallic at pressures above 3GPa[1]. We report direct transport measurements under various pressures on powder samples of FBBO down to low temperature, measured in an anvil pressure cell, that demonstrate the first metallization of a neutral organic radical. [1] A. Mailman, et al., J. Am. Chem. Soc. 134, 9886 (2012). [2] D. Tian et al., J. Am. Chem. Soc. 137, 13146 (2015).
        Speaker: Prof. Stephen Julian (University of Toronto)
      • 09:30
        Pressure-induced collapse of the J_eff = 1/2 ground state in Li2IrO3 15m
        The honeycomb lattice iridate Li2IrO3 displays a novel J_eff = 1/2 Mott insulating ground state driven by strong 5d spin-orbit coupling effects. Due to a combination of J_eff = 1/2 magnetic moments, 90 degree Ir-O-Ir bond geometry, and honeycomb lattice crystal structure, Li2IrO3 represents one of the most promising candidates for the experimental realization of the Kitaev model. This exactly solvable quantum spin model features highly anisotropic, bond-dependent magnetic interactions, and supports an exotic spin liquid ground state. Although the observation of long-range magnetic order (Tn ∼ 15 K) excludes a “pure” Kitaev model description of Li2IrO3, there are many “extended” Kitaev models (including contributions such as isotropic Heisenberg exchange, further-neighbor interactions, symmetric off-diagonal exchange, and structural distortions) that may be relevant to this material. As such, there is considerable interest in potential strategies for “tuning” Li2IrO3 through the use of external perturbations. We have employed a combination of x-ray powder diffraction (XPD), resonant inelastic x-ray scattering (RIXS), and x-ray absorption spectroscopy (XAS) techniques to investigate how the structural, electronic, and magnetic properties of Li2IrO3 evolve as a function of applied pressure. We find evidence of a pressure-induced structural phase transition at P ~ 3 GPa, which is accompanied by a dramatic increase in the non-cubic crystal electric field splitting. Furthermore, we observe a rapid drop in the XAS branching ratio, indicating that applied pressure drives Li2IrO3 out of the strong spin-orbit regime and leads to a collapse of the J_eff = 1/2 ground state.
        Speaker: Patrick Clancy (University of Toronto)
      • 09:45
        Neutron scattering study of magnetism in HoFeO3 15m
        Rare-earth orthoferrites, RFeO3 where R is Y or rare earth elements with perovskite structure exhibit intriguing magnetic properties, including non-collinear structures and magnetic phase transitions due to a combination of antiferromagnetic (AFM) exchange interactions and Dzyaloshinsky-Moriya (DM) anti-symmetric exchange interactions, which make them promising candidates for innovative spintronic applications. Starting from the paramagnetic state at high temperatures, Fe3+ ions order antiferromagnetically at high temperatures (~600 K) [1]. With further cooling many rare-earth orthoferrites undergo spin-reorientation transitions where the direction of the net magnetic moment rotates from one crystallographic axis to another primarily due to the antisymmetric and anisotropic-symmetric exchange interactions between Fe3+ and R3+. Among different orthoferrites, HoFeO3 is of interest as optical measurements indicate the magnetic splitting of the crystal field (CF) ground state doublet of the Ho3+ ion is located directly in the antiferromagnetic–resonance frequencies of the Fe subsystem [2]. However a complete understanding of its magnetic properties including spin-reorientation transitions, exchange interactions among different magnetic ions, and the crystal field schemes for the lowest J-levels of the Ho3+ ions is still lacking. Here we report the results of our neutron scattering study of HoFeO3. Our inelastic experiments indicate the presence of at least three CF excitations below 30 meV at energy levels different from the indirect estimates obtained from heat capacity measurements. We also identify three temperatures associated with the Fe3+ spin-reorientation transitions in this material. 1. S. E. Hahn, A. A. Podlesnyak, G. Ehlers, G. E. Granroth, R. S. Fishman, A. I. Kolesnikov, E. Pomjakushina, and K. Conder, Phys. Rev. B 89 (2014) 01442. 2. A. M. Balbashov, G.V. Kozlov, S. P. Lebedev, A. A. Mukhin, A. Yu. Pronin, and A. S. Prokhorov, Sov. Phys. JETP 68 (1989) 629.
        Speaker: zahra yamani (CNL)
      • 10:00
        Dynamics in integrable quantum systems 30m
        In integrable quantum many-body systems exact results for the ground state and the thermodynamic properties can be derived. These results are an important building block in our understanding of quantum systems with strong correlations. They are also a point of reference to judge the quality of approximative analytical and numerical approaches. Within the last years, a number of experiments on cold atomic gases have been performed studying the dynamics of almost integrable systems. In my talk I will present new theoretical results which allow to understand the transport properties of such systems and to gain insight into the connections between quantum integrability and non-ergodic dynamics.
        Speaker: Jesko Sirker (U Manitoba)
    • 08:30 10:30
      R1-3 Advances in Nuclear Physics and Particle Physics Theory (DTP-DNP-PPD) / Progrès en physique nucléaire et en physique des particules théoriques (DPT-DPN-PPD) Colonel By B205

