2015 CAP Congress / Congrès de l'ACP 2015

America/Edmonton
University of Alberta

University of Alberta

Edmonton, AB
Description

The 2015 CAP Congress is being hosted by University of Alberta, June 15-19, 2015. 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/2015 ) for easy access to updates and program information.

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Link to online registration:  https://www.cap.ca/CAP_Meetings/default.aspx

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Le Congrès 2015 de l'ACP se tiendra à la University of Alberta (Edmonton) du 15 au 19 juin 2015. 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/congress/2015) pour accéder facilement aux mises à jour et au contenu de la programmation.

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2015 CAP Congress Poster
    • 13:30 18:00
      CINP Town Hall (Sat) / Consultation publique du ICPN CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Prof. Garth Huber (University of Regina)
      • 13:30
        Welcome & Introduction 10m
        Speaker: Garth Huber (University of Regina)
        Slides
      • 15:07
        Coffee and Discussion 33m
      • 16:59
        Discussion on Hadron Structure/QCD (21) 21m
      • 17:20
        Discussion on HQP Issues (40) 40m
        Speaker: Juliette Mammei
    • 13:40 15:07
      CINP Town Hall (Sat) / Consultation publique du ICPN: FUNDAMENTAL SYMMETRIES I
      Convener: Gerald Gwinner
      • 13:40
        ALPHA Antihydrogen Symmetry Test (20+5) 25m
        Slides
      • 14:05
        MOLLER Parity Violation Experiment at JLab (20+5) 25m
        Slides
      • 14:30
        Cold Neutrons at SNS (10+2) 12m
        Slides
      • 14:42
        UltraCold Neutrons at TRIUMF (20+5) 25m
        Slides
    • 15:40 17:24
      CINP Town Hall (Sat) / Consultation publique du ICPN: Hadron Structure/QCD
      Convener: Adam Garnsworthy
      • 15:40
        Compton Scattering Measurements at MAMI (15+3) 18m
        Speaker: Prof. David Hornidge (Mount Allison University)
        Slides
      • 15:58
        Nucleon electromagnetic form factor measurements at JLab (15+3) 18m
        Speaker: Adam Sarty (Saint Mary's University)
        Slides
      • 16:16
        The GlueX and Exclusive Meson Production Programs at JLab (20+5) 25m
        Slides
      • 16:41
        Extreme QCD: Characterizing the Quark-Gluon Plasma (15+3) 18m
        Speaker: Prof. Charles Gale (McGill University)
        Slides
    • 08:00 12:00
      CAP Board Meeting (Old and New) / Réunion du CA de l'ACP (ancien et nouveau) CCIS 3-003

      CCIS 3-003

      University of Alberta

    • 08:00 10:00
      Long Range Planning Committee Kick-off Meeting / Reunion du comite de planification a long terme CCIS 4-003

      CCIS 4-003

      University of Alberta

    • 09:00 17:45
      IPP Town Hall - AGM / Consultation publique et AGA de l'IPP NINT Taylor Room

      NINT Taylor Room

      University of Alberta

      Convener: Michael Roney (University of Victoria)
      • 10:00
        Introduction-IPP Director's Report 20m
        Speaker: Michael Roney (University of Victoria)
        Slides
      • 10:20
        Particle Astrophysics CFREF 10m
        Speaker: Prof. Tony Noble (Queen's University)
        Slides
      • 10:30
        DEAP 20m
        Speaker: Mark Boulay (Q)
        Slides
      • 10:50
        SNO+ 20m
        Speaker: Christine Kraus
        Slides
      • 11:10
        SuperCDMS 20m
        Speaker: Prof. Gilles Gerbier (Queen's University)
        Slides
      • 11:30
        PICO 20m
        Speaker: Tony Noble (Queen's University)
        Slides
      • 11:50
        EXO 20m
        Speaker: Prof. David Sinclair (Carleton University)
      • 12:10
        NEWS Experiment 20m
        Speaker: Prof. Gilles Gerbier (Queens' University)
        Slides
      • 12:30
        LUNCH 30m
      • 13:00
        IceCube 20m
        Speaker: Prof. Darren Grant (University of Alberta)
        Slides
      • 13:20
        Theory review-Higgs, EW, BSM 40m
        Speakers: Dr David Morrissey (TRIUMF), Prof. Heather Logan (Carleton University)
        Slides
      • 14:00
        Moller Experiment at JLAB 10m
        Speaker: Michael Gericke (University of Manitoba)
        Slides
      • 14:10
        ALPHA 10m
        Speaker: Makoto Fujiwara (TRIUMF (CA))
        Slides
      • 14:20
        UCN 20m
        Speaker: Prof. Jeffery Martin (University of Winnipeg)
        Slides
      • 14:40
        Belle II 20m
        Speaker: Dr Christopher Hearty (IPP / UBC)
        Slides
      • 15:00
        HEPNET/Computing in HEP 10m
        Speaker: Randy Sobie (University of Victoria (CA))
        Slides
      • 15:10
        BREAK 20m
      • 15:30
        MRS - Alberta/Toronto 5m
        Speaker: James Pinfold (University of Alberta (CA))
        Slides
      • 15:35
        MRS - Carleton/Victoria/Queens 10m
        Speaker: Prof. Kevin Graham (Carleton University)
        Slides
      • 15:45
        NA62 20m
        Speaker: Dr Toshio Numao
        Slides
      • 16:05
        Halo+upgrade at LNGS 15m
        Speaker: Prof. Clarence Virtue (Laurentian University)
        Slides
      • 16:20
        VERITAS 10m
        Speaker: Prof. David Hanna (McGill University)
        Slides
      • 16:30
        g-2 at JPARC 10m
        Speaker: Dr Glen Marshall (TRIUMF)
        Slides
      • 16:40
        Theory Review - QCD 15m
        Speaker: Prof. Randy Lewis (York University)
        Slides
      • 16:55
        ATLAS 30m
        Speaker: Prof. Alison Lister (UBC)
        Slides
      • 17:25
        Technical support for experiment development and construction 10m
        Speaker: Dr Fabrice Retiere (TRIUMF)
        Slides
    • 10:00 18:30
      CINP Town Hall (Sun) / Consultation publique du ICPN CCIS L1-029

      CCIS L1-029

      University of Alberta

      Convener: Prof. Garth Huber (University of Regina)
      slides
      • 10:00
        Introductory Comments 10m
        Speaker: Garth Huber (University of Regina)
        Slides
      • 12:08
        Lunch (provided) 42m
      • 14:21
        Discussion on Nuclear Astrophysics (19) 19m
        Speaker: Iris Dillmann
      • 14:40
        Discussion on Nuclear Structure (20) 20m
        Speaker: Adam Garnsworthy
      • 15:00
        Coffee 20m
      • 16:44
        Discussion on Fundamental Symmetries (20) 20m
      • 17:41
        General Discussion 49m
        Speaker: Garth Huber (University of Regina)
    • 10:10 12:08
      CINP Town Hall (Sun) / Consultation publique du ICPN: NUCLEAR STRUCTURE & ASTROPHYSICS I
      Convener: Garth Huber (University of Regina)
      slides
      • 10:10
        Nuclear Structure aspects of the Gamma-Ray program (20+5) 25m
      • 10:35
        Nuclear Astrophysics aspects of the Gamma-Ray program (20+5) 25m
        Speaker: iris Dillmann
      • 11:00
        Fundamental Symmetries aspects of the Gamma-Ray program (20+5) 25m
        Speaker: Carl Svensson
      • 11:25
        Nuclear Astrophysics with DRAGON/TUDA/EMMA (15+3) 18m
        Speaker: Chris Ruiz (TRIUMF)
      • 11:43
        TITAN Ion Trap Program at ISAC (20+5) 25m
        Slides
    • 12:30 17:00
      CAP Advisory Council (Old and New) / Conseil consultatif de l'ACP (ancien et nouveau) CCIS L1-029

      CCIS L1-029

      University of Alberta

    • 12:50 14:26
      CINP Town Hall (Sun) / Consultation publique du ICPN: NUCLEAR STRUCTURE & ASTROPHYSICS II
      Convener: Charles Gale
      slides
      • 12:50
        Canadian Penning Trap & Related Ion-Trap Expts @ ANL (15+3) 18m
      • 13:08
        Reaction spectroscopy of rare isotopes with low and high-energy beams (15+3) 18m
        Speaker: Rituparna Kanungo (TRIUMF)
      • 13:26
        Electroweak measurements of nuclear neutron densities via PREX and CREX at JLab (15+3) 18m
        Speaker: Juliette Mammei (University of Manitoba)
      • 13:44
        Ab initio nuclear theory for structure and reactions (20+5) 25m
        Speaker: Francesco Raimondi
        Slides
      • 14:09
        From nuclear forces to structure and astrophysics (10+2) 12m
        Speaker: Alexandros Gezerlis
    • 15:20 16:44
      CINP Town Hall (Sun) / Consultation publique du ICPN: FUNDAMENTAL SYMMETRIES II
      Convener: Iris Dillmann
      slides
      • 15:20
        TRIUMF's Neutral Atom Trap for Beta Decay (15+3) 18m
        Slides
      • 15:38
        Francium Trap Project (15+3) 18m
      • 15:55
        Neutrinoless Double Beta Decay (25+5) 25m
        Speaker: David Sinclair
        Slides
      • 16:21
        Electroweak Physics (15+3) 20m
        Slides
    • 17:04 17:41
      CINP Town Hall (Sun) / Consultation publique du ICPN: New Facilities
      Convener: Juliette Mammei
      slides
      • 17:04
        Science Opportunities of ARIEL (20+5) 25m
      • 17:29
        Resources for Detector Development in the Canadian Subatomic Physics Community (10+2) 12m
    • 19:30 21:30
      CINP Board Meeting / Réunion du conseil de l'ICPN CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Prof. Garth Huber (University of Regina)
    • 19:30 21:30
      IPP Inst. Members and Board of Trustees Meetings / Réunions des membres inst. et du conseil de l'IPP NINT Taylor Room

      NINT Taylor Room

      University of Alberta

      Convener: Michael Roney (University of Victoria)
    • 08:30 10:45
      Joint CINP-IPP Meeting / Réunion conjointe de l'ICPN et de l'IPP (DPN-PPD) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Conveners: Prof. Garth Huber (University of Regina), Michael Roney (University of Victoria)
      • 08:30
        Report from NSERC SAP ES 35m
        Speaker: John Martin (York University (CA))
        Slides
      • 09:05
        Canada Foundation for Innovation and Subatomic Physics 20m
        Speaker: Olivier Gagnon (Fondation canadienne pour l'innovation)
        Slides
      • 09:25
        Report from TRIUMF Director 35m
        Speaker: Jonathan Bagger (Johns Hopkins University)
        Slides
      • 10:00
        Report from SNOLAB Director 25m
        Speaker: Nigel Smith (SNOLab)
        Slides
      • 10:25
        Report from Subatomic Physics Long Range Plan Committee Chair 20m
        Speaker: Dean Karlen (University of Victoria (CA))
        Slides
    • 09:30 11:00
      PiC Editorial Board Meeting / Réunion du Comité de rédaction de La Physique au Canada CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Bela Joos (University of Ottawa)
    • 10:45 11:00
      IPP / CINP Health Break / Pause santé IPP / ICPN CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • 11:00 12:00
      CINP Annual General Meeting / Assemblée générale annuelle de l'ICPN CCIS L1-029

      CCIS L1-029

      University of Alberta

      Convener: Prof. Garth Huber (University of Regina)
      slides
    • 11:00 12:45
      IPP Town Hall - AGM / Consultation publique et AGA de l'IPP CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Michael Roney (University of Victoria)
      • 11:00
        Status and future plan of KEK and J-PARC 35m
        Speaker: Yasuhiro Okada (KEK)
        Slides
      • 11:35
        T2K+HyperK 30m
        Speaker: Hirohisa A. Tanaka (University of British Columbia)
        Slides
      • 12:05
        ILC 20m
        Speaker: Alain Bellerive (Carleton University (CA))
        Slides
      • 12:25
        Long Range Plan: Next Steps for IPP 20m
        Speaker: Michael Roney (University of Victoria)
        Slides
    • 12:00 13:00
      Lunch / Diner
    • 13:00 13:45
      M-PLEN Plenary Session - Start of Conference - Sara Seager, MIT / Session plénière - Ouverture du Congrès - Sara Seager, MIT CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
    • 13:45 15:15
      M1-1 Topological States of Matter (DCMMP) / États topologiques de la matière (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Kaori Tanaka (University of Saskatchewan)
      • 13:45
        Nematic and non-Fermi liquid phases of systems with quadratic band crossing 30m
        I will review the recent work on the phases and quantum phase transitions in the electronic systems that feature the parabolic band touching at the Fermi level, the celebrated and well-studied example of which is the bilayer graphene. In particular, it will be argued that such three-dimensional systems are in principle unstable towards the spontaneous formation of the (topological) Mott insulator at weak long-range Coulomb interaction. The mechanism of the instability can be understood as the collision of non-Fermi liquid fixed point, discovered by Abrikosov in the `70s, with another, critical, fixed point, which approaches it in the coupling space as the system's dimensionality reaches certain ``critical dimension" from above. Some universal characteristics of this scenario, the width of the non-Fermi liquid crossover regime, and the observability of the nematic Mott phase in common gapless semiconductors such as gray tin or mercury tellurude will be discussed.
        Speaker: Prof. Igor Herbut (Simon Fraser University)
        Slides
      • 14:15
        Collective modes and interacting Majorana fermions in topological superfluids 30m
        Topological phases of matter are characterized by the absence of low-energy bulk excitations and the presence of robust gapless surface states. A prime example is the three-dimensional (3D) topological band insulator, which exhibits a bulk insulating gap but supports gapless 2D Dirac fermions on its surface. This physics is ultimately a consequence of spin-orbit coupling, a single-particle effect within the reach of the band theory of solids. The phenomenology of topological superfluids (and superconductors, which are charged superfluids) is rather similar, with a bulk pairing gap and gapless 2D surface Majorana fermions. The standard theory of topological superfluids exploits this analogy and can be thought of as a band theory of Bogoliubov quasiparticles. In particular, this theory predicts that Majorana fermions should be noninteracting particles. Band insulators and superfluids are, however, fundamentally different: While the former exist in the absence of interparticle interactions, the latter are broken-symmetry states that owe their very existence to such interactions. In particular, unlike the static energy gap of a band insulator, the gap in a superfluid is due to a dynamical order parameter that is subject to both thermal and quantum fluctuations. In this talk, I will argue that order parameter fluctuations in a topological superfluid can induce effective interactions among surface Majorana fermions. Possible consequences of these interactions will be discussed.
        Speaker: Joseph Maciejko (University of Alberta)
        Slides
      • 14:45
        Dilute limit of an interacting spin-orbit coupled two-dimensional electron gas 15m
        The combination of many-body interactions and Rashba spin-orbit coupling in a two-dimensional fermion system gives rise to an exotic array of phases in the ground state. In previous analyses, it has been found that in the low fermion density limit, these are nematic, ferromagnetic nematic, and spin-density wave phases. At ultra-low densities, the ground state favours the ferromagnetic nematic phase if the interactions are short range (contact), and the nematic phase if the interactions are long range (dipolar). In this talk, we examine interacting two-fermion systems with spin-orbit coupling. These systems retain the physics of the dilute limit of the many-body system, while allowing us to solve the ground state exactly for each type of interaction. We determine the symmetries of the ground state, which uniquely determine the phase of the system. These phases could potentially be observed in two-dimensional GaAs heterostructures with quantum wells that lack inversion symmetry.
        Speaker: Mr Joel Hutchinson (University of Alberta)
        Slides
      • 15:00
        Andreev and Josephson transport in InAs nanowire-based quantum dots 15m
        Superconducting proximity effects are of fundamental interest and underlie recent proposals for experimental realization of topological states. Here we study superconductor-quantum dot- superconductor (S-QD-S) junctions formed by contacting short- channel InAs nanowire transistors with Nb leads. When the carrier density is low, one or more quantum dots form in the nanowire due to spatial potential fluctuations. Low-temperature electrical transport shows clear signatures of proximity superconductivity, such as regions of negative differential conductance, Multiple Andreev Reflections (MAR) and spectroscopic features hinting at the formation of Andreev Bound States (ABS). These features can coexist with the Coulomb diamond structure resulting from the dot charging energy. The theory of Andreev and Josephson transport in S-QD-S structures is invoked in order to elucidate the experimental data. Particular attention is devoted to an intermediate coupling regime, wherein the superconducting energy gap $\Delta$ is on the same order of magnitude as the tunnel coupling strength $\Gamma$, but smaller than the Coulomb charging energy of the dot $U$. In this model, a rich interplay exists between $U$, which favours a spin-doublet ground state for the quantum dot, $\Delta$, which favours a BCS- like singlet ground state, and Kondo correlations in the dot, which favour a Yu-Shiba-Rusinov-like singlet ground state. A quantum phase transition can occur from the doublet to the BCS- like singlet ground state, marking a $0$-$\pi$ transition in the Josephson current of the junction. The significance of these results to the search for topological states in semiconductor nanowire junctions is discussed.
        Speaker: Kaveh Gharavi (University of Waterloo)
        Slides
    • 13:45 15:15
      M1-10 NSERC's Partnership Program: Panel Discussion and Q&A / Programmes de partenariats du CRSNG : Table ronde et Q&R CAB 235

      CAB 235

      University of Alberta

      Convener: Bill Whelan (University of Prince Edward Island)
      • 13:45
        NSERC's Partnership Program: Panel Discussion and Q&A / Programme de partenariats du CRSNG : Table ronde et Q&R 1h 30m
        This session is a panel discussion and Q&A on researcher-industry collaborations and NSERC funding opportunities. Panelists include: Irene Mikawoz (NSERC Prairies Regional Office), Donna Strickland (U. of Waterloo), Wayne Hocking (Western U.), Kristin Poduska (Memorial U.), Chijin Xiao (U. of Saskatchewan) and Andranik Sarkissian (Plasmionique Inc). -- Cette séance consistera en un débat d’experts et en une période de questions sur les collaborations entre les chercheurs et l’industrie et sur les possibilités de financement du CRSNG. Au nombre des experts figurent Irene Mikawoz (Bur. régional des Prairies du CRSNG), Donna Strickland (U. de Waterloo), Wayne Hocking (U. Western), Kristin Poduska (U. Memorial), Chijin Xiao (U. de Saskatchewan) et Andranik Sarkissian (Plasmionique Inc).
    • 13:45 15:15
      M1-2 Organic and Molecular Electronics (DCMMP-DMBP-DSS) / Électronique organique et moléculaire (DPMCM-DPMB-DSS) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Doug Bonn (Univ. of British Columbia)
      • 13:45
        Principles and methods enabling atom scale electronic circuitry 30m
        Quantum dots are small entities, typically consisting of just a few thousands atoms, that in some ways act like a single atom. The constituent atoms in a dot coalesce their electronic properties to exhibit fairly simple and potentially very useful properties. It turns out that collectives of dots exhibit joint electronic properties of yet more interest. Unfortunately, though extremely small, the still considerable size of typical quantum dots puts a limit on how close multiple dots can be placed, and that in turn limits how strong the coupling between dots can be. Because inter-dot coupling is weak, properties of interest are only manifest at very low temperatures (milliKelvin). In this work the ultimate small quantum dot is described – we replace an “artificial atom” with a true atom - with great benefit. It is demonstrated that the zero-dimensional character of the silicon atom dangling bond (DB) state allows controlled formation and occupation of a new form of quantum dot assemblies - at room temperature. It is shown that fabrication geometry determines net electron occupation and tunnel-coupling strength within multi-DB ensembles and moreover that electrostatic separation of degenerate states allows controlled electron occupation within an ensemble. Single electron, single DB transport dynamics will be described as will conduction among collectives of DBs. Some results and speculation on the viability of a new “atomic electronics” based upon these results will be offered. As new technologies require new fabrication and analytical tools, a few words about robust, readily repairable, single atom tips will be offered too. This tip may be an ideal scanned probe fabrication tool.
        Speaker: Robert Wolkow (University of Alberta)
      • 14:15
        Polarization induced energy level shifts at organic semiconductor interfaces probed on the molecular scale by scanning tunnelling microscopy 30m
        The inter- and intra- molecular energy transfer that underlies transport, charge separation for photovoltaics, and catalysis are influenced by both the spatial distribution of electronic states and their energy level alignment at interfaces. In organic materials, the relevant length scales are often on the order of a single molecular unit. Scanning tunneling microscopy (STM) and spectroscopy (STS) stands as one of few techniques with the ability to resolve both the spatial structure of these interfaces while probing energy levels on the nanometer scale. Here, we have used STM/STS in a spectroscopic mapping mode to investigate the spatial shifts in energy levels across well-defined 2-dimensional nanoscale clusters of 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) decoupled from an Ag(111) substrate by a bilayer of NaCl. We find a striking difference between the HOMO and LUMO states of molecules residing at the edges of these clusters and those in the centre. Edge molecules exhibit a gap that is up to 0.5eV larger than observed for inner molecules. Most of this difference is accounted for by the shift of the occupied states, strongly influencing level alignment for a boundary region of single molecular width. As STS is a single-particle spectroscopy – adding or removing a charge – the energy levels measured are influenced by the local polarization environment. The shifts observed for several different geometries of islands correspond well with calculations of the stabilization of this transient charge via the polarization of the other molecules in the cluster. These effects are expected to influence organic semiconductors that exhibit hopping-like transport, and processes such as charge separation occurring at interfaces in organic photovoltaic devices. As the polarizability of most molecular semiconductors is anisotropic, the structure and orientation of molecules at interfaces will play a significant role in the resulting energy level alignment.
        Speaker: Sarah Burke (University of British Columbia)
      • 14:45
        On the Road to Low Power Circuitry: Analysis of Si Dangling Bond Charging Dynamics 15m
        Undesired circuit heating results from the billions of electrons flowing through our devices every second. Heating wastes energy (leading to shorter battery life), and also puts a limit on computational speeds. The solution to excess heat generation is of huge commercial interest and has led to a large push towards nanoscale electronics which are smaller and more energy efficient. Proposed hybrid atom-scale schemes have already been formed to reduce power consumption of Complementary Metal Oxide Semiconductor (CMOS) chips commonly used in many consumer electronics including digital cameras and computers. At the heart of these schemes are atomic silicon dangling bonds (DBs) which can theoretically be used to form ultra-low power nanowires. In order to move towards the realization of these practical schemes, however, fundamental physical properties of DBs must first be characterized and studied. One of the properties inherent to DBs is their ability to store electrons. They can exist in a positive, neutral, or negative charge state when storing zero, one, or two electrons respectively. When imaging a DB with a scanning tunneling microscope (STM), fluctuations of the DB charge state can be observed that are driven by influence of the STM tip. A correlation analysis method adapted from biophysics was utilized to study these fluctuations in charge state to help uncover intrinsic transition rates between states for a given DB. Analysis such as this also opens the doors to study more complex systems of interacting DBs as well, which is another important step towards making practical devices.
        Speaker: Roshan Achal (University of Alberta)
      • 15:00
        Set Point Effects in Fourier Transform Scanning Tunneling Spectroscopy 15m
        Fourier Transform Scanning Tunneling Spectroscopy (FT-STS) has become an important experimental tool for the study of electronic structure. By combining the local real space picture of the electronic density of states provided by scanning tunneling microscopy with the energy and momentum resolution of FT-STS one can extract information about the band structure and dispersion. This has been thoroughly demonstrated in studies of the superconducting cuprates, the iron arsenides, and heavy fermion compounds. FT-STS relies on the Fourier transform of the dI/dV, the derivative of the tunneling current with respect to the applied bias. Under the approximations of zero temperature, a flat tip density of states, and an energy independent tunneling matrix element it can be shown that the dI/dV signal is proportional to the local density of states of the sample. Under real experimental conditions, however, these approximations are not strictly valid, leading to additional functional dependencies of the dI/dV. A variety of artifacts can result when one considers the three most common measurement modes: constant current maps, constant height maps, and spectroscopic grids. We illustrate the different artifacts that can appear in FT-STS using data taken from the well understood surface state of an Ag(111) single crystal at 4.2 K and under ultra-high vacuum conditions. We find that constant current dI/dV maps taken with a lock-in amplifier lead to a feature in the FT-STS dispersion that disperses as a function of energy below the Fermi level (E$_F$) and becomes constant above E$_F$. This result shows the importance of distinguishing dispersing features caused by quasiparticles in the sample from those caused by the measurement. We compare the set point artifacts in all three modes of measurement to scattering model simulations based on the T-matrix formalism. Finally we propose a guide to help identify and isolate these set point artifacts for future studies in systems where the band structure and correlations create a complex scattering space.
        Speaker: Mr Andrew Macdonald (University of British Columbia)
    • 13:45 15:15
      M1-3 Theory, modelling and space weather I (DASP) / Théorie, modélisation et climat spatial I (DPAE) CAB 243

      CAB 243

      University of Alberta

      Convener: David Knudsen (University of Calgary)
      • 13:45
        Examples of exact solutions of charged particle motion in magnetic fields and their applications. 30m
        There are very few exact solutions for the motion of a charged particle in specified magnetic field. These solutions have considerable theoretical as well as pedagogical value. In this talk I will briefly describe several known analytical solutions, such as motion in the equatorial plane of a dipole and in a constant gradient field. Particular attention will be given to a relatively unknown solution corresponding to magnetic field inversely proportional to the radius. This case leads to relatively simple expressions involving only elementary functions. I will discuss applications of this solution to validation of numerical methods of particle tracing, such as symplectic integration. Another interesting use of this solution is comparison with the adiabatic drift theory. Finally, this solution can be used as a building block for developing new numerical integration schemes for particle tracing.
        Speaker: Konstantin Kabin (RMC)
      • 14:15
        Energetic Electron Precipitation Model 15m
        Energetic electron precipitations cause atmospheric ionization - a complicated process which depends on many parameters. We present our energetic particles precipitation model which consists of three main parts: Energetic electron sources; Coupled electron/photon transport in the earth atmosphere; RIOMETERs and Very Low Frequency (VLF) receivers response to energetic electron precipitations. The primary source of energetic electrons - Van-Allen radiation belts - occupy a vast region of space and accumulate an immense amount of energy. In the Northern hemisphere they map to a broad ring crossing Canada. Under certain conditions trapped electrons can penetrate even deeper into the atmosphere causing modulations of free electron densities of D-Layer. The model implements coupled electron/photon transport based on MCNP 6 general transport code. Model verification uses data from the Medium Energy Proton and Electron Detector instrument on NOAA's POES satellite. Calculated electron fluxes and estimated electron density altitudinal profiles are used to construct and validate a realistic transport model that maps energetic electron fluxes incident on the upper atmosphere to GO CANADA (RIOMETERs and VLF receivers) instrument responses.
        Speaker: Alexei Kouznetsov (University of Calgary)
        Slides
      • 14:30
        Properties of the lunar wake inferred from hybrid-kinetic simulations and an analytic model 15m
        There is renewed interest in the Moon as a potential base for scientific experiments and space exploration. Earth's nearest neighbour is exposed directly to the solar wind and solar radiation, both of which present hazards to successful operations on the lunar surface. In this paper we present lunar wake simulation and analytic results and discuss them in the context of observations from the ARTEMIS mission. The simulation results are based on hybrid-kinetic simulations while the analytic model is based on the formalism developed by [Hutchinson, 2008]. The latter makes assumptions of cylindrical geometry, a strong and constant magnetic field, and fixed transverse velocity and temperature. Under these approximations the ion fluid equations (with massless electrons) can be solved analytically by the method of characteristics. In this paper the formalism presented by Hutchinson is applied by including plasma density variations and flow within the lunar wake. The approach is valid for arbitrary angles between the interplanetary magnetic field and solar wind velocity, and accounts for plasma entering the wake region from two tangent points around the Moon. Under this condition, two angle-dependent equations for ion fluid flow are obtained, which can be solved using the method of characteristics to provide the density inside the wake region. it is shown in Fig1 and Fig2 that the model provides excellent agreement with observations from the ARTEMIS mission [Angelopoulos, 2011], and with large-scale hybrid-kinetic plasma simulations [Paral and Rankin, 2012]. It will be shown that the analytic model provides a practical alternative to large-scale kinetic simulations, and that it is generally useful for determining properties of the lunar wake under different solar wind conditions. It will be useful as well for predicting properties of the plasma environment around the Moon that have not yet been visited by spacecraft. Acknowledgments. This work was partially supported by grants from the Canadian Space Agency and the Natural Sciences and Engineering Research Council of Canada (NSERC). The simulations also benefited from access to the Westgrid Compute Canada facilities. The ARTEMIS data for this paper are available at NASA’s Space Physics Data Facility (SPDF) (http://spdf.gsfc.nasa.gov/). Hossna Gharaee extends thank to THEMIS software manager Jim Lewis for his help on using ARTEMIS satellite data. -Hutchinson, I. (2008),Oblique ion collection in the drift approximation:How magnetized Mach probes really work, Physics Of Plasmas, 15, 123503, doi: 10.1063/1.3028314 -Angelopoulos, V. (2011), The ARTEMIS mission, Space Sci. Rev. (Netherlands), 165(1-4), 3–25. -Paral and Rankin (2012),Dawn-dusk asymmetry in the Kelvin-Helmholtz instability at Mercurry, Nature Communications, 4, 1645, doi:10.1038/ncomms2676,
        Speaker: Hossna Gharaee (university of Alberta, Departement of Physics)
      • 14:45
        Explaining the Newly Discovered Third Radiation Belt 15m
        Accurate specification of the global distribution of ultra-low frequency (ULF) wave power in space is critical for determining the dynamics and acceleration of outer radiation belt electrons. Current radiation belt models use ULF wave radial diffusion coefficients which are analytic functions of Kp based on ULF wave statistics. In this presentation we show that these statistical based analytic models for the radial diffusion coefficients can produce electron flux values in surprising agreement with the observations during geomagnetically quiet intervals. However, during some storm intervals the radial diffusion rates derived directly from ULF wave observations can become orders of magnitude higher than those given by the analytic expressions based on ULF wave statistics. During these storm intervals only the radiation belt models driven by the radial diffusion coefficients derived directly from ULF wave measurements produce electron flux values in agreement with the observations. Utilizing Van Allen Probe data and CARISMA magnetometer data results will be presented of the electron flux obtained using the diffusion coefficients derived directly from the ULF wave measurements which shed new light on some interesting observations made by the Van Allen Probes
        Speaker: Dr Louis Ozeke (University of Alberta)
      • 15:00
        Fast damping of Alfven waves: Observations and modeling 15m
        Results of analysis of Cluster spacecraft data will be presented that show that intense ultra-low frequency (ULF) waves in the inner magnetosphere can be excited by the impact of interplanetary shocks and solar wind dynamic pressure variations. The observations reveal that such waves can be damped away rapidly in a few tens of minutes. We examine mechanisms of ULF wave damping for two interplanetary shocks observed by Cluster on 7 November 2004, and 30 August 2001. The mechanisms considered are ionospheric joule heating, Landau damping, and waveguide energy propagation. It is shown that Landau damping provides the dominant ULF wave damping for the shock events of interest. It is further demonstrated that damping is caused by drift-bounce resonance with ions in the energy range of a few keV. Landau damping is shown to be more effective in the plasmasphere boundary layer due to the relatively higher proportion of Landau resonant ions that exist in that region. Moreover, multiple energy dispersion signatures of ions were found in the parallel and anti-parallel direction to the magnetic field immediately after the interplanetary shock impact in the November 2004 event. These dispersion signatures can be explained by flux modulations of local ions (rather than the ions from the Earth’s ionosphere) by ULF waves. Test particle simulations will be used to simulate the energy dispersions of particles caused by ULF waves. In our study, particles will be traced backward in time until they reach a region with known distribution function. Liouville’s theorem is then used to reconstruct the distribution function at the location of Cluster in a model magnetosphere.
        Speaker: Chengrui Wang (University of Alberta)
        Slides
    • 13:45 15:15
      M1-4 Theoretical Astrophysics (DTP) / Astrophysique théorique (DPT) CAB 239

