This is an international conference associated to the African School of Physics. Participation is open to anyone. The scientific program will cover topics in the following areas:
For additional information (accommodation, travel visa, etc), please look here:
http://www.africanschoolofphysics.org/acp2018/
The Large Hadron Collider at CERN has raised its collision energy, and collision rate, since the discovery of the Higgs boson in 2012. This provides a huge, rapidly growing, data sample enabling increasingly sophisticated studies of the Higgs boson, including of its production and decay, from which the couplings to the other Standard Model particles can be inferred. The large data sample also allows new high statistics studies of the electroweak gauge bosons. Selected key results in these areas from the ATLAS and CMS experiments are discussed in this talk.
At the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN), protons and heavy ions are made to collide together near the speed of light to study particle interactions and give us an insight to the fundamental laws of nature. Three experiments that are located on the circular ring of the LHC specialize in proton-proton collisions, namely a toroidal LHC apparatus (ATLAS), a compact muon solenoid (CMS), and the large hadron collider beauty (LHCb). The energy and intensity of the particle beams at the LHC are unprecedented. The data recorded by the detectors that are located on the circular ring of the LHC already exceeded 200 petabytes in summer last year, and a petabyte a day is processed at the CERN data center alone. These data are used to study known particles of the well-established Standard Model of particle physics including the long expected and recently discovered Higgs boson.
With predictions such as the existence of the W and Z bosons, gluon, top and charm quarks, and Higgs boson, and experimental confirmations with good precision, the standard model is the most successful theory of particle physics to date describing the strong, weak and electromagnetic forces of nature. The standard model cannot, however, accommodate experimentally observed phenomena like gravity, neutrino masses, and dark matter. The theory can also be theoretically unsatisfying as a result of parameters that go unexplained, such as the value of the Higgs mass despite its large quantum corrections, implying a lack of understanding. For this reason, in addition to precision measurements of standard model observables, experiments search for new physics beyond the the standard model that could explain some of the shortcomings of the standard model. A selection of results for searches for new physics beyond the Standard Model using data recorded by ATLAS, CMS, and LHCb are presented in this talk.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
Southern Africa is becoming a beacon for astronomy throughout the electromagnetic spectrum: In all wavebands accessible from ground, the largest astronomical facilities are either operational or in the process of being set up in the region, see e.g. [1].
The Southern African Large Telescope (SALT) in Sutherland (South Africa), measuring 11m in diameter, is the largest single optical telescope in the Southern hemisphere [2]. The deployment of the telescopes of the MeerKAT radio telescope, being the largest and most powerful radio telescope in the Southern hemisphere, has just completed [3]. The 64-dish MeerKAT telescopes will later develop into the Square Kilometre Array (SKA), the most sensitive radio telescope on Earth, utilizing outlier station all over Southern Africa [4]. The High Energy Stereoscopic System (H.E.S.S.) telescopes [5] in the Khomas highlands in Namibia are the largest and most powerful system of Cherenkov telescopes to study very high energy (E>100 GeV) gamma-rays. For its successor, the Cherenkov Telescope Array (CTA) [6,7], Namibia has been voted second of possible countries to host the Southern part [8,9].
Against this background, the current situation of astronomical research and education in Namibia will be reviewed, specifically focusing on recent developments.
The models of atomic nuclei as we know them today have largely been developed based on results from experiments using stable isotopes as beams and targets, or from beta-decay experiments following fission or spallation. However, such experiments have inherent limitations. Due to the tendency of the heavier elements to have a neutron excess compared to the number of protons, an effect of Coulomb repulsion, stable beam on stable target experiments create fusion products that lie dominantly on the neutron deficient side of stability. Some other possibilities exist, e.g. via particle transfer and deep-inelastic reactions to create residues away from stability, but the neutron rich isotopes remain largely unexplored using reactions. This is an interesting situation since we also know that the neutron drip line should extend far beyond the current limits of known isotopes. There are presumably still thousands of isotopes that could be synthesized and studied in the laboratory that are yet unknown.
For practical reasons it is most reasonable to pursue reactions where radioactive isotopes are involved by creating a beam of the isotope in question. Two techniques, in-flight fragmentation and Isotope Separation OnLine (ISOL) exist today, and are pursued at laboratories in Europe, North America and Japan. I will introduce both methods with some focus on ISOL and discuss a handful of physics cases, stretching from fundamental physics to applications, that can be addressed with radioactive beams.
After a short introduction to neutrino physics in general the lecture will focus on accelerator-based neutrino-oscillation experiments. A summary of the current status and results of running experiments, in particular NOvA and T2K will be given, to be followed by an overview of the status of the proposed long-baseline experiments Hyper-K, DUNE and ESSnuSB with a special focus on the potential for discovery of leptonic CP violation.
High energy electron beams have enabled the study of the nucleus and nucleons with unprecedented statistical and systematic precision. This is achieved using continuous wave beam with high intensity and 90% polarization, while interacting through the well modeled electroweak interaction aids interpretation. This opens up a wide variety of physical studies including the longitudinal, transverse and 3D structure of hadrons, studies of the hadronic spectrum, searches for physics beyond the Standard Model and searches for dark sector particles. This talk will focus on nuclear physics using electron beams, presenting a basic introduction and highlighting a few of the more surprising of the rich and varied recent results that have emerged.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
Since the discovery of graphene in 2004, many new 2 dimensional materials have been synthesised. These form ideal systems to model quantum mechanically and to modify computationally, for example by doping or the creation of various defects, with the view to alter the physical, electronic, magnetic, etc., properties. Within the framework of density functional theory, a number of 2D systems will be discussed for their often unique and novel properties. In addition, a new theoretical scheme will be presented that enables the computation of the elastic properties of these materials.
We include effects of self-gravitation in the self-interaction of single electrons with the electromagnetic field. When the effect of gravitation is included there is an inevitable cut-off of the k-vector - the upper limit is finite. The inward pressure of the self-gravitating field balances the outward pressure of self-interaction. Both pressures are generated by self-interactions of the electron with two fields - the vacuum electromagnetic field and the self-induced gravitational field. Specifically we claim that gravitational effects must be introduced to stabilize the electron. We use the Einstein equation to perform an exact calculation of the bare mass. We find a close-form solution. We find the electron radius $r_{e}=\sqrt{\alpha /4\pi }\sqrt{\hbar G/c^{3}}$. Traditionally the second quantity which is called the Planck length $\ell_{P}$, is educed here from first principles. We find that the electromagnetic and gravitational fields merge at $\sqrt{\alpha /16\pi }%\sqrt{\hslash c/G}=$ $\sqrt{\alpha /16\pi }m_{P}=10^{17}GeV$ in terms of the Planck mass $m_{P}$. Renormalization is accomplished by requiring continuity
of the interior and exterior metrics at $r_{e}$.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
I will present my journey from a childhood in the South African Kalahari, to studying physics at the Massachussetts Institute of Technology (MIT), then specializing in astrophysics for graduate studies, working at the NASA Ames Research Centre -- among others, and eventually becoming a Professor at the University of South Africa (UNISA). The presentation will include results from the submillimeter-bright galaxies that I study and a small tribute to one of my heros and inspirations, Professor Stephen Hawking, who just passed on this year.
Abstract:
Physics, the study of the basic principles that rule the physical world, was instrumental in the “Scientification” of Psychology, the study of the mind and behaviour. The physicist and philosopher, Gustave Theodor Fechner (1801-1887), coined the term of psychophysics in his seminal work Elemente der Psychophysik in 1860 which aimed at connecting physical stimuli to the different components of consciousness, particularly sensation. Although, psychophysics presents today rather a chapter in the history of psychology – the interdisciplinary journey between physics and psychology continued – and it needed to continue because “mental processes are connected with material processes” (Ebbinghause, 1990). My lecture will provide an overview of this more than a century lasting journey by presenting examples that will not only outline how physics shaped the methodological approaches and theories of psychology but also how psychological knowledge shaped the physical sciences.
