Conveners
Nuclear, Particle and Radiation Physics-1
- Sifiso Ntshangase
Nuclear, Particle and Radiation Physics-1
- Khuliso Murulane (University of Johannesburg)
Nuclear, Particle and Radiation Physics-1
- Pete Jones (iThemba LABS)
Nuclear, Particle and Radiation Physics-1
- Pete Jones (iThemba LABS)
Nuclear, Particle and Radiation Physics-1
- Retief Neveling (iThemba LABS)
Nuclear, Particle and Radiation Physics-1
- Retief Neveling (iThemba LABS)
Nuclear, Particle and Radiation Physics-1
- Linda Mdletshe (University of Zululand)
Nuclear, Particle and Radiation Physics-1
- Siyabonga Majola (University of Johannesburg)
Nuclear, Particle and Radiation Physics-1
- Manny Mathuthu (CENTER FOR APPLIED RADIATION SCIENCE AND TECHNOLOGY (CARST), NORTH-WEST UNIVERSITY (Mafikeng Campus))
Nuclear, Particle and Radiation Physics-1
- Sifiso Ntshangase
- Mukesh Kumar (University of the Witwatersrand)
Nuclear, Particle and Radiation Physics-1
- Thuthukile Khumalo (NRF-iThemba LABS)
Nuclear, Particle and Radiation Physics-1
- Thuthukile Khumalo (NRF-iThemba LABS)
Author : Beatrice Similindi
Co-author : Dr E.A Lawrie
Dr S.N.T Majola
Gamma ray spectroscopy is a powerful tool in nuclear structure, but the interpretation of the intrinsic properties of the nucleus becomes complex if the parity of the emitted radiation is not known. This study aimed at developing a technique...
The systematic study of octupole bands in rotating even-even nuclei has gained interest in understanding features of the octupole deformation, including octupole rigidity and softness. Furthermore, one could study how nuclear rotation influences this rigidity or softness and how experimental data from gamma-ray spectroscopy aligns with theoretical predictions for octupole deformation. Nuclear...
The electromagnetic properties of nuclei excited to the quasi-continuum region are best studied and explained using statistical decay observables, such as the nuclear level density (NLD) and ฮณ-ray strength function (ฮณSF). These quantities can be extracted from experimental particle-ฮณ coincidence matrix using the Oslo method and Shape method, respectively. In this study, experiments were...
The accurate measurement, analysis, and correct interpretation of the neutron flux distribution within the reactor core are essential for reactor safety, optimum performance, and understanding of reactor operations. In the SAFARI-1 research reactor, axial thermal neutron flux profiles of fuel-containing assemblies are measured at the beginning of each operational cycle by activating natural...
In this study the effect of radiation ionization of the 40SrOโ30B2O$_{3}$โ10TeO$_2$โ20Bi$_2$O3, 35SrOโ30B$_2$O$_3$โ10TeO$_2$โ25Bi2O$_3$, 30SrOโ30B$_2$O$_3$โ10TeO$_2$โ30Bi$_2$O$_3$, 25SrOโ30B$_2$O$_3$โ10TeO$_2$ 35Bi$_2$O$_3$, 20SrOโ30B$_2$O$_3$โ10TeOS$_2$โ40Bi$_2$O$_3$ glass was investigated using the Phy-X/PSD, XCOM simulation Software and ratified using the geant4 simulation. Between the high...
Environmental radioactivity monitoring and protection often require measurement and modelling of natural radionuclides in environmental media and exposure pathways. In this study, the activity concentration of natural radionuclides determined using Broad energy germanium detector, was used to model the radiological risks for a hypothetical resident using Residual Radioactivity (RESRAD)...
The rise in global demand for nuclear technology has resulted in an increase in radioactive waste and radioactive material. Some of these radioactive materials and nuclear waste undergo radioactive decay, emitting alpha and beta particles. Beta particles are energetic electrons with a single negative charge, while alpha particles are equivalent to a helium atom with a charge of +2. Both alpha...
An assessment of the radiation concentration in abandoned mines located near settlements in the west of Johannesburg was carried out, and the corresponding radiological indices were determined. In this study, a gamma spectrometer was used to measure the activity concentrations of radionuclides in the soil samples. The activity concentrations for 226Ra, 232Th, and...
The electric dipole response in nuclei is characterised at high energies by the isovector Giant Dipole Resonance (IVGDR) and, for neutron-rich nuclei, by the Pygmy Dipole Resonance (PDR) around the neutron separation energy. Even though these two excitation modes have been extensively studied, some of their characteristics are still not understood. This talk will concentrate on the discussion...
Nuclear structure studies are essential for unraveling the complex interactions between the nucleus and nuclear forces, as well as understanding how shell effects emerge throughout the nuclear chart. High-precision measurements of nuclear propertiesโincluding energy levels, spins, parities, and spectroscopic factorsโoffer valuable insights into the nucleus's internal structure and play a key...
Our natural environment is endowed with natural radioisotopes to which humans are exposed through the ingestion of foodstuffs with consequent health implications. In this study, an assessment of the radioactivity levels in powdered and liquid milk available in South Africa was conducted to evaluate their associated radiological health risks. Both natural radioactivity sources such as 226Ra...
The question of whether atomic nuclei can have triaxial shapes at their ground states is still an ongoing subject of debate. In this study, we systematically analyze the ground-state bands of rotating even-even nuclei to identify the presence of triaxiality across the nuclear chart using experimental data. We apply the newly proposed Coriolis analysis method, which involves plotting...