      CAB 239

      University of Alberta

      Convener: Arundhati Dasgupta (University of Lethbridge)
      • 13:45
        Probing Physics with Observations of Neutron Stars and White Dwarfs 30m
        White dwarfs and neutron stars are two of the densest objects in the Universe. Discovered 105 and 45 years ago, these objects are two of the best astrophysical laboratories of fundamental physics. The simple existence of white dwarfs is a stellar-size manifestation of quantum physics. I will describe how we use these objects today to study quantum-chromodynamics, quantum-electrodynamics, neutrino and axion physics and even thermodynamics in realms inaccessible to Earth-bound laboratories. In the process we also discover the detailed fate of our own Earth and Sun.
        Speaker: Jeremy Heyl (UBC)
        Slides
      • 14:15
        Observations and Theory of Supernova Explosions and their Remnants 30m
        A supernova explosion occurs to end the life of a massive star (with mass of more than 8-10 times that of the sun). These explosions create and eject the elements that make up everything around us, including the earth. The life of a massive star will be outlined, and its sudden death in a supernova event. Following the explosion, the ejected material and energy interacts with the surrounding interstellar medium to produce a supernova remnant. Supernova remnants provide mass and kinetic energy to the interstellar medium, and accelerating most of the cosmic rays we observe. The observational aspects of supernova remnant will be reviewed and related to theoretical models.
        Speaker: Denis Leahy
        Slides
      • 14:45
        No "End of Greatness": Superlarge Structures and the Dawn of Brane Astronomy 15m
        Several groups have recently reported observation of large scale structures which exceed the size limits expected from standard structure formation in a 13.8 billion years old LambdaCDM universe. On the other hand, the concept of crosstalk between overlapping 3-branes carrying gauge theories was recently introduced in arXiv:1502.03754[hep-th]. Crosstalk impacts the redshift of signals from brane overlap regions by making signals with the redshift z of the overlap region appear to have lower or higher redshift, depending on the electromagnetic crosstalk couplings. This leads to brane induced appearance of structure in redshift observations. The Lyman-alpha forest is a natural candidate to look for brane overlap at redshift z<6.
        Speaker: Dr Rainer Dick (University of Saskatchewan)
        Slides
    • 13:45 15:15
      M1-5 Nuclear Techniques in Medicine and Safety (DNP-DIAP) / Techniques nucléaires en médecine et en sécurité (DPN-DPIA) CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Zisis Papandreou (University of Regina)
      • 13:45
        Evaluation of SiPM Arrays and Use for Radioactivity Detection and Monitoring 30m
        Silicon photomultipliers (SiPMs) are novel photo sensorss that are needed for many applications in a broad range of fields. The advantages of such detectors are that they feature low bias ($<$100V) operation, high gain (10$^5$ to 10$^6$), insensitivity to magnetic fields, excellent photon detection efficiency (PDE), and the ability to operate in field conditions over a range of temperatures; they are compact, easy to use, require simple electronics and can be produced commercially in various formats. To evaluate and operate SiPM Arrays, we developed novel techniques of measurement of the PDE, the cross-talk probability and the breakdown voltage for the SiPM-arrays with summed output, which is most popular type of SiPMs on the market; these techniques allow one to make the required measurements when the separation of individual photopeaks in the output spectrum (that was crucial for the "conventional" techniques used before) is not available. I will also present our study of prototypes of gross counting gamma and neutron detectors for first responders that use SiPMs coupled to appropriate scintillators.
        Speaker: Andrei Semenov
        Slides
      • 14:15
        Neutron Generator Facility at SFU - GEANT4 Dose Prediction and Verification 15m
        A neutron generator facility under development at Simon Fraser University (SFU) utilizes a commercial deuterium- tritium neutron generator (Thermo Scientific P 385) to produce 14.2 MeV neutrons at a nominal rate of $3\times10^8$ neutrons/s. The facility will be used to produce radioisotopes to support a research program including nuclear structure studies and neutron activation analysis. As a prerequisite for regular operation of the facility and as a personnel safety consideration, dose rate predictions for the facility were implemented via the GEANT4 Monte-Carlo framework. Dose rate predictions were compared at two low neutron energy cutoffs: 5 keV and 1 meV, with the latter accounting for low energy thermal neutrons but requiring significantly more computation time. As the SFU facility geometry contains various openings through which thermal neutrons may penetrate, it was necessary to study their contribution to the overall dose rate. A radiation survey of the facility was performed as part of the commissioning process, consisting of a neutron flux measurement via copper foil activation and dose rate measurements throughout the facility via a $^3$He gas filled neutron detector (Thermo Scientific WENDI-2). When using the 1 meV low neutron energy cutoff to account for thermal neutrons in the dose rate predictions, the predictions and survey measurements agree to within a factor of 2 or better in most survey locations.
        Speaker: Mr Jonathan Williams (Simon Fraser University)
      • 14:30
        Rapid Elemental Analysis of Human Finger Nails Using Laser-Induced Breakdown Spectroscopy 15m
        Zinc is a crucial element needed for many processes in the human body. It is essential for enzymatic activity and many cellular processes, such as cell division. A zinc deficiency can lead to problems with the immune system, birth defects, and blindness. This problem is especially important to address in developing countries where nutrition is limited. Supplements can be taken to increase the zinc intake, however it is difficult to determine who is zinc deficient and requires these supplements. The gold standard tests for determining the zinc concentration in the human body are both expensive and time-consuming. Zinc in human fingernails can be shown to represent the overall zinc concentration in the body. Laser-induced breakdown spectroscopy (LIBS) provides a quick analysis of the zinc concentration in a human fingernail with minimal sample preparation, thus LIBS could serve as a real-time biomedical assay for zinc deficiency. LIBS was performed on a collection of healthy human finger nails in an argon environment. The intensities of the zinc ion lines observed in the plasma were proportional to the zinc concentrations of each nail as measured by SIDMS. The variance of the measured zinc intensities between fingers of a given hand and between left and right hands for a single person was studied. Normalization of the zinc lines to other emission lines in the spectrum to reduce shot to shot variation was investigated. Studies were also performed to determine the spatial distribution of zinc within the nail. The influence of nail preparation prior to LIBS testing is an ongoing area of study.
        Speaker: Ms Vlora Riberdy (University of Windsor)
        Slides
      • 14:45
        The 2018 Shutdown of the NRU Reactor 30m
        The federal government recently announced its decision to shut down the NRU reactor in 2018. The National Research Universal (NRU) reactor commenced operation in 1957, to provide neutrons for several missions simultaneously, including the production of neutron beams to support fundamental experimental research on solids and liquids, advancing knowledge of condensed matter physics. Today, the Canadian Neutron Beam Centre manages six thermal neutron beam lines at the NRU reactor, and sustains a team of scientific and technical experts who enable collaborative research projects to be performed effectively by students and scientists from over 30 Canadian universities, as well as over 100 foreign institutions from about 20 countries. The Canadian Institute for Neutron Scattering has organized a meeting for Canada’s physics community to consider whether and how the imminent loss of this unique Canadian resource should be addressed. This presentation will provide historical context and details of the current situation, as background for an informed conversation about options and actions over the next few years.
        Speaker: Dr John Root (Canadian Neutron Beam Centre)
    • 13:45 15:15
      M1-6 Neutrinoless Double-beta Decay I (PPD-DNP) / Double désintégration beta sans neutrino I (PPD-DPN) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Rudiger Picker (TRIUMF)
      • 13:45
        Neutrino in the Standard Model and beyond 30m
        The Standard Model teaches us that in the framework of such general principles as local gauge symmetry, unication of weak and electromag- netic interactions and Brout-Englert-Higgs spontaneous breaking of the elec- troweak symmetry nature chooses the simplest possibilities. Two-component left-handed massless neutrino elds play crucial role in the determination of the charged current structure of the Standard Model. The absence of the right-handed neutrino elds in the Standard Model is the simplest, most economical possibility. In such a scenario Majorana mass term is the only possibility for neutrinos to be massive and mixed. Such mass term is gener- ated by the lepton-number violating Weinberg eective Lagrangian. In this approach three Majorana neutrino masses are suppressed with respect to the masses of other fundamental fermions by the ratio of the electroweak scale and a scale of a lepton-number violating physics. The discovery of the neu- trinoless double -decay and absence of transitions of avor neutrinos into sterile states would be evidence in favor of the minimal scenario we advocate here. 1
        Speaker: Prof. Samoil Bilenky (JINR (Dubna))
      • 14:15
        Status of the SNO+ Experiment 30m
        The SNO+ experiment, at the SNOLAB underground laboratory, consists of 780 Mg of linear alkylbenzene scintillator contained in the 12 m diameter SNO acrylic sphere and and observed by the SNO photomultiplier tubes. SNO+ will be loaded with tellurium, at approximately the 0.3% level to enable a sensitive search for neutrinoless double beta decay. This talk will detail the experiment, the sensitivity and the status of the detector.
        Speaker: Prof. Aksel Hallin (University of Alberta)
        Slides
      • 14:45
        Extraction of optical parameters in SNO+ with an in-situ optical calibration system 15m
        SNO+ is a multi-purpose neutrino physics experiment investigating neutrinoless double beta decay and neutrino oscillations. The SNO+ detector consists of a 12m diameter acrylic vessel (AV), surrounded by ultra-pure water and approximately 9500 photomultiplier tubes (PMTs) which are positioned on a stainless steel PMT support structure (PSUP). The acrylic vessel will be filled with liquid scintillator. An in-situ optical calibration system based on LEDs and laser sources has been deployed. These optical sources feed light into the detector via optical fibres mounted on the PSUP, resulting in various beams of light. A collimated source will be used to measure the scattering in the liquid scintillator. Data have been taken while the AV was empty to understand the optical properties of the detector. We have analyzed the data to establish properties of the calibration system and to quantify the surface parameters, reflectivity and surface roughness responsible for scattering, as well as various parameters of the optical calibration system. These parameters will be a valuable input to the position and energy reconstruction algorithms, as well as the simulation, of SNO+.
        Speaker: Dr Kalpana Singh Singh (Department of Physics, University of Alberta)
        Slides
      • 15:00
        Double-beta decay half-life of 96Zr – nuclear physics meets geochemistry 15m
        Double-beta (\beta\beta) decay measurements are a class of nuclear studies with the objective of detecting the neutrinoless (0\nu) decay variants. Detection of a 0\nu\beta\beta decay would prove the neutrino to be massive and to be its own anti-particle (i.e., a Majorana particle). A key parameter in the detection of the 0\nu\beta\beta decay is the energy, or Q-value, of the decay. ^{96}Zr is of particular interest as a double-beta decay candidate. A geochemical measurement of its \beta\beta decay half-life by measuring an isotopic anomaly of the ^{96}Mo daughter in ancient zircon samples yielded a value of 0.94(32)x10^{19} yr [1]. More recently, the NEMO collaboration measured the half-life directly to be 2.4(3)x10^{19} yr [2], twice as long as the geochemical measurement. As the geochemical result could be contaminated by a sequence of two single \beta-decays, the first being a 4-fold unique forbidden \beta-decay of ^{96}Zr to the 44 keV J^{\pi}=5^+ excited state in ^{96}Nb, followed by the 23 h \beta-decay of ^{96}Nb to ^{96}Mo, further study is mandated. Depending on the Q-value for the first decay, the estimated half-life could be of the same order as the one for the \beta\beta-decay [3]. However, the key parameter is the Q-value for the single \beta-decay, which enters in leading order as Q^{13} into the phase-space factor of the decay. Such a study is being carried out at the TRIUMF TITAN experiment and at the University of Calgary Isotope Science Lab. At TITAN we are measuring the Q-values for the ^{96}Zr to ^{96}Mo \beta\beta-decay and for the ^{96}Zr to ^{96}Nb single \beta-decay, with the goal of reaching a precision near 0.1 keV. At the UCalgary ISL, we are repeating the measurement of the ^{96}Mo isotopic anomaly using modern equipment and techniques. Combined, these measurements will remove a long-standing discrepancy of the two independent ^{96}Zr \beta\beta-decay half-life measurements. [1] M. E. Wieser and J. R. De Laeter, Phys. Rev. C 64, 024308 (2001). [2] NEMO-3 Collaboration, Nucl. Phys. A 847, 168-179 (2010). [3] J. Suhonen, Univ. Jyväskylä, private communication.
        Speaker: Adam Mayer (University of Calgary)
        Slides
    • 13:45 15:15
      M1-7 Advances in Nuclear Physics and Particle Physics Theory (DNP-PPD-DTP) / Progrès en physique nucléaire et en physique des particules théoriques (DPN-PPD-DPT) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Pierre Ouimet (University of Regina)
      • 13:45
        Ab initio calculations of nuclear structure and reactions 30m
        The description of nuclei starting from the constituent nucleons and the realistic interactions among them has been a long-standing goal in nuclear physics. In recent years, a significant progress has been made in developing ab initio many-body approaches capable of describing both bound and scattering states in light and medium mass nuclei based on input from QCD employing Hamiltonians constructed within chiral effective field theory. We will discuss recent breakthroughs that allow for ab initio calculations for ground states, spectroscopy and reactions of nuclei and even hypernuclei throughout the p- and sd-shell and beyond with two- and three-nucleon interactions. We will also present results for nuclear reactions important for astrophysics, such as 7Be(p,γ)8B and 3He(α,γ)7Be radiative capture, and for 3H(d,n)4He fusion.
        Speaker: Petr Navratil (TRIUMF)
        Slides
      • 14:15
        New horizons for MCAS: heavier masses and alpha-particle scattering. 15m
        The Multi-Channel Algebraic-Scattering (MCAS) method, developed in 2003 for the analysis of low-energy nuclear spectra and of resonant scattering, continues to be effectively used for nuclear-structure studies. The MCAS approach allows the construction of the nucleon-core 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. This presentation deals with 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. New results will be shown for n+18O and p+18O, n+22Ne, and α scattering on targets from mass A=3 to A=16, the last of these yielding structure information for 20Ne.
        Speaker: Dr Juris P. Svenne (University of Manitoba, Dept. of Physics and Astronomy)
        Slides
      • 14:30
        The coefficient of restitution of inflatable balls 15m
        The bouncing of sports balls is often characterized in terms of the coefficient of restitution, which represents the ratio of the after-impact velocity to the before-impact velocity. While the behaviour of the coefficient of restitution as a function of the internal pressure of the ball has been studied, no theoretical justification has been given for any parametric curve fitted to the data. In this talk, we present a mechanistic model of the ball, leading to a simple two-parameter fit. The model will be compared to several commonly available sports balls.
        Speaker: Mr Gaëtan Landry (Dalhousie University)
        Slides
    • 13:45 15:15
      M1-8 Energy frontier: Standard Model and Higgs Boson I (PPD) / Frontière d'énergie: modèle standard et boson de Higgs I (PPD) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Bhubanjyoti Bhattacharya (University of Montreal)
      • 13:45
        Summary of ATLAS Standard Model measurements (including top quark) 30m
        While the LHC is ramping up for it's second run at yet higher centre-of-mass energy, the experimental Collaborations are not only preparing for this run, but also ensuring that the maximum amount of information is extracted from the data taken in 2011 and 2012 at a centre-of-mass energy of 7 and 8 TeV, respectively. Many precision standard model measurements have been carried out, spanning some 14 orders of magnitude in production cross section. Some striking examples of achievements by the ATLAS Collaboration in measurements of production and properties of standard model particles will be presented. Particular focus will be placed on the observation of new processes or novel experimental techniques used to improve the precision of the analyses.
        Speaker: Alison Lister (University of British Columbia (CA))
        Slides
      • 14:15
        Measurement of the Higgs-boson properties with the ATLAS detector at the LHC 30m
        A detailed review on the properties of the Higgs boson, as measured with the ATLAS experiment at the LHC, will be given. The results shown here use approximately 25 fb-1 of pp collision data, collected at 7 TeV and 8 TeV in 2011 and 2012. The measurements of the mass, couplings properties and main quantum numbers will be presented. Prospects for the upcoming Run2, starting in May 2015, will be reviewed.
        Speaker: Manuela Venturi (University of Victoria (CA))
        Slides
      • 14:45
        Measurement of the yy -> WW cross-section and searches for anomalous quartic gauge couplings WWAA at the ATLAS experiment 15m
        Searches for the anomalous quartic gauge coupling of two photons to two W bosons (WWAA) were made at LEP and Tevatron. More recently many searches have been performed by the CMS and ATLAS collaborations at the Large Hadron Collider (LHC). Among the processes sensitive to these couplings are the Wy and yy -> WW production. In hadron colliders, yy -> WW events where the W bosons decay into leptons (electrons, muons or taus that subsequently transform into electrons or muons) have a clean signature. The two charged leptons originate from a vertex devoid of other outgoing particles, because they are produced by an electroweak interaction. Isolating the lepton vertex from other tracks suppresses strong interactions that produce many extra charged particles including higher cross-section processes such as Drell-Yan and top production. In this talk, I will present the measurement of the yy -> WW cross-section and searches for the WWAA anomalous quartic gauge couplings using the data collected by the ATLAS experiment during 2012.
        Speaker: Chav Chhiv Chau (University of Toronto (CA))
        Slides
    • 13:45 15:15
      M1-9 Ultrafast and Time-resolved Processes (DAMOPC) / (DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Chitra Rangan (University of Windsor)
      • 13:45
        Following an Auger Decay by Attosecond Pump-Probe Measurements 30m
        Attosecond Physics is an emerging field at the international level which now provides tabletop attosecond (as=10^-18 s.) light sources extending from the extreme ultraviolet (XUV, 10-100 eV) to X-rays (keV) [1]. This feat opens new avenues in atomic and molecular spectroscopies [2], especially, to perform time-resolved experiments of ultrafast electron dynamics on the unexplored attosecond timescale [3]. I will present the first attosecond pump-probe measurement where an XUV attosecond pulse initiates an Auger decay and where an attosecond broadband optical pulse probes this ultrafast process. Supported by our model, we suggest that the optical probe acts as a gate of the Auger transition, in analogy with the FROG (frequency-resolved optical gating) technique commonly-used for measuring femtosecond laser pulses [4]. We believe this is a universal idea that will prevail in attosecond measurements [5]: I will show how our pump-probe scheme and modeling can reveal few-femtoseconds (atomic) to sub-fs (condensed matter) Auger lifetimes. [1] T. Popmintchev *et al.*, Nature Photonics 4, 822 (2010). [2] J. B. Bertrand *et al.*, Nature Physics 9, 174 (2013). [3] S. R. Leone *et al.*, Nature Photonics 8, 162 (2014). [4] R. Trebino, FROG, Kluwer Academic Publishers, Boston (2002). [5] A. Moulet, J.B. Bertrand *et al.*, Okinawa, Ultrafast Phenomena (2014).
        Speaker: Prof. Julien Beaudoin Bertrand (Université Laval)
      • 14:15
        Ultrafast imaging of nonlinear terahertz pulse transmission in semiconductors 15m
        Terahertz pulse spectroscopy has been widely used for probing the optical properties and ultrafast carrier dynamics of materials in the far-infrared region of the spectrum. Recently, sources of intense terahertz (THz) pulses with peak fields higher than 100 kV/cm have allowed researchers to explore ultrafast nonlinear THz dynamics in materials, such as THz-pulse-induced intervalley scattering in semiconductors. Here, we use a gated intensified CCD camera and full-field electro-optic imaging with femtosecond laser pulses to directly observe dipole electric fields arising from shift currents induced by intense THz pulses in n-doped InGaAs. Voltage pulses generated by the THz-pulse-induced shift currents are also measured directly on a high speed oscilloscope. The polarization of the shift current with respect to that of the THz pump beam is determined. The simultaneous measurement of both the induced dipole and transmitted THz pulse allows for sub-picosecond resolution imaging of nonlinear THz dynamics in semiconductors.
        Speaker: Haille Sharum (University of Alberta)
      • 14:30
        Energy transfer dynamics in blue emitting functionalized silicon nanocrystals 15m
        We use time-resolved photoluminescence (TRPL) spectroscopy to study the effects of surface passivation and nanocrystal (NC) size on the ultrafast PL dynamics of colloidal SiNCs. The SiNCs were passivated by dodecylamine and ammonia, and exhibit blue emission centered at ~473 nm and ~495 nm, respectively. For both functionalizations, increasing the size of the NCs from ~3 nm to ~6 nm did not result in a PL red-shift, but instead show an identical spectral profile. More interestingly, the nanosecond PL decay dynamics are size- and wavelength-independent with a radiative recombination rate on the order of ~108/s, characteristic of PL from charge transfer states associated with silicon oxynitride bond. Based on TRPL and fluence-dependent measurements, we hypothesize that electrons are first photoexcited within the SiNCs and then rapidly transferred to silicon oxynitride bonds at the surface, creating charge transfer states responsible for the nanosecond blue PL.
        Speaker: Glenda De los Reyes (Physics Department, University of Alberta)
      • 14:45
        Molecular SuperRotors: Control and properties of molecules in extreme rotational states 30m
        Extremely fast rotating molecules, known as “super-rotors”, may exhibit a number of unique properties, from rotation-induced nano-scale magnetism to formation of macroscopic gas vortices. Orchestrating molecular spinning in a broad range of angular frequencies is appealing from the perspectives of controlling molecular dynamics. Yet in sharp contrast to an optical excitation of molecular vibration, laser control of molecular rotation is rather challenging. I will report on our recent progress in generating and controlling molecular super-rotors (e.g. oxygen molecules occupying ultrahigh rotational states, J > 120, or carbon dioxide with J>400) with a specially designed intense laser pulses, known as an “optical centrifuge”. I will discuss the results of our study of collisional, optical and magnetic properties of molecular superrotors.
        Speaker: Valery Milner (UBC)
    • 15:15 15:45
      Health Break / Pause santé CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • 15:45 17:15
      CAP-NSERC Liaison Cttee Mtg / Réunion du comité de liaison ACP-CRSNG CCIS 4-285

      CCIS 4-285

      University of Alberta

      Convener: Bill Whelan (University of Prince Edward Island)
    • 15:45 17:15
      M2-1 Computational methods in condensed matter physics (DCMMP) / Méthodes numériques en physique de la matière condensée (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Jesko Sirker (U Manitoba)
      • 15:45
        Extrinsic Spin Hall Effect in Graphene 30m
        The intrinsic spin-orbit coupling in graphene is extremely weak, making it a promising spin conductor for spintronic devices. However, for many applications it is desirable to also be able to generate spin currents.Theoretical predictions and recent experimental results suggest one can engineer the spin Hall effect in graphene by greatly enhancing the spin-orbit coupling in the vicinity of an impurity. The extrinsic spin Hall effect then results from the spin-dependent scattering of carriers by impurities in the presence of spin-orbit interaction. This effect can be used to convert charge currents into spin currents efficiently. I will discuss recent experimental results on spin Hall effect in graphene decorated with adatoms and metallic clusters[1,2] and show that a large spin Hall effect can appear in graphene in the presence of locally enhanced spin-orbit coupling. I will present results from single impurity scattering calculations [3], and also from a real-space implementation of the Kubo formalism [4] for tight-binding Hamiltonians with different forms of spin-orbit coupling. [1] J. Balakrishnan et al., Nat. Phys. 9, 284 (2013). [2] J. Balakrishnan et al., Nat. Commun. 5, 4748 (2014). [3] A. Ferreira, T. G. Rappoport, M. A. Cazalilla, A. H. Castro Neto, Phys. Rev. Lett. 112, 066601 (2014). [4] Jose H. Garcia, Lucian Covaci and Tatiana G. Rappoport, arXiv:1410.8140.
        Speaker: Tatiana Rappoport (Federal University of Rio de Janeiro)
      • 16:15
        Klein Tunnelling in Graphene 15m
        In 1929 Oskar Klein solved the Dirac equation for electrons scattering off of a barrier. He found that the transmission probability increased with potential height unlike the non-relativistic case where it decreases exponentially. This phenomenon can also been in a graphene lattice where the energy bands form a structure known as a Dirac cone around the points where they touch. In this project we analyze phenomenon without substituting the graphene hamiltonian for the Dirac hamiltonian. First we analyse the propagation of gaussian wave packets on the one dimensional lattice, the two dimensional square lattice, and the graphene lattice. Here we look at how the wave packet evolves in time as it propagates. We then study how the packet tunnels through barriers on the graphene lattice, focusing on the region where the Dirac cone is formed We compare this tunnelling to the case of the non-relativistic and the relativistic free particle.
        Speaker: Mr Kameron Palmer (University of Alberta)
      • 16:30
        Extensions of Kinetic Monte Carlo simulations to study thermally activated grain reversal in dual-layer Exchange Coupled Composite recording media. 15m
        Thermal activation processes represent the biggest challenge to maintain data on magnetic recording media, which is composed of uniformly magnetized nano-meter grains. These processes occur over long time scales, years or decades, and result in reversing magnetization of the media grains by rare events. Typically, rare events present a challenge if modelled by conventional micromagnetic techniques as they are limited to time scales on the order of microseconds even with the best computer resources. A convenient approach that can access long time scales and be able to simulate such rare events processes is the Kinetic Monte Carlo method (KMC). The KMC method computes the time between successive grain reversals induced by an external magnetic field based on an Arrhenius-Neel approximation for thermally activated processes. The KMC method has recently been applied to model single-layer media [1], and we have now extended the method to study dual-layer Exchange Coupled Composition (ECC) media used in current generations of disc drives. A complication to using the KMC method for ECC media is governed by the complex reversal process of coupled grains due to the existence of metastable states. The energy barrier separating the metastable states is obtained from the minimum energy path (MEP) using a variant of the nudged elastic band method [2] and the attempt frequency is calculated based on the Langer formalism [3]. To simplify carrying KMC from single layer media to a dual-layer, we have performed a detailed study for only two coupled grains to help us understand and explore the energy landscape of ECC media and be able to handle the complications associated with ECC media [4]. Applications to study characteristic MH hysteresis loops for multi-grained dual-layered systems is made. 1. M. L. Plumer, T. J. Fal, J. I. Mercer, J. P. Whitehead, J. van Ek, and A. Ajan, IEEE Trans. Mag, 50, 3100805 (2014). 2. R. Dittrich, T. Schrefl, D. Suess, W. Scholz, H. Forster and J. Fidler, R. J.M.M.M. 250, L12–L19 (2002). 3. J. S. Langer, Ann. Phys. 54 258, N.Y. (1969). 4. A. M. Almudallal, J. I. Mercer, J. P. Whitehead, M. Plumer, J. van Ek and T. J. Fal (submitted).
        Speaker: Dr Ahmad Almudallal (Memorial University of Newfoundland)
      • 16:45
        The Kronig-Penney model extended to arbitrary potentials via numerical matrix mechanics 15m
        We present a general method using matrix mechanics to calculate the bandstructure for 1D periodic potential arrays, filling in a pedagogical gap between the analytic solutions to the Kronig-Penney model and more complicated methods like tight-binding. By embedding the potential for a unit cell of the array in a region with periodic boundary conditions, we can expand in complex exponential basis states to solve for the matrix elements. We show that Bloch's condition can be added in a potential-independent way, and so repeated diagonalizations of the unit cell matrix with different parameters of the crystal momentum will fill out the bandstructure. Comparisons with the analytic solutions to the Kronig-Penney model show excellent agreement. We then generate bands for two variants of the Kronig-Penney model, the periodic harmonic oscillator and its inverted form, and a symmetric linear well such that each has similarly-bounded electrons at the peak of the third energy band. We show how these different, more "realistic", potentials can be used to tune electron-hole effective mass asymmetries. Finally, preliminary results for the extension to 2D are demonstrated.
        Speaker: Mr Pavelich Robert (University of Alberta)
        Slides
      • 17:00
        A Multiorbital DMFT Analysis of Electron-Hole Asymmetry in the Dynamic Hubbard Model 15m
        The dynamic Hubbard model (DHM) improves on the description of strongly correlated electron systems provided by the conventional single-band Hubbard model through additional electronic degrees of freedom, namely a second, higher energy orbital and associated hybridization parameters for interorbital transitions. The additional orbital in the DHM provides a more realistic modeling of electronic orbital "relaxation" in real lattices. One result of orbital relaxation is a clear electron-hole asymmetry, absent in the single-band case. We have employed the computational technique of dynamical mean field theory, generalized to the two-orbital case, to study this asymmetry with respect to varying system parameters, including both intersite and intrasite orbital hybridization as well as the role played by Mott physics. Our results stand in good agreement with previous exact diagonalization studies of the DHM.
        Speaker: Christopher Polachic
        Slides
    • 15:45 17:15
      M2-10 Atomic and Molecular Spectroscopy: microwave to X-ray (DAMOPC) / Spectroscopie atomique et moléculaire: des micro-ondes aux rayons X (DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Steven Rehse (University of Windsor)
      • 15:45
        SPECTROSCOPIC LINE-SHAPE STUDIES FOR ENVIRONMENTAL AND METROLOGIC APPLICATIONS 30m
        Our research group has investigated the spectra of several gases of environmental importance using our 3-channel laser spectrometer or the experimental facility at the far-infrared beamline at the Canadian Light Source. Our results have been used by others through our contributions to the HITRAN and GEISA databases used by the atmospheric community and we have made our own contributions to the field. Our group has also performed accurate measurements of the fundamental Boltzmann constant based on a line-shape analysis of acetylene spectra recorded using a tunable diode laser. This study is of high importance since the accuracy of our laser spectroscopy based measurement is the second best in the world.
        Speakers: Li-Hong Xu (University of New Brunswick), Ronald Lees (University of New Brunswick)
        Paper
        Slides
      • 16:15
        CLS Synchrotron FIR Spectroscopy of High Torsional Levels of CD3OH: The Tau of Methanol 15m
        Structure from high torsional levels of the CD$_3$OH isotopologue of methanol has been analyzed in Fourier transform spectra recorded at the Far-Infrared beamline of the Canadian Light Source synchrotron in Saskatoon. Energy term values for $A$ and $E$ torsional species of the third excited torsional state, v$_t$ = 3, are now almost complete up to rotational levels $K$ = 15, and thirteen substates have so far been identified for v$_t$ = 4. The spectra show interesting close groupings of strong high-v$_t$ sub-bands related by Dennison’s torsional symmetry index $/tau$, rather than $A$ and $E$, that can be understood in terms of a simple and universal free-rotor “spectral predictor” chart. The energy curves for the v$_t$ = 3 and 4 ground-state torsional levels pass through several of the excited vibrational states, and a number of anharmonic and Coriolis interactions have been detected through perturbations to the spectra and appearance of forbidden sub-bands due to strong mixing and intensity borrowing.
        Speaker: Dr Ronald Lees (Centre for Laser, Atomic and Molecular Sciences, Department of Physics, University of NB)
        Slides
      • 16:30
        Analysis of Quantum Defects in high energy Helium P states 15m
        Quantum defects are useful in interpreting high energy atomic states in terms of simple Hydrogenic energy levels. We will find the energy levels for 1snp singlet and triplet P state Helium from $n = 2$ to $n = 12$ with some of the most accurate helium atom calculations to date using the exact non-relativistic Hamiltonian with wave functions expanded in a basis set of Hylleraas coordinates. The results will be used to determine accurate values for the coefficients in the quantum defect expansion: $\delta = \delta_0 + \delta_2/n^{*2} + \delta_4/n^{*4} + \cdots$, where $n^* = n - \delta$. We will also test the usual assumption that only the even powers of $1/n^*$ need be included [1]. In addition, we will study the effectiveness of a unitary transformation in reducing the numerical linear dependence of the basis set for large basis sets.
        Speaker: Ryan Peck
      • 16:45
        Precision Measurement of Lithium Hyperfine and Fine Structure Intervals 15m
        A number of experiments have precisely measured fine and hyperfine structure splittings as well as isotope shifts for several transitions at optical frequencies for 6,7Li [1]. These data offer an important test of theoretical techniques developed by two groups to accurately calculate effects due to QED and the finite nuclear size in 2 and 3 electron atoms. The work by multiple groups studying several transitions in both Li+ and neutral Li permits a critical examination of the consistency of separately the experimental work as well as theory. Combining the measured isotope shifts with the calculated energy shifts passing these consistency tests permits the determination of the relative nuclear charge radius with an uncertainty approaching 1 x 10-18 meter which is more than an order of magnitude better than obtained by electron scattering. Progress toward a precision measurement of the fine structure constant is also discussed. 1. W. A. van Wijngaarden & B. Jian, European Physical Journal D, 222, 2057-2066 (2013)
        Speaker: Prof. William van Wijngaarden (Physics Department, York University)
        Slides
      • 17:00
        Dual Co-Magnetometer using Xe129 for Measurement of the
 Neutron’s Electron Dipole Moment 15m
        A new high-density ultra cold neutron source is being constructed and developed at TRIUMF in Vancouver, BC with collaborators from Japan and several Canada research groups. One of the first goals of this collaboration is to measure the electric dipole moment (EDM) of the neutron to an uncertainty of <10$^{-27}$ e-cm. To measure the nEDM, a magnetic resonance (MR) experiment on polarized neutrons is performed and the uncertainty of these measurements is limited by how well the magnetic field surrounding the neutrons is known. Previous nEDM experiments relied on a precise in-situ measurement of the homogeneous magnetic field using a Ramsey fringe measurement of the spin precession of Hg$^{199}$ (co-habituating with the cold neutrons). Our efforts are to develop a co-magnetometer for nEDM measurements in which both Hg$^{199}$ and a second atomic species (Xe$^{129}$) are introduced into the same region as the neutrons and measured simultaneously to better characterize the geometric phase effects which dominate the systematic uncertainties in the magnetic field determination. Xe$^{129}$ was chosen, in part, due to its negligible interactions with the neutrons and the Hg$^{199}$. The spin precession of Xe$^{129}$will be detected by measuring the fluorescence decay following a spin-selective 2-photon transition (driven by 252 nm light) from the ground 5p$^6$($^1$S0) state to the 5p$^5$($^2$P$_{3/2}$)6p excited state. For this purpose, we have first developed a high power (~200 mW) continuous wave UV laser. In this talk we will discuss the next steps in our co- magnetometer development: our latest results on characterizing the precision of Xe$^{129}$in the excited state using this laser and subsequently measuring the Larmor frequency of the polarized Xe$^{129}$ in a magnetic field.
        Speaker: Joshua Wienands (University of British Columbia)
    • 15:45 17:15
      M2-2 Material growth and processing (DCMMP) / Croissance et traitement des matériaux (DPMCM) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: David Broun (Simon Fraser University)
      • 15:45
        Field-tuned quantum criticality of heavy fermion systems 30m
        Intensive study of strongly correlated electronic systems has revealed the existence of quantum phase transitions from ordered states to disordered states driven by non-thermal control parameters such as chemical doping, pressure, and magnetic field. In this presentation I will discuss a recent progress of magnetic field-tuned quantum criticality with particular emphasis on the Fermi liquid instabilities of conduction electrons in heavy fermion metals and emergent phases around quantum critical points. In particular, a wide range of strange metallic behavior has been observed beyond the quantum critical point in Yb-based materials; YbAgGe, Ge-doped YbRh2Si2, YbPtBi. In the H-T phase diagram of YbPtBi, for example, three regimes of its low temperature states emerges: (I) antiferromagnetic state, characterized by spin density wave like feature, which can be suppressed to T = 0 by the relatively small magnetic field of Hc ~ 4 kOe, (II) field induced anomalous state in which the electrical resistivity follows r(T) ~ T1.5 between Hc and ~ 8 kOe, and (III) Fermi liquid state in which r(T) ~ T2 for H > 8 kOe. Regions I and II are separated at T = 0 by what appears to be a quantum critical point. Whereas region III appears to be a Fermi liquid associated with the hybridized 4f states of Yb, region II may be a manifestation of a spin liquid state. The observation of a separation between the antiferromagnetic phase boundary and the small to large Fermi surface transition in recent experiments has led to the new perspective on the mechanism for quantum criticality. In this new approach, the global phase diagram includes the effects of magnetic frustration, which is an important additional tuning parameter in the Kondo lattice model of heavy fermion materials. Frustration leads to the enhanced quantum fluctuations, as the system tunnels between different competing magnetic states.
        Speaker: Prof. Eundeok Mun (Simon Fraser University)
      • 16:15
        Ge:Mn Dilute Magnetic Semiconductor 15m
        This work aims to develop Ge:Mn dilute magnetic semiconductor and study the fundamental origin of ferromagnetism in this system. Using ion implantation at $77$ K, a single crystal Ge wafer was doped with magnetic Mn ions. The implantation was done at ion energy of $4.76$ MeV with a fluence of 2 x 10$^{16}$ ion/cm$^2$. X-ray diffraction (XRD) of the as-implanted sample showed that the implanted layer was amorphous. Therefore, different samples were annealed at $200$⁰C, $330$⁰C and $600$⁰C in a tube furnace to achieve a solid phase epitaxial regrowth of the implanted layer. XRD of the sample annealed at $330$⁰C for $33$ hours showed a polycrystalline layer. The depth profile of Mn in the as-implanted sample and the post-annealed sample at $330$⁰C was determined using secondary ion mass spectroscopy (SIMS) and it was found that some Mn diffused to the surface during the annealing. XRD of the sample annealed at $600$⁰C for $35$ minute showed peaks corresponding to an unknown phase in addition to peaks from amorphous and polycrystalline Ge. The sample annealed at $200$⁰C for $168$ hour showed no evidence of solid phase epitaxy. A SQUID was used to measure the magnetic properties of all samples. At low temperature, the as-implanted sample showed a paramagnetic behaviour. A magnetic hysteresis at $5$K and up to $200$K was observed for the samples annealed at $330$⁰C and $200$⁰C. The $600$⁰C annealed sample showed no ferromagnetic response and a significant reduction in the paramagnetic response at low temperature compared to the as-implanted sample.
        Speaker: Laila Obied (Brock University)
      • 16:30
        The nanostructure of (Ybx, Y1-x)2O3 thin films obtained by reactive crossed-beam laser ablation using bright-field and high-angle annular dark-field STEM imaging. 15m
        Ytterbium-doped yttrium oxide thin films were obtained with a variant of pulsed laser deposition, called reactive crossed-beam laser deposition, wherein a cross-flow of oxygen, synchronized with the laser pulses, is used for oxidizing and entraining the ablation products of a Yb/Y alloy target towards a substrate placed inside a vacuum chamber [1]. The nanostructure of the films is examined using X-ray and electron diffraction, as well as Scanning Transmission Electron Microscopy (STEM). As-produced coatings are amorphous and become nanocrystalline cubic yttria after annealing. STEM images taken in the Bright-Field and in the High-Angle Annular Dark-Field modes reveal complementary aspects of the nanostructure of yttria, namely the presence of oxygen vacancies as well as distortion of the cationic lattice respectively. These peculiarities of the crystalline structure play an important role in the luminescence properties of the Yb3+ ions, since they lower the crystal-field symmetry of the Yb3+ substitution site, which directly affect the luminescence spectra. Thin films made of luminescent materials are attractive for many applications such as coherent miniature optical sources [2], optical converter from the infrared to the visible range for in-vivo imaging [3], to name a few. Des revêtements d’oxyde d’ytterbium et d’yttrium (YbxY1-x)2O3 nanostructurés ont été déposés à l’aide d’une variante de l’ablation laser, pour laquelle le transport et l’oxydation des produits d’ablation d’une cible métallique vers le substrat se font à l’aide de courtes bouffées d’oxygène synchronisées avec le laser [1]. La nanostructure et les propriétés de luminescence de nos revêtements ont été étudiées par diffraction aux rayons X et diffraction électronique ainsi que par microscopie électronique à transmission. Les dépôts obtenus sont amorphes et deviennent nanocristallins après recuit. Pour la première fois à notre connaissance, nous avons mis en évidence, en tirant profit de la complémentarité des images obtenues par microscopie électronique à transmission en champ sombre et en champ clair, la présence de lacunes d’oxygènes et la distorsion du réseau cationique. Ces deux particularités jouent un rôle important dans les propriétés de luminescence des ions d’Yb3+ puisqu’elles permettent l’apparition de sites de substitution à faible symétrie, augmentant ainsi la probabilité de relaxation radiative de l’ion excité. La capacité de contrôler la taille des nanocristaux par un recuit permet de contrôler la forme du spectre de luminescence. Les matériaux luminescents déposés sous forme de couches minces sont très attrayants pour plusieurs applications comme les sources lumineuses cohérentes miniaturisées [2], la conversion dans domaine du visible pour l’imagerie ou la détection in-vivo [3], etc. References : [1] J.-F Bisson, G. Patriarche, T. Marest, J. Thibodeau, (2015) Nanostructure and luminescence properties of amorphous and crystalline ytterbium-yttrium oxide thin films obtained with pulsed reactive crossed-beam deposition, J. Mater. Sci., 50(3), 1267-1276 [2] I C Robin, R Kumaran, S Penson, S E Webster, T Tiedje and A Oleinik (2008) Structure and photoluminescence of Nd:Y2O3 grown by molecular beam epitaxy. Opt. Mat. 30: 835-838 [3] G S Yi, G M Chow, Synthesis of hexagonal-phase NaYF4 : Yb,Er and NaYF4 : Yb,Tm nanocrystals with efficient up-conversion fluorescence (2006) Adv. Funct. Mater. 16(18), 2324-2329
        Speaker: Prof. Jean-François Bisson (Université de Moncton)
        Slides
      • 16:45
        Investigation of the effect of growth condition on defects in MBE grown GaAs1-xBix 15m
        Incorporation of Bismuth into GaAs causes an anomalous bandgap reduction (88 meV/% for dilute alloys) with rather small lattice mismatch compared to ternary In or Sb alloys. The bandgap can be adjusted over a wide range of infrared wavelengths up to 2.5 μm by controlling the Bi content of the alloy which is useful for laser, detector and solar cell applications. Semiconductor lasers are compact and efficient so they are the preferable choice in many applications. GaAs1-xBix can be used as the light emitting material for the 1-1.3 μm communication wavelengths. Another application is vertical-external-cavity surface-emitting- lasers (VECSEL) to generate high power infrared output and then doubling the frequency to achieve yellow laser light. The first step to make a laser is optimizing GaAs1-xBix growth parameters to realize the best material quality which cannot be achieved unless the defects in the crystal are understood. The three requirements for MBE growth of GaAs1-xBix are: low growth temperature (compared to standard GaAs), small As2:Ga ratio and controlled Bi flux. In this research, we tried to understand the relation between the growth conditions and the crystal defects using photoluminescence (PL) and deep level transient spectroscopy (DLTS). PL intensity is a good relative gauge for the number of defects as the defects are typically non-radiative recombination centres. Our results show that the reduction of growth temperature from 400°C to 300°C with all other growth conditions fixed causes the Bi concentration in the deposited films to increase from 1% to 5% but the PL intensity decreases by more than a factor of 1000. Changes in the other two growth conditions, As2:Ga ratio and Bi flux, affect the Bi incorporation but they are not as important factors in the PL intensity as the growth temperature. Two samples were grown at different temperatures (330°C and 375°C) with approximately the same Bi concentration (~2%) at a stoichiometric As:Ga flux ratio. The temperature dependence of the PL shows that the sample grown at higher temperature has less photoluminescence emission from shallow defect states and a stronger temperature dependence of the bandgap. We interpret the shallow defects as intrinsic localized states close to the valence band edge associated with Bi next nearest neighbour clusters. DLTS measurements on GaAs and GaAsBi samples show that the density of deep levels increases at low growth temperature and that a Bi surfactant reduces the density of deep levels. DLTS measurements on dilute GaAsBi samples grown at different temperatures will be presented.
        Speaker: Vahid Bahrami Yekta (University of Victoria)
      • 17:00
        Atomic Force Microscopy Characterization of Hydrogen Terminated Silicon (100) 2x1 Reconstruction 15m
        Hydrogen terminated silicon (100) $2 \times 1$ (H:Si(100)) is examined using a novel non-contact atomic force microscopy (NC-AFM) approach. NC-AFM gives access to unique information on the surface such as unperturbed surface charge distributions, chemical bonding, and surface forces. H:Si(100) is an attractive surface for examination due to its potential for nano-electronics. Dangling bonds on the surface act as atomic silicon quantum dots and have application in quantum dot cellular automata-based nano-computing, which through geometrical arrangement can be used to create ultra-fast, ultra-low-power wires and logic gates. It also provides a promising platform for AFM examination of electronically decoupled adsorbed atoms, physisorbed molecules, and chemisorbed molecular structures. As part of this AFM analysis of H:Si(100), images were taken in the as yet unexplored constant height scanning mode. By incrementing the tip-sample distance above the surface, different force regimes were accessed. Attractive van der Waals forces were observed in the long range, and repulsive interactions indicative of Pauli-repulsive forces were seen at close range. An evolution of surface topography from attractive to repulsive surface forces is demonstrated, with the repulsive regime showing the first direct observation of the chemical bond structure of H:Si(100). Furthermore, site-specific force spectroscopy on key surface lattice points reveals unique force contributions. These location-specific profiles are compared to Density Functional Theory modeling for the surface, with catalogued site-specific differences having application in subtraction of background forces for the aforementioned deposited molecule or atom examination. NC-AFM contributes strongly to our understanding of forces at play in the surface structure of H:Si(100), opening the way for many future experiments.
        Speaker: Ms Taleana Huff (University of Alberta)
    • 15:45 17:15
      M2-3 Theory, modelling and space weather II (DASP) / Théorie, modélisation et climat spatial II (DPAE) CAB 243