New materials have always added to new technology and subsequently new society. The simplest example can be going to history where we can see the transitions from Stone Age which developed into Bronze and then Iron Age. Each age is levelled by the material, bearing the new technology and new society. The present age is levelled by the Silicon material and is known as Silicon age. Now question is – what will be the next age? Scientists assume that age may be the CARBON or GRAPHENE age because the carbon/graphene is the substitute of silicon material. Graphene is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice that can be viewed as an atomic-scale chicken wire made of carbon atoms and their bonds. It is the world’s first two dimensional (2D) material isolated from graphite in 2004 by two physicists Andre Gem and Konstantin Novoselov who received the novel prize on physics in 2010. Graphene, the "wonder material", is made of a single atom thick carbon atom layer in a honeycomb-like hexagonal lattice and is the thinnest, strongest and hardest material available. Graphene is strongest, lightest, thinnest and smallest material in the world. The last few years have seen extensive research into the properties and applications of graphene, and the material has been suggested as being the potential replacement for silicon in many electronics applications. It is highly stretchable, transparent and impermeable and useful in different device applications in our day to day life. Graphene has several useful properties that include high mechanical strength, very high electron mobility, and superior thermal conductivity. Graphene could be used to create electronic components which are transparent and flexible, creating a new paradigm in electronic product design. Graphene is flexible, transparent electronics and closer to reality with the creation of graphene-based electrodes.
In conclusion, graphene is a promising material for new types of system, circuits and devices where several functionalities can be combined into a single material. Presently, highly critical issues with the extensive use of graphene in electronics are related to manufacturing. Although growth on copper surfaces has made bulk manufacture of large area graphene layers possible, there are a number of technical challenges to be overcome both in terms of cost and quality before the first consumer products using graphene are actually commercialized.
In this present talk, I will present the process of extraction of graphene, its different properties and various applications. In addition magnetic properties of graphene and graphene oxide will be discussed for the future spintronic applications.
This research seeks to understand the role of ScCl3, ZrCl4, and VCl3 catalysts in NaAlH4. Some researchers suggests that the catalyst serves to decrease the H2 gas desorption temperature in these materials by influencing the reaction rates. Others suggest that the catalyst acts more as a dopant, thereby mitigating (enhancing) diffusion rates is in the solid phases. Changes in the hydride powders during desorption occurs at multiple length scales. To study this problem, we have examined these hydrides at multiple length scales using an Xray scattering instrument which is capable of capturing nine decades of scattering intensity from a scattering wave vector, Q, of 0.0001Å to 6.0 Å . The ultrasmall angle Xray scattering (USAXS) instrument sector 9ID-D of the Advanced Photon Source (APS) offers the capability to simultaneously collect morphology information using USAXS and SAXS data while examining the crystallographic changes using wideangle
Xray scattering (WAXS) data. Studies were performed on aspurchased, neat, and catalyzed NaAlH during insitu heating up to 170C (just below the H desorption temperature for uncatalyzed NaAlH4). Results showed that NaAlH has a surface fractal (highly porous) morphology. Isothermal studies performed at 30C, 65C, 100C, 135C, and 170C reveals changes at low Q (Q~.001 Å to 0.01 Å ) associated with highly interconnected intraparticle porosity which is suitably described by a power-law slope for a Gaussian polymer chain structure of p~2. At high scattering wave vector, Q~0.03Å , the presence of a pore population which obeys Porod scattering and appears to have a size at 21nm is present. These fine pores increase in their population density as temperature is elevated. These morphological changes are all believed to occur because of hydrogen diffusion out of the powders. The WAXS data reveals thermal expansion to occur, but no solid state phase transformation to the product phase. Next steps will involve correlating these changes with hydrogen desorption temperatures for each catalyzed sample.
Chalcogenide glasses containing S, Se or Te constitute a rich family of vitreous semiconductors. There has been intense research activity based on these glasses in the view of basic Physics as well as device technology. The freedom allowed in the preparation of glasses in varied composition brings about changes in their short-range order and thus results in variation of their physical properties. It is therefore easy to tailor their various properties as desired for technological applications. These materials have a wide range of applications such as making optical fibers, memory devices, reversible phase change optical recording etc. Besides the wide commercial/device applications like switching, memory and xerography etc. of Se, it also exhibits a unique property of reversible transformation . This very property makes it very useful in optical memory devices.
The effects of impurities on the electronic properties of amorphous chalcogenide glasses have been the subjects of serious debate ever since their discovery . It has long been known that these glasses, which behave like intrinsic P-type semiconductors, are insensitive to doping and that this behavior is attributed to the local valence saturation of the dopant atom. Fermi level is considered to be pinned due to the equilibrium between the negatively and positively charged (D- and D+) daggling (D) bonds . The concept of pinned Fermi level is not consistent with the discovery of the surprising phenomenon of P-N transition or conductivity type reversal first observed in bismuth germanium chalcogenide glasses. This discovery has led to extensive research on these materials and to a reconsideration of the existing theories of electronic structure of chalcogenide glasses. The carrier type reversal in germanium chalcogenides requires incorporation of a significant amount of bismuth.
In this talk we present a overview of recent trends and research on these materials and our contribution towards understanding their optical and structural properties and applications.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
The iThemba Laboratory for Accelerator Based Sciences has been operating a K=200 Separated Sector Cyclotron for nuclear physics research, isotope production and hadron therapy since about 1986. The conflicting demands of these diverse application place severe restrictions on research capacity and on the possibility to respond to future demands.
To increase the beam time for research and isotope production, the establishment of a new facility, the South African Isotope Facility (SAIF) has been proposed. The new facility will consist of two parts:
1. The Accelerator Centre for Exotic Isotopes (ACE Isotopes) will be a dedicated facility for radioisotope production. A commercial high-current 70 MeV H- cyclotron for this purpose will free the SSC and allow an increase in beam time for nuclear physics and related research.
2. The Accelerator Centre for Exotic Beams (ACE Beams) will be a radioactive ion beam (RIB) facility for nuclear physics research. The SSC will be used as a driver for an isotope separation on-line (ISOL) facility. A 66 MeV proton beam of up to 50 μA will be delivered by the SSC for producing radioactive beams from a target ion source. The first stage of this project will be a low-energy radioactive ion beam (LERIB) project without post acceleration. The second stage will be the post acceleration of the radioactive beams with a linear accelerator to energies of between 4 and 5 MeV per nucleon.
After a brief overview of iThemba LABS facilities and research opportunities he talk will describe how the Long Range Plan of iThemba LABS will create the South African Isotope Facility (SAIF) which will put South Africa in a prominent position in the future to address the new challenges both in research and training within the subatomic field and beyond.
A Study of the Front-End Electronics of the Compact High Energy Camera prototype for the Gamma-Ray Cherenkov Telescope Project of the Cherenkov Telescope Array
M.S. Nekwaya1,*, S. Leach2, M. Backes1,3, J.Lapington2, G. Cotter4, for the CTA Consortium
1Department of Physics, University of Namibia, Namibia
2Space Research Centre, University of Leicester, UK
3Centre for Space Research, North-West University, South Africa
4Department of Physics, University of Oxford, UK
*corresponding author: sananekwaya@gmail.com
Abstract
The Compact High Energy Camera (CHEC) is a camera-development project for the dual-mirror Small-Sized Telescopes (SST-2M) of the Cherenkov Telescope Array (CTA) [1].