      Colonel By B205

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Dr Aleksandrs Aleksejevs (Memorial University of Newfoundland)
      • 08:30
        12 years of MCAS: Multi-Channel Algebraic Scattering 30m
        The Multi-Channel Algebraic-Scattering (MCAS) method was developed in 2003 for the analysis of low-energy nuclear spectra and of resonant scattering. It continues to be used effectively for nuclear-structure studies. The MCAS approach allows the construction of the nucleon-core-nucleus model Hamiltonian which can be defined in detail (coupling to the collective modes, rotational or vibrational, diverse components of the interaction operators, nonlocal effects due to Pauli exclusion). As reported at previous CAP congresses, MCAS analyses have given good descriptions of bound states and low-lying resonant spectra of medium-light nuclei, including nuclei well off the line of stability. We are currently moving into new directions for MCAS, specifically, moving to heavier target nuclei (mass A = 18-23) and new projectiles in the scattering process, recently, the α particle. As this is an invited paper, likely having a wider audience than previous presentations, a summary of the MCAS method will be presented with emphasis on its distinctive features. A significant feature is the way the Pauli principle is preserved, while a single nucleon interacts with a nucleus that may have filled neutron or proton shells. This we refer to as the OPP method, which will be presented in this review talk. Some of the results that have been achieved with MCAS, and already published elsewhere will be presented, and present and future plans for our collaboration will conclude this talk. Institutions: University of Manitoba, Dept. of Physics and Astronomy (JPS); School of Physics, University of Melbourne, Victoria 3010, Australia (KA, DvdK); Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Padova I-35131, Italy (LC, WP); Department of Physics, University of Johannesburg, P.O. Box 524 Auckland Park, 2006, South Africa (SK); ARC Centre for Antimatter-Matter Studies, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia (PRF).
        Speaker: Juris Svenne (University of Manitoba)
      • 09:00
        (TBC) New physics efforts at the intensity frontier 30m
        Speaker: Maxim Pospelov
      • 09:30
        Near-BPS Skyrme Models for Nuclei 15m
        We present our most recent results regarding Near-BPS Skyrmions and argue that they provide an improved description of nucleons and nuclei. For some years now, the Skyrme Model and extensions have been considered natural candidates for a low-energy effective theory of QCD, a point of view supported by results coming from $1/N$ expansion and holographic QCD. This framework leads to an attractive picture: baryons (and nuclei) emerge as topological solitons with a topological number identified to the baryon number. But the most naive Skyrme Model extensions have been plagued with the same problem: they predict large binding energies for the nuclei. On the other hand, the solutions that arise from the more recently proposed near-BPS Skyrme models nearly saturate the Bogomol’nyi bound which means that by construction there must have small binding energies. We address a number of issues related to the strength of each terms in the Lagrangian and the form of the potential of these models with their consequences on the baryon density configurations, Coulomb energies, isospin symmetry breaking, binding energies and mean radius of the nuclei, the pion mass and more.
        Speaker: Luc Marleau (Université Laval)
      • 09:45
        The Unified Formulation of Scattering 15m
        In 2003 Witten showed that the leading order of scattering amplitudes in the maximally supersymmetric gauge theory (MSYM) in four dimensions can be computed using a string-like formulation. Amplitudes are correlation functions computed on a punctured Riemann sphere. For many years this phenomenon was thought to be special to MSYM. In 2013, an explosion of string-like formulations were discovered which are now known as CHY formulas. In this talk I will explain the CHY formulation and how it provides a unified description of the S-matrix of theories such as Einstein gravity, Yang-Mills, Dirac-Born-Infeld, the non-linear sigma model and Galileons.
        Speaker: Dr Freddy Cachazo (Perimeter Institute)
      • 10:00
        Careful treatment of the effects of $c\bar c$ narrow resonances in $B\to K^*\mu^+\mu^-$ observables 15m
        A careful analysis of $B\to K^*\mu^+\mu^-$ observables should consider the long-distance effects of the resonances in the short-distance dominated region. Here, we take into account the narrow resonance effects in the nonresonance region when calculating the differential decay rate and the forward-backward asymmetry in this decay. In doing so, we use a Breit- Wigner model for the resonances with momentum-dependent decay constants, a model that fits the data on photoproduction and the leptonic width of $\psi$ and $\psi^\prime$ simultaneously
        Speaker: Mohammad Ahmady (Mount Allison University)
      • 10:15
        Diffractive vector meson production using a holographic AdS/QCD light-front wavefunction 15m
        We use the colour dipole formalism to compute the rate for diffractive phi meson production using a holographic AdS/QCD wavefunction for the phi. We use a dipole cross-section with parameters fitted to the most recent and very precise 2015 HERA data on the proton's structure function. We compare our predictions on diffractive phi production to the data collected at the HERA collider and find good agreement.
        Speaker: Ruben Sandapen (Acadia University)
    • 08:30 10:30
      R1-4 Nuclear Physics in Medicine (DPMB-DNP-DIAP) / Physique nucléaire en médecine (DPMB-DPN-DPIA) Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Christopher Bergevin (York University)
      • 08:30
        Diffusion-Controlled Drug Release: Beyond Weibull 15m
        Characterizing and predicting time release profiles is crucial in order to optimize the performance of drug devices. The exact analytical expression for the drug release function, which is a solution of the diffusion equation, is generally too complex to be employed for this purpose. Therefore, it is convenient to use simpler fitting functions which reproduce qualitatively the overall release profile. When the dominant release process is diffusion, the most used fitting function is a stretch exponential called Weibull function. Nevertheless, the Weibull function has a major drawback: it does not reproduce the short- and long-time behaviors imposed by diffusion theory. We propose a new fitting function, built from a semi-analytical approach, which reduces correctly to both limiting behaviors. Therefore, it allows to extract a crossover time between the transient and the stationary states which is crucial to characterize the release dynamic. Furthermore, thanks to Lattice Monte Carlo simulations, we show that our fitting function greatly outperforms the Weibull function and enables one to obtain the microscopic physical properties of the drug release system.
        Speaker: maxime Ignacio (University of Ottawa)
      • 08:45
        Quantitative Magnetic Resonance Imaging of the Hippocampus in Single Transgenic Mouse Models of Alzheimer’s Disease 15m
        In this study, quantitative magnetic resonance imaging (MRI) was used to determine if it could detect atrophy and microstructural changes in the hippocampus, and damage to peripheral white matter (WM) structures in mouse models of Alzheimer’s disease (AD). The aim of our study was to determine if T1 relaxation, diffusion tensor imaging (DTI), and quantitative magnetization transfer imaging (qMTI) metrics could reveal changes within the hippocampus and surrounding WM structures in ex vivo transgenic mouse brains with the goal of these changes being used as biomarkers for AD. Mice were either wild type controls (n=6), or had overexpression of the presenilin-1 (PS1) protein (n=6) or the amyloid precursor protein (APP) (n=6), and were imaged at 7.5 months of age using a 7T MRI system. Three coronal slices were selected in each mouse to span the hippocampus. Anatomical details visible in DTI color maps allowed delineation of hippocampal cell layers, which contained more significant differences between groups of mice than did the entire unsegmented hippocampus. This work demonstrates that multiparametric quantitative MRI methods are useful for characterizing changes within the hippocampus and surrounding WM tracts of APP and PS1 mouse models of AD.
        Speaker: Melanie Martin (Physics, University of Winnipeg and Radiology University of Manitoba)
      • 09:00
        Myocardial Flow Reserve Imaging to Direct Optimal Therapies for Ischemic Heart Disease 30m
        Nuclear cardiology imaging with SPECT or PET is used widely in North America for the diagnosis and management of patients with coronary artery disease. Conventional myocardial perfusion imaging (MPI) can identify areas of reversible ischemia, as suitable targets for coronary artery revascularization by angioplasty or bypass surgery. However, the accuracy of this technique is limited in patients with early disease in the micro-vasculature or advanced disease in multiple coronary arteries, where there is no normal reference territory against which to assess the 'relative' perfusion defects. We have developed methods for the routine quantification of absolute myocardial blood flow (MBF mL/min/g) and coronary flow reserve (stress/rest MBF) using rubidium-82 dynamic PET imaging. The incremental diagnostic and prognostic value of absolute flow quantification over conventional MPI has been demonstrated in several recent studies. Clinical use of this added information for patient management to direct optimal therapy and the potential to improve cardiac outcomes remains to be proven, but may be informed by recent progress and clinical adoption of invasive fractional flow reserve (FFR)-directed revascularization. This talk will present recent progress in this field, towards non-invasive CFR image-guided therapy with cardiac PET and SPECT imaging.
        Speaker: Robert deKemp (uOttawa Heart Institute)
      • 09:30
        Towards reducing the dose needed for Megavoltage Cone Beam CT 30m
        Megavoltage (MV) x-ray beams generated from a linear accelerator (linac) are commonly used to deliver the prescribed radiation dose to the tumor while minimizing the dose to the surrounding healthy tissues. The geometric accuracy of such treatment is crucial for its success. Currently, there are a number of ways to verify the positional accuracy of the treated target. Megavoltage cone-beam computed tomography (MV-CBCT) is the simplest and arguably least error-prone solution of all the commercially available volumetric imaging methods to locate the position of the target in the treatment room prior to the start of the treatment. MV-CBCT uses an electronic portal-imaging device (EPID) attached to the linac to acquire CT data by rotating the MV x-ray source, emitting a cone beam, and the EPID around the patient. However, due to poor x-ray quantum efficiency of EPIDs that are utilized in clinics presently, the imaging dose required to achieve sufficient contrast to visualize and delineate soft tissue targets can be prohibitively large for daily verification with this imaging modality. Recently, a family of detector designs that have the potential to solve the low x-ray conversion efficiency challenge faced by current clinical EPID systems has been investigated. In these, over an order of magnitude higher quantum efficiency, when compared to current clinical systems, is achieved by using a few centimeters thick x-ray conversion layer. To maintain spatial resolution the x-ray conversion layer is segmented in the directions parallel to the incident x-rays.
        Speaker: Dr Aram Teymurazyan
      • 10:00
        Simultaneous PET/MRI with Clinical and Preclinical Systems 30m
        In our experiences with simultaneous PET/MRI (Siemens Biograph mMR), we have seen several inherent advantages beyond improved anatomical information. In the heart, for example, new insight can be gained when fusing cine, gadolinium-enhanced, and relaxation time mapping MRI with PET tracers sensitive to glycolysis (18F-FDG), perfusion (13N-ammonia), or sympathetic innervation (11C-HED). Simultaneous PET/MRI with combined contrast infusions of both MRI and PET tracers may help improve pharmacokinetic modeling in tissue. Simultaneity can also be used to retrospectively correct PET data for motion and partial volume effects based on information derived from the MRI. Efforts at Lawson to improve the quantitative accuracy of clinical PET/MRI have also included improvements to MR-based attenuation corrections, multi-site phantom measurements, and implementation of novel, PET-compatible, 32-channel RF coils designed specifically for the Siemens Biograph mMR. For PET images, the Biograph mMR performs better than most clinical PET systems, with a spatial resolution of 4.3 mm in the centre of its field-of-view and a peak sensitivity of 1.5%. In contrast, small animal PET systems can achieve <1 mm resolution with >5% peak sensitivity. The entire brain of an adult mouse is ~ 400 μL in volume. In order to develop novel PET tracers and perform imaging studies with small animal models that are comparable to our clinical 3T PET/MRI, a truly simultaneous, preclinical PET/MRI system capable of sub-millimeter spatial resolution is required. We have been working with industry and academic partners, led by Dr. Andrew Goertzen at the University of Manitoba, to develop a high-resolution PET insert designed to operate in a preclinical MRI. This technology has been licensed by a Canadian company (Cubresa, Winnipeg) who will deliver the first commercially available, preclinical PET/MRI insert to Lawson in the first half of 2016. Although it will initially be installed in our clinical 3T PET/MRI, this system is small enough (113 mm outer diameter) to operate simultaneously in most high-field preclinical MRI systems. The design and initial results from this system will be presented. **Acknowledgements**: NSERC, ORF, Mitacs, Siemens Canada, Cubresa, MMI, and the Lawson Interal Research Fund.
        Speaker: Jonathan Thiessen (Lawson Health Research Institute)
    • 08:30 10:30
      R1-5 Photonics II: Optoelectronics and Devices (DAMOPC-DCMMP) / Photonique II : optoélectronique et dispositifs (DPAMPC-DPMCM) SITE H0104