      CAB 243

      University of Alberta

      Convener: David Knudsen (University of Calgary)
      • 15:45
        Development of Comprehensive Model of Earth Ionosphere and its Application for Studies of MI-coupling 30m
        A comprehensive model of the Earth ionosphere has been developed [Sydorenko and Rankin, 2012 and 2013]. The model is two-dimensional, it resolves the meridional direction and the direction along the geomagnetic field. The dipole coordinates are used, the azimuthal symmetry is assumed. The model considers torsional Alfven waves and includes the meridional convection electric field. The electric field along the geomagnetic field is calculated from the condition of quasineutrality. The ions (H+, N+, O+, N2+, NO+, and O2+) and the electrons are represented as conducting fluids. The neutrals (H, N, O, N2, NO, and O2) are considered as a stationary background, the meridional wind can be included but it does not change the neutral parameters. Numerous heating and cooling processes, chemical reactions between ions and neutrals, recombination, and effects of energetic electron precipitation and EUV radiation are included. The main simulation area covers the altitude range from 100 km to few thousand km, the width of the main area at the bottom is up to few hundred km. The model was applied to study oxygen ion upwelling caused by electron precipitation and Alfven waves. Recently, the model was used to investigate plasma density and temperature oscillation observed by EISCAT during the period of intense magnetospheric activity and predicted that the event was accompanied by significant modification of the composition of neutrals in the thermosphere. Sydorenko, D., and R. Rankin (2012), Simulation of ionospheric disturbances created by Alfvén waves, J. Geophys.Res., 117, A09229, doi:10.1029/2012JA017693. Sydorenko, D., and R. Rankin (2013), Simulation of O+ upflows created by electron precipitation and Alfvén waves in the ionosphere, J. Geophys. Res. Space Physics, 118, 5562–5578, doi:10.1002/jgra.50531.
        Speaker: Dr Dmytro Sydorenko (University of Alberta)
      • 16:15
        Solar wind modelling for operational forecasting 30m
        Dark regions seen in extreme ultraviolet and X-ray images of the solar corona, called coronal holes (COHO), are known to be sources of fast solar wind streams. These streams often impact the Earth’s magnetosphere and produce geomagnetic storms to which Canada is susceptible. COHO are associated with open coronal magnetic field lines along which fast solar wind streams emanate from the Sun. COHO can survive several Sun’s rotations, especially near the solar minimum, giving rise to recurrent enhancements in the solar wind speed and geomagnetic activity. While solar wind forecasting can be based on COHO images by taking into account a statistical correlation between COHO area and solar wind parameters at the Earth, a more physics based approach considers open magnetic field lines that extend from the photosphere to the corona. To forecast the solar wind, a numerical code based on the coronal field approach has been developed. To derive the global coronal magnetic field a potential field source surface and Schatten current sheet models are used. Empirical relations, including Wang-Sheeley-Arge, are used to establish a link between the solar wind speed and properties of open magnetic field lines. Investigations of the solar wind speed and magnetic field polarity forecasts at the Earth for 2007-2014 show a good agreement with observations, most notably around solar minimum. Disagreements, excluding those due to transient solar disturbances, are discussed. In particular, the role of COHO area size, their latitudinal location and proximity to active regions is discussed. Prospects of using the solar wind forecast in forecasting geomagnetic activity over Canada are examined.
        Speaker: Ljubomir Nikolic (Natural Resources Canada)
      • 16:45
        Using an information theory-based method for statistical detection of high-frequency climate signals in northern-hemisphere water supply variations 15m
        Water scarcity is an acute global concern under population and economic growth, and understanding hydroclimatic variation is becoming commensurately more important for resource management. Climatic drivers of water availability vary complexly on many time- and space-scales, but serendipitously, the climate system tends to self-organize into coherent dynamical modes. Two of these are El Niño-Southern Oscillation (ENSO) and the Arctic Oscillation (AO), which have hemisphere- to planet-wide impacts on regional climate through intricate relationships called teleconnections. Traditionally, statistical studies assume such teleconnections are linear, or at least monotonic. Recent work instead suggests ENSO and AO impacts can be strongly nonlinear – specifically, parabolic. However, these phenomena remain incompletely understood, and river flows spatiotemporally integrate upstream climatic influences in complicated ways, sensitive to local terrestrial hydrologic characteristics. We therefore directly examine annual flow volume time series from 42 of the northern hemisphere’s largest ocean-reaching rivers for highly nonlinear teleconnections. We apply a novel approach based on optimal polynomial selection using the Akaike information criterion, which combines the Kullback-Leibler information, quantifying how much information content is lost when approximating truth using a model, with maximum likelihood concepts. Unlike conventional null-hypothesis significance testing, the method provides a rigorously optimal balance between model performance and parsimony; explicitly accommodates no-effect, linear-effect, and strongly nonlinear-effect models; and estimates the probability that a model is true given the data. While we discover a rich diversity of responses, parabolic relationships are formally consistent with the data for almost half the rivers and are optimal for eight. Highly nonlinear teleconnections could radically alter the standard conceptual model of how water resources respond to climate variability. For example, the Sacramento River in drought-ridden California exhibits no significant linear ENSO teleconnection but a 92% probability of a quadratic relationship, improving simple mean predictive error by up to 65% and implying greater opportunity for climate-informed early-season water supply forecasting than previously appreciated.
        Speaker: Dr Sean W. Fleming (Environment Canada, MSC Science Division)
    • 15:45 17:15
      M2-4 Cosmic Frontier: Cosmology I (DTP-PPD-DIMP) / Frontière cosmique: cosmologie I (DPT-PPD-DPIM) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: James Pinfold (University of Alberta (CA))
      • 15:45
        Probing the Nature of Inflation 30m
        The idea that the early universe included an era of accelerated expansion (Inflation) was proposed to explain very qualitative features of the first cosmological observations. Since then, our observations have improved dramatically and have lead to high precision agreement with the predictions of the first models of inflation, slow-roll inflation. At the same time, there has been significant growth in the number of mechanisms for inflation, many of which are qualitatively distinct from slow-roll. Nevertheless, most of these ideas are also consistent with current data. In this talk, I will review inflation and its current observational status. I will then discuss the important theoretical targets for the future and the prospects for achieving them.
        Speaker: Daniel Green
        Slides
      • 16:15
        Determining Power Spectra of High Energy Cosmics 15m
        The angular power spectrum is a powerful observable for characterizing angular distributions, popularized by measurements of the cosmic microwave background (CMB). The power spectra of high energy cosmics ($\gamma$-rays, protons, neutrinos, etc.) contains information about their sources. Since these cosmics are observed on an event-by-event basis, the nature of the power spectrum measurement is fundamentally different from the CMB. We present new progress on the statistical properties of these power spectrum measurements and discuss the new information about the sources that can be gleaned from these observations.
        Speaker: Sheldon Campbell (The Ohio State University)
        Slides
      • 16:30
        Searching for the echoes of inflation from a balloon - The first SPIDER flight 15m
        SPIDER is a balloon-borne polarimeter designed to detect B-modes in the CMB at degree angular scales. Such a signal is a characteristic of early universe gravitational waves, a cornerstone prediction of inflationary theory. Hanging from a balloon at an altitude of 36 km allows the instrument to bypass 99% of the atmosphere and get an unobstructed view of the sky at 90 and 150 GHz. The multi-band nature of the experiment will help characterize galactic foregrounds, which need to be well understood before a primordial polarization signal can be extracted from the data. During its first flight from Antarctica in January 2015, SPIDER probed 8% of the sky with 2000 polarization-sensitive bolometers. These were distributed amongst six cryogenically cooled telescopes housed in a 1300 liter liquid-helium cryostat. This massive cryostat was supported and steered by a light-weight carbon fibre structure, equipped with two sets of motors that controlled its pointing on the sky through real-time position feedback from a variety of sensors. I will discuss the performance of the instrument over the 16 day flight and what we might learn from the dataset. I will also give a glimpse into the capabilities of the upgraded instrument, scheduled to fly in 2018.
        Speaker: Ivan Padilla (University of Toronto)
        Slides
    • 15:45 17:15
      M2-5 Nuclear Astrophysics (DNP) / Astrophysique nucléaire (DPN) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Barry Davids (TRIUMF)
      • 15:45
        The turbulent hydrodynamics and nuclear astrophysics of anomalous stars from the early universe 30m
        The anomalous abundances that can be found in the most metal-poor stars reflect the evidently large diversity of nuclear production sites in stars and stellar explosions, as well as the cosmological conditions for the formation and evolution of the first generations of stars. Significant progress in our predictive understanding of nuclear production in the early universe comes now within reach through advancing capabilities to perform large-scale 3D stellar hydrodynamic simulations of the violent outbursts of advanced nuclear burning. When complemented with comprehensive nucleosynthesis simulations we can characterize the chemical evolution of stellar populations. Nuclear production sites in the early universe involves unstable species on the p- and n-rich side of the valley of stability, and nuclear data in key cases is presently too uncertain to enable the required predictive simulation capability. These are the underpinnings to decipher the messages from the early universe hidden in the anomalous abundances of metal poor stars.
        Speaker: Falk Herwig (University of Victoria)
      • 16:15
        Quark-Novae : Implications to High-Energy and Nuclear Astrophysics 30m
        After a brief account of the physics of the Quark-Nova (explosive transition of a neutron star to a quark star), I will discuss its implications and applications to High Energy and Nuclear Astrophysics.  The talk will focus on Quark-Novae in the context of Super-Luminous Supernovae and in the context of the origin of heavy elements (r-process nucleosynthesis). The Quark-Nova has the potential to provide new insight into  explosive astrophysical phenomena and the origin of some elements in the periodic table, by naturally combining  the might of researchers in nuclear physics, sub-nuclear physics and astrophysics. Rachid Ouyed (UofC)
        Speaker: Prof. Rachid Ouyed (University of Calgary)
      • 16:45
        Hadronic-to-Quark-Matter Phase Transition: Effects of Strange Quark Seeding. 15m
        When a massive star depletes its fuel it may undergo a spectacular explosion; the supernova. If the star is massive enough, it can undergo a second explosion; the Quark nova. The origin for this second explosion has been argued to be the transition from Hadronic-to-Quark-Matter (Ouyed et al. 2013). Hadronic-to-Quark-Matter phase transition occurs when hadronic (nucleated) matter under high temperatures and/or densities deconfines into what is called a quark-gluon plasma (QGP). This talk will explore the required conditions for a star to undergo a Quark nova. In particular, under which conditions should the transition from Hadronic-to-Quark-Matter occur so that there is a second explosion for a massive star? The talk will be at an introductory level and will present the results of theoretical and computational calculations performed to estimate the production rate of strange quarks by self-annihilation of dark matter determining whether or not dark matter self-annihilation can be responsible by itself to start a combustion in the core of a star for it to undergo a Quark nova.
        Speaker: Mr Luis Welbanks (University of Calgary)
    • 15:45 17:15
      M2-6 Radiation Therapy (DMBP-DNP) / Thérapie par rayonnement (DPMB-DPN) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Melanie Martin (University of Winnipeg)
      • 15:45
        Medical linear accelerator mounted mini-beam collimator: transferability study 15m
        Background: In place of the uniform dose distributions used in conventional radiotherapy, spatially-fractionated radiotherapy techniques employ a planar array of parallel high dose ‘peaks’ and low dose ‘valleys’ across the treatment area. A group at the Saskatchewan Cancer Agency have developed a mini-beam collimator for use with a medical linear accelerator operated at a nominal energy of 6MV. Purpose: The goal of this work was to characterize various attributes of the mini-beam collimated dose distribution and assess consistency of those attributes across a set of medical linear accelerators. Materials and Methods: Three “beam matched” Varian iX accelerators were used in this study. All measurements were made using a PTW scanning water tank set with a 100 cm source to surface distance. Dose profiles perpendicular to the plane of the mini-beam collimator were measured at a depth of 10.0 cm for a square field of side 4.0 cm. Percentage depth dose (PDD) curves along the central peak dose were made for a square field of side 4.0 cm. Relative point dose measurements were made at a depth of 10.0 cm along the central peak dose using two different diode detectors (PTW TN60017 and IBA stereotactic field diode (SFD)). A collimator factor (CF), defined as the ratio of the collimated point dose to that of the open field point dose, was determined at a depth of 10 cm for each linac for square field sizes of side 2.0, 3.0, 4.0 and 5.0 cm. Results: When normalized to the central peak dose, the profile data revealed a variation in the relative valley dose across the three linacs. However, the PDD data was consistent indicating no variation in beam energy across the three linacs. As previously determined, the measured CF did differ as a function of detector. This results from the active volume of the detectors being different. The measured CF also differed across the set of linacs. The PTW diode measurements showed an average difference of 2.65% across accelerators, and the SFD showed an average difference of 5.6% across accelerators. The difference in CF and valley dose is believed to result from differences in the electron source width incident on the Bremsstrahlung target for each of the accelerators. Conclusion: The dose profile and collimator factors of the mini-beam collimated dose were not found to be consistent across a set of medical linear accelerators.
        Speaker: Mr William Davis (Department of Physics and Engineering Physics, University of Saskatchewan)
        Slides
      • 16:00
        Cancer cell targeting gold nanoparticles for therapeutics 15m
        Polyethylene glycol (PEG) has promoted the prospective cancer treatment applications of gold nanoparticles (GNPs). *In vivo* stealth of GNPs coated with PEG (PEG-GNPs) takes advantage of the enhanced permeability and retention effect in tumor environments, making them suitable for targeted treatment. Because PEG minimizes gold surface exposure, PEG-GNP interaction with ligands that mediate cancer cell uptake is lower than uncoated GNPs. Hence, the cellular uptake of PEG-GNPs is significantly lower than uncoated GNPs *in vitro*. As intracellular localization of GNPs maximizes its therapeutic enhancement, there is a need to improve the uptake of PEG-GNPs. To enhance uptake, receptor mediated endocytosis peptides were conjugated with PEG-GNPs of varying core sizes. Spherical GNPs of diameters 14 nm, 50 nm and 70 nm and a PEG chain length of 2 and 5 kDa were used to determine a preferred core size and chain length for uptake *in vitro* in HeLa and MDA-MB-231 cells. Radiosensitization of HeLa cells to a 6 MVp clinical photon beam via GNP conjugates were observed to assess its therapeutic application.
        Speaker: Charmainne Cruje (Ryerson University)
      • 16:15
        Development and Imaging of the World’s first Whole-Body Linac-MRI Hybrid System 30m
        **Purpose:** We designed and first whole-body clinical linac-MRI hybrid (linac-MR) system to provide real-time MR guided radiotherapy with current imaging and treatment. Installation began in our clinic in 2013, and the world-first images from a linac-MR on a human volunteer were obtained in July 2014. **Methods:** The linac-MR consists of an isocentrically mounted 6 MV linac that rotates in-unison with a biplanar 0.6 T MRI in transverse plane. The Bo field and the central axis of the 6 MV beam are parallel to each other. The optimized fringe field results in insignificant increase in entrance dose. The parallel configuration avoids large increases in dose at tissue/air interfaces and at beam exit due to electron return effect that occurs in the perpendicular configuration. We were first to demonstrate concurrent MR imaging and linac-irradiation of head-size phantoms in 2008, on a single gantry. The head prototype have been described in our 40 peer-reviewed articles (linac-MR.ca/publications.html). The current functional whole-body rotating linac-MR system is built on the engineering and physics obtained from the head prototype. **Results:** The current system is mechanically well balanced and rotates at 1 rpm. The 3D magnetic field mapping demonstrates minimal perturbation in magnetic field homogeneity with gantry rotation which is easily and effectively shimmed by gradient coils. The Larmor Frequency varies with gantry angle due to the Bo interaction with room shielding and to the directional changes of the Earth’s magnetic relative, and closely follows our predictions calculated previously. Angle dependent 3D magnetic field maps and Larmor Frequency are used to automatically and optimally create image acquisition parameters for any gantry angle. Metrics obtained at different rotating angles show that the image quality is comparable to those of clinical MRI systems, and thus satisfy the requirements for real-time MR-guided radiotherapy. **Conclusions:** The system highlights are: 1) 6 MV linac, 2) high-quality MR images during irradiation, 3) simultaneous linac and MR rotation in parallel configuration to avoid strong angle-dependent shimming, and to avoid increased dose at beam exit and tissue/air interfaces, 3) installation through the maze of an existing vault, 4) cryogen-free superconducting magnet not requiring a helium vent, and 5) ability to turn magnet off or on in a few minutes for servicing.
        Speaker: Prof. B. Gino Fallone (University of Alberta)
      • 16:45
        A SYSTEMATIC APPROACH TO STANDARDIZING SMALL FIELD DOSIMETRY IN RADIOTHERAPY APPLICATIONS 15m
        Small field dosimetry is difficult, yet consistent data is necessary for the clinical implementation of advanced radiotherapy techniques. In this work we present improved experimental approaches required for standardizing measurement, Monte Carlo (MC) simulation based detector correction factors as well as methods for reporting experimental data. A range of measurements and MC modelling studies have been reported by our group. Based on these methods and results, recommendations are given as to: (1) commissioning/fine-tuning MC models for use in small field dosimetry, (2) correction factors for a range of shielded and unshielded diode detectors, (3) what constitutes a ‘very small field size’ - based on the different effects as field size gets smaller, (4) measurement methods necessary to control uncertainties at these very small field sizes and (5) reporting against an effective field size - taking into account measured dosimetric field size. The results of the work clearly show that measurement and modelling based methods can be standardized to improve the consistency in small field dosimetry. Through standardization the best accuracy possible can be achieved in these increasingly clinically-used conditions.
        Speaker: Dr Gavin Cranmer-Sargison (Department of Medical Physics, Saskatchewan Cancer Agency)
      • 17:00
        Multifunctional perfluorocarbon nanoemulsions for cancer therapy and imaging 15m
        There is interest for the use of nanoemulsions as therapeutic agents, particularly Perfluorocarbon (PFC) droplets, whose amphiphilic shell protects drugs against physico-chemical and enzymatic degradation. When delivered to their target sites, these PFC droplets can vaporize upon laser excitation, efficiently releasing their drug payload and/or imaging tracers. Due to the optical properties of gold, coupling PFC droplets with gold nanoparticles significantly reduces the energy required for vaporization. In this work, nanoemulsions with a perfluorohexane core and Zonyl FSP surfactant shell were produced using an oil-in-water technique. Droplets were characterized in terms of size and morphology using high resolution fluorescence techniques (i.e. Total Internal Reflection Fluorescence Microscopy, TIRFM, and Fluorescence Correlation Spectroscopy, FCS), electron microscopy, and light scattering techniques (i.e. Dynamic Light Scattering, DLS). The ability of PFC droplets to vaporize are demonstrated using Optical Microscopy (OM). Our emulsion synthesis technique has given a reproducible, unimodal size distribution of PFC droplets corresponding to an average hydrodynamic diameter of 53.5 ± 3.8 nm, from DLS and FCS, with long-term stability at physiological conditions. Their size and stability makes them cost effective drug delivery vehicles suitable for efficient internalization within cancer cell lines. To vaporize the nanoemulsions, silica coated gold nanoparticles (scAuNPs) were used and excited with a 532 nm laser. Taken together, TIRFM, dual-colour FCS, and OM show that scAuNPs are within the same diffraction-limited spot of these PFC droplets before vaporization.
        Speaker: Mr Donald A. Fernandes (Ryerson University)
    • 15:45 17:15
      M2-7 Cosmic frontier: Dark matter I (PPD-DTP) / Frontière cosmique: matière sombre I (PPD-DPT) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Kevin Graham (Carleton University)
      • 15:45
        Status of Dark Matter Theories 30m
        The existence of dark matter is a prominent puzzle in model physics, and it strongly motivates new particle physics beyond the standard model.I will review theoretical candidates for dark matter as proposed in the literature, and their status in light of recent experimental searches. I will also discuss new possibilities of dark matter theories and related research avenues.
        Speaker: Yanou Cui (Perimeter Institute)
        Slides
      • 16:15
        The DEAP-3600 Dark Matter Experiment -- Updates and First Commissioning Data Results 30m
        The DEAP-3600 experiment uses 3.6 tons of liquid argon for a sensitive dark matter search, with a target sensitivity to the spin-independent WIMP-nucleon cross-section of 10^{-46} cm^2 at 100 GeV WIMP mass. This high sensitivity is achievable due to the large target mass and the very low backgrounds in the spherical acrylic detector design as well as at the unique SNOLAB facility. Scintillation light in liquid argon is collected with 255 high efficiency photomultiplier tubes. Pulse shape discrimination is used to reject electromagnetic backgrounds from the WIMP induced nuclear recoil signal. We have started taking commissioning data. In this talk we will present the status of the experiment and results from analysis of the first commissioning data.
        Speaker: Dr Bei Cai (Queen's University)
      • 16:45
        Direct Detection Prospects for Higgs-portal Singlet Dark Matter 15m
        There has recently been a renewed interest in minimal Higgs-portal dark matter models, which are some of the simplest and most phenomenologically interesting particle physics explanations of the observed dark matter abundance. In this talk, we present a brief overview of scalar and vector Higgs-portal singlet dark matter, and discuss the nuclear recoil cross sections of the models. We show that, given a reasonable range for the theoretical uncertainties in the calculation, the expected cross sections are found in the region of the parameter space that will be probed by next generation direct detection experiments. In particular, within two years of operation the XENON1T experiment should be able to make a strong statement about Higgs-portal singlets.
        Speaker: Fred Sage (University of Saskatchewan)
      • 17:00
        Status of the PICO-60 Dark Matter Search Experiment 15m
        The PICO collaboration (formerly PICASSO and COUPP) uses bubble chambers for the search for Weakly Interacting Massive Particle (WIMP) dark matter. Such bubble chambers are scalable, can have large target masses and can be operated at regimes where they are insensitive to backgrounds such as beta and gamma radiation. The PICO-60 experiment is a bubble chamber that has been developed and operated at SNOLAB with 37 kg of CF$_3$I as a target liquid. The experiment is currently being upgraded for the use with 60 kg of ultra clean C$_3$F$_8$ to focus on the search for spin dependent dark matter. The PICO-60 detector is expected to have a world leading sensitivity to spin dependant dark matter interactions. In this talk an overview of the progress of PICO-60 experiment, the results from the dark matter runs with existing data and future plans are presented.
        Speaker: Pitam Mitra (University of Alberta)
        Slides
    • 15:45 17:15
      M2-8 Teaching Physics to a Wider Audience (DPE) / Enseigner la physique à un auditoire plus vaste (DEP) CAB 239

      CAB 239

      University of Alberta

      Convener: Adam Sarty (Saint Mary's University)
      • 15:45
        Asymmetric Wavefunctions from Tiny Perturbations 15m
        We present an undergraduate-accessible analysis of a single quantum particle within a simple double well potential through matrix mechanics techniques. First exploring the behavior in a symmetric double well (and its peculiar wavefunctions), we then examine the effect that varying well asymmetry has on the probability density. We do this by embedding the potential within a larger infinite square well, expanding in this simple basis, and solving for the matrix elements. The resulting wavefunctions are drastically different than those of the unperturbed system. A relatively tiny drop in one of the well depths results in a nearly complete collapse (localization) of the wavefunction into one of the wells. This system can be accurately mapped to a much simpler two-state "toy model"; this makes it clear that this localization is also a property of a generic double well system.
        Speaker: Tyler Dauphinee
      • 16:00
        An online resource for teaching about energy 15m
        Energy issues are important to Canada, and a logical topic for Canadians to teach. The Energy Education group at the University of Calgary has built a free on-line resource suitable for teaching an 'energy for everyone' course from a physics department. This resource includes interactive data visualizations and real world simulations to help students understand the role of energy in modern society
        Speaker: Prof. Jason Donev (University of Calgary)
      • 16:15
        Essential Psychology in Physics - MBTI and You 15m
        According to the wikipedia entry, psychology is an academic and applied discipline that involves the scientific study of mental functions and behaviours. Since learning involves mental functions, it only makes sense that psychology has a role in the classroom - including a post-secondary physics class. The Myers-Briggs Type Indicator (MBTI) is one model that provides a framework for identifying differences in how individuals perceive the world, make decisions, and communicate. By becoming aware of one's own type, individuals can understand why they may be perceived as 'different' from their colleagues, which is often more than just their gender. Furthermore, utilizing MBTI can help instructors become more effective in the classroom by maximizing their strengths and minimizing their vulnerabilities. In this talk, I will present an introduction to MBTI, and give some ideas on how to use this framework to improve working relationships both inside and outside the classroom.
        Speaker: Dr Jo-Anne Brown (University of Calgary)
      • 16:30
        Essential Psychology in the Physics Classroom - Five Steps to Improve Classroom Effectiveness 15m
        Teaching large physics classes - especially to non-physics majors that may have developed an extraordinary aversion to anything math-related - can be a challenge, even for the best instructors. However, there are a few techniques, drawn from psychology, that can help improve the experience for both the instructor and the students. In this talk, I will present a 'five-step program' I developed that works effectively for any level of class I teach. The result of this program has been high student satisfaction for the course, as well as a retention of my sanity.
        Speaker: Jo-Anne Brown (University of Calgary)
    • 15:45 17:15
      M2-9 Advanced Instrumentation at Major Science Facilities: Accelerators (DIMP) / Instrumentation avancée dans des installations scientifiques majeures: accélérateurs (DPIM) CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 15:45
        CLS 2.0: The Next 10 Years 30m
        The Canadian Light Source (CLS) is Canada’s premier source of intense light for research, spanning from the far infrared to hard x-rays. The facility has been in operations for 10 years and in that time has hosted over 2,000 researchers from academic institutions, government, and industry, from 10 provinces and 2 territories, and provided a scientific service critical in over 1,000 scientific publications. As the CLS reaches this important milestone, a series of workshops at the Annual Users’ Meeting (May 2015), will help define the scientific direction of the facility for the next 10 years, to address the Canadian research community’s scientific challenges. This presentation will present scientific and technical highlights from the CLS today and give an outlook of where photon science using light sources may go in the future.
        Speaker: Dr Dean Chapman (Canadian Light Source Inc.)
      • 16:15
        Acquaman: Scientific Software as the Beamline Interface 15m
        The Acquaman project (Acquisition and Data Management) was started in early 2010 at the Canadian Light Source. Over the past four years, the project has grown to support five beamlines by providing beamline control, data visualization, workflow, data organization, and analysis tools. Taking advantage of modular design and common components across beamlines, the Acquaman team has demonstrated that a framework dedicated to synchrotron beamlines can deliver high quality interfaces while also reducing overall development cost and production time. Acquaman supports scientific researchers by allowing them to focus on the scientific techniques they know while reducing the need to understand specific hardware, which changes from beamline to beamline. Focus will be given to this topic in the broader context of how to manage a modular, scalable, and flexible framework. Additionally, two small case studies – the IDEAS and SXRMB beamlines – will be used to demonstrate the ease of deployment on new beamlines.
        Speaker: David Chevrier (Canadian Light Source)
        Slides
      • 16:30
        A Phase Space Beam Position Monitor for Synchrotron Radiation 15m
        Synchrotron radiation experiments critically depend on the stability of the photon beam position. The position of the photon beam at the experiment or optical element location is set by the electron beam source position and angle as it traverses the magnetic field of the bend magnet or insertion device. An ideal photon beam monitor would be able to measure the photon beam’s position and angle, and thus infer the electron beam’s position in phase space. Monochromatic x-ray beams at synchrotrons are typically prepared by x-ray diffraction from crystals usually in the form of a double crystal monochromator. Diffraction couples the photon wavelength or energy to the incident angle on the lattice planes within the crystal. The beam from such a monochromator will contain a spread of energies due to the vertical divergence of the photon beam from the source. This range of energies can easily cover the absorption edge of a filter element such as iodine at 33.17 keV. A vertical profile measurement with and without the filter can be used to determine the vertical angle and position of the photon beam. In these measurements an imaging detector measures these vertical profiles with an iodine filter that horizontally covers part of the monochromatic beam. The goal was to investigate the use of this combined monochromator, filter and detector as a phase space beam position monitor. The system was tested for sensitivity to position and angle under a number of synchrotron operating conditions, such as normal operations and special operating modes where the beam is intentionally altered in position and angle. The results are comparable to other methods of beam position measurements and indicate that such a system is feasible in situations where part of the white synchrotron beam can be used for the phase space measurement.
        Speaker: Nazanin Samadi (University of Saskatchewan)
      • 16:45
        Observation of Wakefields in Coherent Synchrotron Radiation at the Canadian Light Source 15m
        Synchrotron light sources routinely produce brilliant beams of light from the infrared to hard X-ray. Typically, the length of the electron bunch is much longer than the wavelength of the produced radiation, causing the electrons to radiate incoherently. Many synchrotron light sources, including the Canadian Light Source (CLS), can operate in special modes where the electron bunch, or structures in the electron bunch, are small enough that they radiate coherently, producing coherent synchrotron radiation (CSR). Using a Michelson interferometer and RF diodes at CLS, we observe structure in THz CSR which is due to the electromagnetic wake following the electron bunch. The RF diode measurements provide direct observations of the wakefields, and we compare against wakefield simulations. Given the complexity of the vacuum chamber geometry, the agreement between simulation and measurement is quite satisfactory.
        Speaker: Ward Wurtz (Canadian Light Source Inc.)
        Slides
    • 17:15 19:30
      Welcome BBQ Reception / Réception d'accueil avec BBQ CCIS Ground Level Foyer