Some of the components of the Front-End Electronics (FEE) of the CHEC are photo-sensors, preamplifiers, TARGET modules and a backplane board [2]. This study will focus on the signal generated by the preamplifier buffer boards in order to characterise the output waveform as well as to identify any faulty preamplifier channels depending on their output.
This research project will establish an automated waveform analysis procedure that will highlight any variation from the expected channel response and help ensure that each assembled CHEC has 2048 validated and uniform FEE channels.
References
[1] M.K. Daniel., et.al, (2013). A Compact High Energy Camera for the Cherenkov Telescope Array. Power, 10, 4.
[2] L. Tibaldo., et.al, (2017). The gamma-ray Cherenkov telescope for the Cherenkov telescope array. In AIP Conference Proceedings, Vol. 1792, No. 1, p. 080004
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
The South African Astronomical Observatory (SAAO) turns 200 years in 2020. It is the premier optical astronomy research facility on the African continent. The Southern African Large Telescope (SALT) is a 10m class telescope, the largest one in the Southern Hemisphere, and the flagship facility at the Sutherland observing site that SAAO operates. I will summarise the current status of SALT and highlight some recent science results. I will present the new science focus strategy including transient astrophysics, exoplanets, and galaxy evolution, that both SALT and SAAO have recently adopted. I will talk about the development plans for the next years supporting those focused science goals.
General relativistic astrophysics and elementary particle and nuclear physics are strongly connected and their results are interdependent. Although the physical systems are quite different, the 4D-simulation of a merger of a binary system of two neutron stars and the properties of the hot and dense matter created in high energy heavy ion collisions, strongly depend on the equation of state of fundamental elementary matter. Neutron star mergers represent optimal astrophysical laboratories to investigate the QCD phase structure using a spectrogram of the post-merger phase of the emitted gravitational waves. These studies can be supplemented by observations from heavy ion collisions to possibly reach a conclusive picture on the QCD phase structure at high density and temperature. As gravitational waves (GWs) emitted from merging neutron star binaries have just been detected, it is important to understand the main characteristics of the underlying merging system in order to predict the expected GW signal. Numerical-relativity simulations of merging neutron star binaries helps in studying the emitted GWs and the interior structure of the generated hypermassive neutron stars. The spectral properties of emitted GWs are then studied with the appearance of the hadron-quark phase transition in the interior region of the hypermasive neutron star and the results are confronted with the simulation results of high energy heavy ion collisions.
We will review the most relevant results on heavy-ion physics at ultra-relativistic energies. This will include a brief overview of the current status on the characterization of the QGP medium created in a heavy-ion collision and will also touch on the intriguing finding of collective-like phenomena exhibited by results obtained in small collision systems.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
Reionization was a very critical process in the Universe in the transition from an opaque to a transparent Universe. However, we do not fully understand how this event happened. Using the kinetic Sunyaev-Zel'dovich Effect (kSZ), we can look critically into the reionization epoch of the Universe. This work predicts how well we can constrain cosmological parameters using forecasted data from the Simons Observatory (SO), to explain the transition from dark matter to stars. We use the model developed by alvarez et. al. to test whether we can determine the shape of the kSZ spectrum from patchy reionization. Using different specifications for SO, we find the best configuration of telescope parameters that provide tight constraints on the cosmological parameters.
The Africa Millimetre Telescope (AMT) will be built on Mount Gamsberg in Namibia, to form part of a world-wide interferometric network of millimetre-wave telescopes to resolve the event horizon of the Galaxy's supermassive blackhole. At a distance of 8kpc and a mass of about 4 million solar masses, the event horizon should subtend an angle of about 10 micro arc seconds from Earth. This is too small to be currently imaged at any wavelength other than using very long baseline interferometry at mm-wavelengths. The AMT will form part of this world-wide network, providing a vital link with telescopes in Hawaii and India, allowing the very longest baseline and thus the highest angular resolution to be achieved. The AMT will use a 15-metre dish which is currently in Chile, and Mount Gamsberg's exceptionally dry weather will allow the galactic centre to be imaged at mm-wavelengths during June-September, as it passes high overhead from Namibia's latitude. In this talk, I will summarise the current status of the AMT project.
The closest known active galaxy is Centaurus A (Cen A) at a distance of 3.8 Mpc. Due to its proximity, Cen A has been observed over a wide range of energy bands. These extensive observations enabled various astrophysical phenomena associated with active galaxies to be studied in great detail. Cen A has recently been observed by H.E.S.S. and Fermi-LAT in gamma-rays. In describing the spectral energy distribution (SED) of the core of Cen A, as observed by these two instruments, it became evident that there is a need for going beyond a single-zone synchrotron self-Compton (SSC) description of the gamma-ray emission. We consider here modelling the high-energy SED in Cen A with the appearance of a second gamma-ray emission component due to gamma-gamma absorption.
Keywords: Catalyst, Water Splitting, Molecular Dynamics, Semi-empirical, Fuel Cells
Theme: Computational Materials Science
The twin problems of electricity shortage and limited access to clean drinking water in Africa can be solved by the development of catalysts. Abundant catalysts that can facilitate the splitting of water into hydrogen gas (and oxygen gas) are required as well as cheaper catalysts that can be used in fuel cells to produce electricity by the oxidation of hydrogen. An important by product of the fuel cell is clean water from the combination of hydrogen and oxygen. Thus, even dirty water can be used to produce electricity and clean water. While platinum and platinum-ruthenium alloys work as catalysts in fuel cells, they are costly and cheap and abundant alternatives are needed. The goal of this work is to understand the mechanism of action of these expensive catalysts as a guide to developing alternative cheap and abundant catalysts for fuel cells. Semi-empirical molecular dynamics (SEMD) simulation will be used to study the oxidation of hydrogen by platinum and comparisons made with the same process but in the presence of a recently discovered catalyst Fe(PO3)2. Preliminary SEMD simulations of possible catalysts for photocatalytic water splitting will also be presented.
The concentrations of naturally occurring radionuclides 238U, 232Th, and 40K in the soil samples collected from the Ohorongo Cement Plant near Otavi, Namibia have been determined and used to estimate the baseline natural radiation level in the cement plant. A total of 50 soil samples were collected from inside and outside of the plant and analyzed using an HPGe detector. The concentrations vary from 7.3 ± 1.2 to 25.6 ± 1.8 Bq/kg with an average of 15.0 ± 4.7 Bq/kg for 238U, 12.7 ± 2.0 to 43.1 ± 3.5 Bq/kg with an average of 25.1 ± 9.9 Bq/kg for 232Th, and 132.2 ± 9.7 to 507.8 ± 22.5 Bq/kg with an average of 310.7 ± 97.2 Bq/kg for 40K. These concentrations were used to calculate the mean absorbed dose rate and the mean annual effective dose for the plant. The value of 0.04 mSv obtained for the mean annual effective dose is less than the maximum permissible dose of 1 mSv a year recommended for the public by the International Commission on Radiological protection. In order to evaluate the associated health hazard, the concentrations were also used to calculate the mean Radium equivalent activity (Req) and the mean external hazard index (Hex) for the plant. The values of 74.9 Bq/kg and 0.20 obtained respectively for Req and Hex are again much below their respective permissible values. These results and the low value obtained for the mean annual effective dose indicate that radiation hazard is negligible in the plant.