      SITE H0104

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Matt Reid (University of northern british columbia)
      • 08:30
        Fiber lasers: Detection of gases and chemicals 30m
        Fiber lasers operating either in the CW or PULSED mode are established as robust and reliable devices. They have wide applications in industry and medicine because of their unique characteristics such as an all-fiber design, compact size, cost-effective production and operation, and lack of need for re-alignment and external cooling. A fiber laser emitting single-longitudinal-mode, single-wavelength or multi-wavelength output in the infrared region of the electromagnetic spectrum is attractive for applications in optical communication, sensing, spectroscopy and nonlinear optics. Trace-gas sensing is a rapidly growing field. It has applications in breath diagnostics, environmental monitoring, and homeland security. Several methods and devices are commercially available for the identification and quantification of trace gases. Most of the commonly used devices are based on gas chromatography (GC) coupled with mass spectroscopy (MS). Laser spectroscopy is an alternative to the GC/MS methods. Laser spectroscopy is based on the light-absorbing property of a chemical and can detect a compound in real time with very high sensitivity. The author has developed a new technique, based on a CW fiber laser, for the detection of trace gases. In the talk, the author will present the details of the gas detection system and its unique features. Further, detecting a single molecule of a substance (e.g. the protein responsible for cancer) is a real challenge using existing devices, most of which are also very expensive. A system based on fiber lasers will be efficient and cost-effective. The author will also present the details of a chemical sensor based on SERS (Surface Enhanced Raman Spectroscopy). This work was supported by Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Foundation for Innovation (CFI) and Agrium Inc.
        Speaker: Dr Gautam Das (Lakehead University)
      • 09:00
        Detection of C2H2 at a concentration of ppmv levels using a fiber laser system 15m
        A gas sensor based on optical fiber technology is in demand for applications in environmental monitoring. Authors will present an acetylene (C2H2) gas sensor which was developed using the principle of intracavity laser absorption spectroscopy operating at room temperature. An intracavity gas cell based on hollow core photonic crystal fiber was developed and used inside a fiber ring laser cavity. Authors will present the details of the construction of the gas cell and the advantages of using a gas cell based on photonic crystal fiber in comparison to the existing cells reported in the literature. The laser wavelength was selected by a fiber Bragg grating (FBG) with a peak wavelength close to one of the absorption lines of the acetylene gas in the 1.55 micron band. The system was capable of detecting acetylene gas in concentrations of ~ 10 ppmv. It is possible to operate the system to detect other gases such as CH4 by changing the FBG in the cavity or using a tunable FBG. The research was financially supported by Natural Sciences and Engineering Research Council of Canada (NSERC) and Agrium Inc.
        Speaker: Jonas Valiunas (Lakehead University)
      • 09:15
        Shaping the light by nonlinear flat optics 15m
        Classical optical lenses shape the light beam based on gradual phase shifts accumulated during the propagation. This results in devices which are difficult to integrate. In recent years, plasmonic metasurfaces opened the field of flat optics. Abrupt changes in the properties of the light, such as phase and polarization, can be introduced at the sub-wavelength scale by the meta-atoms. These meta-atoms act as Huygen's sources, allowing to shape the beam in the far-field. New thin-film filter and photonic devices can be realized and easily integrated into existing technologies. We propose a scheme to realize nonlinear flat optics. It uses enhanced nonlinear optics from metasurfaces, where we are able to precisely design not only the enhancement, but also the phase and polarization of emitted nonlinear signals. The meta-atom we use is a novel plasmonic nanoantenna we call the butterfly. This structure exhibits a field enhancement in the gap which can be exploited for nonlinear optics. The field enhanced in the gap is polarization independent, quasi linearly polarized, and its phase changes as a function of the incident polarization angle. We show a meta-lens made of butterfly antennas, which converts a linearly polarized CW beam into an structured second harmonic beam carrying orbital angular momentum. Nonlinear optics allows us to access a wavelength range otherwise impossible by linear plasmonics, due to the losses in metals. The idea finds application in spatial multiplexing for optical communications, opto-mechanics, molecule orientation and trapping, nonlinear optics enhancement and light structuring. The simulations are performed with the finite-difference time-domain (FDTD) method exploiting the IBM BlueGene/Q supercomputer of the Southern Ontario Smart Computing Innovation Platform (SOSCIP).
        Speaker: Antonino Calà Lesina (University of Ottawa)
      • 09:30
        Shifted nanorods to increase the density of plasmonic hot-spots for nonlinear optics enhancement 15m
        The confinement of the light at the nano-scale and the intense fields due to plasmonics, allow us to enormously increase the local density of states of molecule and nano-objects close to the hot-spots. This can be exploited to enhance nonlinear optical processes, such as surface enhanced Raman scattering (SERS), second harmonic generation (SHG), sum and difference frequency generation (SFG and DFG). Nonlinear optical processes can be enhanced by metasurfaces and nanoantenna arrays with nano-gaps. Plasmonic structures can concentrate the light to sub-wavelength volumes, resulting in hot-spots with very strong fields. A nano-gap is the volume between two pieces of metal, in order to observe a strong field enhancement the distance between the two pieces of metal has to be small, ${\it e.g.}$, $\sim 10$ nm. Nano-gaps are realized by dipole, bowtie, cross-dipole nanoantennas, thus exhibiting polarization dependence and low density, ${\it i.e.}$, number of hot-spots per unit area, due to the physical dimensions of the structures. We show how to increase the hot-spot density taking advantage of high order resonance modes in shifted plasmonic nanorods. This configuration allows us to get a field enhancement in the gap for every incident polarization. This can be exploited for all those nonlinear processes where two or more frequencies are involved and the hot-spots need to be co-located and/or co-polarized, for several crystal classes.
        Speaker: Antonino Calà Lesina (University of Ottawa)
    • 08:30 10:30
      R1-6 General Instrumentation I (DIMP) / Physique générale des instruments I (DPIM) SITE J0106