      CCIS Ground Level Foyer

      University of Alberta

    • 19:30 20:30
      Herzberg Memorial Public Lecture - Miguel Alcubierre, National Univ. of Mexico / Conférence commémorative publique Herzberg - Miguel Alcubierre, National Univ. of Mexico Myer Horowitz Theatre

      Myer Horowitz Theatre

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
      • 19:30
        Faster than the Speed of Light 1h
        In this talk I will give a short introduction to some of the basic concepts of Einstein’s special theory of relativity, which is at the basis of all of modern physics. In particular, I will concentrate on the concept of causality, and why causality implies that nothing can travel faster than the speed of light in vacuum. I will later discuss some of the basic ideas behind Einstein’s other great theory, General Relativity, which is the modern theory of gravity and postulates that the geometry space-time is dynamic and the presence of large concentrations of mass and energy produce a “curvature” in space-time. I will then talk about how the curvature of space-time can be used in several ways to travel “faster than the speed of light” by distorting the geometry away from that of flat space. In particular, I will discuss the ideas behind the geometric model for a “warp drive”.
        Speaker: Prof. Miguel Alcubierre (National University of Mexico)
    • 20:30 21:30
      Post-talk Reception Dinwoodie Lounge

      Dinwoodie Lounge

      University of Alberta

    • 07:30 09:00
      CAP Foundation Annual General Meeting / Assemblée annuelle de la Fondation de l'ACP CCIS 4-285

      CCIS 4-285

      University of Alberta

      Convener: Robert Mann (University of Waterloo)
    • 08:30 16:00
      Exhibit booths open 08:30-16:00 / Salle d'exposition ouverte de 08h30 à 16h00 CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • 08:30 10:00
      Teachers' Day - Session I / Journée des enseignants - Atelier I CCIS L1-047

      CCIS L1-047

      University of Alberta

      • 08:30
        Opening and Welcome, Calvin Kalman from CAP 15m
      • 08:45
        Changing student's approach to learning physics, Calvin Kalman, Chair of CAP Division of Physics Education 30m
      • 09:15
        Metamaterials: Controlling light,heat,sound and electrons at the nanoscale, Zubin Jacob, Electrical and Computer Engineering, UofA 45m
    • 08:45 10:15
      T-PUB Commercial Publishers' Session: Resources to Enhance University Physics Teaching (DPE) / Session des éditeurs commerciaux : Ressources visant à améliorer l’enseignement de la physique à l’Université (DEP) CCIS L1-029

      CCIS L1-029

      University of Alberta

      Convener: Don Mathewson (Division of Physics Education, CAP)
      • 08:45
        Pearson Education’s digital resources for supporting Physics teaching: Mastering Physics 45m
        This presentation will provide an overview of the online resources which Pearson Education can provide to help support your university physics teaching. We will begin with an overview of how one faculty member has implemented and used Pearson resources in his first-year physics course sequence, and the plans in place for including further tools in the coming year. The presentation will then review other available tools that can help enhance your teaching toolkit.
        Speakers: Adam Sarty (Saint Mary's University), Mrs Claire Varley (Customer Experience Manager – Higher Education, Pearson Canada)
        Slides
      • 09:30
        A panel discussion of PER and Enhanced WebAssign in teaching physics 45m
        Join Nelson Education and some of Canada’s leading physics educators for a demonstration of enhanced WebAssign and a discussion around physics education research in practice including the use of digital learning tools to promote better learning outcomes.
        Speakers: Ernie McFarlane (University of Guelph), Marina Milner-Bolotin (The University of British Columbia), Martin Williams (University of Guelph)
    • 08:45 10:15
      T1-1 Superconductivity (DCMMP) / Supraconductivité (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Tatiana Rappoport (Federal University of Rio de Janeiro)
      • 08:45
        Scanning Tunneling Spectroscopy of LiFeAs 30m
        LiFeAs is one of several pnictide and chalcogenide superconductors that can be grown in single-crystal form with relatively few defects. Spectroscopy away from any native defects reveals a spatially uniform superconducting gap, with two distinct gap edges. Quasiparticle interference over the gap energy range provides evidence for an S+- pairing state. We further explore the spectroscopy of both native, and deliberately introduced defects and compare to theoretical calculations for defects in an S+- superconductor.
        Speaker: Prof. D,A. Bonn (University of British Columbia)
      • 09:15
        Interplay of charge density waves and superconductivity 30m
        We examine possible coexistence or competition between charge density waves (CDW) and superconductivity (SC) in terms of the extended Hubbard model. The effects of band structure, filling factor, and electron-phonon interactions on CDW are studied in detail. In particular, we show that van Hove singularities per se can lead to the formation of CDW, due to a substantial energy gain by electron-phonon coupling. While this is contrary to the conventional view that CDW are caused by nesting of Fermi surfaces, it is consistent with recent experimental findings.
        Speaker: Kaori Tanaka (University of Saskatchewan)
      • 09:45
        Quantum oscillation studies of quantum criticality in PrOs$_4$Sb$_{12}$ 15m
        PrOs$4$Sb${12}$ is a cubic metal with an exotic superconducting ground state below 1.8 K. The crystal fields around the Pr site are such that it has a singlet ground state and a magnetic triplet just 8K above the ground state. Under an applied magnetic field, the triplet splits, and the S$_z = +1$ state crosses the singlet state at easily accessible magnetic fields. In the region of the level crossing the ground state reconstructs, creating a so-called “antiferroquadrupolar” (AFQ) phase that exists at temperatures below $1$ K and magnetic fields between about $4.5$ and $12$ tesla. This state offers a rare opportunity to observe the behaviour of quantum oscillations upon crossing a phase transition. In a recent paper [$1$] we argued that the lower boundary of the AFQ phase should have exotic behaviour as T $\rightarrow 0$ K due to mixing of hyperfine states with the AFQ order. We will describe our attempts to observe this behaviour via magnetic susceptibility and quantum oscillation measurements. [$1$] A. McCollam, B. Andraka and S. R. Julian, Physical Review B 88 (2013) 075102.
        Speaker: Dr Stephen Julian (University of Toronto)
      • 10:00
        A Variational Wave Function for Electrons coupled to Acoustic Phonons 15m
        We survey briefly the electron-phonon interactions in metals with an emphasis on applications in electron-phonon mediated superconductivity. While BCS theory and Eliashberg theory have significant predictive power, the microscopic Hamiltonians for the processes they describe are still an open area of study. We will examine the hitherto unsolved BLF-SSH model of electrons interacting with acoustical phonons and present a novel variational wave function for the solution of this model. We examine the validity of this variational wave function across applicable parameter regimes.
        Speaker: Carl Chandler (University of Alberta)
    • 08:45 10:15
      T1-10 THz science and applications (DAMOPC) / Sciences et applications des THz (DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Matt Reid (University of northern british columbia)
      • 08:45
        Ultrafast dynamics of mobile charges and excitons in hybrid lead halide perovskites 30m
        In this talk we discuss recent experiments using ultra-broadband time-resolved THz spectroscopy (uTRTS) studying charge and excitonic degrees of freedom in the novel photovoltaic material CH3NH3PbI3. This technique uses near single-cycle and phase stable bursts of light with an ultra-broad bandwidth spanning 1 - 125 meV to take snapshots of a material's dielectric function or optical conductivity on femtosecond time scales after photoexcitation. These transient spectra reveal free charge transport properties on unprecedented time scales, and at the same time can probe internal excitations of Coulombically bound excitons. It is therefore an ideal technique for studying materials related to solar energy conversion such as semiconducting polymers, quantum dots and even the new hybrid metal halide perovskites. We apply uTRTS to a single crystal of CH3NH3PbI3, temporally resolving the charge carrier generation dynamics, the screening of infrared active phonons and the dissociation of excitons. Our measurements reveal remarkably high charge carrier mobilities on ultrafast time scales, as well as the importance of screening at elevated carrier densities.
        Speaker: David Cooke (McGill University)
      • 09:15
        Carrier dynamics in semiconductor nanowires studied using optical-pump terahertz-probe spectroscopy 30m
        The advance of non-contact measurements involving pulsed terahertz radiation presents great interests for characterizing electrical properties of a large ensemble of nanowires. In this work, InP and Si nanowires grown by molecular beam epitaxy or by chemical vapor deposition on silicon substrates were characterized using optical-pump terahertz probe (OPTP) transmission experiments. The influence of various fabrication parameters (v.g. doping and NW diameter) on the carrier dynamics has been investigated. Photocarrier lifetimes and mobilities can be extracted from such OPTP measurements.
        Speaker: Prof. Denis Morris (Département de physique, Université de Sherbrooke)
      • 09:45
        Towards quantum repeaters using frequency multiplexed entanglement 15m
        Quantum communication is based on the possibility of transferring quantum states, generally encoded into so-called qubits, over long distances. Typically, qubits are realized using polarization or temporal modes of photons, which are sent through optical fibers. However, photons are subject to loss as they travel through optical fibers or free space, which sets a distance barrier of around 100 kilometers. In classical communications, this problem can be straightforwardly solved by amplification, but this is not an option in quantum mechanics because of the non-cloning theorem. Fortunately, photon loss can be overcome by implementing quantum repeaters [1], which create long-distance entanglement via entanglement swapping from shorter-distance entanglement links. Such protocols require the capacity to create entanglement in a heralded fashion, to store it in quantum memories, retrieve it after feed-forward information, and to swap it. A variety of architectures and protocols have been proposed for implementing quantum repeaters [2]. Ideally, a quantum repeater protocol should minimize the physical resources required to establish entanglement between two points. Our team is working on a specific quantum repeater scheme that explores frequency multiplexing. This will allow us to increase the probability of generating short-distance entanglement, with a success rate close to 100%, while taking maximum benefit of the quantum memories developed by other members of our group [3]. The proposed scheme requires quantum memories and entangled photons pair sources capable to work in the frequency multiplexing domain. This presentation will focus on the description of the general scheme and on the multiplexed entangled photon pair sources that we are developing.
        Speaker: Mr Pascal Lefebvre (University of Calgary)
      • 10:00
        True Random Number Generation based on Interference between Two Independent Lasers 15m
        Reliable true random number generation is essential for information theoretic security in a quantum cryptographic system based on quantum key distribution (QKD) and one-time pad encryption [1]. Various random number generation methods have already been proposed and demonstrated, such as schemes based on the detection of single photons [2], whose rate is limited by the dead time of single photon detectors. Alternative approaches are based on the chaotic light emission from a semiconductor laser [3, 4]. In this talk we propose and demonstrate a novel scheme to generate random numbers based on interference between two independent lasers, i.e. a continuous wave (CW) laser and a gain-switched pulsed laser, each emitting light at around 1550 nm wavelength. The physical basis of our random number generator is the randomness of the phase difference between light emitted from the two independent lasers. Using only off-the-shelf components, we achieve a random number generation rate of 250 MHz. The properties of the generated random numbers are tested using National Institute Standards and Technology (NIST) statistical test suite. We also discuss the extension of our methods from random bits to randomly selected symbols with more than two different values. References [1] N. Gisin, and R. Thew, “Quantum communication,” Nature Photon. 1, 165 (2007). [2] A. Stefanov, N. Gisin, O. Guinnard, L. Guinnard, and H. Zbinden, “Optical quantum random number generator,” J. Mod. Opt. 47, 595 (2000). [3] T. Symul, S. M. Assad, and P. K. Lam, “Real time demonstration of high bitrate quantum random number generation with coherent laser light,” Appl. Phys. Lett. 98, 231103 (2011). [4] A. Uchida, K. Amano, M. Inoue, K. Hirano, S. Naito, H. Someya, I. Oowada, T. Kuashige, M. Shiki, S. Yoshimori, K. Yoshimura, and P. Davis, “Fast physical random bit generation with chaotic semiconductor lasers,” Nature Photon. 2, 728 (2008).
        Speaker: Caleb John (University of Calgary)
        Slides
    • 08:45 10:15
      T1-11 Medical Imaging (DMBP) / Imagerie médicale (DPMB) CAB 239

      CAB 239

      University of Alberta

      Convener: Melanie Martin (University of Winnipeg)
      • 08:45
        The Rate of Reduction of Defocus in the Chick Eye is Proportional to Retinal Blur 15m
        PURPOSE. Calculations of retinal blur and eye power are developed and used to study blur on the retina of the growing chick eye. The decrease in defocus and optical blur during growth is known to be an active process. Here we show that the rate of defocus reduction is proportional to the amount of blur on the retina. METHODS. From literature values of chick eye parameters, the amounts of defocus and optical axial length were fitted as a function of age. Pupil size was used to calculate blur on the retina due to defocus. Eye length and calculated eye power were compared up to day 75 to examine their contributions to decreasing retinal blur. Novel equations were used to calculate eye power and a new definition of the end point of active defocus reduction is introduced. RESULTS. During initial growth, eye length increases while blur from defocus decreases. Eye power decreases exponentially reaching and closely matching eye length after day 35. This gives an almost stable value of defocus beyond day 50. Retinal blur decreases almost exponentially until between days 40 and day 50. After day 50, angular retinal blur changes in agreement with predictions of a uniformly expanding eye model and passive growth. CONCLUSIONS. Concurrent variations in eye power and length produce smaller changes in defocus. We define the time at which angular retinal blur becomes stable as the completion of active reduction of defocus. Prior to this time, the rate of defocus reduction is proportional to the amount of blur on the retina. After this time, the measured eye properties are consistent with uniform eye expansion and angular blur is close to the presumed resolution limit of the cone photoreceptors. The eye power calculation presented is accurate and simpler than other approaches without the need for additional dimensional data.
        Speaker: Prof. Melanie Campbell (University of Waterloo)
      • 09:00
        Image Analysis and Quantification for PET Imaging 15m
        Introduction: Positron emission tomography (PET) is a highly sensitive, quantitative and non-invasive detection method that provides 3D information on biological functions inside the body. There are several factors affecting the image data, including normalization, scattering, and attenuation. In this study we have quantified the effect of scattering and attenuation corrections on the PET data. Methods: The image quality phantom (approximating the size of a mouse) was modified to match the diameters of the rat and monkey count rate phantoms by creating high density polyethylene (HDPE) sleeves that fit over the standard phantom. The emission and transmission data from the phantom, filled with 18F, were acquired with a microPET P4 scanner. The data were histogrammed, reconstructed, using various algorithms, with required corrections applied, including normalization and physical decay of 18F. The data were analyzed using volume of interest (VOI) analysis with and without attenuation or scattering corrections. Signal–to-noise ratio values were calculated and the results were correlated with the phantom size, correction methods and reconstruction algorithm. Results: The signal to noise using OSEM3D/MAP algorithm provided the highest signal-to-noise ratio values for all three phantoms, followed by OSEM2D. Since both are iterative algorithms and reduce the noise in the images. Attenuation correction, along with scattering correction had a significant impact on the quantitative results. Conclusion: Both attenuation and scattering corrections need to be included in image quantification for PET imaging. OSEM3D/MAP provides the images with highest signal-to-noise ratio values.
        Speaker: Dr Esmat Elhami (University of Winnipeg)
      • 09:15
        Magnetic Susceptibility Mapping in Human Brain using High Field MRI 30m
        Magnetic Resonance Imaging (MRI) is a powerful imaging method for examining hydrogen protons and their local environment. Inferences can be made about the local environment from the signal relaxation (decay or recovery) or phase evolution. For many years, phase images were largely discarded in favor of magnitude images only, which dominate clinical MRI. Although the sensitive nature of phase images to magnetic field perturbations can cause a high degree of artifact, phase images also provide a means to examine the underlying local susceptibility distribution. Extraction of the local susceptibility requires removing nonlocal field effects that arise from strong air-tissue susceptibility differences, then performing an ill-posed inverse problem on the local magnetic field to yield the susceptibility map. This emerging MRI research area named Quantitative Susceptibility Mapping (QSM) provides a means to discriminate between tissues such as myelin, calcium and iron. This talk will introduce QSM and explore its value in human brain, particularly for measurement of iron accumulation in grey matter. These measures are further enhanced by using higher magnetic field strengths, greater than the clinical standards of 1.5 and 3.0 T. The value of these stronger magnetic fields will also be explored.
        Speaker: Dr Alan Wilman (University of Alberta)
      • 09:45
        Correlating quantitative MR changes with pathological changes in the white matter of the cuprizone mouse model of demyelination 15m
        Mouse brain white matter (WM) damage following the administration of cuprizone was studied weekly using diffusion tensor imaging, quantitative magnetization transfer imaging, T2-weighted MRI (T2w), and electron microscopy (EM). A previous study examined correlations between MR metrics and EM measures after 6 weeks of feeding. The addition of weekly *ex vivo* tissue analysis allows for a more complete understanding of the correlations between MR metrics and EM measures of tissue pathology. Signal inversion is apparent in the T2w images as the number of weeks of cuprizone feeding increased. A decreased magnetization transfer ratio (MTR) is observed in the WM regions of the cuprizone mouse as cuprizone feeding continued. Many changes are observed in the *ex vivo* data including directionality changes in the external capsule in the directional encoded map of diffusion tensor imaging from weeks 1 to 6. From the EM images, myelinated axons are apparent in both cuprizone and control mice. Cuprizone is associated with oligodendroglial swelling and apoptosis. The significant change between control and cuprizone mice in the corpus callosum peaks in T2w at week 3 whereas it peaks at week 4 in MTR. The first large change in T2w occurs between weeks 2 and 3 in the external capsule and between weeks 3 and 4 in the MTR. Radial diffusivity appears to be different between control and cuprizone mice even in week 1. The weekly changes in radial diffusivity follow a different time course than MTR and T2 in the cuprizone mouse. The different time courses of the MR metrics suggest that T2, MTR and diffusivity are sensitive to different pathological features in WM. ANOVA will be used to determine when significant changes occur in MRI metrics. EM analysis of the tissue is in progress for correlations with WM pathology. Visually it can be seen in the EM images at week 3 that the control and cuprizone corpus callosum show a similar amount of myelinated axons. Our results are consistent with EM from other studies suggesting MTR likely reflects demyelination. The addition of the weekly *ex vivo* tissue analysis allows for a more complete understanding of the correlations between MR metrics and EM measures of tissue pathology.
        Speaker: Prof. Melanie Martin (Physics, University of Winnipeg, Radiology, University of Manitoba)
        Slides
      • 10:00
        Interstitial point radiance spectroscopy in turbid media 15m
        Optical spectroscopy has become a valuable tool in biomedical diagnostics because of its ability to provide biochemical information on endogenous and exogenous chromophores present in tissues. In this work, point radiance spectroscopy using a white light source is investigated 1) to measure the optical properties of bulk tissues and 2) to detect localized gold nanoparticles in tissue mimicking Intralipid and porcine muscle phantoms. An angular sensitive detector made from a side-firing fiber was developed and used to measure the angular distribution of light (up to 180 degree rotation of the fiber) in selected locations in a phantom. Rotation provides angular optical data for analysis. An alternative approach is to use non-directional fluence data, but for optical property recovery, this requires translation of the fiber which is not desirable. In our radiance approach, the white light source also provides some spectroscopic information (focused in the 650-900 nm band) in addition to spatial information of a target (i.e. gold nanoparticles). We have measured the effective attenuation coefficient, diffusion coefficient, absorption coefficient and reduced scattering coefficient of Intralipid phantoms and thermally coagulated porcine muscle. Further, gold nanoparticle inclusions embedded in tissue mimicking media and ex vivo tissues were detectable via a novel spectro-angular analysis technique. This work is focused on the development of a new optical fiber based tool for disease detection. Funding: NSERC Discovery Grant, Atlantic Innovation Fund, Canada Foundation for Innovation and Canada Research Chairs Program
        Speaker: Dr Bill Whelan (Dept of Physics, University of Prince Edward Island)
    • 08:45 10:15
      T1-2 Many body physics & Quantum Simulation (DAMOPC-DCMMP) / Physique des N corps et simulation quantique (DPAMPC-DPMCM) CAB 235

      CAB 235

      University of Alberta

      Convener: Shohini Ghose
      • 08:45
        Universal features of quantum dynamics: quantum catastrophes 30m
        Tracking the quantum dynamics following a quench of a range of simple many-body systems (e.g. the two and three site Bose-Hubbard models, particles on a ring), we find certain common structures with characteristic geometric shapes that occur in all the wave functions over time. What are these structures and why do they appear again and again? I will argue that they are quantum versions of the catastrophes described by catastrophe theory [R. Thom (1975), V.I. Arnol’d (1975)]. Quantum catastrophes occur in quantum fields: they are singular in the mean-field limit and require second-quantization to be well behaved, i.e. the essential discreteness of the excitations of the quantum field needs to be taken into account for a quantum catastrophe to be regularized. They are second quantized versions of more familiar catastrophes such as rainbows and the bright lines on the bottom of swimming pools (although the latter are rarely described in these terms!). Their universality stems from the fact that they are generic (need no symmetry) and structurally stable (immune to perturbations) as guaranteed by catastrophe theory.
        Speaker: Duncan O'Dell (McMaster University)
        Slides
      • 09:15
        Hot and Cold Dynamics of Trapped Ion Crystals near a Structural Phase Transition 15m
        Small arrays of laser-cooled trapped ions are widely used for quantum information research, but they are also a versatile mesoscopic system to investigate physics with a flavor reminiscent of familiar models in condensed matter. For example, in a linear rf Paul trap, laser-cooled trapped ions will organize into a linear array when the transverse confinement of the trap is strong enough; however, at a critical trap anisotropy the ions will undergo a symmetry–breaking structural transition to a two-dimensional zigzag configuration. We have studied what is effectively the melting behavior of the ion arrays near to the linear-zigzag transition. We have also investigated the classical non-equilibrium dynamics during rapid quenches of the transition in order to test the Kibble-Zurek mechanism of topological defect formation across a symmetry-breaking transition. In this talk I will present our current investigations of dynamics near the linear-zigzag transition at ultralow temperatures, corresponding to just a few quanta of thermal energy in the vibrations of the ion array. I will discuss our implementation of a new laser cooling technique for trapped Ytterbium ions and our progress towards experiments in the quantum regime. For example, we are interested in whether decoherence effects can be sufficiently suppressed to prepare superpositions of the symmetry-broken configurations.
        Speaker: Paul C Haljan (Simon Fraser University)
      • 09:30
        Simulating Anderson localization via a quantum walk on a one-dimensional lattice of superconducting qubits. 15m
        Quantum walk (QW) on a disordered lattice leads to a multitude of interesting phenomena, such as Anderson localization. While QW has been realized in various optical and atomic systems, its implementation with superconducting qubits still remains pending. The major challenge in simulating QW with superconducting qubits emerges from the fact that on-chip superconducting qubits cannot hop between two adjacent lattice sites. In this talk, I discuss how to overcome this barrier and develop a gate-based scheme to realize the discrete time QW by placing a pair of qubits on each site of a 1D lattice and treating an excitation as a walker. It is also shown that various lattice disorders can be introduced and fully controlled by tuning the qubit parameters in our quantum walk circuit. We observe a distinct signature of transition from the ballistic regime to a localized QW with an increasing strength of disorder. Finally, an eight-qubit experiment is proposed where the signatures of such localized and delocalized regimes can be detected with existing superconducting technology.
        Speaker: Joydip Ghosh (University of Calgary)
        Slides
      • 09:45
        Cold Atom Metrology: Progress towards a New Absolute Pressure Standard 30m
        Laser cooling and trapping of atoms has created a revolution in physics and technology. For example, cold atoms are now the standard for time keeping which underpins the GPS network used for global navigation. In this talk, I will describe a research collaboration between BCIT, UBC (Kirk Madison) and NIST (Jim Fedchak - Sensor Science Division) with the goal of creating a cold atom (CA) based primary pressure standard for the high- and ultra-high vacuum regimes: A cold, trapped atom can act as a sensitive detector for a particle that passes through its collision cross-section and imparts momentum to it. The collision event is registered if the sensor atom's momentum gain is high enough to escape the trap. Thus, an ensemble of confined atoms measures the flux of particles via the observed loss rate of sensor atoms from the trap. In short, the particle flux (pressure) passing through the sensor atom volume transduces a timing signal (loss rate). The loss rate is sensitive to the type of collision and to the trap depth confining the atoms [1]. These factors afford an opportunity to study collision physics and the physics of the trap while working towards a new standard. The advantages of a CA standard include the fact the sensor relies on immutable properties of atomic matter and their interactions and that it will be a primary pressure standard, tied directly to the second, a base SI unit. This absolute standard would provide a valuable alternative to gas expansion/orifice flow transfer standards currently in use. In this talk I will review the basic ideas supporting the science and technology, along with an update on our progress. [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: Dr James Booth (British Columbia Institute of Technology)
    • 08:45 10:15
      T1-3 Ground-based / in situ observations and studies of space environment I (DASP) / Observations et études de l'environnement spatial, sur terre et in situ I (DPAE) CAB 243