Global competitiveness is intrinsically linked to the level of scientific development. Adequate investment in research and development remains a key factor in fostering meaningful capacity building. While coordinated efforts have been made towards the realisation of sustainable capacity building within the broader African context, there is a crucial need to go beyond capacity building with a view to reverse the African science diaspora. This talk provides a contextual review in terms of the impact of existing scientific interventions geared towards sustainable capacity building within Africa. While the existing scientific interventions within Africa played a transformative role in the enhancement of human capital development, adequate investment in research and development is required to make further significant strides going forward. Regular assessment of the impact of existing scientific interventions ought to be undertaken as a key strategic imperative through the establishment of the African evaluation and monitoring committee. Inadequate expenditure in research and development as a percentage of gross domestic product by African countries paints a gloomy picture in terms of the realisation of sustainable scientific development. Yet, Africa is expected to play a meaningful role as part of the global community of nations. Key recommendations providing a roadmap in intensifying and harnessing capacity building efforts for purposes of accelerating socio-economic development within Africa are advanced.
Particle physics in schools but also during undergraduate studies can be taught most effectively by designing and conducting own experiments. In the past years, we developed two construction manuals for fully functional cloud chambers as well as a counting detectors using only material which can be purchased by private persons with total costs below 200 USD. We tested the construction of these detectors with undergraduate students during lectures on detector physics. The resulting prototype detectors can be further used in high schools. In this presentation we will summarize the construction manuals, discuss the performance of the detectors as well as present on the feedback which we received from students and high school teachers alike.
The Physics Education session concludes with a panel discussion to enable further discussion of topics covered in the session as well topics suggested by the panelists or those in attendance. Each panelist will give a 2-3 minute introduction; this will be followed by discussions between panelists and attendees in a question-and-answer format. The overall theme will center on finding ways forward to foster understanding of fundamental physics and applications by learners and appropriate support for and development of instructors at all levels of education in Africa.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
"Blue sky" research, like the one carried in large particle physics laboratories can be seen by the general public as something daunting, abstract, detached from daily experience and too difficult to understand. On the other hand, people are fascinated by the big questions, and by the complexity of the challenge the scientists are presented with. Since most of the research in fundamental physics is publicly funded, it is important that the public gets engaged beyond the simplistic attitude of "I do not understand it, but it must be great".
CERN has been engaging with public communication since the beginning, and its educational and outreach activities span very different targets, from the general public to students from school or universities. This diversified outreach program can be used as an example on how to convey the message of physics education and outreach even in very different contexts.
The speaker will also present his experience as lecturer in the ICTP-based Physics without Frontiers program.
Africa is the only habitable continent without a synchrotron light source. There are many socio-economic benefits to positioning a synchrotron in Africa such as,
• Boosting African Scientific Research, Research Capacity, and Capacity Building
• Establishing a Global Research Community on the continent of Africa
• Tackling Disease from a molecular level using protein crystallography
• Opportunity for researchers to pursue “unique to Africa” research related to the environment, energy (e.g. solar, geothermal, wind, etc.), study of human origins and the origins of human culture, mineral extraction, agriculture, etc.
• Using Science for Peace (e.g. the SESAME Light Source Project)
• Return of the African Science Diaspora – by presenting a new opportunity for young excellent scientists
• An opportunity for African countries to take control of their destinies and become major players in the international community.
Momentum is building for an African light source, as a collaboration involving several African countries. An interim Steering Committee was formed on August 16, 2014 in Dakar, Senegal at the African School on Fundamental Physics. The interim steering committee’s role was to plan the African Light Source Conference and Workshop. A workshop was held at the European Synchrotron Radiation Facility (ESRF) on Nov. 16-19, 2015 where 72 presentations were delivered. Among those presentations, 32 were scientific talks, 16 were policy strategy talks and 20 were posters (many highlighting research of African students performed at synchrotron light sources). The meeting concluded with large group discussions on the Roadmap for Africa, Workshop Resolutions, and Terms of Reference. A fully mandated Steering Committee was elected. A second conference on the African Light Source will be held on Jan 28 to Feb 2, 2019 in Accra, Ghana. This ACP2018 talk will highlight key points of my presentation delivered at the World Science Forum in November of 2017. The full presentation can be found at https://worldscienceforum.org/?ajax=1&block=Wsfresztvevok_Download&id=399 . For additional information and updates on the AfLS project, see also http://www.africanlightsource.org or follow on Twitter @AfSynchrotron.
In this talk, we present preliminary measurements of type Ia supernova spectral features such as equivalent widths and flux ratios and how such measurements are applied to the derivation of dust reddening in galaxies in which type Ia supernovae are discovered and the way they can be used to standardise type Ia supernova light curves in a more accurate manner than the traditional photometric method of standardising the light curves. While such studies have been conducted within the local Universe (i.e. at low redshifts, z < 0.1) by some authors, this has not been done extensively at intermediate and high redshifts (z > 0.1). Our understanding of whether or not the conclusions drawn at z < 0.1 also hold at z > 0.1 is therefore limited. It is for this reason that our type Ia supernova data sample for this study - part of which was taken with the Southern African Large Telescope and the rest from the literature - is from within the redshift range 0.1 < z < 0.4 (which we refer to herein as intermediate redshifts). Our preliminary measurements of equivalent widths of two spectral features show no change in values compared to the same measurements obtained at low redshifts, i.e. we see no redshift evolution. As a result there is currently no evidence that the dust reddening law in galaxies, as derived from type Ia supernova spectral studies, evolves significantly with redshift, at least out to z = 0.3, something that can be better checked with more data. Further, our goal is to demonstrate whether or not flux ratio measurements at intermediate redshifts result in improved light-curve standardisation of type Ia supernovae at intermediate redshifts, a result also obtained by some authors at z < 0.1.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
Feynman integrals are important for describing elementary particle interactions in quantum field theory. From the mathematical point of view, they give rise to interesting special functions. The latter can be computed from differential equations that the integrals satisfy. I will review methods for transforming the equations to a canonical form, from which the answer can be conveniently read off.
We investigate the parameter space in which the dark photon may still explain the muon g-2 anomaly. We consider a model of an inelastic dark sector which couples directly to the dark photon. This scenario may lead to semi-visible decays of the dark photon leading to a parameter space in which the dark photon interpretation of the muon g-2 anomaly may still be viable as opposed to both exclusively visible and invisible decays, which have been excluded by experiments. Furthermore, we show that one of the dark sector states may contribute to the required dark matter relic abundance.
Implementation of gas type emulation in the digitization software of the ATLAS TRT. The primary purposes of emulation are to be able to accommodate for a sudden change in the gas mixture used for data, and for efficiently simulating different gas type geometries to test particle identification performance.
Cosmological and astrophysical observations strongly support the presence of a non-baryonic dark matter component in the universe. A broad search program was designed to look for dark matter particles in the cosmos, either by searching for direct interaction or dark matter annihilation. Alternatively, dark matter particles might be produced in the laboratory. The Large Hadron Collider (LHC) might produce dark matter particles via proton-proton interactions. The LHC offers a unique opportunity to search for low mass dark matter particles and provides complementary information at higher masses. Since dark matter particles will escape detection, these particles will have a signature characterised by missing transverse momentum. An overview of recent searches for dark matter production in association with visible particles with the ATLAS detector at LHC will be presented. The constraints placed by the ATLAS searches will be compared to direct dark matter detection experiments.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
Hidden sector or dark sector states appear in many extensions to the Standard Model, to provide a candidate for the dark matter in the universe or to explain astrophysical observations of positron excesses. A hidden or dark sector can be introduced with an additional U(1)d dark gauge symmetry. The presence of the dark sector could be inferred either from deviations from the SM-predicted rates of Drell-Yan (DY) events or from Higgs boson decays through exotic intermediate states. The discovery of the Higgs boson during Run 1 of the Large Hadron Collider opens a new and rich experimental program that includes the search for exotic decays H —> Z Zdark —> 4l and. H —> Zdark Zdark ->4l, where Zdark is a dark vector boson.