      SITE J0106

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Kirk Michaelian (Natural Resources Canada)
      • 08:30
        Nuclear Emergency Response: Comparison of Different Methodologies to Measure γ-Radiation from Ground Deposition 15m
        T.J. Stocki1, M. A. Rodrigues1, R. McCutcheon-Wickham1, L. Chaloner1, J. Rollings1, M.-O. Boudreau1, A. Parujanwala1, J.-F. Mercier1, M. Cooke1, A. Bilton2, A. Ethier2, J. Whitlock2, D. Hunton2, B. Wilson2, D. Killey2, H. Seywerd3, R. Fortin3, L. Sinclair3, D. Oneschuk3, M. Coyle3, F. Grenier4, T. Cunning4, K. Henderson4, R. Hugron4, D. Swann4 and C. Bouchard1* 1Radiation Protection Bureau, Health Canada, Ottawa, Canada 2Canadian Nuclear Laboratories, Chalk River, Canada 3Natural Resources Canada, Ottawa, Canada 4Director Nuclear Safety, Department of National Defence, Ottawa, Canada The federal radiation assessment field team, led by Health Canada (HC), can be deployed in the event of a domestic nuclear emergency to measure radioactive contamination in areas where the public could be impacted. Several techniques are used to evaluate ground contamination levels including in-situ gamma spectrometry, soil sampling and field/aerial surveys. A better understanding of the inter-comparability of these methods can be obtained through measurements at a contaminated site. A known and previously characterized contaminated site at Canadian Nuclear Laboratories (CNL) in Chalk River was used to compare different emergency response techniques. A ground contamination survey using RaDCAMS (Radiation Data Collection and Mapping System), developed by HC, was performed to confirm the known distribution of radiation in the field. This survey was supported by an aerial survey performed by Natural Resources Canada. In-situ gamma spectrometry was performed by HC and Department of National Defence using HPGe detectors. Soil samples were collected in a cross pattern geometry centered at the location of the in-situ measurements. Samples were also collected in a square pattern geometry at the same location and were prepared and measured in-field using HC’s Mobile Nuclear Laboratory (MNL). Soil samples from the cross pattern were measured in the MNL and compared to measurements performed by CNL and HC’s National Monitoring Section (fixed laboratories). Results of an inter-comparison analysis, performed to identify areas of improvement and limitations in the detection and analysis of soil samples, will be presented. In addition, comparisons between in-situ measurements and soil samples will be shown. Finally, lessons learned that will be used to adapt methodologies in the event of a real nuclear emergency will be discussed.
        Speaker: Dr Matthew Rodrigues (Health Canada)
      • 08:45
        Measurements of 236U by Accelerator Mass Spectrometry 15m
        236U is used as a signature in nuclear forensic, environmental and oceanographic studies. Its atomic ratio with the most abundant uranium isotope (238U) in environmental and bioassay samples can vary widely from 10-8 to 10-12. Therefore, its full-range measurement is a challenge by conventional radiometric or mass spectrometric methods. Accelerator Mass Spectrometry (AMS) offers interference-free measurement with ultra-high abundance sensitivity for several long-lived radioactive isotopes, including 236U. This is mainly due to the molecular destruction process involved in AMS. For 236U, however, AMS suffers from poor ionization and transmission efficiencies compared to other mass spectrometric methods such as ICP-MS and TIMS, due to the low formation probability of negatively charged uranium-containing ions. The main objective of this work is to enhance a negative ion current of the analyte, in this case UO- ion, from the cesium-sputter ion source used in AMS. We tested various diluents including Al, Ag, Nb, SiC, Ta, Si and Ta+Si with Fe-UOx for the UO- anion beam using the AMS system at A.E. Lalonde AMS Laboratory, University of Ottawa. The addition of Ta and Si to the Fe-UOx target matrix increases the production of UO- ion beam current by three fold to about 9nA from 2.5nA when using Al powder. Preliminary results from these tests will be presented and possible mechanism for the UO- anion beam increase will be discussed.
        Speaker: Dr Zakir Kazi (University of Ottawa)
      • 09:00
        Measurement of Fissiogenic Cs Radioisotopes in Seawater by QQQ-ICPMS: Progress Report 15m
        The anthropogenic radioisotope, Cs-137, is routinely used in oceanographic studies and the monitoring of radioactive contamination. Currently, this isotope is measured radiometrically by observing its characteristic 662 keV gamma emission. In low concentrations, however, this method of measurement can take days per sample. Recently there has been much interest in the measurement of this isotope by mass spectrometry, specifically, inductively coupled plasma mass spectrometry (ICPMS). Currently, the efficiency and limit of detection of these isotopes limit measurements to soil samples which have relatively high concentrations of the isotopes of interest (>100 mBq/g). Seawater samples, however, have a much lower concentration (<1 mBq/g) and have yet to be measured by ICPMS. Therefore, the development of a method for Cs measurement by mass spectrometry would result in much higher sample throughput and more precise measurements. The primary challenge in achieving this measurement is the isobaric interference from Ba isotopes (135 amu and 137 amu) which cannot be distinguished from the Cs radioisotopes by mass spectrometry. The “Agilent 8800” is an ICPMS with two quadrupole mass analyzers and one on-line octupole reaction cell located between the mass analyzers. The on-line reaction cell exploits the chemical nature of isobars, such as Ba, so the interference can be reduced during the measurements. This instrumentation has been used to successfully quantify Cs-135 and Cs-137 in samples with high concentrations of the radionuclides. Here we outline the developments made towards low concentration ICPMS Cs radioisotope measurements including sea water cleanup chemistry, measurement methods, and isobaric removal using the online reaction cell.
        Speaker: Cole MacDonald (University of Ottawa)
      • 09:15
        Improve Determination of ⁹⁹Tc in Environmental Samples by ICP-MS using TRU® Resin 15m
        Technetium-99 (⁹⁹Tc) is one of the most important fission products of ²³⁵U (~6% yield). It is a long lived radioisotope (2.11X10⁵ years half-life), which decays by emiting beta radiation. ⁹⁹Tc is of environmental concern because it is very mobile in the environment as Tc(VII) (TcO₄⁻) and can be bio-accumulated in some plants and animals. ⁹⁹Tc can be measured by ICP-MS, but ruthenium (Ru) (⁹⁹Ru⁺) and molybdenum (Mo) (⁹⁸Mo¹H⁺) interfere and have to be chemically removed. ⁹⁹Tc is frequently purified from these interferents using an anion exchange or TEVA® resin. The main issue regarding these resins is that ⁹⁹Tc is eluted with a high acid concentration solution, which cannot be directly introduced into an ICP-MS without causing corrosion issues. The acid solution has to be evaporated, but Tc(VII) is partially volatile in acidic solutions. Also, there is no adequate long-lived Tc isotope that could be used as a tracer to correct the recovery losses. We have demonstrated that ⁹⁹Tc can be rapidly and selectively extracted on a TRU resin. It can be easily eluted from the resin using near boiling water, a solvent compatible with ICP-MS instrument. Rhenium (VII) (Re) has a similar chemical behavior to Tc(VII) on the resin in some conditions and can be used as a recovery tracer. Ru and Mo interferents can be removed effectively. A method was developed to determine ⁹⁹Tc in environmental waters. ⁹⁹Tc was pre-concentrated from a 1 L water sample using an anion exchange resin and then purified with a TRU® resin. There was no heating step for this method.
        Speaker: Nicolas Guérin (Canadian Nuclear Laboratories)
      • 09:30
        DHCAL with Minimal Absorber: Measurements with Positrons 15m
        The CALICE Digital Hadron Calorimeter (DHCAL) is a highly-granular 1m$^3$ large prototype, based on Resistive Plate Chambers (RPCs) with digital readout of $1 x 1$ cm$^2$ pads. In special tests, 50 of its active layers were exposed to low energy particle beams, without interleaved absorber plates. The thickness of each layer corresponded approximately to 0.29 radiation lengths or 0.034 nuclear interaction lengths, defined mostly by the copper and steel skins of the detector cassettes. The results of the measurements performed at the Fermilab test beam with positrons in the energy range of 1 to 10 GeV will be presented and compared to simulations based on GEANT4. It is found that the default GEANT4 simulation of electromagnetic showers is not able to reproduce the measurements of the energy resolution and the detailed shower shapes. With the use of the so-called 'Option 3' or '_EMY' good to excellent agreement is obtained.
        Speaker: Benjamin Freund (Universite de Montreal (CA))
      • 09:45
        SELECTION OF OPTIMAL REGRESSION MODELS FOR INSTRUMENT CALIBRATION 15m
        Instrument calibration is an integral part of many physical and chemical measurement systems. Commonly, instrument response is plotted against a series of known values (standards) of the measurand to establish a calibration line by linear regression. For example, the relationship is established between emitted light intensity versus concentration in Emission Spectrometry, or ion counts against concentration in quantitative Mass Spectrometry. In the simplest and ideal situation, signal intensity is assumed to be directly proportional to the concentration. In reality, however, significant errors can originate from uncertainty of the measurement, as well as non-linear dependence of the response within the chosen dynamic range. In this presentation, we will discuss about the selection of optimal calibration models and evaluate their relative effectiveness using simulated and practical examples.
        Speaker: Nimal De Silva (University of Ottawa)
      • 10:00
        Advancing Canada's Martian In Situ Spectrometer: Sub-cm Chemistry for the Ongoing Assessment of Past Habitability on Mars 15m
        Canada's Martian spectrometer, the Alpha Particle X-ray Spectrometer (APXS), is a physics-based third-generation chemical analysis instrument carried by NASA's newest rover on Mars. Mounted at the end of the arm of the Mars Science Laboratory rover *Curiosity*, the fourth and most-recent APXS conducts high-precision in situ measurements of Martian rocks and soils, playing a significant role in understanding the surface composition and geochemical processes of Mars. Sample excitation is provided by 1.1 GBq Curium-244 sources utilizing both PIXE and XRF excitation. This results in a higher sensitivity that varies only slowly across the range of geochemically important elements (Z>10) than would be the case with either excitation method alone. Use of radionuclides confers the additional benefits of low weight, low power, and high durability, all critical for space exploration missions. Trace elements can be quantified in as little as 10-20 minutes to the 10s of ppm level thanks to a Peltier-cooled silicon drift detector providing a resolution (FWHM) of 140 eV at 5.9 keV. This enables multiple laterally offset measurements of a single target during the cool Martian mornings or evenings, important for quantifying sub-cm scale chemistry. Unlike in a laboratory setting on Earth, targets on Mars are not always flat, can be dust covered, are shrouded by 10 mbar CO$_2$, and can be laterally heterogeneous on the scale of the field of view (FOV) of the APXS. Additionally, uncertainty in the placement of arm-mounted instruments, like the APXS, can lead to misinterpretation of spectra acquired in these heterogeneous regions. The fingerprints of a warmer, wetter Mars are hidden in the chemistry, often at a scale that does not fill the dime-sized APXS FOV. Oversampling targets with multiple APXS measurements in close proximity and combining these spectra with images from the rover-arm-mounted Mars Hand Lens Imager allows us to localize the APXS FOVs, mitigating placement uncertainty, compensate for the effects of cm-scale surface relief, and arrive at sub-cm-scale chemistry. Quantitative chemistry at these small scales, including elements important to life such as P and S, is critical for elucidating the formation mechanisms of ancient Mars and further contributes to *Curiosity*'s quest for finding and understanding past habitable environments on Mars.
        Speaker: Mr Scott VanBommel (University of Guelph)
    • 10:30 11:00
      Health Break (with exhibitors) / Pause santé (avec exposants) SITE Atrium

      SITE Atrium

      University of Ottawa

    • 11:00 11:30
      R-MEDAL1 CAP Medal Talk - Freddy Cachazo, Perimeter Institute (CAP-CRM Prize in Theoretical and Mathematical Physics Recipient / Récipiendaire Prix ACP-CRM en physique théorique et mathématique) Marion 150

      Marion 150

      University of Ottawa

      • 11:00
        S-Matrix Theory: A Bridge Between Physics and Mathematics 30m

        Scattering amplitudes of massless particles have proven to be very interesting mathematical objects. While clearly defined in terms of Feynman diagrams, these seemingly complicated functions of several complex variables become shockingly simple after miraculous cancellations. In this talk I will explain how Riemann surfaces, cluster algebras and the positive Grassmannian are some of the mathematical ideas responsible for this surprising behavior of standard quantum field theory S-matrices.

        Speaker: Freddy Cachazo (Perimeter Institute)
    • 11:00 11:30
      R-MEDAL2 CAP Medal Talk - Richard Boudreault, Chairman Polar Knowledge Canada (CAP-INO Medal for Outstanding Achievement in Applied Photonics) Colonel By C03

      Colonel By C03

      University of Ottawa

      • 11:00
        POLAR Science for Physicists 30m

        Canada occupies 25% of the Arctic and, of our three ocean coasts, the Arctic Ocean’s is by far the longest while being the least known. The strategic and economic importance of the North for Canadians and the world cannot be minimized. More than 100 000 people live in the north, a majority of whom are First Nations and Inuit. In view of the importance of the Polar Regions to Canadians, our government decided a year ago to create its own national polar agency, Polar Knowledge Canada (POLAR), with a goal of reconciling our knowledge base of the Arctic with the challenges we face. The objective of this presentation is enlighten my fellow physicists to the challenges and opportunities that comes from polar research.

        There are presently some significant gaps in our polar knowledge which much be filled to safeguard the region and its people, as well as Canadians in general. The Arctic suffers from a phenomenon of Polar Amplification of its climate temperature as compared to pre-industrial times. While in the south we must adapt to a present 0.8°C rise, in the north, this value is more like an additional 6°C. For example, no fewer than five of the global climate change tipping points, locations where a small perturbation to the climatic stable state triggers a transition to an alternate climatic state, are located within our national boundaries or are tributary to the Canadian Arctic. In Earth System Science, a tipping point occurs when a small perturbation to a global climatic stable state, triggers a disproportionate transition to an alternate climatic state. Challenges to our Canadian sovereignty is of usual occurrence there, as marked by the frequent presence of foreign vessels. Our people, north of the 70th parallel, must burn costly, low-efficiency diesel to power and heat their communities, resulting in high economic and environmental impacts that constrain both their livelihood and quality of life. Sadly, Canada does not have the requisite 25% of the world’s polar-interested scientists to fill the knowledge gaps inhibiting solutions from being implemented. Photonics as a prime role to play in the Arctic. POLAR must work with international and national partners to achieve its national mission.