      CAB 243

      University of Alberta

      Convener: Konstantin Kabin (RMC)
      • 08:45
        Exoplanet Atmospheres: Triumphs and Tribulations 30m
        From the first tentative discoveries to veritable spectra, the last 15 years has seen a triumphant success in observation and theory of exoplanet atmospheres. Yet the excitement of discovery has been mitigated by lessons learned from the dozens of exoplanet atmospheres studied, namely the difficulty in robustly identifying molecules, the possible interference of clouds, and the permanent limitations from a spectrum of spatially unresolved and globally mixed gases without direct surface observations. Nonetheless the promise and expectation is that the next generation of space telescopes will have the capability of detecting atmospheric biosignature gases if they exist on planets orbiting nearby stars, and the vision for the path to assess the presence of life beyond Earth is being established.
        Speaker: Prof. Sara Seager (Massachusett institute of technology)
      • 09:15
        The Far-Infrared Universe: from the Universe's oldest ligth to the birth of its youngest stars 15m
        Over half of the energy emitted by the Universe appears in the relatively unexplored Far-Infrared (FIR) spectral region, which is virtually opaque from the ground and must be observed by space-borne instrumentation. The European Space Agency (ESA) Planck and Herschel Space Observatories, launched together on 14 May 2009, have both provided pioneering observations in this spectral range from star and planet formation to the intensity and polarization of the cosmic microwave background. Herschel and Planck completed observations in April and October of 2013, respectively. Although data analysis efforts within the instrument teams are ongoing, both have provided data and analysis tools to ESA public archives, with more software updates and data releases expected to continue into 2015 and 2016, including the much anticipated Planck polarisation data and results. Recent Planck and Herschel results are presented with a discussion of the development of, and Canadian participation in, the future of FIR astrophysics.
        Speaker: Jeremy Scott (University of Lethbridge)
        Slides
      • 09:30
        Neutron Monitor Atmospheric Pressure Correction Method Based on Galactic Cosmic Rays tracing and MCNP Simulations of Cascade Showers 15m
        Nuclear spallations accompanying Galactic Cosmic Ray (GCR) propagation through the atmosphere forms a so-called "cascade shower" by means of production of secondary protons, photons, neutrons, muons, pions and other energetic particles. World-wide Neutron Monitor (NM) network has been deployed for the ground-based monitoring of energetic protons and neutrons precipitations. Real time data from 36 NMs (including Calgary NM) are collecting in the Neutron Monitor Database (NMDB) [http://www.nmdb.eu]. However, each monitor has its own detection efficiency, which depends on NM location, design, operational and atmospheric parameters, so NM counting rates must be normalized. We developed and implemented a numerical technique which allows NM count rates estimation based on the spectrum of primary GCR, NM location, its internal design, and atmospheric parameters. Primary GCR are tracing to the top of atmosphere using our in-home computational tool [Kouznetsov, 2013]. The background proton and neutron particle fluxes are computed at Calgary NM location based on MCNP6 simulations and MSIS-E-90 Atmosphere Model [http://omniweb.gsfc.nasa.gov/vitmo/msis_vitmo.html]. Results obtained for Calgary NM improve standard atmospheric pressure correction procedure and can be used to normalize counting rates for the world-wide NM network.
        Speaker: Alexei Kouznetsov (University of Calgary)
      • 09:45
        Ionospheric Sounding Opportunities Using Signal Data From Pre-existing Amateur Radio And Operational Networks 15m
        Amateur radio and other signals used for dedicated purposes, such as the Automatic Position Reporting System (APRS) and Automatic Dependent Surveillance Broadcast (ADS-B), are signals that exist for another reason, but can be used for ionospheric sounding. Whether mandated and government funded or voluntarily constructed and operated, these networks provide data that can be used for scientific and other operational purposes which rely on space weather data. Given the current state of the global economic environment and fiscal consequences to scientific research funding in Canada, these types of networks offer an innovative solution with pre-existing hardware for more real-time and archival space-weather data to supplement current methods, particularly for data assimilation, modelling and forecasting. Furthermore, the mobile ground-based transmitters offer more flexibility for deployment than stationary receivers. Numerical modeling has demonstrated that APRS and ADS-B signals are subject to Faraday rotation as they pass through the ionosphere. Ray tracing techniques were used to determine the characteristics of individual waves, including the wave path and the state of polarization at the satellite receiver. The modeled Faraday rotation was computed and converted to total electron content (TEC) along the ray paths. TEC data can be used as input for computerized ionospheric tomography (CIT) in order to reconstruct electron density maps of the ionosphere. The primary scientific interest of this study was to show that these signals can be used as a new source of data for CIT to image the ionosphere, possibly other data assimilation models, and to obtain a better understanding of magneto-ionic wave propagation.
        Speaker: Alex Cushley
      • 10:00
        SELF- AND AIR-BROADENED LINE SHAPE PARAMETERS OF METHANE IN THE 2.3 MICRONS RANGE 15m
        Methane is an important greenhouse gas in the terrestrial atmosphere and a trace gas constituent in planetary atmospheres. We report measurements of the self- and air-broadened Lorentz widths, shifts and line mixing coefficients along with their temperature dependences for methane absorption lines in the 2.22 to 2.44 microns spectral range. This set of highly accurate spectral line shape parameters is needed for radiative transfer calculations in terrestrial or planetary atmospheres. This research was performed in collaboration with colleagues from the College of William and Mary, Williamsburg,VA, NASA Langley Research Center and Jet Propulsion Laboratory.
        Speaker: Adriana Predoi-Cross (University of Lethbridge)
        Slides
    • 08:45 10:15
      T1-4 Mathematical Physics (DTP) / Physique mathématique (DPT) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Andrew Frey (University of Winnipeg)
      • 08:45
        Geometrization of N-Extended 1-Dimensional Supersymmetry Algebras 30m
        The problem of classifying off-shell representations of the N-extended one-dimensional super Poincare algebra is closely related to the study of a class of decorated graphs known as Adinkras. We show that these combinatorial objects possess a form of emergent supergeometry: Adinkras are equivalent to very special super Riemann surfaces with divisors. The method of proof critically involves Grothendieck's theory of "dessins d'enfants", work of Cimasoni-Reshetikhin expressing spin structures on Riemann surfaces via dimer models, and an observation of Donagi-Witten on parabolic structure from ramified coverings of super Riemann surfaces.
        Speaker: Charles Doran (University of Alberta)
      • 09:15
        Some discrete-flavoured approaches to Dyson-Schwinger equations 30m
        I will discuss two recent ideas on how to better understand the underlying structure of Dyson-Schwinger equations in quantum field theory. These approaches use primarily combinatorial tools; classes of rooted trees in the first case and chord diagrams in the second case. The mathematics is explicit and approachable.
        Speaker: Karen Yeats (Simon Fraser University)
        Slides
      • 09:45
        Novel Charges in CFT's 15m
        In this talk we construct two infinite sets of self-adjoint commuting charges for a quite general CFT. They come out naturally by considering an infinite embedding chain of Lie algebras, an underlying structure that share all theories with gauge groups U(N), SO(N) and Sp(N). The generality of the construction allows us to carry all gauge groups at the same time in a unified framework, and so to understand the similarities among them. The eigenstates of these charges are restricted Schur polynomials and their eigenvalues encode the value of the correlators of two restricted Schurs. The existence of these charges singles out restricted Schur polynomials among the number of bases of orthogonal gauge invariant operators that are available in the literature.
        Speaker: Dr Pablo Diaz Benito (University of Lethbridge)
      • 10:00
        Yang-Mills Flow in the Abelian Higgs Model 15m
        The Yang-Mills flow equations are a parabolic system of partial differential equations determined by the gradient of the Yang-Mills functional, whose stationary points are given by solutions to the equations of motion. We consider the flow equations for a Yang-Mills-Higgs system, where the gauge field is coupled with a scalar field. In particular we consider the Abelian case with axial symmetry. In this case we have vortex-type classical solutions corresponding to Ginzburg-Landau model of superconductivity. In this case the flow equations are reduced to two coupled partial differential equations in two variables, which we can solve numerically given initial conditions. Looking at the behaviour of the flow near the solutions in this model tells us about the stability of the solutions, and in the case of stable solutions allows us to approximate the solutions numerically. Study of the flow in the dimensionally reduced Abelian case provides a starting point for studying flows in more complicated cases, such as non-Abelian Higgs models, or full 3+1 dimensional theories. Using the AdS/CFT correspondence, which provides an equivalence between a field theory and a gravitational theory in one higher dimension where Yang-Mills flow could be compared with more well known geometric flow equations such as Ricci flow.
        Speaker: Paul Mikula (University of Manitoba)
        Slides
    • 08:45 10:15
      T1-5 Energy Frontier: Susy & Exotics I (PPD-DTP) / Frontière d'énergie: supersymétrie et particules exotiques I (PPD-DPT) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Reyhaneh Rezvani (Université de Montréal)
      • 08:45
        Natural and unnatural SUSY 30m
        After the first run of LHC, the parameter space of supersymmetric theories is under serious pressure. In this talk I will present attempts at natural SUSY model building and also discuss the consequences of relaxing the naturalness assumption of supersymmetric theories.
        Speaker: Thomas Gregoire (Carleton University)
        Slides
      • 09:15
        Hunt for Supersymmetry with the ATLAS detector at LHC 30m
        Supersymmetry is one of the most motivated theories beyond the Standard Model of particle physics. It explains the mass of the observed Higgs boson and provides a Dark Matter candidate among other attractive features. A striking prediction of Supersymmetry is the existence of a new particle for each Standard Model one. I will highlight results of the extensive program of the ATLAS Collaboration searching for supersymmetric particles with the Run 1 data of 2012 and show the discovery potential of Run 2 starting in the summer of 2015.
        Speaker: Zoltan Gecse (University of British Columbia (CA))
        Slides
      • 09:45
        A search for heavy gluon and vector-like quark in the 4b final state in pp collisions at 8 TeV 15m
        Searches for vector-like quarks are motivated by Composite Higgs models assuming a new strong sector and predict the existence of new heavy resonances. A search for single production of vector-like quarks is performed for the through the exchange of a heavy gluon in the $p p \to G^* \to B\bar b/\bar B b \to H b \bar b \to b~\bar b~b~\bar b$ process, where $G^*$ is a heavy color octet vector resonance and $B$ a vector-like quark of charge -1/3. The largest background, QCD multi-jet, is estimated using a data-driven method. In case of no excess of events, upper limits on the production cross sections and lower limits in the 2D plane {m_G^*, m_B} will be set.
        Speaker: Frederick Dallaire (Universite de Montreal (CA))
        Slides
      • 10:00
        Electroweak Baryogenesis and the LHC 15m
        It is not known how to explain the excess of matter over antimatter with the Standard Model. This matter asymmetry can be accounted for in certain extensions of the Standard Model through the mechanism of electroweak baryogenesis (EWBG), in which the extra baryons are created in the early Universe during the electroweak phase transition. In this talk I will review EWBG, connect it to theories of new physics beyond the Standard Model, and show that in many cases the new particles and interactions required for efficient EWBG can be discovered using existing and expected data from the LHC.
        Speaker: David Morrissey (TRIUMF)
        Slides
    • 08:45 10:15
      T1-6 Cosmic Frontier: Cosmology II (PPD-DTP-DIMP) / Frontière cosmique: cosmologie II (PPD-DPT-DPIM) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Claudio Kopper (University of Alberta)
      • 08:45
        New results from Planck 30m
        The Planck satellite has completed its mission to map the entire microwave sky at nine separate frequencies. A new data release was made in February 2015, based on the full mission, and including some polarization data for the first time. The Planck team has already produced more than 100 papers, covering many different aspects of the cosmic microwave background (CMB). We have been able to learn in detail about the physics of the interstellar medium in our Galaxy, and to remove this foreground emission in order to extract the cosmological information from the background radiation. Planck's measurements lead to an improved understanding of the basic model which describes the Universe on the very largest scales. In particular, a 6 parameter model fits the CMB data very well, with no strong evidence for extensions to that sceneraio. There are constraints on inflationary models, neutrino physics, dark energy and many other theoretical ideas. New cosmological probes include CMB lensing, CMB-extracted clusters of galaxies, the Cosmic Infrared Background and constraints on large-scale velocities. This talk will highlight some of the new results of the 2015 papers, including the improvements coming from the addition of polarization dimension.
        Speaker: Douglas Scott (UBC)
      • 09:15
        **WITHDRAWN** Planck, gravity waves, and cosmology in the 21st century 30m
        In this talk I'll survey the current observational status in cosmology, highlighting recent developments such as results from the Planck satellite, and speculate on what we might achieve in the future. In the near future some important milestones will be exploration of the neutrino sector, and much better constraints on the physics of the early universe via B-mode polarization. In the far future we can hope to measure a variety of cosmological parameters to much higher precision than they are currently constrained.
        Speaker: Kendrick Smith (Perimeter Institute for Theoretical Physics)
      • 09:45
        The CHIME Dark Energy Project 15m
        The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a novel radio telescope currently under construction at the Dominion Radio Astrophysical Observatory in Penticton, BC. Comprising four 20-m by 100-m parabolic cylinders, each equipped with 256 antennas along its focal line, CHIME is a `software telescope' with no moving parts. It will measure the 21-cm emission from neutral hydrogen to map the distribution of matter between redshifts 0.8 and 2.5, over most of the northern sky. By following the apparent size of the baryon acoustic oscillation (BAO) feature in the data, we can measure the expansion history of the Universe over an epoch where the effects of Dark Energy began to become important and thereby improve our understanding of this recently discovered phenomenon. The science goals, technical details, and current status of CHIME will be presented.
        Speaker: Prof. David Hanna (McGill University)
        Slides
    • 08:45 10:15
      T1-7 Nuclear Structure I (DNP) / Structure nucléaire I (DPN) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Adam Garnsworthy (TRIUMF)
      • 08:45
        Light Exotic Nuclei Studied via Resonance Scattering 30m
        Remarkable advances have been made toward achieving the long-sought-after dream of describing properties of nuclei starting from realistic nucleon-nucleon interactions in the last two decades. The ab initio models were very successful in pushing the limits of their applicability toward nuclear systems with ever more nucleons and exotic neutron to proton ratios. Predictions of these models often are very close to the experimental data, but sometimes deviate from experiment substantially. For example, the exotic isotope of helium, $^9$He, represents a curious case of stark disagreement between the predictions of modern theories and what is believed to be the experimental knowledge of this nucleus. In this talk I will present recent experimental results that shed light on structure of $^9$He and some other light exotic nuclei that were studied using resonance scattering approach and will discuss these findings in view of predictions of the ab initio models.
        Speaker: Grigory Rogachev (Texas A&M University)
      • 09:15
        Low-energy, precision experiments with ion traps: mass measurements and decay spectroscopy 30m
        The atomic mass is a unique identifier of each nuclide, akin to a human fingerprint, and manifests the sum of all interactions among its constituent particles. Hence it provides invaluable insights into many disciplines from forensics to metrology. At TRIUMF Ion Trap for Atomic and Nuclear science (TITAN), Penning trap mass spectrometry is performed on radioactive nuclides, particularly those with half-lives of as short as 9 ms. The TITAN mass values of Mg-20 and Mg-21 have been used to test the isobaric multiplet mass equation (IMME), revealing its dramatic breakdown. On the other side of the valley of stability, the increasingly detailed mass survey in the island of inversion on nuclides has exposed the lowest shell gap of any magic nucleus and the first crossover in the two-neutron separation energy. At heavier masses, neutron-rich Rb and Sr isotopes have been charge bred and their masses measured to probe the r-process, which is believed to be responsible for the production of roughly 50% of the abundance of elements heavier than Fe. A highlight of recent results and an overview of the advanced ion-manipulation techniques used will be presented.
        Speaker: Anna Kwiatkowski (TRIUMF)
      • 09:45
        Electric Monopole Transition Strengths in $^{62}$Ni 15m
        Excited states in $^{62}$Ni were populated with a (p, p') reaction using the 14UD Pelletron accelerator at the Australian National University. The proton beam had an energy of 5 MeV and was incident upon a self-supporting $^{62}$Ni target of 1.2 mg/cm$^2$. Electric monopole transition strengths were measured from simultaneous detections of the internal conversion electrons and $\gamma$-rays emitted from the de-excitating states, using the Super-e spectrometer coupled with a Germanium detector. The Super-e spectrometer has a superconducting solenoid magnet with its magnetic axis arranged perpendicular to the beam axis, which transports the electrons from the target to the 9 mm thick Si(Li) detector array which is situated 350 mm away from the target. The strength of the $0_2^+ \rightarrow 0_1^+$ transition has been measured to be 77$^{+23}_{-34} \times 10^{-3}$ and agrees with previously reported values. Upper limits have been placed on the $0^+_3 \rightarrow 0^+_1$ and $0^+_3 \rightarrow 0^+_2$ transitions. The measured $\rho^2(E0)$ value of the $2^+_2 \rightarrow 2^+_1$ transition in $^{62}$Ni has been measured for the first time and found to be the largest $\rho^2(E0)$ value measured to date in nuclei heavier than Ca. The low-lying states of $^{62}$Ni have previously been classified as one- and two-phonon vibrational states based on level energies. The measured electric quadrupole transition strengths are consistent with this interpretation. However as electric monopole transitions are forbidden between states which differ by one phonon number, the simple harmonic quadrupole vibrational picture is not sufficient to explain the large $\rho^2 (E0)$ value for the $2^+_2 \rightarrow 2^+_1$ transition. A discussion of the results and experimental technique will be presented, along with preliminary shell model calculations.
        Speaker: Mr Lee J. Evitts (TRIUMF)
      • 10:00
        **WITHDRAWN** Fast-timing mesurements in neutron-rich $^{65}$Co 15m
        The region below $^{68}$Ni has recently attracted great attention, from both experimental and theoretical studies, due to the observation of a sub-shell closure at N=40 and Z=28. The collectivity in the region is revealed in the even-even Fe and Cr isotopes by the low energy of the first 2$^+$ states and the enhanced $B(E2;2^+\rightarrow0^+)$ reduced transition probabilities, which peak at 21(5) W.u. for $^{64}$Cr[1], $^{66}$Fe[2] and 22(3) W.u. for $^{68}$Fe[1]. These effects can only be reproduced by large-scale shell model calculations with the inclusion of the $\nu g_{9/2}$ and $\nu d_{5/2}$ orbitals. Precise experimental information on the Co isotopes is important for understanding the nuclear structure in this region, with particular interest in the transition rates, as they can be interpreted as originating from a $\pi f^{-1}_{7/2}$ proton hole coupled to its even-even Ni neighbor. With this aim, a fast-timing ATD $\beta\gamma\gamma$(t) [3] experiment was performed at ISOLDE in CERN, where the $\beta$-decay chain of exotic neutron-rich Mn were measured. In this work we report on the investigation of the low-energy structure of $^{65}$Co populated in the $\beta$-decay of $^{65}$Fe by means of $\gamma\gamma$ and fast-timing spectroscopy. Our $^{65}$Co level scheme confirms the transitions previously observed in [4] and expands it with several new gammas and levels up to $\sim$2.5 MeV. Employing the ATD $\beta\gamma\gamma$(t) method, the half-lives and lifetime limits of some of the low-lying states have been measured for the first time. Some of the deduced transition rates are significantly lower than expected by the systematics of the region, yet this remains to be to be explained by shell model calculations. Making use of the measured half-lives, tentative spin-parities are proposed for some of the lower levels. [1] H.L. Crawford et al., Phys. Rev. Lett. 110, 242701 (2013). [2] W. Rother et al., Phys. Rev. Lett. 106, 022502 (2011). [3] H. Mach et al., Nucl. Instrum. Meth. A280, 49 (1989). [4] D. Pauwels et al. Phys. Rev. C 79, 044309 (2009).
        Speaker: Bruno Olaizola Mampaso (Nuclear Physics Group - University of Guelph)
    • 08:45 10:15
      T1-8 Special session to honor Dr. Akira Hirose I (DPP) / Session speciale en l'honneur de Dr. Akira Hirose I (DPP) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Luc Stafford (U.Montréal)
      • 08:45
        Overview of the Recent J-TEXT Results 30m
        The experimental research in recent years on the J-TEXT tokamak are summarized, the most significant results including observation of core magnetic and density perturbations associated with sawtooth events and tearing instabilities by a high-performance polarimeter-interferometer (POLARIS), investigation of a rotating helical magnetic field perturbation on tearing modes, studies of resonant magnetic perturbations (RMP) on plasma flows and fluctuations, and explorations of high density disruptions in ohmic heating and gas puffing discharges. The POLARIS system developed on J-TEXT has time response up to 1 μs, phase resolution < 0.1o and spatial resolution ~3 cm (17 chords). Such high resolution permits investigations of fast equilibrium dynamics as well as magnetic and density perturbations associated with magnetohydrodynamic (MHD) instabilities. Based on the measurement, temporal evolution of the safety factor profile, current density profile and electron density profile are obtained during sawtooth crash events as well as disruptions. In addition, core magnetic and density perturbations associated with MHD tearing instabilities are clearly detected. Particle transport due to the sawtooth crashes is analyzed. It found that the sawteeth only partially flatten the core density profile, but enhanced particle diffusion on the time scale of the thermal crash occurs over much of the profile. The RMP system on J-TEXT can generate a rotating helical field perturbation with a maximum rotation frequency up to 10 kHz, and dominant resonant modes of m/n = 2/1, 3/1 or 1/1. It is found that tearing modes can be easily locked and then rotate together with a rotating RMP. During the mode locking and unlocking, instead of amplifying the island, the RMP can suppress the island width, especially when there is a small frequency gap between the island and the RMP. The effects of RMPs on plasma flows and fluctuations are studied with Langmuir probe arrays at the plasma edge. Both toroidal rotation velocity and radial electric field increase with RMP coil current when the RMP current is no more than 5kA. When the RMP current reaches 6kA, the toroidal velocity profile becomes flatter near the last closed flux surface. The absolute amplitude of Er also significantly decreases at IRMP = 6 kA. At the same time, the behavior of the poloidal and toroidal turbulent stresses from simultaneous probe measurements are consistent with the Er trends. Both LFZF and GAM are also damped by strong RMPs. Some interesting features of high density disruptions are identified by interpreting the measured POLARIS data and the radiation power measurements. In the density ramp-up phase of a high density disruption shot, an asymmetry of density profile between the Low-Field-Side (LFS) edge (r>0.8a) and the High-Field-Side (HFS) edge (r<-0.8a) would appear and increase gradually. At the same time, an asymmetry of radiation power profile also arises as the result of the asymmetry of density profile at the edge. When the density at the HFS edge increases to nearly twice as large as the density at the LFS edge, a low-frequency (<1kHz) density perturbation suddenly stimulates at the HFS edge and gradually expanded into the center region. The disruption takes place when the density perturbation reaches the location nearly the q=2 surface. All the details will be presented at the meeting.
        Speaker: Ge Zhuang (Huazhong University of Science and Technology)
      • 09:15
        Magnetic Fluctuations Measurements in Magnetized Confinement Plasmas 30m
        Both the magnetic fluctuations and electron density fluctuations are important parameters for fusion-oriented plasma research since fluctuation-driven transport dominates in high temperature magnetic confinement devices. The far-infrared laser systems are employed to measure both the Faraday rotation and electron density simultaneously with time response up to a few microseconds in reversed filed pinch, tokamaks. Fast time response combined with low phase noise also enables us to directly measure magnetic and density fluctuations. The various MHD activities such as sawtooth crash, tearing reconnection and fast particle modes have been observed in various magnetic confinement devices. The high temporal resolution of polarimetry provides excellent platform to study internal magnetic fluctuations and magnetic fluctuation induced transport. The work is supported by US Department of Energy.
        Speaker: Dr Weixing Ding (UCLA)
      • 09:45
        Plasma Ion Implantation for Photonic and Electronic Device Applications 30m
        Plasma Ion Implantation (PII) is a versatile ion implantation technique which allows very high fluence ion implantation into a range of targets. The technique is conformal to the surface of the implanted object, which makes it suitable for a wide range of applications. The ease with which high ion fluences can be delivered means that the technique can be used to change the stoichiometry (e.g. elemental composition) as well as the atomic-level structure of the target material in the implanted region. When combined with masking techniques and post-implant thermal processing, PII offers a powerful way to make new materials in-situ (e.g. within an existing solid-state matrix). The Plasma Physics Lab (PPL) at the University of Saskatchewan is home to a custom PII system with ion implantation energies ranging from 0-20 keV. This system is capable of a delivering very high ion doses in short times (e.g. high ion fluences) and has been employed in a range of applications, primarily oriented toward applications in photonics, to modify the properties of a variety of semiconductor materials. It has been used to fabricate luminescent silicon Schottky diodes based on silicon nanocrystals as well as SiC nanocrystallites. A more recent, low energy application of the system is N-doping of graphene, a technologically important new material for future electronic and photonic applications.
        Speaker: Prof. Michael Bradley (Physics & Engineering Physics, University of Saskatchewan)
    • 08:45 10:15
      T1-9 Nanostructured Surfaces and Thin Films (DSS-DCMMP) / Surfaces et couches minces nanostructurées (DSS-DPMCM) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Steve Patitsas (University of Lethbridge)
      • 08:45
        **WITHDRAWN** Electrical and optical properties of electrochromic Tungsten trioxide (WO3) thin films at temperature range 300 to 500K 15m
        During the past decade a great interest has been shown in the study of transition tungsten trioxide (WO3) thin films. The reason is that this transition presents a number of interesting optical and electrical properties. While their optical properties are very well studied in view of their application in smart windows, not much study is focussed on their electrical properties as a function of temperature. In this work we will present a detailed study of the electrical properties of lithium intercalated as a function of the temperature coefficient of resistance (TCR) of WO3 thin films as well as the electrochromic properties of these films. Using the variable range hoping model we calculated the density of states at the Fermi level of a samples prepared by thermal evaporation and inserted with lithium by a dry process. The TCR measurements were performed in temperature range 300 to 500 K. The understanding of this temperature dependent electrical behavior is expected to enhance our understanding of the electrochromic process in these films.
        Speaker: Bassel Abdel Samad (Moncton University)
      • 09:00
        Characterization of the 2D percolation transition in ultrathin Fe/W(110) films using the magnetic susceptibility 15m
        The growth of the first atomic layer of an ultrathin film begins with the deposition of isolated islands. Upon further deposition, the islands increase in size until, at some critical deposition, the merging of the islands creates at least one connected region of diverging size. This universal phenomenon describing connectivity is termed “percolation” and occurs at a “percolation transition” that can be described in renormalization group theory. In the context of a 2-dimensional ultrathin ferromagnetic film, geometric percolation can be monitored through the magnetic susceptibility, since as the island size diverges so does the correlation length of the ferromagnetic state. Although much work has been done studying films of known deposition as a function of temperature to detect percolation, very little work has characterized the transition as it occurs as a function of deposition at constant temperature. We report on measurements of the magnetic susceptibility, using the surface magneto-optic Kerr effect (SMOKE) under ultrahigh vacuum (UHV), as a function of deposition (at constant temperature) for the Fe/W(110) system as the first atomic layer is formed. Two regimes were detected: a high temperature regime with a broad susceptibility peak at larger depositions that represent a standard Curie transition from paramagnetism to ferromagnetism in a continuous film, and a low temperature regime with a much sharper peak in the susceptibility that occurs at the same deposition regardless of temperature. The low temperature regime is a good candidate for a geometric 2-dimensional percolation transition. Preliminary analysis gives a percolation critical exponent of $\gamma = 2.4 \pm 0.2$, in agreement with the result from the 2D Ising model.
        Speaker: Randy Belanger (McMaster University)
        Slides
      • 09:15
        You don't know what you've got 'till it's gone: ambient surface degradation of ZnO powders 15m
        ZnO has rich electronic and optical properties that are influenced by surface structure and composition, which in turn are strongly affected by interactions with water and carbon dioxide. We correlated the effects of particle size, surface area, and crystal habit with data from X-ray photoelectron spectroscopy and zeta potential measurements to compare the degradation of ZnO powders prepared by several different synthesis methods. Neither surface polarity nor surface area, on their own, can account for the differences in the extent of carbonation among differently synthesized ZnO samples, and dissolution is a very significant in some samples [1]. Furthermore, ambient surface carbonation appears to be self-limiting for some ZnO powders (solvothermal synthesis), while ZnO produced by other synthesis methods (solid-state metathesis) can be completely converted to hydrozincite, Zn$_5$(OH)$_6$(CO$_3$)$_2$ in a matter of weeks. We show how these differences in surface carbonation correlate with frequency-dependent electrical properties, emphasizing the impact of ambient humidity variations. [1] J. Cheng and K.M. Poduska, ECS Journal of Solid State Science and Technology, 3 (5) P133-P137 (2014).
        Speaker: Kristin Poduska (Memorial University of Newfoundland)
      • 09:30
        **WITHDRAWN** Density Functional Theory Study of Hydrogen on Metal Oxide and Insulator Surfaces 15m
        Hydrogen molecule is being promoted as an environmentally clean energy source of the future. In order to use hydrogen as a source of energy, infrastructures have to be built. These infrastructures are efficient processes for hydrogen extraction, and efficient processes and materials for hydrogen storage. The major problem facing the use of hydrogen as a clean source of energy is the storage of liquid hydrogen. Hydrogen fuel can be concentrated into a small volume and store it in fuel tanks. The concentration of hydrogen can be done simply by cooling the hydrogen to an extremely low temperature or by compressing it under very high pressure as liquid. The concentrated normal mixture consist 25% *p*-H2, 75 % *o*-H2 and after hours of storage, about 40 % of the original content of the tank evaporates. The reason of this evaporation is the spontaneous conversion of orthohydrogen (*o*-H2) to parahydrogen (*p*-H2) over a period of time. This conversion is releasing enough heat to evaporate most of the liquid hydrogen and yield the explosion of the tank storage. In order to overcome this problem and limit the boil-off to low levels, the tank most be fill with a liquid hydrogen that has already been converted to a mixture close to 100 % *p*-H2. Special procedures are needed to maintain the composition (proportion) of the two types of hydrogen molecules (*o*-H2) and parahydrogen (*p*-H2) to be 100 % *p*-H2. In this presentation we will discuss the results of DFT methods of hydrogen molecule physisorbed on SrTiO3, Fe(OH)3 and MgO(001) surfaces. Energies, orbitals, positions and vibration frequencies of H2 molecule on these surfaces are calculated. Our results show that H2 molecules can physisorbed on these surfaces and that these surfaces induce o–p conversation of H2. The effect of molecular orientations and positions of H2 molecules on the catalysts surface on the *o-p* H2 conversion yield will be presented.
        Speaker: Prof. Abdulwahab Sallabi (Physics Department, Misurata University, Misurata , Libya)
    • 09:00 10:30
      CAP Foundation Board Meeting / Réunion du CA de la Fondation de l'ACP CCIS 4-285

      CCIS 4-285

      University of Alberta

      Convener: Robert Mann (University of Waterloo)
    • 10:15 10:45
      T-MEDAL CAP Medal Talk - Chitra Rangan, U. Windsor (Teaching Undergraduate Physics / Enseignement de la physique au 1er cycle) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Adam Sarty (Saint Mary's University)
      • 10:15
        Generating Ideas for Active and Experiential Learning in Physics 30m
        The Physics community has known the importance of Active Learning (AL) for the last twenty years (see [1,2]). A recent analysis of 225 studies on AL [3] has demonstrated that “active learning appears effective across all class sizes --- although the greatest effects are in small (n <= 50) classes.” Physicists have innovated both technologies and techniques for AL [4,5]. Yet, most classes, particularly in institutions where research is conducted, are primarily delivered via lectures. Many research-active faculty members do not feel like they have the time or incentive to explore AL methodologies. At the University of Windsor, we have started a Faculty Network called “Promoters of Experiential, Active, and Research-based Learning” [6] to support our teacher-researcher colleagues in the Faculty of Science. Inspired by the activities of this network, in this session, I will lead a discussion on how very busy, teacher-researchers can adopt proven Active Learning strategies in their own classes. [1] Richard Hake, “Interactive-engagement vs. traditional methods: A six-thousand-student survey of mechanics test data for introductory physics courses” American Journal of Physics, v. 66, pp. 64-74 (1998). [2] Deslauriers, L., E. Schelew, and C. Wieman, "Improved Learning in a Large-Enrollment Physics Class" Science, v. 332, pp. 862-864 (2011). [3] Scott Freeman et al., “Active learning increases student performance in science, engineering, and mathematics” PNAS, v.111, pp. 8410–8415 (2014). [4] David E. Meltzer and Ronald K. Thornton, "Resource Letter ALIP–1: Active-Learning Instruction in Physics" Am. J. Phys. v. 80, pp. 478 -496 (2012). [5] Multimedia Educational Resource for Learning and Online Teaching, http://www.merlot.org, © 1997–2015 MERLOT. Retrieved May 2, 2015. [6] P.E.A.R.L. @ UWindsor, www.uwindsor.ca/pearl.
        Speaker: Chitra Rangan (University of Windsor)
        Slides
    • 10:45 11:15
      Health Break (with exhibitors) / Pause santé (avec exposants) CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • 11:00 12:00
      Teachers' Day - Session II / Journée des enseignants - Atelier II CCIS L1-047

      CCIS L1-047

      University of Alberta

      • 11:00
        Quantum superposition and the uncertainty principle in the class room; a hands-on experience, Martin laforest, Senior manager, Scientific Outreach, Institute for Quantum Computing, University of Waterloo 1h
    • 11:15 11:45
      NSERC Presentation by Elizabeth Boston / Présentation du CRSNG par Elizabeth Boston CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
    • 11:45 12:15
      NSERC EG Chair Report (L.-H. Xu) / Rapport de la présidente du GE (L.-H. Xu) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Donna Strickland (University of Waterloo)
    • 12:15 12:30
      CAP-NSERC Liaison Committee Report (W. Whelan) / Rapport du Comité de liaison ACP-CRSNG (W. Whelan) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Donna Strickland (University of Waterloo)
    • 12:30 13:45
      CAP Past Presidents' Meeting / Réunion des anciens présidents de l'ACP CCIS 4-285

      CCIS 4-285

      University of Alberta

      Convener: Ken Ragan (McGill)
    • 12:30 13:45
      DAMOPC Annual Meeting / Assemblée annuelle DPAMC CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Chitra Rangan (U)
    • 12:30 13:45
      DMBP Annual Meeting / Assemblée annuelle DPMB CAB 239

      CAB 239

      University of Alberta

      Convener: Maikel Rheinstadter (McMaster University)
    • 12:30 13:45
      DNP Annual Meeting / Assemblée annuelle DPN CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Zisis Papandreou (University of Regina)
    • 12:30 13:45
      DPP Annual Meeting / Assemblée annuelle DPP CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Chijin Xiao (Univ. of Saskatchewan)
    • 12:30 13:45
      IPP Scientific Council Meeting / Réunion du comité scientifique de l'IPP CCIS 2-122

      CCIS 2-122

      University of Alberta

      Convener: Michael Roney (University of Victoria)
    • 12:30 13:45
      Lunch / Dîner
    • 12:30 13:45
      New Faculty Lunch Meeting with NSERC / Dîner-rencontre des nouveaux professeurs avec le CRSNG CCIS L1-029

      CCIS L1-029

      University of Alberta

    • 13:00 18:00
      Teachers' Day - Lunch / Journée des enseignants - Diner CCIS L2 Teaching Labs