The Large Hadron Collider (LHC), which is the world’s largest and most powerful particle accelerator, will be upgraded from 2024 to mid 2026 to become the High Luminosity LHC (HL-LHC). This will enable instantaneous peak luminosities of 7.5 × 1034 cm−2 s−1 and allow CMS to collect integrated luminosities of the order of 300 fb−1 per year and up to 3000 fb−1 during the HL-LHC projected lifetime of ten years. The HL-LHC is expected to run at a centre-of-mass energy of 14 TeV and with a bunch spacing of 25 ns. The CMS detector needs to be substantially upgraded during LS3 in order to exploit the increase in luminosity provided by the HL-LHC. This upgrade is referred to as the CMS Phase-2 Upgrade. The increase in radiation levels requires improved radiation hardness, while the larger pileup and associated increase in particle density requires higher detector granularity to reduce occupancy, increased bandwidth to accommodate higher data rates, and improved trigger capability to keep the trigger rate at an acceptable level while not compromising physics potential. The entire silicon tracking system, presently consisting of pixel and strip detectors, will be replaced.
This talk would present the HL-LHC upgrade program of the ATLAS detector. High luminosity constraints and expected performances will be covered. A review of the planned upgrades for the Tracking system (ITK), the muon spectrometer, level-0 and HLT trigger and the new high granularity timing detector (HGTD). Finally, expectations on SM and Higgs boson measurements as well as searches for new physics (Dark matter, SUSY, beyond SM processes) will be presented.
Despite their frequent use, the hadronic models implemented in Geant4 have shown severe limitations in
reproducing the measured yield of secondaries in ions interaction below 100 MeV/A, in term of
production rates, angular and energy distributions [1,2,3]. We will present a benchmark of the Geant4
models with double-differential cross section and angular distributions of the secondary fragments
produced in the 12C fragmentation at 62 MeV/A on thin carbon target; such a benchmark includes the
recently implemented model INCL++ [4,5]. Moreover, we will present the preliminary results, obtained
in simulating the same interaction, with SMF [6] and BLOB [7]. Both, SMF and BLOB are semiclassical
one-body approaches to solve the Boltzmann-Langevin equation. They include an identical treatment of
the mean-field propagation, on the basis of the same effective interaction, but they differ in the way
fluctuations are included.
In particular, while SMF employs a Uehling-Uhlenbeck collision term and introduces fluctuations as
projected on the density space, BLOB introduces fluctuations in full phase space through a modified
collision term where nucleon-nucleon correlations are explicitly involved. Both of them, SMF and BLOB,
have been developed to simulate the heavy ion interactions in the Fermi-energy regime. We will show
their capabilities in describing 12C fragmentation coupled with the de-excitation phase of Geant4, as their
implementation in Geant4 is foreseen.
[1] B. Braunn et al. “Comparisons of hadrontherapy-relevant data to nuclear interaction codes in the
Geant4 toolkit,” J. Phys.: Conf. Ser., 2013, vol. 420, p. 012163
[2] M. De Napoli et al. “Carbon fragmentation measurements and validation of the Geant4 nuclear
reaction models for hadrontherapy,” Phys. Med. Biol., 2012, vol. 57, no. 22, pp. 7651–7671.
[3] J. Dudouet et al. “Benchmarking geant4 nuclear models for hadron therapy with 95
MeV/nucleon carbon ions,” Phys. Rev. C, 2014, vol. 89, no. 5, p. 054616.
[4] A. Boudard et al. “New potentialities of the Liège intranuclear cascade model for reactions
induced by nucleons and light charged particles” Phys. Rev. C, 2013, vol. 87, p. 014606.
[5] D. Mancusi et al., “Extension of the Liège intranuclear-cascade model to reactions induced by
light nuclei” Phys. Rev. C, 2014, vol. 90 p. 054602.
[6] M. Colonna et al. “Fluctuations and dynamical instabilities in heavy-ion reactions,” Nucl. Phys.,
1998, vol. A642, p. 449
[7] P. Napolitani and M. Colonna “Bifurcations in Boltzmann-Langevin one body dynamics for
fermionic systems”, 2013, Phys. Lett. B vol. 726, pp. 382-386
1.Motivation
High energy multi-cycle (narrow band) terahertz pulses are necessary for linear electron acceleration [1]. Due to the low damage threshold of periodically poled Lithium Niobate (PPLN) crystals, high absorption of the material at the terahertz frequencies and low quantum efficiency, efficient generation of high energy terahertz beams is extremely challenging.
Here, we consider a consecutive arrangement of PPLNs as shown in Fig.1 that recycles the pump pulse for further terahertz generation. The arrangement increases the effective length (Leff) and circumvents excessive terahertz absorption through the out-coupling of the terahertz pulse after each stage. An quartz out-coupler is designed. The terahertz experiences Brewster's angle refraction at both S1,S2 surfaces, whereas the pump refracts at Brewster's angle at S3 surface (see Fig.1(a) ). The transmission efficiency and terahertz beam profile with respect to incident angle, terahertz beam size and variation of the refractive index are examined.
The simulation is based on 2-D cylindrical coordinate using the split step Fourier method, 3-point finite difference method and low storage Runge-Kutta update scheme [2], which largely enhances computational performance and saves memory. The entire problem is updating in propagation direction z explicitly rather than in time t. The calculation is performed in C++ with MPI and openmp for parallelization. The illustration of the numerical method is shown in Fig.2.
2.Conclusion
A 2-D simulation from terahertz generation in PPLN to out-coupling though quartz is developed to calculate high efficiency terahertz generation with pump recycling.
Solar energy can be used for heat generation and electricity supply. According to the International Energy Agency (IEA) solar installations will supply approximately 45% of world energy demand in 2050. This will happen through a wide variety of system configurations for various applications. This paper presents a summary of such systems and applications. The case of novel non-concentrating evacuated flat-plate solar collectors for medium temperature applications will be presented in details.
Dye sensitized solar cells (DSSC) are of great interest for the conversion of solar energy into electrical energy and are future alternatives to silicon solar cells. The increase in conversion efficiency of DSSC depends not only the differences in the conductivities of the transparent layers but on the antireflection of the multilayers and the transmittance of the incident light. Therefore, proper arrangement of the thickness of each layer in the multilayer film along with suitable deposition of nanocrystalline TiO2/dye stack is necessary for a high photocurrent and conversion efficiency of the DSSC. In this work suitable multilayer of doped ZnO and metal are synthesized using sputtering process and used as transparent layer. Small quantity of ZnO incorporated TiO2 matrix is used for the fabrication of DSSC. Chemical vapour deposition method is used to prepare ZnO covered TiO2 film. The DSSC on the Al doped ZnO and Ag multilayer covered with ZnO/TiO2 film yielded an overall cell efficiency 5.45 % at one sun light intensity. The dye sensitization process with the low-cost mercurochrome is sensitive in ZnO based multilayer. The overall energy conversion efficiency of the DSSC using low cost transparent conducting oxide film and mercurochrome dye is a nice step to develop DSSC. Details study on the optimization of the film preparation along with the merits of such film as an electrode with reference to TiO2 film electrode in DSSC will presented during presentation
Keywords: DSSC, TiO2, Transparent conducting layer, transmittance.