        Speaker: Mr Boudreault Richard (Chair, Polar Knowledge Canada)
    • 11:30 12:00
      R-MEDAL3 CAP Medal Talk - Akira Konaka, TRIUMF (CAP-TRIUMF Vogt Medal Recipient/Récipiendaire de la médaille Vogt de l'ACP-TRIUMF) Marion 150

      Marion 150

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 11:30
        Quest for CP violation in neutrino oscillations 30m

        Neutrino oscillation shows that different flavours of neutrinos, νe, νμ, and ντ, mix like quarks. Thus CP violation is expected due to the complex phase in the mixing matrix as is in the quark case. Since the observables of CP violation, namely difference between neutrino and anti-neutrino oscillations, is proportional to the three mixing angles, sinθ12, sinθ23 and sinθ13, all the three angles need to be large enough for the CP violation to be accessible. Since the discovery of the first neutrino oscillation in 1998, all these three mixing angles have been observed to be surprisingly large. The last angle sinθ13 was observed by T2K long baseline neutrino and Daya Bay/Reno reactor neutrino experiments. Because the T2K observable is also sensitive to CP violation, the comparison between T2K and reactor experiments shows a hint of potentially large effect due to CP violation phase. If the CP violation in neutrino oscillation is indeed large, it could naturally explain the matter vs. anti-matter asymmetry of the universe. An extension of T2K is being proposed to discover this leptonic CP violation in the decade. In this talk, I will present the status and prospect of the CP violation measurement in neutrino oscillation.

        Speaker: Akira Konaka (TRIUMF)
    • 12:00 13:00
      DHP Annual Meeting / Assemblée annuelle DHP Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Louis Marchildon (Universite du Quebec a Trois-Rivieres)
    • 12:00 13:00
      DTP Annual Meeting / Assemblée annuelle DPT SITE J0106

      SITE J0106

      University of Ottawa

      Convener: Svetlana Barkanova (Acadia University)
    • 12:00 13:00
      Lunch / Dîner
    • 12:00 13:00
      PPD Annual Meeting / Assemblée annuelle PPD SITE C0136

      SITE C0136

      University of Ottawa

      Convener: Christine Kraus
    • 13:15 14:45
      R2-1 Computational Condensed Matter (DCMMP) / Matière condensée numérique (DPMCM) SITE H0104

      SITE H0104

      University of Ottawa

      Convener: Mohamed Amine Gharbi (McGill University)
      • 13:15
        Complex ordered phases of multiblock copolymers 30m
        Self-assembly of multiblock copolymers presents a great opportunity to generate tailored polymeric materials with hierarchically ordered nano-scale domains. At the same time, the phase complexity of multiblock copolymers presents a great challenge to experimental and theoretical study of their phase behavior. Theoretically the self-consistent field theory (SCFT) provides a powerful framework for the study of inhomogeneous polymeric systems. In particular, many researchers have demonstrated that SCFT can be used to describe the phase behavior of block copolymers. Our recent research focuses on the development of theoretical and simulation methods for the prediction of block copolymer phases, resulting in a generic strategy to discover complex ordered phases of block copolymers within the SCFT framework. Specifically, the strategy utilizes a combination of real-space and reciprocal-space techniques to explore possible ordered phases that could be formed by multiblock copolymer melts, resulting in an array of candidate structures. A comparison of the free energy of the candidate phases can then be used to construct phase diagrams. Our extensive calculations have demonstrated that this strategy could be used to predict the formation of complex and hierarchically ordered phases from multiblock copolymers. In particular, application of this strategy to multiblock copolymers, including linear and star ABC triblock copolymers and BACBA pentablock copolymers, has led to the discovery and understanding of a rich array of ordered phases.
        Speaker: An-Chang Shi (McMaster University)
      • 13:45
        Electrophoresis of a charged polymer attached to an uncharged object: does the nature of the object matter? 15m
        Electrophoresis is the motion of charged objects in a fluid in an electric field. Electrophoretic separation of DNA molecules by length is important in many biomedical applications. It is normally done in a nanoporous medium, such as a gel, since uniformly charged polymers move at the same speed, regardless of their length. This is because such polymers are electrophoretically free-draining, meaning that their parts move in the fluid independently (essentially in "free fall"), with negligible hydrodynamic interactions (HI) between them. Separation by length without a gel becomes possible, if identical neutral objects are attached to the DNA molecules, thus breaking the uniformity. If one still naively assumes free-draining for such composite objects, neglecting HI, then the DNA length dependence of the electrophoretic mobility is predicted to have a universal form, independent of the nature of the object (a linear or branched polymer, a globular protein, a micelle, etc.) and the way it is attached to the DNA, with a single parameter depending only on the hydrodynamic friction coefficient of the object. Taking HI into account in the pre-averaging approximation, we show that, in fact, the form of the length dependence of the electrophoretic mobility depends strongly on the nature of the neutral object and the place of attachment, with, for example, power laws with different exponents observed for short DNA in different cases and a much stronger, exponential dependence when the DNA is attached inside a cavity in a solid object. The mobility can differ by several orders of magnitude for different objects with the same friction coefficient, or even between different attachment points for the same object. Electrostatic analogies help explain some of these cases qualitatively. For a heteropolymer, the electrophoretic mobility is a weighted average of the mobilities of its parts; when an object is attached, the way the weights are modified can be described by an “influence function” that, in many cases, has interesting properties.
        Speaker: Dr Mykyta V. Chubynsky (Department of Physics, University of Ottawa)
      • 14:00
        Conformational free energy of polymers under confinement 15m
        An understanding of the physical properties of polymers in confined environments is essential for the development of nanofluidic devices for DNA analysis, as well as for understanding the organization of bacterial chromosomes. Theoretical treatments of the dynamical behaviour of confined polymers often employ analytical approximations of the conformational free energy. Monte Carlo (MC) computer simulation methods provide an effective means to directly measure the free energy for simple model systems and test these approximations. In this study, we employ MC simulations measure the free energy for linear, ring, and star polymers subject to cylindrical confinement. The free energy is measured as a function of intramolecular overlap along the cylinder axis, in the case of single-polymer systems, and intermolecular overlap for two-polymer systems. We examine the variation of the free energy functions with polymer length, stiffness and confinement dimensions. The results are compared with theoretical predictions using the de Gennes blob model, and we identify the parameter regime in which this scaling theory is valid. Finally, we discuss the relevance of the results to the following phenomena: the unfolding of cylindrically confined DNA, the arm-retraction relaxation mechanism of star polymers, and entropic separation of confined ring polymers.
        Speaker: Prof. James Polson (University of Prince Edward Island)
      • 14:15
        Molecular insight to biocompatibility of carbon-based nanomaterials 30m
        Biomaterials are widely used for manufacturing implants. One of the most common reasons for implant failure is its immune rejection. Changes in the conformation of blood proteins (e.g., fibrinogen) due to their binding to nonbiological surfaces are the initial step in a chain of immunological reactions to foreign bodies. Despite the large number of experimental studies that have been performed on fibrinogen adsorption to nonbiological surfaces, a clear picture describing this complex process has eluded researchers to date. Here we focus on modeling the interaction between carbon-based nanomaterials and fibrinogen at the microscopic level by taking into account the physico-chemical properties of the surfaces with the use of empirical force field potential within molecular dynamic (MD) simulations. Carbon-based materials are chosen as a model system for this study due to an increasing interest in their bio-medical applications and the possibility of functionalization (e.g., graphene oxide). The accuracy of the force field was verified by comparing the adsorption energies of individual amino acids on graphene surface with *ab initio* calculations. All-atom MD simulations of the adsorption of a fibrinogen fragment onto a graphene surface reveal significant conformational changes on immune-reactive sites. In contrast, the interaction with polyethylene glycol (PEG) does not induce structural rearrangements in fibrinogen, which is consistent with the bio-inert nature of PEG
        Speaker: Oleg Rubel (Department of Materials Science and Engineering, McMaster University)
    • 13:15 14:45
      R2-2 Energy Frontier: Further Developments (PPD) / Frontière d'énergie: développements futurs (PPD) Colonel By B205