      CCIS L2 Teaching Labs

      University of Alberta

      • 13:00
        Afternoon workshops: 5h
        List of proposed workshops, teachers will be asked to sign up for three workshop at most. A separate registration form for workshops will be sent to the teachers by the teachers local committee. - Cavendish experiment (measuring G) - Millikan oil drop. (obtaining the basic electron charge) - e/m for electrons. - Electron diffraction (verifying particle wave duality). - Video analysis of Galileo's ramp. - Frank-Hertz experiment (quantization of energy). - Faraday's rotation (polarization, field induced polarization). - Visit to Dr. Jacob's lab.
    • 13:45 15:15
      T2-1 Materials characterization: microscopy, imagining, spectroscopy (DCMMP) / Caractérisation des matériaux: microscopie, imagerie, spectroscopie (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Eundeok Mun (Simon Fraser University)
      • 13:45
        Ultrafast Transmission Electron Microscopy and its Nanoplasmonic Applications 30m
        Understanding matter at the dynamic and microscopic levels is fundamental for our ability to predict, control and ultimately design new functional properties for emerging technologies. Reaching such an understanding, however, has traditionally been difficult due to limited experimental methodologies that can simultaneously image both in space and time. Ultrafast transmission electron microscopy (UTEM), a newly emerging field, offers the means to overcome this limitation by merging the femtosecond domain of pulsed lasers with the nanoscale domain of transmission electron microscopes. With UTEM, it is possible to capture ultrafast events in real space, diffraction and even spectroscopy. In this particular contribution, we emphasize the plasmonic imaging capability of UTEM in space and time. Localized electric fields that are induced optically exhibit unique phenomena of fundamental importance to nanoplasmonics. UTEM enables direct visualization of these fields as they rise and fall within the duration of the excitation laser pulse (few hundreds of femtoseconds) with several nanometers of spatial resolution. This imaging approach is based on an inelastic photon-electron interaction process, where the probing electrons gain energy equal to the integer multiple of the photon quanta (2.4 eV in these experiments). This new phenomenon in electron energy loss spectroscopy and its fundamentals will be discussed. Furthermore, images, and movies, of plasmonic near-fields of particle dimers, nanoparticles with different sizes and shapes, particle ensembles and standing-wave plasmons at the step edges of layered-graphene strips are presented. These results establish UTEM as a tool with unique capabilities to approach nanoplasmonics.
        Speaker: Prof. Aycan Yurtsever (INRS-EMT)
      • 14:15
        Means of mitigating the limits to characterization of radiation sensitive samples in an electron microscope. 30m
        The scattering of the fast electrons by a sample in the transmission electron microscope (TEM) results in a measurable signal and also leads to sample damage. In an extreme case, the damage can be severe and can proceed faster than data can be collected. The fundamental limit on whether a measurement can be performed is set by the interaction cross section and collection efficiency for the desired signal and by the total damage cross section. Mitigation strategies involve selecting the strongest possible signal, modifying the microscope optics and hardware to maximize the collection efficiency and preparing the sample in a way that maximizes the signal. A major recent breakthrough is the practical implementation of Zernike-like imaging in a TEM. The Zernike-like imaging in a TEM increases the contrast by a factor of two to four compared to conventional bright field TEM. The corresponding decrease in the irradiation dose needed to obtain desired signal to noise ratio translates either to higher resolution in the images or less damage to the sample at the same resolution. The mechanism utilized in this case is the local charging of an uniform thin film placed in the back focal plane of the objective lens of a TEM. The application of the Zernike-like imaging in TEM range from imaging of magnetic fields in vacuum to imaging of DNA strands.
        Speaker: Marek Malac
      • 14:45
        Terahertz Scanning Tunneling Microscopy in Ultrahigh Vacuum 15m
        The terahertz scanning tunneling microscope (THz-STM) is a new imaging and spectroscopy tool that is capable of measuring picosecond electron dynamics at the nanoscale. Free-space THz pulses are commonly used for non-contact conductivity measurements, but they are diffraction limited to millimeter length scales. We can overcome this limit by coupling THz pulses to a sharp metal tip through propagating surface modes. At the STM junction, the THz pulse acts as a picosecond voltage transient which drives electron tunneling on an ultrafast timescale. This effect can be used to spatially and temporally probe the local conductivity of a surface after an excitation. Here we demonstrate THz-STM in an ultrahigh vacuum (UHV) environment for the first time. We have measured a THz-induced-tunnel-current over highly-oriented pyrolytic graphite (HOPG), and Si(111) in UHV. The experimental results agree well with our model, providing insight for the THz-STM mechanism. Recent progress towards atomic resolution and the nature of THz-induced-tunneling in an STM will be presented.
        Speaker: Mr Vedran Jelic (University of Alberta)
      • 15:00
        Identifying differences in long-range structural disorder in solids using mid-infrared spectroscopy 15m
        Structural disorder in calcium carbonate materials is a topic of intense current interest in the fields of biomineralization, archaeological science, and geochemistry. In these fields, Fourier transform infrared (FTIR) spectroscopy is a standard material characterization tool because it can clearly distinguish between amorphous calcium carbonate and calcite. Earlier theoretical work based on density functional theory (DFT) showed that calcite's in-plane bending mode in FTIR is very sensitive to changes in local (intra-unit-cell) disorder, which accounts for the near vanishing amplitude of this peak for amorphous calcium carbonate [1]. In a subsequent study of polycrystalline calcites, DFT investigations showed that local disorder was also qualitatively consistent with changes in the in-plane bending modes for these materials [2]. Here, we examine this assumption by presenting our study of the structural differences among several different sources of crystalline calcite, all of which show differences in the widths of their FTIR in-plane bending mode peaks. We used X-ray diffraction (XRD) to assess disruptions to long-range periodicity including lattice strain, microstrain fluctuations, and crystalline domain size (crystallinity). These quantities were then correlated with mid-FTIR (carbonate vibrational mode) peak positions, widths and relative intensities. Unlike the earlier studies [2], our results show that the in-plane bending mode can be strongly affected by the long-range disorder (based on XRD data) even when the local environments (based on Extended X-ray Absorption Fine Structure data) are identical. This apparent discrepancy between calculated and experimental models of structural disorder is, in fact, strong evidence for the near continuum of local and long-range structural differences that calcium carbonate materials can accommodate. Thus, we conclude that mid-FTIR spectra can be a powerful diagnostic for identifying differences in long-range structural disorder in carbonate-containing materials. References: [1] R. Gueta, A. Natan, L. Addadi, S. Weiner, K. Refson and L. Kronik, Angew. Chem., Int. Ed., 2007, 46, 291–294. [2] K. M. Poduska, L. Regev, E. Boaretto, L. Addadi, S. Weiner, L. Kronik and S. Curtarolo, Adv. Mater., 2011, 23, 550–554.
        Speaker: Ben Xu (Memorial University)
    • 13:45 15:15
      T2-10 Cold and trapped atoms, molecules and ions (DAMOPC) / Atomes, molécules et ions froids et piégés (DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Chitra Rangan (University of Windsor)
      • 13:45
        Project ALPHA: Applying AMO Physics to Antimatter and Using Antimatter to Study AMO Physics 30m
        In 2010, the ALPHA Collaboration working at the AD Facility at CERN achieved the first capture and storage of atomic antimatter with our confinement of low temperature antihydrogen in an Ioffe-type magnetic minimum atom trap. [1] This achievement was only reached through the application of a range of tools and techniques from an interdisciplinary spectrum of fields, including AMO Physics. Examples of AMO Physics tools used in antihydrogen capture and storage include charged particle confinement and manipulation in a Penning-Malmberg trap, evaporative cooling [2], and sympathetic (i.e. charged particle collisional) processes. With the achievement of stable and long-term storage of antihydrogen, focus at ALPHA has now shifted to using antihydrogen as a system for carrying out a range of atomic physics studies, including completion of proof of principle microwave spectroscopy [3], charge neutrality, and gravitational force measurements. With the completion of commissioning of our 2nd-geenration ALPHA-2 apparatus, we now aim to move into the field of high precision spectroscopy of antihydrogen. This invited talk will focus on discussing the AMO physics aspects of the ALPHA experiment, both the tools from AMO physics used for ALPHA and the AMO physics measurements undertaken and planned for ALPHA. This will include both work completed with the ALPHA-1 apparatus, and that undertaken and planned with the ALPHA-2 system. * Presented on behalf of the ALPHA Collaboration, CERN (http://alpha.web.cern.ch/). [1] G.B. Andresen et al. (ALPHA Collaboration), Nature Physics 7, 558 (2011). [2] G.B. Andresen et al. (ALPHA Collaboration, Phys. Rev. Lett. 105, 013003 (2010). [3] C. Amole et al. (ALPHA Collaboration), Nature 483, 439 (2012).
        Speaker: Prof. Robert Thompson (University of Calgary)
      • 14:15
        Evaporative Cooling in Electromagnetic Radio Frequency Ion Traps 15m
        In 2011, the ALPHA collaboration created and trapped neutral anti-hydrogen particles for the first time in history [1]. Key to this achievement was the demonstration of evaporative cooling of charged particles in a Penning Trap, a cooling method that had not previously been achieved with trapped low temperature ions [2]. Work is currently underway at the University of Calgary to computationally investigate the feasibility of optimum conditions for employing evaporative cooling in Paul-type ion traps, a combination of cooling and trapping that has not been used in the past. Due to the complex ion-ion and ion-trapping field interactions, the system is modelled and equations of motion of particles solved computationally using the RK4 method. This work explored the intrinsic challenges of cooling a system of charged particles constrained by an oscillating field, and showing that, dependent on the precise system parameters, evaporation of particles from a trapped system may or may not reduce the temperature of the remainder of the ensemble. Therefore, an extensive range of simulations have been used to study the evolution of a system of ions trapped in an electromagnetic RF trap under a range of different initial conditions and plasma shapes. For each set of system parameters, the cooling parameters were varied using a Monte-Carlo method to find optimum conditions to achieve evaporative cooling, i.e achieving the highest temperature drop while minimizing the particle loss rate. This presentation will include the results of the work and it’s future applications in fields such as spectroscopy and mass measurements will be discussed. [1] G. B. Anderson et al. (ALPHA Collaboration), Nat. Phys., 558, (2011) [2] G. B. Anderson et al. (ALPHA Collaboration), Phys. Rev. Lett. 105, 013003 (2010)
        Speaker: Lohrasp Seify (University of Calgary)
      • 14:30
        Demonstration of a Microtrap Array and manipulation of Array Elements 15m
        A novel magnetic microtrap has been demonstrated for ultracold neutral atoms [1]. It consists of two concentric currents loops having radii r1 and r2. A magnetic field minimum is generated along the axis of the loops if oppositely oriented currents flow through the loops. Selecting r2/r1 = 2.2 maximizes the restoring force to the trap center. The strength and position of the microtrap relative to the atom chip surface can be precisely adjusted by applying an external bias magnetic field. A microtrap array can be formed by linking individual microtraps in series. A linear array of 11 microtraps having r1= 60 microns, was loaded with more than 105 87Rb atoms using three different methods: 1) from a transported quadrupole magnetic trap, 2) directly from a mirror MOT and 3) from an optical dipole trap. A proposal to manipulate atoms in adjacent microtraps will also be presented. 1. B. Jian & W. A. van Wijngaarden, Appl. Physics B: Lasers & Optics. (2014).
        Speaker: Dr Bin Jian (National Research Council)
        Slides
      • 14:45
        Engineered spin-orbit coupling in ultracold quantum gases 30m
        Ultracold quantum gases are an ideal medium with which to explore the many-body behaviour of quantum systems. With a century of research in atomic physics at the foundation, a wide variety of techniques are available for manipulating the parameters that govern the behaviour of these systems, including tuning the interactions between particles and manipulating their potential energy landscapes. In recent years, the ability to generate “artificial gauge fields” has made it possible to simulate, experimentally, the effects of electromagnetic fields among these uncharged particles. Using the same techniques, which selectively transfer momentum from light to atoms, a correlation between the internal state and the motion of the atoms, known as “spin-orbit coupling,” has also be realised in several quantum gas systems. The relationship between spin and motion is quite general: experiments in quantum gases have used it to perform experiments that mimic both Dirac equation (with high-energy phenomena) and the spintronics (with small power consumption). One promising avenue for quantum simulations with spin-orbit coupled systems is to study the competing effects of this coupling and interparticle interactions. To do this, potassium-39 systems are well-suited: they have widely tunable interactions and technically feasible spin-orbit coupling schemes. Unlike conventional solid state systems, both interactions and spin-orbit coupling are tunable, and predictions suggest that the character of the low-temperature ordered systems will depend strongly on these parameters, giving states that have both superfluid and magnetic character. Further, these experiments will allow for the study of non-equilibrium behaviour of the interacting, spin-orbit coupled system, including measuring behaviour at the condensation transition and low-temperature dynamics.
        Speaker: Lindsay LeBlanc (University of Alberta)
    • 13:45 15:15
      T2-11 Laser, Laser-matter interactions, and plasma based applications (DPP) / Lasers, interactions laser-matière et applications basées sur les plasmas (DPP) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Andranik Sarkissian (PLASMIONIQUE Inc)
      • 13:45
        Modification of graphene films in the flowing afterglow of microwave plasmas at reduced-pressure 30m
        Graphene films were exposed to the late afterglow of a reduced-pressure N2 plasma sustained by microwave electromagnetic fields. X-ray photoelectron spectroscopy (XPS) shows that plasma-generated N atoms are incorporated into both pyridinic and pyrrolic groups, without excessive reduction of sp2 bonding. Nitrogen incorporation was found to be preceded by N adsorption, where N adatom density increased linearly with treatment time while aromatic nitrogen saturated. This finding was confirmed by Raman spectra showing a linear increase of the D:G ratio attributed to constant surface flux of plasma generated species. Combined Density Functional Theory calculations with a Nudged Elastic Band (DFT-NEB) approach indicate that incorporation reactions taking place at point vacancies in the graphene lattice requires an activation energy in the 2-6 eV range, but the energy required for the reverse reaction exceeds 8 eV. Stable nitrogen incorporation is therefore judged to be defect-localized and dependent on the energy transfer (6 eV) provided by N2(A)-to-N2(X) metastable-to-ground de-excitation reactions occurring at the late-afterglow-graphene interface. This represents one of the first experimental evidence of the role of metastables during materials and nanomaterials processing in non-thermal plasmas.
        Speaker: Luc Stafford (U.Montréal)
      • 14:15
        Pump-probe Studies of Warm Dense Matter 30m
        Warm Dense Matter (WDM) is a material under extreme conditions which has near solid density but has a temperature of several electron volts. It is a state lies in between condense matter state and plasma state. The study of materials under extreme conditions is currently a forefront area of study in material science and has generated enormous scientific interest. The understanding of WDM is important for laser material processing, which has many scientific and industrial applications, as well as Inertial Fusion Energy, which is a safe energy source that has no carbon emission and almost unlimited fuel supply. The understanding of WDM is also important for planetary science and astrophysics. Ultrafast pump-probe methods can been used to study the evolution of WDM in sub-picosecond time scale. When a high intensity ultrashort laser pulse is absorbed by a solid target, a non-equilibrium WDM with electron temperature of several electron volts, ion temperature near room temperature and density remains as solid is formed initially in less than a picosecond. During the subsequent several picoseconds the electron temperature reduces and ion temperature rises and target eventually disassembles into an expanding plasma. Ultrafast probing techniques based on optical, electron diffraction and x-ray diffraction have been used to study the properties of laser produced WDM led to a better understanding of WDM. An overview of our current understanding of laser produced WDM will be presented in this talk.
        Speaker: Prof. Ying Tsui (University of Alberta)
      • 14:45
        Deposition of functional coatings on glass substrates using a recently-developed atmospheric-pressure microwave plasma jet 15m
        In recent years, atmospheric-pressure plasmas have gained a lot of interest in view of their interest for fast treatment of materials over large area wafers. While such plasmas are typically based on corona or dielectric barrier discharges (DBDs) for processing of thin samples (for example roll-to-roll systems), a number of applications require the treatment of thicker samples and thus the use of plasma jet configurations. We have recently developed a new, atmospheric-pressure plasma source using a surfaguide sustaining simultaneously 3 tubular plasmas based on the propagation of an electromagnetic surface wave. Operated at 2.45GHz, these tubular plasmas are characterized by much higher electron densities (10^13-10^14cm-3) than conventional DBDs (10^9-10^10 cm-3), thus allowing very high fragmentation rates of precursors intended for PECVD, even in a jet configuration. In the waveguide system used in this study, since only the fundamental mode (a cosine maximum of the electric field on the axis of the large section of the rectangular waveguide) is propagating, the first two tubes were placed off-axis, while the last one was placed just after, on the axis. Such configuration enabled important power absorption by the latter tube even if significant amount of power was already used by the first two. Through the displacement of a plunger located at the end of the transmission line, after the surfaguide, selective lengths of the first-row tubes and second-row tube can be achieved. This phenomenon is ascribed to the displacement of the maximum electric field intensity of an established stationary wave in the transmission line. For short tube lengths downward of the surfaguide, a peculiar spatial structure was observed in which off-axis plasma filaments close to the wave launcher converged towards a single on-axis point near the exit followed by a diffuse plasma plume.
        Speaker: Mr Antoine Durocher-Jean (U. Montreal)
      • 15:00
        Measurements of Ionization States in Warm Dense Aluminum with Femtosecond Betatron Radiation from a Laser Wakefield Accelerator 15m
        Study of the ionization state of material in the warm dense matter regime is a significant challenge at present. Recently, we have demonstrated that the femtosecond duration Betatron x-ray radiation from the laser wakefield acceleration of electrons is capable of being employed as a probe to directly measure the ionization states of warm dense aluminum via K-shell line absorption spectroscopy [1]. In order to apply the radiation for such an application, a Kirkpatrick-Baez Microscope is used to selectively focus the radiation around the 1.5 keV photon energy range onto a 50-nm free-standing aluminum foil that is heated by a synchronized 800 nm laser pump pulse. The transmitted x-ray spectrum is spectrally resolved by a flat Potassium Acid Phthalate (KAP) Bragg crystal spectrometer. Here we report the results of the first-time direct measurements of the ionization states of warm dense aluminum using this Betatron x-ray probe setup. Measurements of the ionization states were taken at two pump fluences and various time delays to observe the evolution of the warm dense matter state. Plasmas spectroscopic modeling associated with 1D hydrodynamic simulation is being carried out to interpret the ionized charge distributions from the measured K-shell absorption lines. Details of the measurements and simulations will be presented. [1] M.Z. Mo, et al., Rev. Sci. Instrum. 84, 123106 (2013).
        Speaker: Mianzhen Mo (University of Alberta)
        Slides
    • 13:45 15:15
      T2-2 Condensed Matter Theory (DCMMP-DTP) / Théorie de la matière condensée (DPMCM-DPT) CAB 235

      CAB 235

      University of Alberta

      Convener: Joseph Maciejko (University of Alberta)
      • 13:45
        Many-body localization and potential realizations in cold atomic gases 30m
        Disorder in a non-interacting quantum system can lead to Anderson localization where single-particle wave functions become localized in some region of space. Recently, the study of interaction effects in systems which do exhibit Anderson localization has attracted renewed interest. In my talk I will present recent theorerical progress in understanding localization in many-body systems. I will, in particular, discuss one-dimensional lattice models with binary disorder which can potentially be realized in cold atomic gases using two species of atoms. A purification scheme can be used to perform an exact binary disorder average making such models amenable to numerical studies directly in the thermodynamic limit.
        Speaker: Jesko Sirker (U Manitoba)
      • 14:15
        Light-Trapping Architecture for Room Temperature Bose-Einstein Condensation of Exciton-Polaritons near Telecommunication Frequencies 15m
        While normally quantum mechanical effects are observable at cryogenic temperatures and at very small length scales, our work brings these quantum phenomena to the macroscopic length scale and to room temperature. Our work focuses on the possibility of room-temperature thermal equilibrium Bose-Einstein condensation (BEC) of quantum well exciton-polaritons in micrometer scale cavities composed of photonic band gap materials. Using cavities composed of double slanted pore (SP2) photonic crystals embedded with InGaAs quantum wells, we predict the formation of a 10 $\mu$m to 1 cm sized thermal equilibrium Bose-Einstein condensate at room temperature that allows for the emission of light near the telecommunications band of $\sim$1300 nm. The three-dimensional photonic band gap of the SP2 crystal allows for light to be strongly confined to the quantum wells, resulting in strong light-matter coupling in the exciton-polaritons and vacuum Rabi splittings that are $\sim$2% of the bare exciton recombination energy. The photonic band gap also strongly inhibits the radiative decay of the exciton-polaritons and due to the slow non-radiative decay of excitons as well as fast exciton-phonon scattering in InGaAs at room temperature, the exciton-polaritons that form the BEC are able to reach thermal equilibrium with their host lattice. We consider three InGaAs quantum wells (of width 3 nm surrounded by 7 nm InP barriers) judiciously placed in a 33 nm cavity between SP2 crystals with a lattice constant of 471 nm and polaritons consisting of a superposition of excitons and photons that are tuned below the excitonic recombination energy. This detuning increases the polariton's dispersion depth and increases the number of available photon-like states to enhance the formation of a BEC. We predict the onset of a BEC at a temperature of 364 K in a box-trap of side length 10 $\mu$m at a polariton density of $1.6\times10^{11}$ cm$^{-2}$, indicating that a room temperature, thermal equilibrium BEC can be obtained with light emission near the telecommunications band.
        Speaker: Mr Pranai Vasudev (University of Toronto)
      • 14:30
        Molecular-dynamics simulations of two-dimensional Si nanostructures 15m
        Nanostructed materials make it possible to tailor the vibrational properties of a system for specific uses like thermoelectric applications or phononic waveguides. In this work, the vibrational properties of two-dimensional silicon nanostructures are studied. The nanostructures are build from arrays of nanowires that are arranged in such a manner that they form a periodic lattice. The method of molecular-dynamics simulations is used to calculate the vibrational properties. Results will be shown for the vibrational density of states as well as dispersion relations at long wavelength.
        Speaker: Dr Ralf Meyer (Laurentian University)
      • 14:45
        Inverse melting in a simple 2D liquid 15m
        We employ several computer simulation techniques to study the phase behaviour of a simple, two dimensional monodisperse system of particles interacting through a core-softened potential comprising a repulsive shoulder and an attractive square well. This model was previously constructed and used to explore anomalous liquid behaviour in 2D and 3D, including liquid-liquid phase separation [1]. The calculated phase diagram includes six crystal phases in addition to the liquid and gas. Interestingly, we find that one of the melting curves exhibits inverse melting, for which the liquid freezes to a crystal upon isobaric heating over a very small range of pressure [2]. We find that the range of inverse melting can be enlarged by increasing the extent of the repulsive shoulder, and show that despite occurring in 2D, the melting transition is first order and to a liquid, rather than to a hexatic or quasicrystal phase [3]. As this range increases, the topology of the phase diagram changes systematically until it breaks, leading to even more crystal phases appearing. [1] A. Scala, M. R. Sadr-Lahijany, N. Giovambattista, S. V. Buldyrev, and H. E. Stanley, Phys. Rev. E 63, 041202 (2001). [2] A. M. Almudallal, S. V. Buldyrev, and I. Saika-Voivod, J. Chem. Phys. 137, 034507 (2012). [3] A. M. Almudallal, S. V. Buldyrev, and I. Saika-Voivod, J. Chem. Phys. 140, 144505 (2014).
        Speaker: Ahmad Almudallal (Memorial University of Newfoundland)
      • 15:00
        Cellular Automaton with nonlinear Viscoelastic Stress Transfer to Model Earthquake Dynamics 15m
        Earthquakes may be seen as an example of self-organized criticality. When we transform the Gutenberg-Richter law of earthquake magnitude, the seismic moment, as a measure of the energy released, yields a power law distribution indicating a self-similar pattern. The earthquake dynamics can be modelled by employing the spring-block system, which features a slowly-driving force, failure threshold and interactions between elements as in a complex system. In this approach the earthquake fault is modelled by an array of blocks coupling the loading plate and the lower plate. For computational simplicity, the spring-block model has been mapped to various cellular automata. However, the spring-block model (including the cellular automata version) with its underlying physics, is not sufficient to reproduce some of the empirical scaling laws for real seismicity. In particular, a robust power law time-dependence of the aftershock rate function can not be observed, which indicates the need to introduce new physical mechanisms for the aftershock triggering. Taking into account the rheology of the fault zone, we introduce the nonlinear viscoelastic stress transfer into the interactions between blocks and the tectonic loading force in a basic spring-block model setting. The shear stress of the viscous component is a power-law function of the velocity gradient with an exponent between 0 and 1, showing a shear weakening effect. As a result, the stress transfer function takes a power-law time-dependent form. It features an instantaneous stress transfer during an instantaneous avalanche triggered by the global loading, as well as a power-law relaxation term, which could trigger further aftershocks. In this nonlinear viscoelastic model, avalanches (earthquakes) triggered either by the global loading or the relaxation exhibit a robust power-law frequency-size distribution. Maximum-likelihood fitting of temporal rates of stacked sequences shows a power-law time decay, which agrees with the modified Omori law. Our results also show that the nonlinearity of the viscoelastic interactions plays a key role in determining the type of the stress transfer function. Our study suggests that the nonlinear viscoelastic stress transfer might be a possible triggering mechanism for real aftershocks.
        Speaker: Xiaoming Zhang (University of Western Ontario)
    • 13:45 15:15
      T2-3 Ground-based / in situ observations and studies of space environment II (DASP) / Observations et études de l'environnement spatial, sur terre et in situ II (DPAE) CAB 243

      CAB 243

      University of Alberta

      Convener: Donald Danskin (Natural Resources Canada)
      • 13:45
        New View of Aurora from Space using the e-POP Fast Auroral Imager 30m
        The Fast Auroral Imager (FAI) on the CASSIOPE Enhanced Outflow Probe (e-POP) consists of two CCD cameras, which measure the atomic oxygen emission at 630 nm and prompt auroral emissions in the 650 to 1100 nm range, respectively, using a fast lens system and high quantum-efficiency CCDs to achieve high sensitivity, and a common 26 degree field-of-view to provide nighttime images of about 650 km diameter from apogee (1500 km). The FAI is capable of operating in four viewing modes: nadir viewing, for imaging over a large latitude range; Earth-target viewing, for pointing at an emission target of fixed altitude, latitude and longitude; limb viewing, for measurement of altitude profiles; and inertial pointing, for imaging of an inertial target such as a star field. The near infrared camera provides one image of 0.1 sec exposure per second, and we restrict our examples to this camera. The four viewing modes make possible the observations of a variety of auroral and airglow phenomena, such as rapidly varying and small-scale structures in the auroral oval. The examples shown here illustrate some obvious features in the auroral phenomena that lead to new perspectives in the context of high-resolution studies of ionospheric processes.
        Speaker: Prof. Leroy Cogger (University of Calgary)
        Slides
      • 14:15
        CASSIOPE e-POP and coordinated ground-based studies of polar ion outflow, auroral dynamics, wave-particle interactions, and radio propagation 15m
        The Enhanced Polar Outflow Probe (e-POP) is an 8-instrument scientific payload on the Canadian CASSIOPE small satellite, comprised of plasma, magnetic field, radio, and optical instruments designed for in-situ observations in the topside polar ionosphere at the highest-possible resolution. Its science objectives are to quantify the micro-scale characteristics of plasma outflow in the polar ionosphere and probe related micro- and meso-scale plasma processes at unprecedented resolution, and explore the occurrence morphology of neutral escape in the upper atmosphere. The e-POP mission comprises three important components for the investigation of atmospheric and plasma flows and related auroral and wave particle interaction processes in the topside polar ionosphere: a satellite, a ground-based and a theoretical component. We present an overview of the important, new observations and related results from these three interconnected mission components since the successful launch of CASSIOPE in September 2013.
        Speaker: Andrew Yau (University of Calgary)
      • 14:30
        The nature of GPS receiver bias variabilities: An examination in the Polar Cap region and comparison to Incoherent Scatter Radar 15m
        The problem of receiver Differential Code Biases (DCBs) in the use of GPS measurements of ionospheric Total Electron Content (TEC) has been a constant concern amongst network operators and data users since the advent of the use of GPS measurements for ionospheric monitoring. While modern methods have become highly refined, they still demonstrate unphysical bias behavior, namely notable solar cycle variability. Recent studies have highlighted the potential impact of temperature on these biases, resulting in small diurnal or seasonal behavior, but have not addressed the, far more dominant, solar cycle variability of estimated receiver biases. This study investigates the nature of solar cycle bias variability. We first identify the importance of the strongest candidate for these variabilities, namely shell height variability. It is shown that the Minimizations of Standard Deviations (MSD) bias estimation technique is linearly dependent on the user’s choice of shell height, where the sensitivity of this dependence varies significantly from 1 TECU per 4000km of shell height error in solar minimum winter to in excess of 1 TECU per 90km of shell height error during solar maximum summer. To assess the importance of these sensitivities, we present true shell height derived at Resolute, Canada using the Resolute Incoherent Scatter Radar (R-ISR), operated by SRI International and a Canadian Advanced Digital Ionosonde (CADI) operated by the Canadian High Arctic Ionospheric Network (CHAIN). This investigation demonstrates significant shell height variability translating to bias variabilities of up to several TECU. These variabilities, however, are found to be insufficient to account for all of the observed bias solar cycle variability. To investigate these variabilities further, we next compare Total Electron Content (TEC) measurements made by a CHAIN GPS receiver at Resolute to integrated electron density profiles derived from the nearby Resolute ISR. Taking the ISR measurements as truth, we find that ISR-derived GPS receiver biases vary in the same manner as those derived using the MSD or other bias estimation approaches. Based on these results, we propose that standard receiver DCB estimation techniques may be interpreting a significant portion of plasmaspheric electron content as DCBs, resulting in apparent diurnal, seasonal, and solar cycle DCB variability.
        Speaker: Mr David Themens (University of New Brunswick)
      • 14:45
        Transmission of Waves from a High-Frequency Ionospheric Heater to the Topside Ionosphere 15m
        In the first year of operation of the ePOP instruments on the Canadian small satellite CASSIOPE, a number of passes were recorded during which the Radio Receiver Instrument (RRI) measured radiation from powerful high-frequency ground transmitters that act as ionospheric heaters. In the case of measurements of transionospheric propagation from the Sura heating facility in Russia, located at 56.15°N, 46.10°E, RRI reception of heater waves was accompanied by the operation of the trifrequency Coherent Electromagnetic Radio Tomography (CERTO) beacon on the satellite radiating at 150, 400 and 1067 MHz. CERTO waves, detected at three ground receivers near Sura, allowed total electron content to be measured continuously along the three different paths between CASSIOPE and the three ground sites. Subsequent tomographic processing provided the ionospheric electron density distribution as a function of latitude and altitude. With this density model tool in hand, ray-tracing was applied to the prediction at the spacecraft of various properties of the HF waves from the Sura heater. When compared with the observations, the predictions validate the relevance of geometric-optics principles in transionospheric propagation.
        Speaker: Dr Gordon James (University of Calgary)
      • 15:00
        Dawn-dusk asymmetry in the intensity of polar cap flows as seen by SuperDARN 15m
        Polar cap flow pattern and intensity depend on the IMF Bz and By components. For IMF Bz<0, the pattern is consistently two-celled, and previous studies indicate that flows are fastest near noon and midnight for By<0 and during afternoon-dusk hours for By>0. In this study, we investigate the polar cap flow intensity in two ways. First we consider highly-averaged (over each month of observations in 2007-2013) convection patterns inferred from all SuperDARN radar measurements and discuss typical configurations of the polar cap region with enhanced flows, depending on the IMF By, with a focus on the dusk-dawn asymmetry. We demonstrate seasonal and perhaps solar cycle changes in the asymmetry. We then consider 2 years of Clyde River radar data on the azimuthal component of the flow and show the asymmetry observed directly. We discuss the complexity of the phenomenon in contrast to the more firm conclusions of previous studies.
        Speaker: Alexandre Koustov (U)
        Slides
    • 13:45 15:15
      T2-4 Fields and Strings (DTP) / Champs et cordes (DPT) CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Rainer Dick (University of Saskatchewan)
      • 13:45
        Scale and Conformal Invariance in Quantum Field Theory 30m
        The behavior of coupling constants in quantum field theory under a change of energy scale is encoded in the renormalization group. At fixed points of the renormalization group flow, quantum field theories exhibit conformal invariance and are described as conformal field theories. The larger spacetime symmetry of conformal field theory is not the smallest possible extension of Poincare invariance. Indeed, scale invariance could occur without conformal invariance which would lead to scale field theories. We thus investigate the theoretical implications of scale invariance without conformal invariance in quantum field theory. We argue that renormalization group flows of such theories correspond to recurrent behaviors, i.e. limit cycles or ergodicity. We discuss the implications for the a-theorem, and use Weyl consistency conditions to show that scale invariance implies conformal invariance at weak coupling in four-dimensional quantum field theory. Finally, we clarify the necessary and sufficient conditions for conformality and present new types of conformal field theories.
        Speaker: Prof. Jean-Francois Fortin (Laval University)
        Slides
      • 14:15
        Dynamics of Gravitational Collapse in AdS Space-Time 30m
        Gravitational collapse in asymptotically anti-de Sitter spacetime is dual to thermalization of energy injected to the ground state of a strongly coupled gauge theory. Following work by Bizon and Rostworowski, numerical studies of massless scalar fields in Einstein gravity indicate that generic initial states thermalize, given time, even for arbitrarily small energies. From the gravitational perspective, this appears due to a combination of a turbulent instability in the nonlinear local dynamics and the ability of matter to reflect from the conformal boundary. I will discuss recent work examining the effects of new length scales in the dynamics, including a scalar mass and higher-curvature corrections to the gravitational action.
        Speaker: Andrew Frey (University of Winnipeg)
      • 14:45
        Thermodynamic and Transport Properties of a Holographic Quantum Hall System 15m
        We apply the AdS/CFT correspondence to study a quantum Hall system at strong coupling. Fermions at finite density in an external magnetic field are put in via gauge fields living on a stack of D5 branes in Anti-deSitter space. Under the appropriate conditions, the D5 branes blow up to form a D7 brane which is capable of forming a charge-gapped state. We add finite temperature by including a black hole which allows us to compute the low temperature entropy of the quantum Hall system. Upon including an external electric field (again as a gauge field on the probe brane), the conductivity tensor is extracted from Ohm’s law.
        Speaker: Joel Hutchinson (University of Alberta)
        Slides
      • 15:00
        Constraints and Bulk Physics in the AdS/MERA Correspondence 15m
        It has been proposed that the Multi-scale Entanglement Renormalization Ansatz (MERA), which is efficient at reproducing CFT ground states, also captures certain aspects of the AdS/CFT correspondence. In particular, MERA reproduces the Ryu-Takayanagi-type formula and the network structure is similar to a discretized AdS space where the renormalization direction gives rise to the additional bulk dimension. Such discovery may enable us to study the important features of gravity/gauge duality in a more controlled setting. We will show that in order for MERA to recover bulk physics consistent with our current knowledge of holography, it has to satisfy certain consistency relations and that it can only capture bulk physics much larger than the AdS radius. A more specific framework to construct bulk-boundary dictionary, bulk states and Hilbert space from a boundary theory using MERA will also be discussed.
        Speaker: ChunJun Cao (Caltech)
        Slides
    • 13:45 15:15
      T2-5 Nuclear Structure II (DNP) / Structure nucléaire II (DPN) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Reiner Kruecken (TRIUMF)
      • 13:45
        Single particle structure in neutron-rich Sr isotopes approaching $N=60$ 30m
        The shape coexistence and shape transition at $N=60$ in the Sr, Zr region 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 $^{95-97}$Sr via ($d,p$) one-neutron transfer reactions in inverse kinematics. The experiments presented were performed at TRIUMF's ISAC facility using the TIGRESS gamma-ray spectrometer in conjunction with the SHARC charge 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 landmark being the first high mass ($A>30$) post-accelerated radioactive beam experiments performed at TRIUMF. Recent advances within the facility making the measurements posisble will be highlighted as well as initial results from the experiments discussed in the context of evolving single-particle structure.
        Speaker: Dr Peter Bender (TRIUMF)
      • 14:15
        Doppler shift lifetime measurements using the TIGRESS Integrated Plunger 15m
        Along the $N=Z$ line, shell gaps open simultaneously for prolate and oblate deformations; the stability of these prolate and oblate configurations is enhanced by the coherent behaviour of protons and neutrons in $N=Z$ nuclei. Additionally, amplification of proton-neutron interactions along the $N=Z$ line may yield information on the isoscalar pairing interactions which have been predicted in many nuclear models but not yet experimentally observed. Electromagnetic transition rates measured via Doppler shift lifetime techniques are recognized as a sensitive probe of collective behavior and shape deformation and can be used to discriminate between model calculations. To take advantage of this opportunity, the TIGRESS Integrated Plunger (TIP) has been constructed at Simon Fraser University. The current TIP infrastructure [1] supports lifetime measurements via the Doppler Shift Attenuation Method (DSAM). One advantage of Doppler shift lifetime measurements is that lifetimes can be extracted independent of the reaction mechanism. TIP has been coupled to the TIGRESS segmented HPGe array at TRIUMF as part of the experimental program at ISAC-II. The initial studies using TIP employ fusion-evaporation reactions. Here, reaction channel selectivity can greatly enhance the sensitivity of the measurement. To enable channel selection, the 24-element TIP CsI wall was used for evaporated light charged-particle identification. Reaction channel selectivity has been demonstrated using the TIP infrastructure following the successful production of the $N=Z$ nucleus $^{68}$Se via the $^{36}$Ar + $^{40}$Ca fusion-evaporation reaction. 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. [1] P. Voss et al., Nucl. Inst. and Meth. A746, (2014) 87.
        Speaker: Mr Aaron Chester (Simon Fraser University Department of Chemistry)
      • 14:30
        Isomeric decay spectroscopy of 96Cd 15m
        Self-conjugate nuclei, where $N=Z$, exhibit a strong $pn$ interaction due to the large overlap of wavefunctions in identical orbitals. The heaviest $N=Z$ nuclei studied so far is $^{92}$Pd, and it has demonstrated a strong binding in the $T = 0$ interaction [1]. As the mass number increases, the nucleus approaches the doubly-magic $^{100}$Sn. To investigate the evolution of the $pn$ interaction strength near the shell closure $N = Z = 50$, experimental results on the next self-conjugate, even-even nucleus $^{96}$Cd are needed. Record quantities of $^{96}$Cd 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 HPGe/LaBr$_3$ detectors for gamma-rays, and WAS3ABI, a set of position-sensitive silicon detectors for positrons, protons and ions. A high-spin isomeric state in $^{96}$Cd was found, along with gamma-ray transitions that populate both the ground state and the 16$^{+}$ spin-trap isomeric state. Isomer half-lives and the proposed experimental level scheme of $^{96}$Cd will be presented, followed by a discussion of its $pn$ interaction strength and the decay to $^{96}$Ag.
        Speaker: Jason Park (University of British Columbia/TRIUMF)
        Slides
      • 14:45
        The Electromagnetic Mass Analyser EMMA 15m
        The Electromagnetic Mass Analyser EMMA is a recoil mass spectrometer for TRIUMF's ISAC-II facility designed to separate the recoils of nuclear reactions from the heavy ion beams that produce them and to disperse the recoils according to their mass/charge ratio. In this talk I will present an update on the construction and commissioning of the spectrometer and its components.
        Speaker: Barry Davids (TRIUMF)
      • 15:00
        New decay modes of the high-spin isomer of $^{124}$Cs 15m
        As part of a broader program to study the evolution of collectivity in the even-even nuclei above tin, a series of $\beta$-decay measurements of the odd-odd Cs isotopes into the even-even Xe isotopes, specifically $^{122,124,126}$Xe, have been made utilizing the 8$\pi$ spectrometer at TRIUMF-ISAC. The 8$\pi$ spectrometer consisted of 20 Compton-suppressed high-purity germanium (HPGe) detectors and the Pentagonal Array of Conversion Electron Spectrometers (PACES), an array of 5 Si(Li) conversion electron detectors. The decay of $^{124}$Cs to $^{124}$Xe is the first measurement to be fully analyzed. A very high-statistics data set was collected and the $\gamma\gamma$ coincidence data were analyzed, greatly extending the $^{124}$Xe level scheme. Several weak $\it{E2}$ transitions into excited 0$^+$ states in $^{124}$Xe were observed. The $\it{B(E2)}$ transition strengths of such low-spin transitions are very important in determining collective properties, which are currently poorly characterized in the region of the neutron-deficient xenon isotopes. A new $\beta^+$/EC-decay branch from a high-spin isomeric state of $^{124}$Cs has been observed for the first time. Decay of the isomer ($J^\pi$ = (7)$^+$, $T_{1/2}$ = 6.3(2) s) is seen to populate high-spin states in the $^{124}$Xe daughter nucleus that are otherwise inaccessible through the $\beta$-decay of the 1$^+$ $^{124}$Cs ground state. Combining $\gamma\gamma$ as well as $\gamma$-electron coincidence data, several new transitions in the isomeric decay of the (7)$^+$ state have been observed. The characterization of the new $\beta$-decay branch and the isomeric decay of the high-spin state will be presented.
        Speaker: Allison Radich (University of Guelph)
        Slides
    • 13:45 15:15
      T2-6 Nuclear Physics in Medicine (DNP-DMBP-DIAP) / Physique nucléaire en médecine (DPN-DPMB-DPIA) CAB 239