Despite huge energy potentials in Africa, the energy production costs are high and the consumption is low as compared to other World regions. Less than 40 % of Sub-Saharan Africans have access to electrical energy. Lack of electrical energy hampers the rapid development of the continent. The present yearly economic growth of~ 5-6% will be higher if sufficient electrical energy and infrastructure are present. However, Africa cannot embark on the same path as Europe, USA and China for its development by relying only or strongly on non environment-friendly energy sources. This is imperative in order to achieve the Sustainable Development Goals (SDGs) (2016-2030) and the resolution of COP 21 of maintaining the world temperature rise not above 1.5 °C. The appropriate use of the abundant solar energy and other renewable energy sources can be regarded as a solution to the African energy problem. This requires highly qualified human resources at all levels. The presence of local qualified skills lead to acceptance by the population of the renewable energy technologies and reduction of energy end-price.
This lecture will present the energy situation of Africa followed by an overview of capacity building activities (training, education and research) going on, especially actions taken to address the low experimental research budget in most African institutions of higher learning.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
Providing a solution to deforestation is an environmental issue for the development of the developing countries, especially those in the south. Yet, a significant part of the forest has disappeared quite rapidly in recent years. Environment problems are compounded by health problems. According to 2012 WHO reports, 1.6 millions of women and children die each year from wood and charcoal smoke. So, we are all concerned because one of the most worrying threats at the moment is global warming due to greenhouse gas emissions. Open burning of agricultural residues and deforestation for the production of firewood and charcoal make the recycling and conversion of biomass waste a priority. Moreover, Biomass valorization can be a solution to generate revenue from agro-forestry waste and to produce Green Energy in order to protect the global environment because the awareness of using Eco-friendly & Non-conventional Bio-coal / Bio-fuel is increasing day-to-day due to the increasing of the conventional fuel cost.
Africa is a region with the most significant amount of underutilized renewable energy sources, but … slow at mobilizing this potential.
However, the establishment of sustainable technologies adapted to the recovery of such residues requires prerequisites of technical (conversion costs related to conversion technologies, biomass costs and fossil fuels price) and regulatory (Public policies that affect supply and demand and in some cases the cost of biomass and climate regulations).
And it is in this sense that we try to make our contribution so that this renewable energy obtained from biomass move to bioenergy and biochemicals nationally, regionally and globally.
Ferroelectric lead compounds having a perovskite structure, such as Pb(Zn1/3Nb2/3)O3 (PZN) [1],
Pb(Mg1/3Nb2/3)O3 (PMN) [2], and their solid solutions with PbTiO3 (PT), have been investigated
for high-performance ultrasonic transducer applications [3-4]. The integration of such materials
as thin films have attracted considerable attention these last years thanks to their outstanding
performances that allow to consider new features for the realization of photovoltaic device.
Ferroelectric thin films, especially those derived from BaTiO3 composition, have been studied for
about thirty years for microelectronics, telecommunications and optics applications. For most
applications, it is necessary to approach the single crystal in a thin layer, in order to limit losses
(dielectric, optical ...). The advantage of thin films relative to the solid material is then multiple:
ability to embed on microcircuits, lower cost than single crystals and geometry for new efficient
designs. PZN-4.5PT thin films properties, or ferroelectric materials in general, change
significantly with the structural and constitutive properties of considered material. Thus, to
consider their integration in applications such as microsystems, it is essential to determine
beforehand the influence of these parameters on the electrical performance of the studied
materials.
Our study focuses to investigate structural, dielectric and ferroelectric properties of PZN-4.5PT
nanoparticles thin films on Silicon substrate.
Keywords: perovskite, nanoparticles, thin film.
This presentation will report on experiments that study rare reactions that require challenging data sets and running times to search for Physics phenomenon within the Standard Model and Physics beyond the Standard Model. A general survey of some recent results, current research and future experiments primarily at Fermilab will be featured.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
The LHC is in its sixth year of operation and performing well. The HL-LHC is major upgrade of the existing machine due to come into operation in 2026. Aiming at delivering an annual integrated luminosity of around 250 fb-1 a year to both ATLAS and CMS, it is now in the prototype and construction phase. The essential principles of LHC operation are recalled, and the key aims and components of the upgrade are discussed.
The Future Circular Collider (FCC) is a CERN led study investigating the possibilities of constructing a 98 km circular tunnel housing, in the first instance, a electron-postiron collider (FCC-ee) with a centre-of-mass energy range spanning the range from the Z pole (90 GeV) to above the top pair threshold (~400 GeV). The lepton machine would make way for a proton-proton collider (FCC-hh) with a centre-of-mass energy of 100 TeV. A brief outline of the goals and challenges is presented.
The European Spallation Source (ESS) is a pan-European project composed of 15 European nations (members and observers), constructing together a neutron-scattering facility in Sweden, one of the largest science and technology infrastructure projects being built today. The ESS was designated a European Research Infrastructure Consortium, or ERIC, by the European Commission in October of 2015.The ESS was designated a European Research Infrastructure Consortium, or ERIC, by the European Commission in October of 2015. Scientists and engineers from 50 different countries are members of the workforce in Lund, who participate in the design and construction of the European Spallation Source.
After a description of the ESS collaborative project and its in-kind model, this presentation will introduce the linac accelerator, its tungsten target and the neutron instruments, which will answer the scientific challenges of tomorrow. This unique facility will enable new opportunities for researchers across the spectrum of scientific discovery, including materials and life sciences, energy, environmental technology, cultural heritage and fundamental physics.
In September of 2013 we began working with a medical physicist at the Ocean Road Cancer Institute in Dar es Salaam, Tanzania. We developed a bi-lateral learning partnership over the course of eight qualitative Skype meetings. From these meetings we have ascertained that there is a gap between the installation of new equipment and treating patients. This gap has often been overlooked by international partners attempting to improve radiation therapy access. Relationships with academic institutions abroad can fill these gaps and lead to sustained care of patients needing radiation.
Today, many scenes in hospital wards of public sector hospitals in Tanzania and other African countries are often reminiscent of the battle to get AIDS treatment under way in the early 2000s. But now, hospital beds once filled mostly with AIDS patients are occupied by those afflicted with cancers, and other non-communicable diseases. In 2012 cancer was responsible for 8.2 million deaths globally. The World Health Organization predicts that by 2030 this number will increase to over 13.1 million deaths. In addition, currently 70% of those deaths are in low and middle income countries (LMICs), like Tanzania, which sadly are unable to deal with the growing cancer pandemic without collaborations. A 2007 Institute of Medicine report recommended collaborations between cancer centers in high-income countries with those in LMIC as the appropriate next step for cancer control in the developing world. A critical area of need in cancer control is in radiation therapy, employed in the treatment of over 50% of cancer patients.
My presentation will highlight our long-term goal to develop a USA/Africa Radiation Oncology Core (ROC), with both practical (PROC) and virtual (IROC) components, dedicated to Research Education/training in Radiation oncology in Africa and providing desperately needed quality assurance tools for patient safety and research collaborations for cancer control. The initial partner collaborating institutions in Africa include Muhimbili University of Health and Allied Sciences (MUHAS) and Ocean Road Cancer Institute (ORCI); from the USA side – University of Pennsylvania (UPENN), MD Anderson and Dana Farber/Harvard Cancer Center; from industry – Varian Medical Systems – the establishment of such an ROC will significantly increase research capacity and ensure radiation/patient safety. Our preliminary collaboration and analysis of publications, workshops in Africa and Harvard highlight a great need for such a Core to build research capacity and address an ongoing silent crises which is undoubtedly causing significant loss of life and disability in Africa. A successful launch of this Core program will provide a hub for Radiation Oncology research/education in east Africa; benefiting students/researchers from neighboring countries like Kenya, Uganda, Burundi, Malawi, Zambia DRC, Rwanda, South Sudan and Central Africa Republic.