      Colonel By B205

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Erica Caden (Laurentian University)
      • 13:15
        Searches for new physics with the ATLAS detector 30m
        In 2015, the Large Hadron Collider set a new record, colliding protons at a centre-of-mass energy of 13 tera electron volts. This increase in energy means an increase in sensitivity in searches for new physics for detectors at the LHC. ATLAS has completed a large number of searches for phenomena motivated by theories of physics beyond the Standard Model using the data collected at this energy. One possible hint of new physics has been observed by both ATLAS and CMS in the diphoton spectrum. I will be discussing this excess and its implications for new physics. I will also be presenting results from searches for microscopic black holes, the existence of which could point to new physics. This talk will present new limits from this and other searches with the ATLAS detector, and the subsequent outlook for physics beyond the Standard Model.
        Speaker: James Dassoulas (University of Alberta (CA))
      • 13:45
        PPD PHD award: Joint Three-Flavour Oscillation Analysis of $\nu_\mu$ Disappearance and $\nu_e$ Appearance in the T2K Neutrino Beam 30m
        The T2K experiment is a long-baseline neutrino oscillation experiment based in Japan. An off-axis, high purity $\nu_\mu$ beam is directed towards a near detector complex (ND280), situated 280 m from the neutrino production target, and the Super-Kamiokande (SK) far detector at 295 km. This talk describes the T2K beam and detectors, including a novel optical transition radiation monitor for precisely measuring the parent proton beam in order to determine the neutrino beam direction. A framework for evaluating the uncertainties in neutrino interactions and pion hadronic interactions in ND280 and SK is presented. A new SK event reconstruction algorithm is described and the SK detector systematic errors are evaluated based on atmospheric neutrino and cosmic ray muon data. These developments are used in a Markov Chain Monte Carlo neutrino oscillation analysis of the T2K Run 1-4 data corresponding to $0.657 \times 10^{21}$ protons on target. The analysis simultaneously considers the ND280 $\nu_\mu$ samples, and SK single muon and single electron samples, producing a measurement of $\nu_\mu$ disappearance and $\nu_{\mu} \rightarrow \nu_e$ appearance, and precise estimates of neutrino oscillation parameters. Measurements of $\theta_{13}$ from reactor neutrino experiments are combined with the T2K data resulting in the first hints toward non-zero $\delta_{CP}$.
        Speaker: Dr Patrick de Perio (Columbia University)
      • 14:15
        IceCube-DeepCore-PINGU 30m
        IceCube and its low energy extension DeepCore, located at South Pole Station Antarctica, has now acquired nearly 5 years of data in the final detector configuration. In that time, IceCube has detected the Universe's highest energy neutrinos to date, and DeepCore has achieved measurements of atmospheric neutrino oscillations near 25 GeV that are competitive with dedicated experiments at lower energies. Building on this success of deploying massive Cherenkov neutrino detectors in a natural medium, IceCube is now preparing for next generation detector arrays to extend its reach at both the high and low energy range of the current experiment. The Precision IceCube Next Generation Upgrade (PINGU) is the proposed in-fill to the IceCube array that will further lower the neutrino energy detection threshold, making possible enhanced atmospheric neutrino oscillation measurements and sensitivity to indirect dark matter searches. This presentation will briefly cover the most recent results from IceCube and DeepCore, and will discuss the status of the PINGU project.
        Speaker: Darren Grant (University of Alberta)
    • 13:15 14:45
      R2-3 Testing Fundamental Symmetries II (PPD-DNP-DTP) / Tests de symétries fondamentales II (PPD-DPN-DPT) Colonel By D207

      Colonel By D207

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Dr Ian Lawson (SNOLAB)
      • 13:15
        Neutron EDM Experiment at TRIUMF 15m
        I discuss plans and recent R&D progress for a new neutron electric dipole moment (nEDM) experiment to be conducted at TRIUMF. The nEDM is sensitive to CP violation arising from new physics beyond the standard model, and arising in the strong sector of the standard model (the strong CP problem). The experiment at TRIUMF will feature a new superfluid helium source of ultracold neutrons (UCN) so that the statistical sensitivity can be improved over previous experiments. We aim for a factor of 30 improvement in precision over the previous best nEDM experiment, resulting in a $1\times 10^{-27}$ e-cm uncertainty on the nEDM. At the new level of statistical precision to be reached by this experiment, a host of systematic effects must be handled to higher precision than ever before. This talk will provide an overview of our R&D efforts, aimed at improving the statistical precision and reducing systematic effects to an acceptable level. There will be some focus on our studies of magnetic field generation and characterization.
        Speaker: Prof. Jeffery Martin (The University of Winnipeg)
      • 13:30
        Improved limit on the charge of antihydrogen 15m
        Cold atoms of antihydrogen present a unique opportunity to study the properties of atomic antimatter, and via comparisons with its well-studied matter counterpart, the possibility to test fundamental symmetries such as CPT invariance. In order to probe matter-antimatter symmetry at the highest possible precision, it is essential that the anti-atoms be suspended in vacuum to allow for detailed interrogation via laser light or microwaves. The ALPHA experiment, performed at the CERN AD, has trapped upward of 1000 antihydrogen atoms since 2010. This presentation will describe the physics measurement that we have performed with some of these atoms to study their charge neutrality. By applying stochastic acceleration to trapped antihydrogen atoms, we determine an experimental bound on the antihydrogen charge, Qe, of |Q| < 0.71 parts per billion (one standard deviation), in which e is the elementary charge. This bound is a factor of 20 lower than was determined from the best previous measurement. I will also offer an outlook towards the spectroscopic studies being attempted using the new ALPHA2 trap that we have commissioned. *For the ALPHA collaboration http://alpha-new.web.cern.ch: M. Ahmadi, M. Baquero-Ruiz, W. Bertsche, E. Butler, A. Capra, C. Carruth, C.L. Cesar, M. Charlton, A.E. Charman, S. Eriksson, A.L. Evans, L.T. Evans, N. Evetts, J. Fajans, T. Friesen, M.C. Fujiwara, D.R. Gill, A. Gutierrez, J.S. Hangst, W.N. Hardy, M.E. Hayden,, C.A. Isaac, A. Ishita, S.A. Jones, S. Jonsell, L. Kurchaninov, N. Madsen,M. Mathers, J.T.K. McKenna, S. Menary, J.M. Michan, T. Momose, J.J. Munich, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, R.L. Sacramento, M. Sameed, E. Sarid, D.M. Silveira, C. So, T. D. Tharp. J. Thompson, R.I. Thompson, D.P. van der Werf, J.S. Wurtele, A. I. Zhmoginov.*
        Speaker: Art Olin (TRIUMF (CA))
      • 13:45
        The KDK project: measuring the decay of 40K 15m
        Potassium-40 (40K) is a background in many rare-event searches, including the DAMA/LIBRA experiment whch claims to have detected the elusive dark matter which may make up most of the matter in the universe. The electron capture of 40K to 40Ar releases ~3 keV X-rays and Auger electrons that fall into DAMA’s region of interest. In most cases, the decay is to an excited state of 40Ar and is accompanied by the emission of a 1.46 MeV gamma ray that can be used to tag and reject some of the X-rays and electrons. However, the decay can also go directly to the ground state of 40Ar, leaving no means to tag the low-energy contribution to the background. The branching ratio of the direct decay is predicted to be small, but has never been measured, as pointed out by Pradler, Singh and Yavin (PLB 720 2013). This decay would also be the only known example of a unique third forbidden nuclear decay. In the KDK (40K decay) project, we propose to measure this branching ratio, using a 40K source, a small inner detector to trigger on X-rays, and a large, efficient outer tagger to look for the 1.46 MeV gammas distinguishing between electron capture modes. We present the experiment, which will use the large MTAS (Modular Total Absorption Spectrometer) tagger located at Oak Ridge National Laboratories. It detects gamma rays with high efficiency (total absorption efficiency around 99% at 1.46 MeV). We will also discuss options for X-ray detection, which include novel potassium-based scintillators with very high light yield, and will conclude with the expected sensitivity and status of the project.
        Speaker: Dr Philippe Di Stefano (Queen's University)
      • 14:00
        Upgrades to the ATLAS detector at the LHC 30m
        Following the successful operation of the Large Hadron Collider (LHC) at collision center-of-mass energy of 7 and 8 TeV in the period 2010-2012, the LHC is now colliding protons at the unprecedented center-of-mass energy of 13 TeV. Plans are underway to significantly increase the luminosity of the LHC over the next twenty years through various upgrades of the accelerator complex. In order to take advantage of the planned significant increase in instantaneous luminosity beyond the original nominal design, important upgrades to the ATLAS and CMS experiments are being prepared. In this talk, scientific motivations for the upgade of the ATLAS experiment will be presented. The overall ATLAS upgrade program, including both the so-called Phase-I (2019) and Phase-II (2024) upgrades, will also be described, with emphasis on projects with Canadian efforts.
        Speaker: Brigitte Vachon (McGill University (CA))
      • 14:30
        The spontaneous $\mathbb{Z}_2$ breaking Twin Higgs 15m

        The Twin Higgs model seeks to address the little hierarchy problem by making the Higgs a pseudo-Goldstone of a global $SU(4)$ symmetry that is spontaneously broken to $SU(3)$. Gauge and Yukawa couplings, which explicitly break $SU(4)$, enjoy a discrete $\mathbb{Z}_2$ symmetry that accidentally maintains $SU(4)$ at the quadratic level and therefore keeps the Higgs light. Contrary to most beyond the Standard Model theories, the quadratically divergent corrections to the Higgs mass are cancelled by a mirror sector, which is uncharged under the Standard Model groups. However, the Twin Higgs with an exact $\mathbb{Z}_2$ symmetry leads to equal vevs in the Standard Model and mirror sectors, which is phenomenologically unviable. An explicit $\mathbb{Z}_2$ breaking potential must then be introduced and tuned against the $SU(4)$ breaking terms to produce a hierarchy of vevs between the two sectors. This leads to a moderate but non-negligible tuning. We propose a model to alleviate this tuning, without the need for an explicit $\mathbb{Z}_2$ breaking sector. The model consists of two $SU(4)$ fundamental Higgses, one whose vacuum preserves $\mathbb{Z}_2$ and one whose vacuum breaks it. As the interactions between the two Higgses are turned on, the $\mathbb{Z}_2$ breaking is transmitted from the broken to the unbroken sector and a small hierarchy of vevs is naturally produced. The presence of an effective tadpole and feedback between the two Higgses lead to a sizable improvement of the tuning. The resulting Higgs boson is naturally very Standard Model like.

