Cosmic rays are comprised largely of high energy protons and alpha particles which create large amounts of secondary particles through spallation when they interact with our atmosphere. At aviation altitudes the radiation field is made up predominantly of neutrons in the energy range 1 - 100 MeV [1]. During space weather events, such as solar flares, the number of energetic particles entering...
Tagged neutron method is a non destructive technique of analysing the chemical composition of a material using fast neutron. This technique can be applied in diamond mining industry to separate diamond bearing kimberlite from the barren ores before the secondary crushing of the ore to avoid damaging diamond. It allows detecting diamond within the kimberlite without crushing the ore. The ore is...
Abstract
This study’s aim was to determine the gamma activity concentration of NORM of (238U, 234U, 235U and 232Th); the gross alpha and gross beta activity concentration; estimation of absorbed dose rate; annual ingestion dose rate and the excess lifetime cancer risk (ELCR) in fruits and vegetables collected from Hartbeespoort, Mahikeng, and Pretoria markets. The measured results will help...
The Nuclear level density and (\gamma)-ray Strength Function are primary ingredients for astrophysical reaction rate calculations based on the Hauser-Feshbach approach. These parameters need to be well understood to improve our understanding of (^{182})Hf production in astrophysical environments. The new experimentally constrained (\gamma)SF and NLD in (^{181,182})Hf were extracted,...
Investigation of limit of detection using standard radioactive sources with a LaBr3(Ce) detector
F. van Niekerk (1,3), S.R. Johnson (2), P. Jones (3)
1 Department of Physics, University of Stellenbosch.
2 Department of Physics, University of Cape Town.
3 Department of Subatomic Physics, iThemba LABS.
Keywords: LaBr3(Ce) detector; Background radiation; Gamma radiation; Detection...
Accurate nuclear data is a key factor in determining the suitability and reliability of many theoretical nuclear models and large scale calculations. One of the main ingredients of these calculations is how the nuclei respond to an electromagnetic field. This study investigates the total photoabsorption cross section of $^{24}$Mg by excitation of the giant dipole resonance (GDR). The E1...
$^1$Department of Physics, University of Cape Town, Private Bag X3, Rondebosch, 7701, South Africa
$^2$Department of Subatomic Physics, iThemba LABS, PO Box 722, Somerset West, 7129, South Africa
Positronium (Ps) is a system consisting of an electron and its anti-particle, a positron, bound together into an exotic atom, specifically an onium. The system is unstable: the two particles...
Fibre Optic Sensors (FOS) are fibres with optionally a specific preparation or functional coating, which endows the sensitivity to various environmental parameters. The sensor is designed for extreme environments. Specifically, the environment of a nuclear reactor core, where the dose may be 2 GGy in two weeks of operation. The technologies are based on Fibre Bragg Gratings (FBGs), and also...
Supervisor: Dr. James Keaveney (UCT)
Co-Supervisor: Dr. Sahal Yacoob (UCT)
The production of a single top quark in association with a $W^{\pm}$ and $Z$ boson ($tW^{\pm}Z$) at the CERN LHC is sensitive to both the neutral and charged electroweak couplings of the top quark as the process involves the simultaneous production of a $W$ boson and a $Z$ boson in association with the top quark....
T. W. Seakamela1,3, S. H. Connell1 , B. V. Kheswa2, M. Wiedeking3,12, V. W. Ingeberg4, K. L. Malatji3,6, S. Siem4, H. C. Berg4, A. Avaa3,8, D. L. Bleuel5, C. P. Brits3,6, J. W. Brummer 3,6, T. S. Dinoko10, M. Guttormsen4, P. Jones3, A. C. Larsen4, J. E. Midtbø4, L. Msebi3,7, S. H. Mthembu3,9, G. ONeil7, J. Ndayishimye3, L. Pellegri3,8, O. Shirinda3,6, F. Zeiser4, B. R. Zikhali3,7, D. Negi11...
The ``fragmentation region'', or far forward region, of high-energy heavy-ion collisions provides an opportunity to study the quark-gluon plasma at very high densities. This region of phase space has not been studied in detail. We present a simple model to aid in the development of intuition for the physics of the fragmentation region, including the nature of both the highly boosted matter...
We report on the replacement of E3E4 (Crack) and refurbishment of Minimum Bias Trigger Scintillator (MBTS) counters as part of phase-I upgrade during the long shutdown 2 (LS2) at CERN. Crack and MBTS counters, situated between the central and extended Tile Calorimeter barrels, are used for correcting the electromagnetic energy responses and for providing inputs to the trigger, respectively....
The fragmentation region of a heavy ion collision is a hot and dense place, which makes it ideal for studying the phase diagram of Quantum Chromodynamics (QCD). I will discuss recent work that aims to build an initial state model for the fragmentation region that incorporates the phenomenon of gluon saturation. We find some interesting results on baryon stopping and compression in terms of...
The purpose of this study is to validate the Monte Carlo model of the Varian Clinac IX linear accelerator (Linac). Using the BEAMnrc package, the Linac head was modelled and simulated with 3 x 3 cm2, 6 x 6 cm2, 10 x 10 cm2 and 15 x 15cm2 for 6 MV and 15 MV photons beams based on the manufacturers’ specification. For dose distribution, the scored phase-space file was used as an incident on a 60...