While we are just in the beginning stage of this partnership, we believe there is great potential for success between both parties. We hope that MUHAS and/or Ocean Road Cancer Institute will benefit from potential funding and resources by partnering with a High Income Country to develop affordable solutions to clinical problems in Dar es Salaam. Successful establishment of an ROC could have a significant impact in addressing the rapidly rising burden of cancer in Africa, with publications that will shape the emerging field of global radiation oncology. The current literature shows that this global radiation oncology collaboration/partnership can serve as a platform for bi-directional learning where USA/African researchers can exchange ideas and innovations as well as develop the skills necessary to help their countries succeed in the rapidly advancing world of cancer research. Measurable outcomes should include: 1) joint publications on needs assessment for safe radiation medicine research and practice in Tanzania; 2) a new cadre or diverse new generation of cancer researchers who can collaborate effectively in teams with partners from other nations/cultural backgrounds 3) an innovative ROC for quality assurance, treatment planning, and incident learning system in Tanzania, extendable to other LMICs. The ROC could also be adapted for multi-center clinical trial quality assurance, develop technology for African specific needs, serve as a population-based cancer patient registry and potentially connect other arrays such as genetic or pathology information to appropriate research. Based on the information from our study and the creation of a pilot research program, we can develop a strategy for long-term sustainable research and quality radiotherapy care in Tanzania extendable to other LMICs. This project will leverage the strength of an already ongoing collaboration between the partner institutions. These partner institutions are leading cancer research institutions with the institutional environment to support the establishment of the planned ROC that will benefit cancer research and education, crucial for addressing the growing global burden of cancer and related disparities affecting LMIC.
Studies on radon and its progeny provides strong and compelling evidence that it is the greatest contributor of inhalation dose in the living environment. Indoor radon and the annual effective doses measurements were performed in office buildings at the National University of Science and Technology (NUST), Namibia, using CR-39 nuclear track detectors exposed for 3 months in the offices. The office buildings were classified according to age, occupancy, number of floors and size of the rooms. Based on the dosimetric approach and epidemiological determination conversions for radon exposures the annual effective doses were calculated and compared. The radon concentration in the selected office buildings varied from 32.0 Bq/m3 to 90.5 Bq/m3 in new and buildings old buildings respectively, with an average value of 58.6 Bq/m3. The annual effective dose due to exposure to indoor radon and its progeny was also found to vary from 0.4 to 1.70 mSv/yr. The radon concentration in all the office buildings were significantly lower than 600 Bq/m3 receipted by International Commission on Radiological Protection (ICRP) as the action level for a closed space.
Keywords
Indoor radon, annual effective dose, exposure, nuclear track detectors, Namibia University of Science and Technology
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
The application of particle accelerators in medicine started with the discovery of x-rays by W. Roentgen in 1895. Nowadays there are more than 20,000 particle accelerators in operation worldwide, most of them employed for biomedical uses. Modern medical accelerators can essentially be divided into three classes: 1) electron linacs for conventional radiation therapy, including advanced modalities such as cyberknife, intra-operative radiation therapy (IORT) and intensity modulated radiation therapy (IMRT), 2) low-energy cyclotrons for the production of radionuclides for medical imaging and 3) medium-energy cyclotrons and synchrotrons for hadron therapy with protons (250 MeV) or light ion beams (400 MeV/u 12C ions). The operating principle of the electron linac, the cyclotron and the synchrotron will be briefly reviewed. The lecture will then mainly focus on the use of accelerators for cancer radiation therapy.
Background / Aims: In the 1970’s and 80’s major accelerator facilities operating at 100 MeV and higher were developed and installed in many of the national labs and used for production of radionuclides at much higher energies than can be achieved on the small compact machines. These high energy accelerators play a critical role in supplying radionuclides such as Sr-82 used in Sr-82/Rb-82 generators for cardiac imaging and Ge-68 used in Ge-68/Ga-68 generators for imaging to quantitate receptor imaging for targeted therapy applications. They continue to be upgraded to increase production yields by installing beam rastering systems that have allowed higher intensities and thus higher production yields. Demand for isotopes that can be produced by these systems have also increased. Linear accelerators such as the one at Brookhaven National Laboratory when operating at maximum proton energy of 200 MeV can have simultaneous production of several medically relevant isotopes. Among those are Ac-225 (T1/2=10.0 d), Cu-67 (T1/2=64.83 h), Se-72/As-72 (T1/2=26 h), Sr-82/Rb-82 (T1/2=1.26 min) and Ti-44/Sc-44 (T1/2=3.97 h). Production of these novel radionuclides and recent enhancements will be presented.
Cathy S. Cutler* , Dmitri Medvedev, Leonard Mausner, Vanessa Sanders, Lisa Muench
Collider Accelerator Department, Brookhaven National Laboratory, Upton, NY, United States
The activity concentration of primordial radionuclides such as 238U, 232Th and 40K were determined in shore sediment samples in the Ovambo beach of Walvis bay, Namibia. The activity concentrations were carried out by gamma spectrometry. The average activity measurements were found to range from BDL – 276.39 Bq.kg - 1 with a mean of 142.79 Bq.kg – 1 for 238U, BDL – 40.80 Bq.kg – 1 with a mean of 29.69 Bq.kg – 1 for 232Th and 319.26 – 516.45 Bq.kg – 1 with a mean of 359.78 Bq.kg – 1 40K. The concentrations were converted to assess radiological risks where the values of effective dose, radium equivalent activity, hazard index, excess life cancer risk were evaluated. The assessed values were found to be higher than the maximum allowed levels. Therefore, there is human radiological health risk envisaged along the Ovambo beach.
Keywords
Shore sediment, Radioactivity, Gamma spectrometry, Ovambo beach, Walvis Bay,
The Erongo region of Namibia has been reported to experience high natural background radiation resulting from the presence of uranium bearing ores. In order to estimate the radiation risk to the general populace living in the Erongo region, a total of thirty surface soils samples and twenty radon gas monitors (CR 39) were collected from a Gold Mining town of Karibib. The radon gas monitors were deployed in selected households for three months. Naturally occurring radionuclides 238U, 232Th and 40K present in these soils were measured using HPGe γ-ray spectrometer to evaluate the radiation health hazard indices and excess lifetime cancer risk (ECLR). Average concentrations of 238U, 232Th and 40K in the soil were found to be 62.33±0.10, 66.65±0.06, 1122.20 Bq/kg respectively. The mean concentration of indoor radon gas in the selected households was 79.00±6.68 Bq/m3. The average radium equivalent activity 244.05 Bq /kg, the total annual effective dose 1.23 mSv/yr due to 238U, 232Th and 40K and the effective indoor dose rate due to radon was found to be 2.28x10-3 mSv/yr. The higher values for some of the health parameters in the town may present a serious public health problem because the soil is used as a constructing material for building. The excess lifetime cancer risk (ELCR) due to radionuclides in soil was found to be 4.08E-3 which slightly higher than the world value of 0.29x10-3.
Keywords
HPGe γ-ray spectrometer, health hazard indices, lifetime cancer risk, radioactivity
I will present a brief overview of optical astronomy in South Africa in the context of the multi-wavelength astronomy strategy of South Africa. I will focus on the role of optical astronomy in support of radio and gamma-ray observations, and highlight the new and unique MeerLICHT optical telescope which will provide a real-time view at optical wavelengths of the MeerKAT radio sky. By exclusively linking MeerLICHT to MeerKAT, we will, for the first time ever, provide optical multi-band observations of every night-time observation conducted by a radio telescope, ensuring that every transient in the field of view will be simultaneously covered in the radio and the optical.