        Speaker: Kevin Earl (Carleton University)
    • 13:15 14:45
      R2-4 Biophotonics (DPMB-DAMOPC) / Biophotonique (DPMB-DPAMPC) Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Christopher Bergevin (York University)
      • 13:15
        Simultaneous Measurement of Refractive Index and Thickness of Multi Layer Systems Using Fourier Domain Optical Coherence Tomography 15m
        Purpose: To develop and validate a methodology for the simultaneous extraction of index of refraction, n(r), and physical dimension, t(r), profiles from the Spectral OCT data of multi-layered systems without any prior knowledge of the system under test. Method: We first develop a theoretical framework for the simultaneous extraction of index of refraction and thickness. We then use the Transfer Matrix Method (TMM) to simulate Spectral OCT signals for a range of multi-layered systems simulating biological system to validate the methodology and quantify its potential accuracy. Results: Our theoretical framework combines the traditional optical path information and raw spectral response information to generate a set of linearly independent equations that can be solved for the sample’s indices and thicknesses and the rear medium index of refraction assuming that the front medium index of refraction is known. The accuracy of the extracted parameters depends on the sample’s index contrast and is insensitive to the sample’s thickness profile. We have used this methodology for two and three layers systems immersed in aqueous medium. For biological applications we can extract the indices within the error range of ±0.001 when the layers indices are <1.55. Conclusions: We have developed the first methodology for extracting both physical dimension and index of refraction profiles of biologically relevant multi-layered systems without using any additional outside measurements.
        Speaker: Payman Rajai (university of Ottawa)
      • 13:30
        Characterization of Gold Nanocages as Contrast Agents for Optoacoustic Imaging 15m
        Optoacoustic (OA) imaging is being investigated as a non-invasive technique for monitoring cancer therapeutics. It involves exposing tissues to nanosecond pulsed near infrared laser light. The optical energy is absorbed by tissue chromophores and converted into heat, leading to thermoelastic expansion, producing acoustic waves in the ultrasonic frequency range which are then detected by transducers. Gold nanocages (AuNCs) are plasmonic particles that are highly absorbing in the near infrared, are biocompatible and their surface chemistry can be functionalized to target specific cells. Hence there is great interest in the capability of AuNCs to enhance OA image contrast at depth. Yet there remains concern about the potential damage to the AuNC structure as a result of pulsed laser exposure. In this work, the stability of AuNCs following pulsed laser exposure was evaluated using absorption spectroscopy and transmission electron microscopy (TEM) imaging. Gold nanocage solutions, of varying concentration, were irradiated by laser pulses for 1 to 5 minutes using a reverse-mode optoacoustic imaging system (Seno Medical, San Antonio, TX). For direct illumination at 775 nm, the AuNCs demonstrated conformational changes including melting (pulse energy of 10 mJ) and fragmentation (pulse energy of 21 mJ) which led to a change in surface plasmon resonance. Optical absorption data demonstrated an 82.9 nm blue shift and 66.7 % decrease in peak amplitude following a 5 min exposure at 10 mJ. However, AuNC targets of varying particle concentrations placed in tissue mimicking phantom materials of varying background optical absorption (up to 4.0 cm-1) exhibited no damage following OA exposure, while improving image contrast by up to 300 %. This study demonstrates the utility of gold nanocages as contract agents for optoacoustics. This research is supported by a NSERC Discovery Grant to W. Whelan
        Speaker: Bill Whelan (University of Prince Edward Island)
      • 13:45
        Changes in ocular properties can be predicted from retinal blur due to defocus during emmetropization in the chick eye 15m
        INTRODUCTION: Emmetropization is an active process involving retinal feedback and is likely driven by the amount of defocus of the image on the retina. Normal emmetropization has long been assumed to result in zero refractive error, but recently this has been questioned. We wish to objectively determine, in chicks, when emmetropization is complete and how much retinal blur due to defocus remains. Secondly, we examine ocular properties during emmetropization to determine which changes are proportional to the retinal blur due to defocus. METHODS: From literature values including work in our lab, functions were fit to MOR (mean ocular refraction or spherical equivalent) and optical axial length (OAL; anterior cornea to anterior retina) vs. age. Dioptric length (K’) and eye power (F) were derived up to day 75 using our previously reported method to calculate equivalent eye power. Cornea and lens powers were also calculated. Pupil size data were used to calculate the angular and linear retinal blurs (EB and LRB) due to defocus. The relationships among parameters and between retinal blur and ocular parameters were examined. RESULTS: Eye power and K’ decrease exponentially with age at slightly different rates until power and K’ reach almost equal values about day 35. Subsequently, power and K’ decrease almost identically with age. This gives an initial rapid exponential decrease in MOR, which reaches a relatively stable value of 0.8 D of hyperopia about day 30 to 40 The completion of emmetropization is defined as the time point beyond which MOR remains relatively stable. After emmetropization is complete, MOR and EB remain almost constant and LRB is almost constant or increases slowly from about day 60, suggesting a differing growth pattern following emmetropization. The radius of the blur on the retina is larger than the cone resolution prior to completion of emmetropization, and approaches cone resolution as emmetropization proceeds. Because of its exponential decrease with age during emmetropization, the rate of change of MOR (D/day) varies linearly with MOR. However, it also varies approximately linearly with retinal blur (both EB and LRB; p<0.001) before and after emmetropization is complete. During emmetropization, the rate of increase of OAL decreases, as a linear function of decreasing retinal blur (EB p=0.0009 and LRB p=0.004). This relationship breaks down around the time that emmetropization is complete (~day 30). Similarly, during emmetropization, the rate of increase in corneal radius varies linearly with retinal blur (EB p=0.0008 and LRB p=0.004) and the rate of decrease in lens power varies linearly with the rate of change of retinal blur (EB p=0.001 and LRB p=0.005). As expected from the above results, the rate of change of corneal radius (p<0.0001) and lens power (p<0.0001) are proportional to the rate of change of OAL during but also following emmetropization. CONCLUSIONS: Concurrent variations in eye power and length combine to produce the smaller, more rapid changes in MOR as a function of age during normal emmetropization. The eye is slightly hyperopic at the time point when emmetropization is complete. This time point can be defined objectively. Emmetropization appears to produce an active reduction of angular retinal blur to a value close to cone resolution. In chick during emmetropization, the rates of ocular elongation, corneal radius increase and lens power decrease are proportional to the size of the angular defocus blur on the retina until the blur approaches cone resolution and emmetropization is complete. Beyond this time, MOR is relatively stable, and eye growth is slower to day 75. Many of these results are consistent with findings during emmetropization in infants but here we show a linear dependence on retinal blur.
        Speaker: Melanie Campbell (University of Waterloo)
      • 14:00
        Advances in Raman spectroscopy and its applications 30m
        This talk focuses on the investigation and development of an integrated portable optical biosensor for label-free detection of biomolecules, based on enhanced Raman techniques. This enhancement is achieved by integrating hollow core photonic crystal fibers (HC-PCF) and nanoparticles. Challenges in developing a robust, reusable and reliable sensors will be discussed as well as methods to mitigate these challenges. We will also discuss the use of this biosensor in a variety of applications including the detection of Heparin in blood and the detection of Leukemia cells.
        Speaker: Prof. Hanan Anis (Faculty of Engineering, University of Ottawa)
      • 14:30
        Laser Induced Neuro-Stimulation Analysis 15m
        This paper exploits the effectiveness of neuro-stimulation when induced with a near infrared laser (808 nm). We examine the absorption spectrum of fats, skin, neuromuscular tissues and bones when irradiated trans-cranially through animal models. Thereby, modelling irradiation time versus penetration depth for an optimal dose. The efficacy of high power laser on the viability and the ATP production of neuroblastoma cells (SH-SY-5Y) and cortical neurons are evaluated. The study highlights the correlation between Post-Traumatic Stress Disorder and Adenosine-tri-phosphate production. The MTT and luciferase-luciferin analysis explain the hypothesis of a healthy relationship between the stress disorder and the energy producing molecule. Hence, provide guidelines for prototyping the low cost and effective medical devices.It was found that the 1 second irradiation of neurons (invitro), led to an increase of ATP production by a factor of 3.5.
        Speaker: Kavleen Aulakh (Carleton University)
    • 13:15 14:45
      R2-5 Quantum Information and Quantum Optics (DCMMP-DAMOPC) / Information quantique et optique quantique (DPMCM-DPAMPC) SITE G0103