      CAB 239

      University of Alberta

      Convener: Zisis Papandreou (University of Regina)
      • 13:45
        Accelerator-Based Medical Isotope Production at TRIUMF 30m
        TRIUMF operates a suite of [H-] cyclotrons (13, 2 x 30, 42 and 500 MeV) which, in addition to supplying our basic science program, are used to produce a variety of medical isotopes. Within the next few years TRIUMF will also begin isotope production in our new Advanced Rare IsotopE Laboratory (ARIEL) – a 50 MeV, 10 mA continuous-wave electron linac. The breadth and power of our infrastructure has positioned TRIUMF to be a major producer for some medical isotopes, while enabling access to others that are less common. Since 2010, a TRIUMF-led collaboration has sought to produce Tc-99m directly on small cyclotrons via the Mo-100(p,2n) reaction. Recent successes have shown >30 Ci (1110 GBq) of Tc-99m produced in a single 6 hr irradiation on a 450 µA TR30 cyclotron (at 24 MeV) at TRIUMF. Solutions for 16 and 19 MeV cyclotrons have also been developed. Our goal is to enable all Canadian cyclotron centres to produce Tc-99m in lieu of the imminent cessation of isotope production at the Chalk River reactor. TRIUMF is also pursuing novel methods for producing radiometals that are of interest to the medical community. We have demonstrated the utility of liquid targets for producing research quantities of Zr-89, Ga-68, Y-86 and Sc-44; made by irradiating salt solutions of the appropriate starting material. To date, mCi (MBq) quantities have been isolated and purified, opening the door for the development of novel radiopharmaceuticals. Finally, a brief discussion will ensue on efforts to apply Isotope Separation On-Line (ISOL) infrastructure within the ISAC facility at TRIUMF to produce research quantities of radiotherapeutic isotopes. Progress on the isolation of alpha emitters At-211 and Ac-225 will be presented. TRIUMF seeks to enable clinical trials with these and many other potentially useful radiotherapeutic isotopes available through our existing science program. Overall, TRIUMF’s Nuclear Medicine program seeks to address current and anticipated challenges in the production of important clinical isotopes. With over 1000 small (<30 MeV) cyclotrons in 70 countries, the time is ripe to establish accelerators as a viable, decentralized source of medical radionuclides.
        Speaker: Paul Schaffer (TRIUMF)
        Slides
      • 14:15
        Producing Medical Isotopes with Electron Linacs 30m
        The Canadian Light Source (CLS) has been working on a project to develop a facility that uses a 35 MeV high power (40 kW) electron linac to produce medical isotopes. This project was funded by Natural Resources Canada’s Non-reactor-based Isotope Supply Program which was initiated following the lengthy shutdowns of the NRU reactor at Chalk River that caused significant shortages of molybdenum-99/technetium-99m isotopes for the medical community. The CLS has been collaborating with the Prairie Isotope Production Enterprise (PIPE) in Winnipeg to develop an entire production cycle from molybdenum targets through to clinical approval by Health Canada of linac-derived isotopes. This talk will outline the reasons for using electron linacs for this application, as well as many of the broader challenges encountered to develop an alternate supply chain for these vital isotopes.
        Speaker: Mark de Jong (Canadian Light Source Inc.)
        Slides
      • 14:45
        Calculation of isotope yields for radioactive beam production 15m
        Access to new and rare radioactive isotopes is key to their application in nuclear science. Radioactive ion beam (RIB) facilities around the world, such as TRIUMF (Canada's National Laboratory for Particle and Nuclear Physics, 4004 Westbrook Mall, Vancouver, BC, V6T 2A3), work to develop target materials that generate ion beams used in nuclear medicine, astrophysics and fundamental physics studies. At Simon Fraser University, we are developing a computer simulation of the RIB targets at TRIUMF to augment the existing knowledge and to support future target developments. This simulation will be used to predict the amounts of isotopes produced by the targets in use at TRIUMF to allow for better experiment preparation as well as to gauge the efficiency of using new target materials and varying driver beam intensities to generate different ranges of isotopes. The simulation, built in GEANT4 (Geant4 - A Simulation Toolkit, S. Agostinelli et al., Nuclear Instruments and Methods A 506 (2003) 250-303), a Monte Carlo nuclear transport toolkit, consists of a target of 300 uranium carbide disks, each 120 microns thick, encased in a tantalum container, which is then bombarded by a 480 MeV proton beam, as per the specifications of the TRIUMF target station. The simulation records the isotopes generated as well as their formation process (i.e. fission, fragmentation and neutron capture) and other related properties such as residual kinetic energy of the reaction products. These results are then compared to data gathered at the TRIUMF yield station (P. Kunz, C. Anreoiu, et al. Rev. Sci. Instrum. 85 (2014) 053305), a nuclear spectroscopy experiment dedicated to RIB characterization. Results from the simulation will be presented, along with benchmarking and comparison to the yield station data and other nuclear transport codes.
        Speaker: Ms Fatima Garcia (Simon Fraser University and TRIUMF)
        Slides
      • 15:00
        Coincidence Measurements using the SensL MatrixSM-9 Silicon-photomultiplier Array 15m
        The silicon photomultiplier (SiPM) has emerged as a rival device to traditional photodetectors such as the photomultiplier tube (PMT). Over the past decade, SiPMs - also known as Multi-pixel photon counters (MPPCs) and Single-photon avalanche diodes (SPADs) - have found applications in fields ranging from, for example, high-energy physics and atmospheric lidar, to homeland security, biophotonics and nuclear medicine. Due to their wide-ranging applications, arrays of SiPMs are now available commercially as part of modular, turnkey readout systems. One such device - the MatrixSM-9 manufactured by SensL - has been designed specifically for use in high-resolution medical imaging systems required in, for example, state-of-the-art PET applications. We present preliminary coincidence measurements using the Matrix SM-9 system, coupled to a plastic scintillator, to image a $^{22}$Na positron source.
        Speaker: Dr Jamie Sanchez-Fortun Stoker (University of Regina)
        Slides
    • 13:45 15:15
      T2-7 Energy Frontier: Susy & Exotics II (PPD) / Frontière d'énergie: supersymétrie et particules exotiques II (PPD) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Prof. Dean Karlen (University of Victoria (CA))
      • 13:45
        Searches for Exotic Physics at ATLAS 30m
        The most exciting discovery to come from the LHC would be that of something completely unexpected. To that end, the ATLAS experiment has been enthusiastically analyzing the 2012 LHC data recorded at a centre of mass energy of 8 TeV looking for any possible evidence of new physics. A variety of signatures has been considered, including heavy resonances, excesses above the Standard Model expectation in numerous channels, and particles that are long-lived, highly ionizing, or invisible. This talk will explore some of these searches and touch on the various interpretations, such as dark matter, extra dimensions, and other intriguing extensions to the Standard Model.
        Speaker: Wendy Taylor (York University (CA))
        Slides
      • 14:15
        A Search for Magnetic Monopoles and Exotic Long-lived Particles with Large Electric Charge at ATLAS 15m
        A search for highly ionizing particles produced in 8 TeV proton-proton collisions at the LHC is performed with the ATLAS detector. A dedicated trigger increases significantly the sensitivity to signal candidates stopping in the electromagnetic calorimeter and allows to probe particles with higher charges and lower energies. Production cross section limits are obtained for stable particles in the mass range $200-2500$ GeV for magnetic charges in the range of Dirac charge $0.5<|g|<2.0$ and for electric charges in the range $10<|z|<60$. Limits are presented for various pair-production scenarios, and model-independent limits are presented in fiducial regions of particle energy and pseudorapidity.
        Speaker: Mr Gabriel David Palacino Caviedes (York University (CA))
        Slides
      • 14:30
        The MoEDAL Experiment at the LHC - a New Light on the High Energy Frontier 30m
        In 2010 the Canadian led MoEDAL experiment at the Large Hadron Collider (LHC) was unanimously approved by CERN's Research Board to start data taking in 2015. MoEDAL is a pioneering experiment designed to search for highly ionizing avatars of new physics such as magnetic monopoles or massive (pseudo-)stable charged particles. Its groundbreaking physics program defines over 30 scenarios that yield potentially revolutionary insights into such foundational questions as: are there extra dimensions or new symmetries; what is the mechanism for the generation of mass; does magnetic charge exist; what is the nature of dark matter; and, how did the big-bang develop. MoEDAL's purpose is to meet such far-reaching challenges at the frontier of the field. The innovative MoEDAL detector employs unconventional methodologies tuned to the prospect of discovery physics. The largely passive MoEDAL detector, deployed at Point 8 on the LHC ring, has a dual nature. First, it acts like a giant camera, comprised of nuclear track detectors - analyzed offline by ultra fast scanning microscopes - sensitive only to new physics. Second, it is uniquely able to trap the particle messengers of physics beyond the Standard Model for further study. MoEDAL's radiation environment is monitored by a state-of-the-art real-time TimePix pixel detector array. I shall also briefly discuss a new proposal to include a new active MoEDAL sub-detector to search for millicharged particles.
        Speaker: James Pinfold (University of Alberta (CA))
        Slides
    • 13:45 15:15
      T2-8 Cosmic frontier: Dark matter II (PPD) / Frontière cosmique: matière sombre II (PPD) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Aksel Hallin (University of Alberta)
      • 13:45
        Status of the PICASSO and PICO experiments 30m
        The PICO collaboration, a merger of COUPP and PICASSO experiments, searches for dark matter particles using superheated fluid detectors. These detectors can be operated within a set of conditions where they become insensitive to the typically dominant electron recoil background. Additionally, the acoustic measurement of the bubble nucleation makes possible the rejection of additional backgrounds such as alpha decays. This technique also allows for the target nuclei to be changed within the same experiment in order to confirm the properties of dark matter. This presentation reports on the PICASSO experiment that completed taking data in 2014, and the PICO-2L and PICO-60 experiments that were recently commissioned at the Snolab deep underground laboratory in Sudbury.
        Speaker: Dr Guillaume Giroux (Queen's University)
        Slides
      • 14:15
        DEAP-3600 trigger - the needle in the haystack 15m
        DEAP-3600 is a dark matter experiment based at SNOLAB. It uses 3600kg of liquid argon as a target, and searches for scintillation light from argon nuclei struck by weakly interacting massive particles (WIMPs). Argon-39 atoms also undergo beta decay, and the recoiling electrons also produce scintillation light. Beta decays are expected to occur at least $10^8$ times as frequently as WIMP interactions, and the DEAP-3600 trigger is critical in filtering out the vast majority of background events, while keeping 100% of signal events. This talk will explain the very flexible trigger scheme that was developed, and will detail the commissioning and optimisation of the system.
        Speaker: Ben Smith (TRIUMF)
        Slides
      • 14:30
        Early studies of detector optical calibrations for DEAP-3600 15m
        The DEAP-3600 experiment is looking for dark matter WIMPs by detecting the scintillation light produced by a recoiling liquid argon nucleus. Using a 1 tonne fiducial volume a WIMP-nucleon cross section sensitivity of 10^{-46} cm2 in is expected for 3 years of data taking for a 100GeV WIMP. DEAP-3600 has been designed for a target background of 0.6 events in the WIMP region of interest in 3 years of data taking. In this talk I will present the status of the commissioning of the optical data collected by DEAP.
        Speaker: Dr Berta Beltran (Univeristy of Alberta)
        Slides
      • 14:45
        Single photon counting for the DEAP dark matter detector 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 measures the time distribution of scintillation light from the de-excitation of argon dimers to select events. This measurement allows background events from Ar39 decays to be rejected at a high level. The performance of this analysis critically relies on DEAP’s ability to identify pulses in the waveforms of the photomultilier tubes and accurately assessing the number of photo-electrons contributing to each pulse. Photomultiplier tube effects, such as dark noise and afterpulsing, can degrade the measurement and weaken the level of background discrimination. An algorithm has been developed for finding pulses and identifying the number of photo-electrons.
        Speaker: Thomas McElroy (University of Alberta)
        Slides
    • 13:45 15:15
      T2-9 Gender and Arts in Physics Teaching (CEWIP-DPE) / Genre et arts dans l'enseignement de la physique (CEFEP-DEP) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Dr Marina Milner-Bolotin (The University of British Columbia)
      • 13:45
        Model-Based Reasoning in Upper-division Lab Courses 30m
        Modeling, which includes developing, testing, and refining models, is a central activity in physics. Well-known examples from include everything from the Bohr model of the hydrogen atom to the Standard Model of particle physics. Modeling, while typically considered a theoretical activity, is most fully represented in the laboratory where measurements of real phenomena intersect with theoretical models, leading to refinement of models and experimental apparatus. However, experimental physicists use models in complex ways and the process is often not made explicit in physics laboratory courses. We have developed a framework to describe the modeling process in physics laboratory activities. The framework attempts to abstract and simplify the complex modeling process undertaken by expert experimentalists. The framework can be applied to understand typical processes such the modeling of the measurement tools, modeling “black boxes,” and signal processing. We demonstrate that the framework captures several important features of model-based reasoning in a way that can reveal common student difficulties in the lab and guide the development of curricula that emphasize modeling in the laboratory. We also use the framework to examine troubleshooting in the lab and guide students to effective methods and strategies.
        Speaker: Heather Lewandowski (University of Colorado)
      • 14:15
        Fabulous Physicists from Around the World: The tale of ICWIP 2014 30m
        A century ago it was only Marie Curie and a few other women who were part of the physics community, but in 2014, CAP and IUPAP (International Union of Pure and Applied Physics) brought over 200 women physicists from 52 countries to Waterloo for the 5th IUPAP International Conference on Women in Physics (ICWIP). ICWIP 2014 was held at Wilfrid Laurier University from August 5 to 8, 2014. This was the first time this conference was held in North America. It was a unique opportunity for Canadian scientists and researchers to share ideas and experiences with women and men from around the world. This is the story of this one-of-a-kind conference, including the scientific and gender-focused sessions and talks, the official resolutions approved by the delegates, the amazing personal stories shared, and of course, the closing night dance party.
        Speaker: Shohini Ghose (Wilfrid Laurier University)
      • 14:45
        Gender gaps in a first-year physics lab 15m
        It has been established that male students outperform female students on almost all commonly-used physics concept inventories. However, there is significant variation in the factors that contribute to this gender gap, as well as the direction in which they influence it. It is presently unknown if such a gender gap exists on the relatively new Concise Data Processing Assessment (CDPA). To get at estimates of the gap, we have measured performance on the CDPA at the pre-test and post-test level in the first-year physics lab at the University of British Columbia. We find a gender gap on the CDPA that persists from pre- to post-test and that is as big as, if not bigger than, similar reported gaps. That being said, we ultimately claim no evidence that female students are less capable of learning than their male peers, and we suggest caution when using gain measures alone to draw conclusions about differences in science classroom performance across gender.
        Speaker: Dr James Day (University of British Columbia)
        Slides
    • 15:15 15:45
      Health Break (with exhibitors) / Pause santé (avec exposants) CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • 15:45 17:15
      T3-1 Materials characterization: electrical, optical, thermal (DCMMP) / Caractérisation des matériaux: électrique, optique, thermique (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Wayne Hiebert (National Institute for Nanotechnology)
      • 15:45
        A pump-probe technique to measure the Curie temperature distribution of exchange-decoupled nanoscale ferromagnet ensembles 30m
        Heat assisted magnetic recording (HAMR) has been recognized as a leading technology to increase the data storage density of hard disk drives[1]. Dispersions in the properties of the grains comprising the magnetic medium can lead to grain-to-grain Curie temperature variations, which drastically affect noise in the recorded magnetic transitions, limiting the data storage density capabilities in HAMR[2]. In spite of the need to investigate the origin of the Curie temperature distribution ($\sigma_{Tc}$) and establish means to control it, no approach to measure $\sigma_{Tc}$ has been available. We have recently presented a method to measure the switching temperature distribution of an ensemble of exchange-decoupled grains with perpendicular anisotropy subject to nanosecond heating pulses of varying intensity[3]. The rapid cooling rate ensures that the grain magnetization is not affected by thermal activation, so that the grains switch at Tc. A switching temperature distribution can then be directly interpreted as a measure for $\sigma_{Tc}$. Here we summarize the results of this measurement routine to a series of FePt HAMR media samples in which the degree of *L*$1_{0}$ chemical ordering and alloy composition is systematically varied. We also present modeling results based on the Landau-Lifshitz-Bloch formalism that validates the experimental approach and provides experimental bounds for its validity[4]. Measurements of $\sigma_{Tc}$ reveal a sizable dependence, which we interpret in the context of thermodynamic drive for disordered to ordered crystalline structure phase transformation. Besides the ability to measure $\sigma_{Tc}$, which is of importance to engineer suitable HAMR media capable of high density magnetic recording, the presented technique can be applied to studies on the competition between Zeeman energy and thermal fluctuations that affect the switching probability upon cooling from Tc. [1] D. Weller, O. Mosendz, G.J. Parker, S. Pisana, and T.S. Santos, Phys. Status Solidi A 210, 1245 (2013). [2] H. Li and J.-G. Zhu, IEEE Tran. Magn. 49, 3568 (2013). [3] S. Pisana, S. Jain, J.W. Reiner, C.C. Poon, O. Hellwig, B.C. Stipe, Appl. Phys. Lett. 104, 162407 (2014). [4] S. Pisana, S. Jain, J.W. Reiner, O. Mosendz, G.J. Parker, M. Staffaroni, O. Hellwig, B.C. Stipe, IEEE Tran. Magn., in press.
        Speaker: Prof. Simone Pisana (York University)
      • 16:15
        Optical properties and Fermiology near field-tuned quantum critical points 30m
        In the so-called "heavy-fermion" metals, the hybridization of the conduction band with electrons localized in partially filled $f$ orbitals leads to the formation of heavy quasiparticles, for which the effective mass can be renormalized by a factor of 100 or more. However, the itinerant nature of these quasiparticles competes with a tendency to form more conventional, magnetically ordered states. These materials are therefore situated near a quantum critical point - a zero-temperature phase transition driven by the competition between kinetic energy and potential energy. This conflict between itinerancy and localization lies at the heart of all correlated electron materials, and makes heavy-fermion systems a model system for testing and understanding correlated quantum matter. Along with the formation of ultra-heavy quasiparticles, the scattering dynamics in heavy fermion compounds also undergo a strong renormalization. This critical slowing-down brings important electronic timescales, such as electronic scattering rates, down into the GHz range, where optical-type measurements and analyses can be carried out with microwaves. We have developed a dilution-refrigerator-based system for carrying out these measurements, and have used it to study a range of heavy fermion materials such as CeCoIn5, UBe13 and URu2Si2. Following an overview of the relevant physics, I will present a summary of our most striking results, illustrating the critical slowing down and mass enhancement that accompany a quantum phase transition.
        Speaker: David Broun (Simon Fraser University)
      • 16:45
        Protein Biosensing with Fluorescent-Core Microcapillaries 15m
        Whispering gallery modes (WGMs) are the electromagnetic resonances of dielectric spheres, cylinders, or rings. The WGM wavelengths can shift when the resonant field interacts with a local analyte fluid. This work demonstrates a fluorescent core microcapillary that utilizes WGMs for biosensing applications. This device consists of a glass microcapillary with a 50-μm-diameter inner channel. The channel wall is coated with a film composed of fluorescent silicon quantum dots (SiQDs). Because the SiQD film has a higher index of refraction than the glass capillary wall, it can support cylindrical WGMs. The QD fluorescence spectrum thus consists of a set of sharp peaks at the WGM resonance wavelengths. Part of the WGM field extends into the capillary channel where it samples the fluids pumped inside; thus the cavity resonance wavelengths in the QD fluorescence spectrum depend on the channel medium. The sensitivity of the WGM wavelengths varied between 3 and 24 nm per refractive index unit, depending on the SiQD film thickness. Biosensing with this device was then demonstrated using the standard biotin-avidin system. The QD film in the capillary channel was coated with alternating charged polyelectrolyte (PE) layers with exposed amines for attaching biotin. Biotin in turn has a high specific affinity for the neutravidin protein. These biotinylated PE layers were found to capture neutravidin, yielding a detection limit of 6 nM and an equilibrium association constant of 1.1 x 106 M-1 for biotin-neutravidin in this sensor. Several “blank” runs indicate minimal nonspecific binding. Attractive features of this device include a high degree of physical robustness and minimal equipment requirements (e.g., a tuneable laser is not needed to scan the cavity modes). Future work will aim to increase the so-far moderate detection limit, potentially by improving the device sensitivity via finer control over the SiQD film thickness.
        Speaker: Mr Stephen Lane (University of Alberta)
      • 17:00
        Ultrafast modulation of photoluminescence in semiconductors by intense terahertz pulses 15m
        Terahertz (THz) pulse science is a rapidly developing field, and has been applied extensively in the characterization of ultrafast dynamics in semiconductors and nanostructures. The recent development of intense THz pulse sources in lithium niobate (LN), however, allows the dynamics of transient states to be directly manipulated by the large electric field of the THz pulse itself. We have used an ultrafast laser source to generate intense THz pulses in LN with picosecond duration and peak electric fields up to 300 kV/cm. Here we study how these intense THz pulses affect the ultrafast radiative recombination dynamics of photoexcited carriers in semiconductors and semiconductor nanostructures. In GaAs, we observe a sharp transition between THz-pulse-induced quenching and enhancement of photoluminescence (PL) with increasing photoexcited carrier densities. We present spectrally-resolved PL measurements of this transition, which reveal a competition between enhancement at shorter wavelengths versus quenching at longer wavelengths. The dynamics of this interplay between THz pulse enhanced and quenched PL are presented as a function of excitation fluence and time-delay between the excitation and THz pulses. Possible mechanisms that include THz-induced carrier heating and scattering processes are discussed. The effects of intense THz pulses on the PL dynamics in polycrystalline GaAs, and quantum well structures will also be explored. The ability to control material properties with intense THz pulses may lead to novel optoelectronic devices with the ability to modulate light emission on picosecond timescales. This work was supported by NSERC, CFI, ASRIP, AITF, iCiNano, and nanoBridge.
        Speaker: Mr David Purschke (University of Alberta)
    • 15:45 17:15
      T3-10 Special session to honour Dr. Akira Hirose II (DPP) / Session spéciale en l'honneur du Dr Akira Hirose II (DPP) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Chijin Xiao (Univ. of Saskatchewan)
      • 15:45
        From Plasma to Complex Plasma 30m
        Earlier research on plasma turbulence and later research development on a complex plasma are discussed. Study of nonlinear evolution of instabilities in a collisionless plasma, especially ion acoustic instability and Buneman instability, revealed the role of plasma collective modes in the heating of plasma particles. It was essential for plasma waves to grow in time, resulting in the heating of plasma itself through effective interaction of plasma particles and plasma waves. Theoretical study revealed the time constant for the heating to occur in a plasma. When plasma instabilities are well developed and spread wide in frequency range, the plasma turbulence caused the broadening of wave-particle resonance region. The earlier plasma experiments tried to eliminate any impurities from the vacuum chamber to guarantee the experimental conditions as much as ideal theoretical bases. However, the onset conditions of plasma instabilities are found to be modified in the presence of dust particles, micron in size and negatively charged. The presence of dust particles is found to modify the effective temperature of electrons, resulting in the suppression of the Landau damping. Furthermore, the dust plasma, now known as a complex plasma because of the nature of complex system as a composite of plasma particles and dust particles, is found to be rich in fundamental novel physics including a strongly coupled state and the anomalous nature of electromagnetic propagation in the medium. Dust particles when placed in a sheath interact each other in the presence of ion flow and produce a line along the flow. The paired chain was interpreted as a pair-formation by the exchange of phonons. The dust particles could be floated at the sheath edge producing a one- or a two-dimensional lattice structure, which provides a platform for the study of low-dimensional behavior of Coulomb systems. Some of the current topics of a complex plasma are discussed.
        Speaker: Prof. Osamu Ishihara (Chubu University/Yokohama National University)
      • 16:15
        Fluctuations and Transport in Hall devices with ExB drift 30m
        Devices with stationary, externally applied, electric field which is perpendicular to a moderate amplitude magnetic field B₀, are now a common example of magnetically controlled plasmas. High interest applications involve Penning type plasma sources, magnetrons for plasma processing, magnetic filters for ion separation, and electric space propulsion devices such as Hall thrusters. One common characteristic of these numerous applications are plasma parameters conditions in which electrons are magnetized so the electron Larmor radius is much smaller than the characteristic lengths scale of the devices, while ions have large Larmor radius and do not feel the magnetic field and thus can be easily controlled by the electric field. The latter is a basis of various useful applications for ions extraction, separation and acceleration. Similar conditions also occur in some ionospheric plasmas as well as in some laboratory experiments on magnetic reconnection. The proposed talk reviews physics basis of such Hall plasma discharges. Application of the external electric field perpendicular to the magnetic field, as well as gradients of plasma density, temperature and magnetic field, naturally present in such discharges, result in plasma fluctuations and instabilities that make plasma turbulent and electron transport anomalous. Specific conditions of such plasmas precludes existence of standard drift waves, however other modes, the so called anti-drift modes become possible and unstable. The open magnetic field lines (terminated by the wall) also result in new instabilities, the so called sheath impedance modes. This talk provides physics based description of various modes and instabilities pertinent to such Hall plasmas and resulting anomalous electron transport due to these modes.
        Speaker: Dr Andrei Smolyakov (University of Saakatchewan)
      • 16:45
        Adaptive Matrix Transpose Algorithms for Distributed Multicore Processors 15m
        The matrix transpose is an essential primitive of high-performance parallel computing. In plasma physics and fluid dynamics, a matrix transpose is used to localize the computation of the multidimensional Fast Fourier transform, the engine that powers the pseudospectral collocation method. An adaptive parallel matrix transpose algorithm optimized for distributed multicore architectures running in a hybrid OpenMP/MPI configuration is presented. Significant boosts in speed are observed relative to the distributed transpose used in the state-of-the-art adaptive FFTW library. In some cases, a hybrid configuration allows one to reduce communication costs by reducing the number of MPI nodes, and thereby increasing message sizes. This also allows for a more slab-like than pencil-like domain decomposition for multidimensional Fast Fourier Transforms, reducing the cost of, or even eliminating the need for, a second distributed transpose. Nonblocking all-to-all transfers enable user computation and communication to be overlapped. We apply adaptive matrix transposition algorithms on hybrid architectures to the parallelization of implicitly dealiased pseudospectral convolutions used to simulate turbulent flow. Implicit dealiasing outperforms conventional zero padding by decoupling the data and temporary work arrays. Parallelized versions of our implicit dealiasing algorithms for hybrid architectures are publically available in the open-source library FFTW++.
        Speaker: John Bowman (University of Alberta)
      • 17:00
        Dense Plasma Focus for Short-Lived Isotope Activation 15m
        Short-lived radioisotopes (SLRs) are used for medical applications including positron emission tomography (PET). The required activity for N-13for PET is about 4 GBq for a myocardial blood perfusion assessment. Dense plasma focus (DPF) has been considered as a low cost methods for producing SLRs as an alternative to conventional cyclotron facilities. A low energy dense plasma focus has been built and optimized at the University of Saskatchewan to study the feasibility of SLRs production, in particular N-13 using energetic deuteron ion beams produced in a dense plasma focus. X-ray detectors and a Faraday cup have been used to characterize the DPF properties, particularly the ion beam energy based on time-of-flight measurements. The preliminary results have shown generation of ions with energies up to 2 MeV, well exceeding the threshold energy for N-13 production (328 keV). Electrical signals have been used for circuit analyses in order to interpret the anomalous plasma resistance and plasma inductance during the pinch phase. Simulation of N-13 activation using deuteron beam has been carried out.
        Speaker: Mr R. A. Behbahani (University of Saskatchewan)
    • 15:45 17:15
      T3-2 Quantum Computation and Communication (DTP-DCMMP-DAMOPC) / Communication et calcul quantique (DPT-DPMCM-DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Arundhati Dasgupta (University of Lethbridge)
      • 15:45
        Improving Physical Models of Qubit Decoherence and Readout 30m
        Qubit coherence measurements are now sufficiently accurate that they can be used to perform 'spectroscopy' of noise due to a complex environment. Measuring not only the decay time, but also the form of decay as a function of some external parameter (e.g. temperature) can determine the nature of the dominant decoherence source. I will describe how temperature-dependent measurements of qubit decoherence time and form of decay can distinguish between a number of different possible sources of environmental charge flucutations (including tunneling and cotunneling with a continuum band, as well as one- and two-phonon absorption processes). These results can be used to identify and suppress dominant charge-noise dephasing mechanisms in semiconductor nanostructures. I will also briefly discuss some new tricks to enhance the fidelity of generic qubit readouts by understanding the physical dynamics of these systems.
        Speaker: Prof. Bill Coish (McGill University)
      • 16:15
        NanoQEY Quantum Key Distribution Satellite 15m
        NanoQEY (Nano Quantum EncrYption satellite) is a demonstration satellite which will show the feasibility of implementing Quantum Key Distribution (QKD) between two ground stations on earth using a satellite trusted node approach. One of the main objectives of NanoQEY is to eliminate the necessity for a fine pointing system which will reduce cost and planning time for a satellite. The system will also be simplified from many models that have been proposed due to the smaller space and mass allowances. A few of the QKD satellites that have been proposed are also formatted in the downlink scenario, whereas NanoQEY will be implemented in an uplink scenario. Since the satellite is only used for photon collection and data processing, it is not necessary to have many of the complicated systems on board which would be required for a downlink. The main purpose of NanoQEY is to construct a payload which will be operational for a QKD demonstration and fit onto a nano-satellite in terms of mass and power budgets. However, because of the fine pointing simplification of the satellite, the ground stations will need to compensate for the lack of targeting on the satellite. These ground stations will have to have very fine pointing and tracking capabilities. We have undergone a study to determine the feasibility of a nano-satellite project to implement QKD for world-wide QKD demonstrations and the requirements on a ground station to achieve these goals.
        Speaker: Christopher Pugh (University of Waterloo)
      • 16:30
        Towards a Quantum Non-Demolition Measurement for Photonic Qubits 15m
        Many applications of quantum information processing benefit from, or even require, the possibility to detect the number of photons in a given signal pulse without destroying the photons nor the encoded quantum state. We propose and show first steps towards the implementation of such a Quantum Non-Demolition (QND) measurement for time-bin qubits. To implement this measurement, we first store a ‘probe’ pulse in a cryogenically cooled Tm:LiNbO3 waveguide using an Atomic Frequency Comb (AFC) quantum memory protocol [1]. We then send a ‘signal’ pulse comprised of two temporal modes off-resonantly with the AFC through a previously prepared transparency window. The off-resonant interaction between the propagating signal and the thulium ions, onto which the probe pulse was mapped, results in the atomic state acquiring a phase-shift. This phase shift is imprinted onto the recalled probe pulse and can be determined using an interferometric measurement. The magnitude of this phase-shift depends on the signal pulse's energy, and detuning w.r.t to the probe pulse. Hence, knowing the phase-shift, we can determine the intensity or the number of photons in the signal pulse. [1] E. Saglamyurek et al, … Nature 2011
        Speaker: Chetan Deshmukh (University of Calgary)
      • 16:45
        Evanescent Waveguide Microscopies for Bio-Application 30m
        Two new evanescent field microscopy technologies based on glass slab waveguides with permanent coupling gratings are introduced: waveguide evanescent field fluorescence (WEFF) microscopy and waveguide evanescent field scattering (WEFS) microscopy. The technologies are briefly described and the experimental setup based on a conventional inverted microscope is introduced and compared to existing technologies like TIR and TIRF. The advantages over the existing technologies are clearly addressed. For each technology one application in cell biology is shown. With multimode WEFF microscopy, taking at least two images with two different waveguide modes, it is possible to determine the fluorescence dye location above the waveguide surface. Therefore 2D dye distance maps or 3D contour plots can be calculated for the samples. As an example, the bending of the plasma membranes of cells between focal adhesions and focal contacts to the waveguide surface are investigated. WEFS microscopy which works as a label-free microscopy is used to analyse bacterial biofilm formation: from a parent cell to micro-colonies. In addition experiments on bacterial UV sterilization and its consequences on biofilm formation are shown.
        Speaker: Prof. Silvia Mittler (University of Western Ontario)
    • 15:45 17:15
      T3-3 Ground-based / in situ observations and studies of space environment III (DASP) / Observations et études de l'environnement spatial, sur terre et in situ III (DPAE) CAB 243