ANTARES, the largest deep-underwater Cherenkov neutrino telescope operating in the Northern hemisphere, has been taking data since 2007 with the primary objective of searching for high-energy astrophysical neutrinos in the TeV-PeV range. Thanks to its excellent angular resolution, ANTARES has searched for neutrino sources and set important constraints on the origin of the neutrino cosmic flux, first observed by IceCube. The most recent results of ANTARES searches for neutrinos sources will be reported, as well as from WIMP annihilation in massive objects like the Sun or the Galactic Centre. Moreover, the ANTARES constraints on the neutrino oscillation parameters will be presented.
Building on the successful experience of ANTARES, the next generation KM3NeT neutrino telescope is currently under construction in the Mediterranean Sea to significantly boost the sensitivity. More precisely, two detectors with a combined instrumented volume hundred times larger than ANTARES will be deployed: KM3NeT/ARCA (Gton instrumented volume) focusing on high-energy cosmic neutrinos, and KM3NeT/ORCA (Mton instrumented volume) for the determination of the neutrino mass hierarchy. An overview on the physics potential of KM3NeT will be highlighted.
An electron accelerator for cooling hadron beams in the Relativistic Heavy Ion Collider (RHIC) has been constructed at Brookhaven National Laboratory in the Collider-Accelerator Department and is in the early stages of beam commissioning. Electron cooling is planned to increase the luminosity of the RHIC for heavy-ion beam energies below 10 GeV/nucleon. Such energies are necessary to map the quantum chromodynamic (QCD) phase diagram of quark-gluon plasma, a key goal of the RHIC project. The QCD critical point is a distinct feature of the phase diagram, and the LEReC project is driven by the effort to determine this critical point and characterize its properties. However, the required event statistics are much higher than previously achieved in the RHIC, requiring significant luminosity improvement at energies below γ = 10.7. Application of electron cooling can substantially increase the average integrated luminosity by countering the effect of intrabeam scattering at the lowest hadron energies. The LEReC project is a novel approach to cooling being the first to attempt bunched-electron beam cooling of a relatively high-energy hadron beam. The electron accelerator has been designed to deliver a beam with a range of energies from 1.6 MeV up to 2.6 MeV and a range of beam current up to 50 mA with an average design beam current of 30 mA. Electrons are generated by a DC gun comprising a photo-sensitive cathode contained in a cavity held at a DC potential of 400 kV. The beam then travels through a series of RF cavities, and is directed into the cooling section of the RHIC where the electron beam co-propagates with the hadron beam first into a section of one of the RHIC rings and then, after a 180-degree turn, into a section of the other RHIC ring. After these cooling sections, the electron beam is finally directed into a beam dump where it is discarded. New electron beam is generated by the accelerator and continues the cooling process. This presentation will provide an overview of the LEReC project, briefly discussing the nature of electron cooling and its application at RHIC as well as the key features of the electron accelerator including the requirements for the electron beam; the DC gun, cathode, and laser systems; the various RF cavities including a superconducting cavity; beamline instrumentation; and the mechanism for cooling. The presentation will also discuss the latest results of commissioning along with the plans for future commissioning and operation.
Authors:
Mary Taabu Simiyu, Francis Nyongesa, Bernard Aduda Zephania Birech, Godwin Mwebaze
The outbreaks of water-borne diseases are a common occurrence in developing countries and have claimed millions of lives in the recent years despite the many water purification approaches in use. This is because most of these water purification systems are unaffordable to the poor of developing world and are inefficient in removal of viruses from drinking water. Furthermore, the DE wastes have not found direct application in science. Thus, the wastes pose a challenge to DE industries. In this work, the nanomaterials of diatomaceous earth (DE) wastes and charcoal are employed in the design of efficient and effective water filtration membranes capable of eliminating pathogens and viruses from water. The DE waste and charcoal raw materials were ground to the range of 86.0 nm to 200.0 nm. The DE wastes were characterized in terms of chemical analysis. They were found to contain 89% silica and a total flux content of 11.0% (4.14% of Al2O3, 3.88 of CaO, 0.85% of K2O, 0.19% of MgO and 5.10% of Na2O) making it a suitable material for water filter membranes. The samples for the filter membranes were fabricated from a mixture of DE and charcoal in various ratios and fired at 900 oC. The pore size of the finished filter was in the range of 22.0 nm – 150 nm. The mechanical strength of the filter membranes was enhanced by use of plant derived binders (“Mrenda”) thereby increasing the filter flow rate without compromising on its structural reliability.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)
There are significant number of data (and compute) intensive projects and initiatives of National, regional and international consequence hosted or driven in Africa – including in the areas of earth and spaces sciences – for example, The Square Kilometre. In this area, Africa will host the largest high resolution radio telescope to do fundamental Astrophysiscs science as the continent has access to the Southern hemisphere skies, and quiet zones with respect to minimal radio frequency interference. For this reason - South Africa and SKA African partner countries are investing in space science and astronomy as building blocks for a knowledge economy through developing necessary supporting platforms. Data challenges for next generation telescopes including the SKA have been widely discussed and currently driving innovations in to meet envisaged computational, data storage, processing and high speed networking requirements
There are also significant projects in Earth observation, environment, climate and weather modelling and applications therein in early warning systems and applications including in agrometeorology and hydrometeorology. For example, the African Development Bank is resourcing a Southern Africa Development Community (SADC) Climare Center for a project that recognises the need to generate, disseminate and use reliable and high quality climate information to help decrease the negative impacts of extreme weather and climate related phenomena and risks in the Southern Africa Development Community (SADC) region.
Collectively, all these projects necessitate and facilitate the creation of requisite computational, network and data infrastructure through regional cyber-infrastructures; facilitate collaborative networks; stimulate discussions around data policy frameworks; address issues around data generation, data analysis, data sharing challenges and negotiating fairness in these domains.
Higher up the value chain, through these projects, it is envisaged they will provide necessary impetus in creating new cohorts of scientists, engineers, researchers and technicians ready to work on world-class projects. This will drive the human capital development programme including in transferable skills such as in data science and as consequence, contribute to stemming the historical brain drain away from the continent and spillovers into countries’ economies.
As a result of all this activity, there is an increasing need for governments to put in place the necessary legislation, policies and governance structures to facilitate data sharing and its exploitation for research, innovation and for development. In addition to policy, there is awareness for the need of substantial investments in reliable ICT infrastructure that can sufficiently support data hosting, sharing and analysis. Furthermore, for researchers to generate, curate, manage and preserve and analyse data, they also need specialised skill sets and requisite training.
For the SKA readiness, the Southern African Development Community countries are developing a SADC Cyberinfrastructure and a HPC Ecosystem through a SADC Cyber-infrastructure Framework regional policy instrument.
I will talk about why researchers should care about Python. I will also talk about the different Python communities in Africa and how one can join the Python Namibia society. I will also talk about the importance of RSE (Research Software Engineers) support groups and the Carpentry workshops. I will also talk about the community aspect of Python in Africa and introduce PyCon Namibia.
Structured data storage technologies evolve very rapidly in the IT world, driven by BigData projects. LHC experiments, and ATLAS in particular, select and use these technologies to store a wealth of metadata, balancing the performance for a given set of use cases with the availability, ease of use and of getting support, and stability of the product. We definitely and definitively moved from the “one fits all” (or “all has to fit into one”) paradigm to choosing the best solution for each group of data or metadata and for the applications that use these data. This talk describes the solutions in use, or under study, for the ATLAS experiment and their selection process and performance.
Poster Sessions managed by Prof. Sylvanus Onjefu (NUST) and Prof. Vaino Indongo (NUST)