      SITE G0103

      University of Ottawa

      Convener: Jean-Michel Ménard (University of Ottawa)
      • 13:15
        Testing Landauer’s Principle in a Feedback Trap 30m
        Landauer’s principle, formulated in 1961, postulates that irreversible logical or computational operations such as memory erasure require work, no matter how slowly they are performed. For example, to “reset to one” a one-bit memory requires at least kT ln2 of work, which is dissipated as heat. Bennett and, independently, Penrose later pointed out a link to Maxwell’s demon: Were Landauer’s principle to fail, it would be possible to repeatedly extract work from a heat bath. We report tests of Landauer’s principle in an experimental system consisting of a charged colloidal particle in water. To test stochastic thermodynamic ideas, we create a time-dependent, “virtual” double-well potential via a feedback loop that is much faster than the relaxation time of the particle in the virtual potential. In a first experiment, the probability of “erasure” (resetting to one) is unity, and at long cycle times, we observe that the average work is compatible with kT ln2. In a second, the probability of erasure is zero; the system may end up in two states; and, at long cycle times, the average measured work tends to zero. In individual cycles, the work to erase can be below the Landauer limit, consistent with the Jarzynski equality. Finally, in asymmetric wells, the different well sizes can allow for erasure with an average cost below kT ln2.
        Speaker: John Bechhoefer (Simon Fraser University)
      • 14:15
        Repeated Interaction with Ensemble of Ancillas 15m
        We investigate the general open dynamics of a quantum system S undergoing a bombardment of short (unitary) interactions with an environment made of individual ancillas. We show how decoherence emerges from the fully unitary interaction of S with a large set of (in general non-identical) ancillas, and we compute the master equation that governs the dynamics of the system. Our findings may have applications in a range of fields both fundamental and applied: from the Quantum Zeno effect and the very foundations of the measurement problem to the study of decoherence and quantum thermodynamics.
        Speaker: Mr Daniel Grimmer (University of Waterloo)
      • 14:30
        Shape dependence of two-cylinder Renyi entropies for a free boson lattice field theory 15m
        We study the bipartite von Neumann and $\alpha =2$ Renyi entanglement entropies for a system of free bosons put on a torus cut into two cylinders. The torus is formed out of the $L\times L$ square lattice, and the entropy is supposed to scale as $S = a L + c \gamma (L_A/L) + \cdots$, with $L_A$ being the size of the partitioned region. $c$ and $a$ are some constants and the function $\gamma (L_A/L)$ that is not known analytically is supposed to reflect some universality. We compute $\gamma (L_A/L)$ numerically and compare the results to several candidate functions derived from Quantum Lifshitz model, anti de-Sitter gravity in $3+1$ dimensions, and an Extensive Mutual Information model. Using lattices of different size, we explore the finite-size-scaling behaviour of the residuals for each fit, to attempt to discern which function most effectively describes the thermodynamic limit of the free boson system.
        Speaker: Denis Dalidovich (Perimeter Institute for Theoretical Physics)
    • 13:15 14:45
      R2-6 General Instrumentation II (DIMP) / Physique générale des instruments II (DPIM) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Kirk Michaelian (Natural Resources Canada)
      • 13:15
        **WITHDRAWN** A nanogap, impedance microchip for sensitive and surface tunable sensing 15m
        We have microfabricated and evaluated the performance of nanogap conductivity/dielectric constant sensors with a novel architecture. The “apertured impedance microchips” (AIM) feature aluminum metal/silicon-oxide/silicon layers, where the top metal layer has apertures and the middle oxide layer has wells. This layered yet open geometry enables molecules to have access to detection electric fields induced by a voltage applied between the top metal/bottom silicon electrode layers. Our design rationale surmised that the AIM device’s large footprint area and thin nanoscale oxide layer should enable impedance detection of molecules with high sensitivity in a variety of solvents. The present study confirms this hypothesis and explores the effects that simple surface modifications have on the device’s response. Specifically, devices were incorporated into a high performance liquid chromatography (HPLC) system already equipped with an ultra-violet–visible (UV–vis) detector. A range of analytes was injected using both normal and reverse phase modes; and the signals generated by each microchip device and UV–vis detector were recorded simultaneously and compared. The microchip devices’ responses were found to vary for analytes according to the surface modification used. To demonstrate the novel dielectric constant capability of AIM, as a case study, an AIM device was used to detect left and right handed versions a synthesized chiral molecule separated by a chiral column using an insulating eluent, namely hexanes/isopropanol.
        Speaker: Al-Amin Dhirani (University of Toronto)
      • 13:30
        A 16-Microcantilever Array Sensing System for the Rapid and Simultaneous Detection of Analyte 15m
        A new 16 microcantilever sensor system for performing sensing experiments in liquid or gas will be presented. The system uses two 8-microcantilever arrays held in a sensor cell. The microcantilever deflections are monitored by oscillating two focused optical beams over the microcantilevers such that only one microcantilever is illuminated at one time and each microcantilever is illuminated approximately once per second. The optical beams are moved using a motorized translation stage. The reflected optical beams are detected by a two-axis photo-sensitive detector (PSD) producing a series of two eight peak shaped patterns. The raw data from both the PSD and the translation stage are used to fold the peak shaped patterns from each array one on top of the other so that the deflection of the cantilevers can be obtained from the change in height of each peak. The stability of the data was found to be dependent on the speed of the translation stage. When the translation stage was operated between 0.5 and 1 mm/s, the deflection of each microcantilever in units of surface stress was found to be highly reproducible and consistent between arrays. The system was used to detect Ca$^{2+}$, Sr$^{2+}$ and Cs$^{+}$ ions using different calix[4]arene-based sensing layers. The results obtained were found to be reproducible and completely consistent with results obtained using a typical two single microcantilever sensor system.
        Speaker: Dr Luc Beaulieu (Physics Dept, Memorial University)
      • 13:45
        The automation of the NRC ice load monitoring system at the Confederation Bridge 15m
        Since 1997 the National Research Council Canada has been monitoring ice loads on the Confederation Bridge. It has proven a valuable research platform to examine full scale ice loading events on a sloped structure. Ice loading results from the bridge are still used today in order to validate numerical models which are used to optimize the designs of offshore platforms which could be subjected to ice loads. The ice load monitoring system is comprised of four tilt meters, two video cameras and an anemometer near the navigation span (centre) of the bridge. Historically, the calculation of ice loads on the bridge has been very labour intensive and requires a detailed analysis of the data from each of the 7 sources. This has limited the ice load analysis to extreme ice loading events. Beginning in 2011 the NRC has been connecting the equipment to the internal power and communications network of the Confederation Bridge. By combining these new hardware upgrades with advances in computational power and image processing techniques the National Research Council now have all of the tools to develop a quasi-real-time ice load monitoring system. We will present an update of the current status of the ice load monitoring system and examine specific ice loading event which have occurred at the bridge.
        Speaker: Louis Poirier (National Research Council Canada)
      • 14:00
        Domains of application of microcontrollers and single board linux computers in data acquisition 15m
        More than a decade ago, high function microcontrollers like the Microchip PIC allowed a large step to be made in data acquisition, as compared to fabrication of systems from discrete parts. They had a high level of integrated peripherals relevant to the task, good development environments, and relatively easy programming, including high level languages on the most advanced members of the family. Their level of interaction for the user was limited, and networking generally fell short of the standards needed to ensure reliability. More recently, single board linux computers like the Raspberry Pi and Beagleboard/bone provide a high level of user interaction, good networking, and a standard environment. They are made flexible by a large selection of inexpensive peripheral devices available, generally interconnected by the I2C protocol. Nevertheless, there are limitations on what such a system can do, since it does not usually have a real time operating system, and thus cannot respond to interrupts. Usually the ability to detect events at high speed is also limited. We will relate a hybrid approach using a PIC with a lower-end integrated system known as a Rabbit, which formed the basis of a high performance magnetic instrument known as netPICOmag. We propose extension of this concept to PIC and Raspberry Pi for real-time or time critical applications.
        Speaker: Martin Connors (Athabasca University)
    • 13:15 14:15
      R2-7 Open Educational Resources Discussion (DPE) / Discussion sur les ressources éducatives libres (DEP) SITE J0106

      SITE J0106

      University of Ottawa

      Convener: Daria Ahrensmeier (Simon Fraser University)
    • 14:45 15:00
      Health Break / Pause santé SITE Atrium

      SITE Atrium

      University of Ottawa

    • 15:00 17:00
      R-PLEN1 CAP Best Student Presentations Final Competition / Compétition finale de l'ACP pour les meilleures communications étudiantes Marion 150

      Marion 150

      University of Ottawa

      Convener: Stephen Pistorius (CCMB, University of Manitoba)
    • 17:00 17:45
      R-PLEN Plenary Session - Paul Corkum, Univ. of Ottawa - Session plénière - Paul Corkum, Univ. d'Ottawa Marion 150

      Marion 150

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 17:00
        Probed quantum systems from the inside – on the attosecond time scale 45m
        Attosecond pulses are generated by electrons that are extracted from a quantum system by tunneling in an intense light pulse and travel through the continuum. Portions of each electron wave packet are forced to re-collide with its parent ion by the oscillating force of the time dependent electric field. Upon re-collision, the electron and ion can re-combine, emitting soft X-ray radiation. This highly nonlinear process occurs in atoms, molecules and solids and offers unique measurement opportunities –of the attosecond pulses themselves; of molecular orbitals; and even the band structure of large bandgap semiconductors.
        Speaker: Prof. Paul Corkum (University of Ottawa)
    • 18:30 22:00
      Recognition Reception at the Shaw Centre / Réception de reconnaissance au Centre Shaw Shaw Centre

      Shaw Centre

      Convener: Adam Sarty (Saint Mary's University)
    • 08:30 10:00
      CAP Foundation Annual General Meeting / Assemblée annuelle de la Fondation de l'ACP Colonel By A707A

      Colonel By A707A

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 10:00 11:30
      CAP Foundation Board Meeting / Réunion du CA de la Fondation de l'ACP Colonel By A707A

      Colonel By A707A

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 11:30 14:00
      CAP Board Meeting (New and Old) / Réunion du CA de l'ACP (nouveau et ancien) Colonel By A707A

      Colonel By A707A

      University of Ottawa

    • 14:00 15:15
      Meeting of Local Organizing Committees 2016, 2017 + / Réunion des comites organisateurs locaux 2016, 2017 + Colonel By A707A

      Colonel By A707A

      University of Ottawa