      CAB 243

      University of Alberta

      Convener: Prof. Richard Marchand (University of Alberta)
      • 15:45
        Anisotropic ion temperatures and ion flows adjacent to auroral precipitating electrons 30m
        Large ion temperature anisotropies (temperature perpendicular to magnetic field larger than parallel to magnetic field) in narrow regions of enhanced ion flow have been identified by the Electric Field Instruments on board the Swarm satellites as a persistent feature of the high latitude midnight-sector auroral zone. These flow channels typically span less than 100 km latitudinally with ion flows of several kilometres per second. The largest observed temperature anisotropy ratios exceed the values predicted by currently used cross sections in theories of collisional heating in strong flows by a factor of 2. Coincident optical measurements from ground-base all-sky imagers indicate that these flow channels are immediately adjacent to regions of precipitating electrons, likely in the vicinity of the ionospheric projection of the open-closed boundary. We will be presenting ion velocity, ion temperature, and magnetic field measurements in and around these regions of enhanced ion flow from December 2013. The orbit of the Swarm satellites during this time result in measurements near the Harang discontinuity. The Electric Field Instruments on board the Swarm satellites are ideally suited for analysis of ion temperature anisotropy. The pearls-on-a-string configuration held by the Swarm satellites during these first weeks of the Swarm mission provides a unique opportunity to distinguish temporal from spatial variation in this dynamic region.
        Speaker: William Archer (University of Calgary)
      • 16:15
        Generation, dynamics, and decay of a polar cap patch 15m
        The polar cap ionosphere, an important part of the solar wind-magnetosphere-ionosphere system, is formed by ionization of the neutral atmosphere by solar radiation and particle precipitation under internal transportation and chemical processes. The polar ionosphere is primarily driven by magnetospheric convection and neutral circulation, and undergoes structuring over a wide range of temporal and spatial scale sizes. This structuring is due to the interplay of mechanical forces, electrodynamics, and ionization chemistry. The most prominent and frequent structure of the polar cap ionosphere is the polar patch, which is defined as a region of enhanced F layer ionization distinguishable from the background electron density. Several theories, observations, and hypotheses on the generation and dynamics of these patches are available in the literature. However, a coherent understanding of patch formation is still lacking, mainly due to the lack of high spatial and temporal resolution observations. This is also compounded by our attention to more dramatic patch events. This presentation will focus on a less-dramatic patch event using observations from the Canadian High Arctic Ionospheric Network (CHAIN), in order to provide a coherent view of formation, dynamics, and decay of polar patches.
        Speaker: Dr Thayyil Jayachandran (University of New Brunswick)
      • 16:30
        Temporal and Spatial Evolution of Poynting Flux Measured with Swarm 15m
        Small Scale Dynamics of Poynting Flux Measured With Swarm We present case studies of ionospheric Poynting flux using the instruments onboard the three ESA Swarm spacecraft. The three Swarm satellites each carry an Electric Field Instrument (EFI) that can be used to measure ion drift velocities. During the first months of the mission the satellites were in nearly circular, polar orbits at an altitude of 490 kilometers and were approximately 1000 kilometers from each other. During this time, they followed one after another in a pearls-on-a-string arrangement, separated by about one minute in time. This relatively close spatial formation allows comparisons to be done between electric field measurements on each satellite, revealing spatial and temporal structure. In this project we measure ionospheric Poynting Flux using each Swarm satellite. Cross correlation functions are calculated between measurements on each satellite and are used to determine the temporal and spatial scales of observed features. Acknowledgements: The EFIs were developed and built by a consortium that includes the University of Calgary, the Swedish Institute for Space Physics in Uppsala, and COM DEV Canada. The Swarm EFI project is managed and funded by the European Space Agency with additional funding from the Canadian Space Agency.
        Speaker: Mr Matthew Patrick (University of Calgary)
      • 16:45
        Small Scale Structuring in Electron Precipitation as seen by the ePOP Suprathermal Electron Imager 15m
        Auroral arcs are known to be caused by electrons with keV energies interacting with the neutral atmosphere. However, there is much more to the aurora than auroral arcs. There is a wide range of phenomena that are grouped together as "diffuse aurora". Suprathermal electron precipitation (having energies between 1 eV and a keV) often contributes to the diffuse aurora. Much less is known about suprathermal electron precipitation than the higher energy precipitation. The ePOP Suprathermal Electron Imager (SEI),a high-time-resolution CCD-based detector capable of imaging electron velocity distributions, is currently being used to survey this type of precipitation. We will present observations of dispersed electron busts, where a burst of electron precipitation is dispersed over the distance from source to detector. We will also present observations of "inverse" electron dispersion, in which a low energy population of electrons increases in energy over time. This has not been reported in literature before. We present a simple model that could explain this phenomenon, and results from a simple simulation of it.
        Speaker: Taylor Cameron (University of Calgary)
      • 17:00
        Cusp Ion Upflows Observed by e-POP SEI and RISR-N: Initial Results 15m
        Low-energy ion upflows associated with ion heating processes in the cusp/cleft and polar cap regions are investigated using conjunctions of the Enhanced Polar Outflow Probe (e-POP) satellite and the Resolute Bay Incoherent Scatter Radar (RISR-N) in June 2014 and February 2015. e-POP encountered the cusp/cleft ion fountain at 10-14 MLT and around 1000km altitude during these conjunction experiments. Such intermediate-altitude observations of ion upflow have been recorded only rarely by previous satellite missions and ground-based radars. The Suprathermal Electron Imager (SEI) onboard e-POP measured two-dimensional ion distribution functions with a frame rate of 100 images per second, from which high-precision energy and angle information of entering ions can be inferred. Field-aligned ion bulk flow velocities were estimated from the angle information with a resolution of the order of 25 m/s. The second moments of the ion distribution provide us with information on ion temperature, which was found to increase sharply in the region of cusp ion upflows in most cases. Also, ion composition information is available from ePOP’s ion mass spectometer (IRM). The ion upflow velocity reaches 2.5km/s in the first identified event on June 1st, 2014, during which the IRM indicated the dominant species as O+ (80%) and H+ (20%). We will compare the in situ measurements with RISR-N observations in order to further understanding of the three-dimensional structure of the cusp ion fountain.
        Speaker: Yangyang Shen (University of Calgary)
    • 15:45 17:15
      T3-4 Cosmic Frontier: Dark Matter III (PPD)/ Frontière cosmique: matière sombre III (PPD) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Thomas Gregoire (Carleton University)
      • 15:45
        Status of the SuperCDMS and European Cryogenic Dark Matter experiments 30m
        The SuperCDMS collaboration operates cryogenic germanium detectors to search for particle dark matter (WIMPs), so far at Soudan Underground Laboratory in Minnesota, US. The EURECA collaboration gathers EDELWEISS, a European collaboration also operating cryogenic germanium detectors, at the Laboratoire Souterrain de Modane, and CRESST who operate cryogenic scintillating detectors (CaWO4) at the Laboratori Nazionali del Gran Sasso, Italy, both with same goal of detecting primarily low mass WIMPs. Most recent progress of these searches will be described together with the planned common future at SNOLAB.
        Speaker: Dr Gilles Gerbier (Queens University)
      • 16:15
        New Pulse Processing Algorithm for SuperCDMS 15m
        SuperCDMS searches for dark matter in the form of Weakly Interacting Massive Particles (WIMPs) with cryogenic germanium detectors. WIMPs interacting with atomic nuclei deposit energy in form of lattice vibrations (phonons) which propagate through the cylindrical Ge single crystal (75 mm diameter, 25 mm high) until they are absorbed by the phonon sensors covering part of the flat surfaces of the crystal. A fraction of the phonons are absorbed when they first reach the surface; a large fraction, however are reflected numerous times leading to a homogeneous distribution in the crystal. This leads to a pulse shape with an initial sharp pulse whose amplitude depends on the distance between the interaction side and the individual sensor, followed by a slow pulse which is identical for all sensors. Traditionally CDMS has used an optimal filter algorithm to extract energy information, but the different pulse shapes lead to a noticeable position dependence on the reconstructed energy. A modification of this algorithm de-weights the initial part leading to a considerably improved energy resolution. A combination of both methods has been used to determine energy and position information. We developed a new algorithm which accounts for the pulse shape by fitting two pulse templates simultaneously to each pulse, one for the position dependent sharp peak and one for the position independent slow pulse. This algorithm has the potential to improve the energy and position resolution while reducing the overall processing time. We will present a first study of the performance of this algorithm.
        Speaker: Mr Ryan Underwood (Queens University)
        Slides
      • 16:30
        Alpha particle backgrounds from the neck of the DEAP-3600 dark matter detector 15m
        The DEAP-3600 dark matter detector at SNOLAB will search for scattering of weakly interacting massive particles from a 3600 kg liquid argon target. The liquid argon is held in a spherical vessel made from acrylic, with the highest standards of purity for both bulk acrylic and removal of surface activities. At the top of the vessel there is a neck opening to the cooling system, and alpha particles decays in this region can potentially introduce a background to the dark matter measurement. The steps to eliminate these alpha backgrounds will be presented, including details on the detector construction, radioactivity simulations, and analysis methods for measuring alpha backgrounds.
        Speaker: Dr James Bueno (University of Alberta)
        Slides
      • 16:45
        Optimizing the wavelength-shifter thickness for alpha suppression in the DEAP-3600 detector 15m
        The DEAP-3600 experiment is a spherical dark matter detector searching for WIMPs by detecting scintillation light in a 3600 kg mass of liquid argon. Before the ultraviolet scintillation light passes through the optically clear acrylic vessel and light guides to the surrounding photomultiplier tubes, it must pass through a wavelength-shifting layer of tetraphenyl butadiene (TPB). Trace amounts of polonium 210 will contaminate the inner surface of the acrylic vessel as well as the TPB layer, and alpha particles resulting from its decay is expected to contribute background events to the WIMP signal. This talk will present the dependence of this background alpha signal on the thickness of the TPB layer, as well as the expected background events per 3 years of data taking at the optimized TPB thickness.
        Speaker: Derek Cranshaw (Queen's University)
        Slides
    • 15:45 17:15
      T3-5 Study of Neutrino Oscillations (PPD-DTP-DNP) / Études des oscillations de neutrinos (PPD-DPT-DPN) CAB 235

      CAB 235

      University of Alberta

      Convener: Zoltan Gecse (University of British Columbia (CA))
      • 15:45
        Status of Long-Baseline Neutrino Experiments 30m
        The current generation of long-baseline neutrino oscillation experiments employ an off-axis $\nu_\mu$ (or $\bar{\nu}_\mu$) beam produced by the decay of pions created when a proton beam strikes a target. The beam is monitored at detector facilities near the production point before travelling hundreds of kilometres to a far detector. Aiming the beam centre slightly away from the far detector provides the off-axis configuration which selects a narrow energy band beam tuned to maximize the oscillation probability. The status of these experiments will be presented. The Tokai to Kamioka (T2K) experiment consists of a $\nu_\mu$ beam produced at the Japan Proton Accelerator Research Centre (J-PARC) in Tokai on the East coast of Japan, which is monitored by a suite of detectors before travelling 295 km to the Super-Kamiokande (SK) water Cerenkov detector. T2K has been in operation since 2010 and has been continually releasing new and exciting neutrino oscillation results. The most recent precision $\nu_\mu \to \nu_e$ appearance and $\nu_\mu$ disappearance oscillation measurements as well as initial results running the experiment in the $\bar{\nu}_\mu$ beam configuration will be presented. The NO$\nu\hspace{-0.11ex}$A experiment, utilizing the NuMI beam and a near detector at Fermilab and a far detector at a distance of 810 km, began operation in 2014. The current status of NO$\nu\hspace{-0.11ex}$A will also be shown.
        Speaker: Dr Nicholas Hastings (University of Regina)
        Slides
      • 16:15
        Electron Neutrino Cross Section Measurements at the T2K Off-Axis Near Detector 15m
        T2K is a long baseline neutrino oscillation experiment in Japan, that targets the measurement of the mixing angle between the first and the third neutrino mass eigenstates ($\theta_{13}$) by looking for the appearance of electron neutrinos ($\nu_e$) in a beam of muon neutrinos ($\nu_\mu$), as well as a precision measurement for the mass difference between the the second and the third neutrino mass eigenstates ($\Delta m^2_{32}$) and their mixing angle ($\theta_{23}$). T2K can also probe anti-neutrino oscillation by looking for the appearance of anti-electron neutrinos ($\overline{\nu_e} $) in a beam of anti-muon neutrinos ($\overline{\nu_{\mu}} $). The experiment uses two detectors: a near detector at 280 m from the neutrino production target (in Tokai), and the far detector at 295 km, Super-Kamiokande (SK). The ND280 is a complex detector that includes a Pi0 Detector (P0D), two Fine Grained Detectors (FGDs), three Time Projection Chambers (TPCs), a Segmented Muon Range Detector (SMRD) and Electromagnetic Calorimeters (ECALs). The electron neutrino sample at ND280 is used for cross-section measurements, the search of sterile neutrinos and for the measurement of the $\nu_e$ component of the total neutrino flux. Obtaining a clean electron neutrino sample is complicated by the large muon neutrino background, and backgrounds due to external gamma rays. This talk will present the results of current electron neutrino cross section measurements at the T2K near detector. Status of work on anti-electron neutrino selection, and research on improving the selection of electrons, positrons, proton background, and background gamma samples using multivariate analysis techniques will be presented.
        Speaker: Fady Shaker (university of winnipeg)
        Slides
      • 16:30
        Constraining Oscillation Analysis Inputs at the T2K Near Detector 15m
        The T2K long-baseline neutrino oscillation experiment is composed of a near detector at 280m and a far detector at Super-Kamiokande located 295 km from the neutrino beam in Tokai. The main oscillation analyses are performed using fits to the data collected at the far detector. These analyses depend on our ability to predict the event rates and energy spectra at the far detector, which in turn depend on cross-section and flux uncertainties. We use inputs from external data, such as MiniBooNE and MINER$\nu$A, as well as beam flux measurements to generate prior estimates of these uncertainties. T2K's near detector then provides a direct internal constraint on the convolution of the flux and cross-section, significantly reducing the uncertainties. This talk will discuss how data from the near detector on T2K is used to constrain the oscillation analysis inputs.
        Speaker: Christine Nielsen (University of British Columbia)
        Slides
      • 16:45
        Deep Core and PINGU - Studying Neutrinos in the Ice 15m
        IceCube and its low energy extension DeepCore have been deployed at the South Pole and taking data since early 2010. Originally designed to search for high energy (on the order of PeV) events, IceCube has recently published the detection of the highest energy events ever recorded. At the same time, enhancements to the detector have been installed to focus on lower energy events. With a neutrino energy threshold of about 10 GeV, DeepCore allows IceCube to access a rich variety of physics including searching indirectly for WIMP dark matter and studying atmospheric neutrinos. A proposed new in-fill array, named PINGU, will continue to lower the threshold for neutrino detection. This will in turn provide the potential to study a great deal of new physics, including the determination of the neutrino mass ordering. This talk will discuss the PINGU detector and the new physics it makes available with a focus on the determination of the ordering.
        Speaker: Ken Clark (University of Toronto)
        Slides
      • 17:00
        Experimental test of the unitarity of the leptonic mixing (PMNS) matrix 15m
        In the past decade, a remarkable progress has been made in the neutrino oscillation determining the lepton mixing (PMNS) angles, except for the CP violating phase delta_CP. The next step is to determine this remaining phase and then over-constraining the PMNS matrix to test its unitarity. Testing the unitarity is an effective way to search for physics beyond the standard model, as is demonstrated in the quark sector. For example, existence of right handed neutrinos or sterile neutrinos would violate the unitarity, and so does new interaction beyond the standard model. In this talk, I will describe the potential path towards testing the unitarity of the PMNS matrix. In particular, CP violation in the baseline length of solar neutrino oscillation provides key information, which the existing Super-Kamiokande data may even start to be sensitive. I will conclude with a prospect of the future experiments to make a stringent test of the unitarity of the PMNS matrix, showing that the accelerator and atmospheric neutrino measurement by Hyper-Kamiokande would take the central role.
        Speaker: Dr Akira Konaka (TRIUMF)
        Slides
    • 15:45 17:15
      T3-6 Nuclear Structure III (DNP) / Structures nucléaires III (DPN) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Jens Dilling (triumf/UBC)
      • 15:45
        Beta-decay from $^{47}$K to $^{47}$Ca with GRIFFIN 15m
        Recent developments in many-body calculation methods have extended the application of *ab initio* interactions to medium-mass nuclei near closed shells. Detailed nuclear data from these isotopes are necessary to evaluate the many-body calculation methods and to test the predictive capacity of the interactions. $^{47}$Ca and $^{47}$K are each one nucleon removed from the doubly-magic nucleus $^{48}$Ca. The beta-decay from $^{47}$K to $^{47}$Ca has a reported half-life of 17.5 s and a $Q(\beta^-)$ value of 6643 keV. Transfer reactions from $^{48}$Ca have identified excited states of $^{47}$Ca throughout the available range of beta-decay $Q$-values, but the two published measurements of $^{47}$Ca populated by the beta-decay of $^{47}$K have only identified four states directly populated by beta decay. High-statistics beta-decay studies using modern high-efficiency, high-granularity detection systems can provide detailed information on level energies, beta-decay and gamma-ray branching ratios, as well as spin/parity assignments and transition mixing ratios through gamma-ray angular correlations. A recent experiment at TRIUMF-ISAC used the GRIFFIN spectrometer to investigate the levels populated by beta decay in more detail. A beam of surface-ionized $^{47}$K was provided by the TRIUMF-ISAC facility and implanted onto a mylar tape at the focus of the GRIFFIN spectrometer, where it decayed to $^{47}$Ca. The early implementation of the GRIFFIN spectrometer used in this experiment consisted of 15 close-packed HPGe clovers with 19% absolute full-photopeak efficiency for 1 MeV gamma rays. Beta detection was provided by ten of the plastic scintillators of SCEPTAR and internal electron conversion spectroscopy was possible with the five lithium-drifted silicon detectors of PACES. The intensity of the beam and the efficiency of the GRIFFIN spectrometer allow for the detection of gamma-ray transitions with small branching ratios, enabling the list of states populated by beta decay to be extended from previous publications. In addition, angular correlations between cascading gamma rays provide information about the spins and parities of states that are not currently included in the beta-decay level scheme. An overview of the experimental apparatus as well as a discussion of the results from preliminary analysis will be presented.
        Speaker: Dr Jenna Smith (TRIUMF)
      • 16:00
        Investigating the Structure of $^{46}$Ca through the $\beta^{-}$ Decay of $^{46}$K Utilizing the New GRIFFIN Spectrometer 15m
        Due to its very low natural abundance of 0.004%, the structure of the magic nucleus $^{46}$Ca has not been studied in great detail compared to its even-even Ca neighbors. The calcium region is currently a new frontier for modern shell model calculations based on NN and 3N forces [1,2], so detailed experimental data from these nuclei is necessary for a comprehensive understanding of the region. Excited states in $^{46}$Ca have been identified previously by various reaction mechanisms, most notably from $(p,p')$ and $(p,t)$ reactions [3]. The low-lying structure has been investigated by two previous beta-decay experiments, with large discrepancies present between the reported decay schemes [4,5]. A recent beta-decay of $^{46}$K performed at TRIUMF's ISAC yield station obtained a new $T_{1/2}$ value of 96.303(79) s and identified 33 new gamma rays attributed to $^{46}$Ca [6]. However, since the ISAC yield station is not equipped with gamma-gamma coincidence capabilities the observed gamma rays were not placed into the decay scheme of $^{46}$Ca. In this experiment, using an early-implementation of the new GRIFFIN spectrometer located at TRIUMF-ISAC, a 9$\mu$A 500 MeV proton beam was impinged onto a uranium carbide target to induce spallation and fission reactions. Radioactive species were surface ionized and a high-resolution mass separator was used to select singly-charged $A$ = 46 ions only. The beam consisting almost entirely of $^{46}$K was implanted onto a Mylar tape at the center of the GRIFFIN array. The $^{46}$K source then populated the excited states of $^{46}$Ca through $\beta^{-}$ decay. The resulting gamma-rays were detected with the new GRIFFIN spectrometer, consisting of 15 HPGe clover detectors. The array also included SCEPTAR, an array of ten plastic scintillators mounted down-stream for $\beta$ particle detection, and PACES, an array of Si(Li) detectors used for the detection of conversion-electrons. The high-statistics data set obtained from this experiment makes it possible to extend the current level scheme, including the assignment of new transitions and levels. The spin and parity of excited states in $^{46}$Ca will be determined through a gamma-ray angular correlation analysis. Preliminary results from this experiment will be discussed. [1] J.D. Holt et al., Phys. Rev. C 90, 024312 (2014). [2] A.Ekstrom et al., Phys. Rev. Lett. 110. 192502 (2013). [3] J.Blachot, Nuclear Data Sheets 111, 717 (2010). [4] B. Parsa and G. Gordon, Phys. Lett. 2, 269 (1966). [5] M.Yagi et al., Laboratory Nucl. Sci., Tohoku Univ. 1, 60 (1968). [6] P.Kunz et al., Rev. Sci. Instrum. 85(5), 053305 (2014).
        Speaker: Ms Jennifer Pore (Simon Fraser University)
        Slides
      • 16:15
        The first GRIFFIN Experiment: An investigation of the $s$-process yields for $^{116}$Cd 15m
        In adopted models for the $s$-process, it is assumed that helium shell flashes give rise to two neutron bursts at two different thermal energies $(kT\sim10$ keV and $kT\sim25$ keV). The contribution to the isotopic abundance of $^{116}$Cd from the higher temperature neutron bursts are calculated assuming thermal equilibrium between the ground state and the long-lived isomeric state of $^{115}$Cd. However, it is unknown if the thermal equilibrium between these states is present at the low temperature of the first burst. The presence of thermal equilibrium at low temperatures would significantly decrease the calculated $s$-process yields of $^{116}$Cd. To answer this question, we are searching for gateway levels at slightly higher excitation energy than the isomer in $^{115}$Cd that could be populated from the isomeric state via $(\gamma,\gamma^\prime)$ reactions within stars. Currently, the lowest potential gateway level at an excitation energy of 394 keV has only been observed to decay directly to the isomeric state in $^{115}$Cd. Nonetheless, the observation of this state decaying to the previously known 361 keV level via a weak 33 keV transition would provide a $\gamma$-ray cascade which would bypass the isomeric state. Thus, the observation of this decay would be a direct signature for the presence of thermal equilibrium during the lower temperature neutron burst. However, the direct measurement of a 33 keV transition is difficult due to the large low-energy $\gamma$-ray backgrounds observed in $\beta$-decay experiments. We therefore require high-efficiency $\gamma$-ray detection to indirectly observe this transition via $\gamma$-$\gamma$ coincidences of $\gamma$-rays cascading through this transition. In November 2014, the high-efficiency GRIFFIN HPGe spectrometer was commissioned at TRIUMF's Isotope Separator and Accelerator (ISAC). GRIFFIN is a state-of-the-art array consisting of 16 HPGe clovers, and boasts a large $\gamma$-ray efficiency of roughly 17% at 1 MeV. GRIFFIN also hosts a large suite of auxiliary detectors such as SCEPTAR, which is an array of 20 plastic scintillators designed for $\beta$-particle detection. In this first experiment, beams of $^{115}$Ag and $^{115}$Ag$^{\text{m}}$ were delivered to the GRIFFIN spectrometer equipped with SCEPTAR in order to search for these very-low-intensity $\gamma$-$\gamma$ coincidences following the $\beta$ decay of $^{115}$Ag into $^{115}$Cd. In this talk, results from this first GRIFFIN experiment will be presented.
        Speaker: Mr Ryan Dunlop (University of Guelph)
      • 16:30
        Gamma-Gamma Angular Correlation Measurements With GRIFFIN 15m
        When a excited nuclear state emits successive $\gamma$-rays in a $\gamma-\gamma$ cascade, $X^{**} \rightarrow X^{*} + \gamma_{1} \rightarrow X + \gamma_{2}$ an anisotropy is found in the spatial distribution of $\gamma_{2}$ with respect to $\gamma_{1}$. By defining the direction of $\gamma_{1}$ to be the z-axis, the intermediate level, $X^{*} $, in general will have an uneven distribution of m-states. This causes an anisotropy in the angular correlation of the second $\gamma$-ray with respect to the first. The correlations depend on the sequence of spin-parity values for the nuclear states involved as well as the multipolarities and mixing ratios of the emitted $\gamma$-rays. These angular correlations are expressed by the $W(\theta)$ function: \begin{center} $W(\theta) = 1 + \sum\limits_{k = even}^{2L} a_{k}P_{k}(cos\theta)$ \end{center} where $L$ is the lowest multipole order of the emitted $\gamma$-rays and the $a_{k}$ are coefficients\part{title} for all of the $P_{k}(cos\theta)$ Legendre polynomials. Angular correlations can be used for the assignment of spins and parities to nuclear states and thus provide a powerful means to elucidate the structure of nuclei away from stability through $\beta-\gamma-\gamma$ coincidence measurements. In order to explore the sensitivity of the new 16 clover-detector GRIFFIN $\gamma$-ray spectrometer at TRIUMF-ISAC to such $\gamma-\gamma$ angular correlations, and to optimize its performance for these measurements, we have studied a well known $4^{+}\rightarrow 2^{+}\rightarrow 0^{+}$ $\gamma-\gamma$ cascade from $^{60}$Co decay through both experimental measurements and Geant4 simulations. Results of these investigations will be presented in this talk.
        Speaker: Mr Andrew MacLean (University of Guelph)
        Slides
      • 16:45
        High-Precision Half-Life Measurements for the Superallowed $\beta^+$ emitter $^{10}$C 15m
        High precision measurements of superallowed Fermi beta transitions between 0$^+$ isobaric analogue states allow for stringent tests of the electroweak interaction described by the Standard Model. In particular, these transitions provide an experimental probe of the unitary of the Cabibbo-Kobayashi-Maskawa (CKM) matrix, the Conserved-Vector-Current (CVC) hypothesis, as well as set limits on the existence of scalar currents in the weak interaction. Half-life measurements for the lightest of the superallowed emitters are of particular interest as it is the low-$Z$ superallowed decays that are most sensitive to a possible scalar current contribution. The half-life of $^{10}$C can be measured by directly counting the $\beta$ particles or measuring the $\gamma$-ray activity following $\beta$ decay. Previous results for the $^{10}$C half-life measured via these two methods differ at the 1.5$\sigma$ level, prompting simultaneous and independent measurements of the $^{10}$C half-life using both techniques. Since $^{10}$C is the lightest nucleus for which superallowed $\beta$ decay is possible, a high precision measurement of its $ft$ value is essential for obtaining an upper limit on the presence of scalar currents in the weak interaction. Measurements of the $^{10}$C half-life via both gamma-ray photo-peak and direct beta counting were performed at TRIUMF's Isotope Separator and Accelerator (ISAC) facility using the 8$\pi$ spectrometer and a $4\pi$ gas proportional $\beta$ counter at the ISAC General Purpose Station. The 8$\pi$ $\gamma$-ray spectrometer consists of 20 High Purity Germanium (HPGe) detectors as well as the Zero Degree $\beta$ detector, a fast plastic scintillator located at the end of the beam line within the 8$\pi$. This presentation will highlight the importance of these measurements and preliminary half-life results for $^{10}$C will be presented.
        Speaker: Michelle Dunlop (University of Guelph)
      • 17:00
        The First Radioactive Beam at GRIFFIN: $^{26}$Na for Decay Spectroscopy 15m
        GRIFFIN (Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei) was installed at the TRIUMF-ISAC-I facility during 2014 and represents a major upgrade to the 8$\pi$ spectrometer which operated at ISAC for the past decade. With an array of 16 large-volume hyper-pure germanium (HPGe) clover detectors, instrumented with a state-of-the-art digital data acquisition system, the array promises to bring a new level of sensitivity to decay spectroscopy experiments. GRIFFIN is used to investigate a wide variety of nuclear properties relevant to nuclear structure, nuclear astrophysics, and fundamental symmetries using stopped radioactive beams from ISAC and the future ARIEL facility. The most exotic nuclei produced at these facilities are generally produced with the lowest intensity. Additionally, in modern studies of the decay of intense radioactive beams, it is often the weakest decay branches which are of the greatest interest. The high efficiency of the GRIFFIN spectrometer makes spectroscopy possible in both situations. GRIFFIN was commissioned in the fall of 2014 using a radioactive $^{26}$Na beam produced from impinging 500 MeV protons onto a silicon-carbide (SiC) target. The $^{26}$Na beam was then implanted into a movable tape at the central focus of the array. The auxiliary detector SCEPTAR (an array of 20 plastic scintillator paddles) was used for beta-tagging while the GRIFFIN spectrometer itself was used for the detection of gamma radiation. A previous experiment, also studying the decay of $^{26}$Na, ran under similar conditions using the 8$\pi$ spectrometer at TRIUMF in 2004. Results highlighting the performance of the GRIFFIN array as well as the structure of the $^{26}$Mg daughter will be presented.
        Speaker: Nikita Bernier (TRIUMF)
        Slides
    • 15:45 17:15
      T3-7 Panel on Women in Phyiscs (CEWIP) / Table ronde sur les femmes en physique (CEFEP) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Shohini Ghose (urn:Facebook)
      • 15:45
        Panel Discussion on Women in Physics 1h 30m
        Moderator: Shohini Ghose, Wilfrid Laurier University Panellists: Sara Seager (MIT), Adriana Predoi-Cross (University of Lethbridge) and Wendy Taylor (York University)
    • 15:45 17:15
      T3-8 Advanced Instrumentation at Major Science Facilities: Detectors I (DIMP) / Instrumentation avancée dans des installations scientifiques majeures: détecteurs I (DPIM) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 15:45
        Advanced Instrumentation at TRIUMF 30m
        TRIUMF operates the Isotope Separator and Accelerator (ISAC) rare isotope facility as well as the Centre for Molecular and Materials Science (CMMS), which uses muons and isotopes. The ISAC facility comprises 18 state of the art experiments for experimental programs in nuclear structure, nuclear astrophysics, and fundamental symmetries. CMMS features several state-of-the-art set-ups for muon spin rotation (MuSR) experiments as well as stations for beta detected NMR and NQR using rare isotopes. Most recently, the new electron linac, a cutting-edge superconducting RF accelerator and part of the Advanced Rare Isotope Laboratory (ARIEL), has just been commissioned. In addition to these user facilities TRIUMF carries out developments for a number of particle physics detector projects, including the ATLAS detector at the LHC, the long-baseline neutrino experiment T2K, and the nEXO next generation double beta decay project. The presentation will provide an overview of the facility and highlight selected projects.
        Speaker: Prof. Reiner Kruecken (TRIUMF)
        Slides
      • 16:15
        Development and simulations of the CANREB RFQ buncher and cooler at the TRIUMF facility 15m
        TRIUMF’s new Advanced Rare IsotopE Laboratory (ARIEL) is the up and coming producer of rare isotope beams for nuclear science in Canada. It will triple the number of beamlines available to both of the (rare) Isotope Separator and Accelerator (ISAC) facilities, and will expand their range of available isotopes. An overview of ARIEL and the CANadian Rare-isotope facility with Electron-Beam ion source (CANREB) will be given with the focus on the CANREB Radio Frequency Buncher and Cooler (CANREB RFQ). The theory behind the operation of RFQs will be discussed as well as the results of systematic studies done via simulation to optimize the injection and extraction ion optics. The RFQ is expected to provide bunching and cooling of beams with masses in the range of 15 to 250 amu utilizing two separate RF circuits of different frequencies to span this large range efficiently. Comparisons will be made via simulations between both the TITAN RFQ (located at TRIUMF) as well as the BECOLA RFQ (located at MSU) after which the CANREB’s RFQ novel electrode structure is modeled.
        Speaker: Mr Jeff Bale (TRIUMF)
        Slides
      • 16:30
        Photodetection with SiPM in particle physics and materials science 15m
        Pixelated Geiger-mode avalanche photo-diodes also called silicon photo-multipliers (SiPMs) are replacing traditional vacuum photo-multiplier tubes (PMTs) in numerous applications in subatomic physics, medical imaging and condensed matter. They have several advantages being insensitive to magnetic field, having higher efficiency, more uniform gain, and being more compact. However, they still cannot compete with PMTs for application requiring large areas of photo-detection at room temperature. We will describe their characteristics and performances and show a few specific applications in particle physics, condensed matter and medical imaging.
        Speaker: Fabrice Retiere (TRIUMF)
        Slides
      • 16:45
        The Electrodynamometer of the McPherson Collection of Scientific Instruments 15m
        The Weber electrodynamometer is an instrument used to measure the absolute value of electric power (or current if one knows the voltage). It works by measuring the mechanical torque between two pairs of coils induced by the current in the coils. This is one of the first research instrument bought in 1895 by the newly created McGill Physics Department for 177£. McGill College apparatus originally constructed by Messrs. NALDER from London was intended to be an exact duplicate of the apparatus in the Cavendish Laboratory at Cambridge. When received it did not meet specifications and had to be completely rebuilt by an undergraduate student under the supervision of Prof. Hugh Callendar. After rebuilding it had an absolute precision of the order of one part in a thousand. The repair and operation of the instrument will be described in details.
        Speaker: Jean Barrette (McGill University)
    • 15:45 17:15
      T3-9 Molecular Biophysics (DMBP) / Biophysique moléculaire (DPMB) CAB 239

      CAB 239

      University of Alberta

      Convener: Maikel Rheinstadter (McMaster University)
      • 15:45
        Watching proteins fold: capturing the conformational diffusion of single molecules during structural self-assembly 30m
        The self-assembly of intricate structures by proteins is a complex process involving myriad degrees of freedom. Such “folding” is usually described in terms of a diffusive search over a multi-dimensional energy landscape in conformational space for the lowest-energy structure. The diffusion coefficient, *D*, encodes the rates at which microscopic motions occur during folding and is thus of fundamental interest, but it is very difficult to measure. I show how *D* can be determined from measurements of single proteins folding and unfolding under tension in optical tweezers. By reconstructing the energy landscape for folding from the statistics of the single-molecule trajectories, *D* can be found using classic kinetic rate theories. More sensitive measures of *D* can be obtained by measuring the “transition time” required for the molecule to transit the energy barrier separating two structures. Using the folding of the protein PrP, which forms incorrect structures that lead to “mad cow” disease, as an example, *D* is seen to be orders of magnitude faster for the correct structure of the protein than for incorrect structures. Indeed, the incorrect structures form sufficiently slowly that the path the protein follows during the structural change—never before observed directly for any protein—can now be seen. Finally, I discuss how the properties of such transition paths can be used to show that the multi-dimensional problem of protein folding can be reduced quantitatively to one-dimensional diffusion.
        Speaker: Michael Woodside (University of Alberta)
      • 16:15
        Coarse-Grained computer simulations of Alzheimer’s beta-amyloid peptides, using the Mercedes-Benz Hydrogen Bond Potential 15m
        Protein aggregation is a medically relevant phenomenon that can lead to protein-folding diseases such as Alzheimer’s and Prion’s. The aggregation process is largely determined by hydrogen bonds (HB), involving hundreds of peptides, over a period of days or even months. This rules out molecular dynamics (MD) simulations of all-atom protein models in explicit solvents. However, coarse-grained models of protein aggregation must accurately represent HB. This work considers the coarse-grained model used by Head- Gordon and coworkers to study the beta-amyloid (Aβ) peptides that forms plaques in Alzheimer’s diseases [1]. The model represents one amino-acid residue by a single bead, and used the Mercedes-Benz (MB) model to describes backbone HB. This has been adapted to study residue 25 to 35 of the peptide, Aβ_{25-35}, which is believed to be the most toxic stretch of Aβ. Preliminary work has obtained data on Langevin dynamics of 100 Aβ_{25-35} in a 100A ×100A ×100A box. The model peptides will be immersed in the MB water model of Dias and coworkers [2], used previously to study cold denaturation of proteins. The final model will be used to accurately identify the structure of Aβ intermediates believed to the neurotoxin agents in Alzheimer’s disease. [1] Hui, Fawzi, Head-Gordon, Proteins 70, 626 (2008) [2] Dias, Alla-Nissila, Grant, Kartunnen, J. Chem. Phys. 131, 054505 (2009)
        Speaker: Dr Apichart Linhananta (Lakehead University)
      • 16:30
        The Formation of Alzheimer's Plaques in Synthetic Membranes 15m
        Alzheimer’s disease is a type of dementia that affects memory, thinking, and behaviour. One of the hallmarks of the disease is the formation of neurotoxic senile plaques, primarily consisting of amyloid-β peptides. Despite their importance for the pathogenesis of the disease, little is known about the properties of these plaques and the process by which they form. We developed a model system to study the formation and properties of Alzheimer’s plaques in-vitro. Synthetic anionic lipid membranes with brain-like composition were prepared that included different concentrations of the amyloid-β(25-35), the transmembrane segment of the full 42 amino acid long peptide. The systems were prepared as multi-lamellar membranes supported on silicon chips. We investigated size, density and molecular properties of these plaques using optical microscopy and X-ray diffraction. At concentrations of 3mol%, the peptides were dispersed in the membranes, but at concentrations of 10mol% and 20mol%, peptide aggregates were observed. Plaques formed from amyloid-β aggregates were typically around 12 to 13 micrometers in diameter. With increasing peptide concentration, the density of small plaques increased, however, their size stayed approximately constant. The aggregates were found to form inside the membranes and to coexist with the membrane structure. We used X-ray diffraction to determine the molecular structure of the membranes and peptide structure. At concentrations of 3mol%, only the alpha-helix signal was detected whereas in the 10mol% and 20mol% samples, both alpha-helix and beta-sheet signals were detected. The preparation of synthetic Alzheimer’s tissue is a milestone for the in-vitro testing of anti-Alzheimer’s drugs before they go into clinical studies. By preparing membranes of different composition, such as saturated and unsaturated lipids, cholesterol and hormones, quantitative information about plaque formation can be obtained.
        Speaker: Jennifer Tang (McMaster University)
        Slides
      • 16:45
        Alzheimer's Disease Amyloid Beta(25-35): An Oligomeric Aggregation Simulation From Monomers to Ordered Filaments 15m
        Amyloid Beta (A$\beta$) plaques have long been correlated with Alzheimer's disease; however, efforts made to link the plaques to pathogenic effects or utilize them for diagnostic purposes have not been very fruitful. Modern investigations point to peptide intermediate structures or their oligomers as likely candidates for the toxic agents, yet much remains unknown about the aggregation life cycle from monomers to aggregated ordered filament structure. From a simulation standpoint, this is generally difficult due to the high residue count and long time frames involved in such investigations. Fortunately, in the case of Alzheimer's disease, there is a fragment of the A$\beta$ peptide, A$\beta_{25-35}$ which has a short residue length, aggregates rapidly, and is highly pathogenic[1], making it particularly well suited for biophysical simulation. Our work investigates A$\beta_{25-35}$ utilizing a molecular dynamics simulation and course-grained _C$\alpha$ model based on that presented by Yap et al. in [2] which includes hydrogen bond pairing to stabilize the secondary structure. The entire aggregation process is explored from random-coil monomers, through formation of unordered intermediate oligomeric states, and into ordered filament structure. Utilizing standard cluster criterion, the nucleation free-energy landscape for A$\beta{25-35}$_ as a function of the number of peptides and hydrogen bond count between peptides is mapped and nucleation barriers are determined as in [3]. Also thermodynamic and kinetic measures are determined. The determination of these factors is the necessary first step to conducting future investigations involving solvents and in the presence of surfaces. [1] J. Biosci. 34(2), pp. 293–303, 2009 [2] Proteins 70, pp. 626-638, 2008 [3] PRL 101 (25), 258101, 2008
        Speaker: Robert Girardin (Lakehead University)
      • 17:00
        Kinetics of Chain Motions within the disordered eIF4E-BP2 protein 15m