This study aims to investigate the Pygmy Dipole Resonance (PDR) in the deformed 154Sm nucleus. The present study employs the ( γ , γ โฒ) reaction to examine dipole states in the energy range 3.5 MeV to 7.05 MeV (close to the neutron separation threshold (8 MeV)). The experiment was carried out using the Clover Array at the HIγS facility of the...
X-ray production cross section measurements for the analysis of metal halide perovskite thin films using heavy ion PIXE spectroscopy
M.L. Moremi1, M. Msimanga1, 2, M.C. Masekane2, 3
1 Department of Physics, Tshwane University of Technology, Private Bag X680, Pretoria,001, South Africa
2 _iThemba LABS TAMS, National Research...
Similar to ordinary forensics, nuclear forensic science uses data and modelling to infer historical information such as origin and production processes. To do this, unique characteristics of different nuclear material that make up nuclear fingerprint must be identified. To date, very few characteristics have been identified as signatures for uranium ore and uranium ore concentrate(UOC)...
The structure of neutron-rich carbon isotopes continues to be a subject of interest in nuclear physics, particularly the nucleus $^{16}\text{C}$. One of the key unresolved issues is the variation in measured $B(E2)$ values for the transition from the first-excited $2_1^+$ state to the ground state, with reported values spanning nearly an order of magnitude. Traditional interpretations assume a...
South Africa has four uranium โore provincesโ, and largely based
on the ages of the provinces, they have distinct nuclear forensics signatures. The International Atomic Energy Agency has mandated all its Member States to develop National Nuclear Forensics Libraries in response to the nuclear security threat posed by nuclear material trafficking. South Africa is thus enhancing their...
The formation of elements, particularly those heavier than iron,
predominantly occurs through two neutron capture processes: slow
neutron capture process and rapid neutron capture process, each
contributing approximately 50%. These are known as the s- and
r-processes, respectively [1].
The neutron capture reactions 192Ir(n,ฮณ)193Ir and 193Ir(n,ฮณ)194Ir
were indirectly studied by analyzing...
iThemba LABS has pioneered a mobile gamma-ray detection unit[1] which allows a user to operate in the field and chart the location, strength and energy of gamma radiation.ย The system incorporates a sensitive scintillation detector[2] typically used for accelerator-based spectroscopy at the SSC laboratory and was integrated into a backpack incorporating a fast 125 MHz digitiser for readout and...
This work aims to shed light on the low to medium spin states of 156Er by analysing coincidence relationships following the 147Sm(12C, 3n)156Er reaction at 65 MeV. This experiment was performed using the AFRODITE array of iThemba LABS. A level scheme has subsequently been built using this information and a total number of 9 bands has been observed....
An excited state in 12C close to the 3-alpha breakup was predicted by Fred Hoyle in 1954 and was identified in 1962 by Cook et al. as the 0+ state lying at an excitation energy of 7.65 MeV. It was the key to understanding the production of 12C and heavier elements in the Sun (stars) up to iron. In the Sunโs core, fusion of two alpha-particles leads to the production of excited 8Beand then the...
Abstract:
In the 1970s and 80s, (p, $\gamma$) reactions [1] were successfully utilized to measure the Photon Strength Function (PSF) using the Average Resonance Proton Capture (ARPC) Method [1, 2]. In this research, these reactions have been used to extract the slope of the PSF from the $^{50}$Cr(p, $\gamma$)$^{51}$Mn proton capture data using the Shape method [3] with no s-wave resonance...
INVESTIGATING THE PHOTON STRENGTH FUNCTION FOR 61Cu USING 60Ni (p, ฮณ) REACTION AT iTHEMBA LABS
The Brink-Axel hypothesis assumes that photo-de-excitation only depends on the emitted ฮณ-ray energy Eฮณ and not the detailed structure of the initial and final states (spin and parity) involved in the transition as it is the case for photo-excitation process. While the...
The PANDORA (Photo-Absorption of Nuclei and Decay Observation for Reactions in Astrophysics) project explores photo-nuclear reactions in light nuclei (A $<$ 60) through both experimental and theoretical studies. This research is particularly relevant to ultra-high-energy cosmic rays (UHECRs), where energy and mass loss primarily occur via electromagnetic interactions between nuclei and the...
Ionizing radiation is used in fields such as medical physics and nuclear research, with concrete and lead commonly serving as shielding materials. However, these materials carry health risks: lead is linked to harmful health effects, while concrete is heavy and susceptible to cracking over time, which raises safety concerns. Additionally, both lead and concrete block visible light, leading to...
The NUMEN (NUclear Matrix Elements for Neutrinoless double-beta decay) project aims to obtain the nuclear matrix elements (NME) to be used as inputs in models to determine the lifetime of neutrinoless double-beta (0ฮฝฮฒฮฒ) decay, which is related to the absolute mass of the neutrino [1]. This will be achieved by conducting heavy-ion double charge-exchange (DCE) reactions and measuring the cross...
This study investigates the radiation shielding capabilities of silicate glasses (S1โS4) across photon energies ranging from 1 to 15 MeV. Using Phy-X, XCOM, and GEANT4 simulations, key shielding parameters were estimated, including the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), and effective...
This study extracts new experimental ฮณ-ray strength function (ฮณSF) and nuclear level density (NLD) data for the 106Cd isotope using the newly developed Shape Method, coupled with the Oslo Method. These methods are applied to particle-ฮณ coincidence data from the 106Cd(3He, 3He'ฮณ)106Cd reaction at the Cyclotron Laboratory of Oslo University...
Chirality in nuclear systems requires an aplanar orientation of the total angular momentum and stable triaxial nuclear shape is needed [1-2]. It is expected that the angular momenta of an odd particle and an odd hole (both occupying high-j orbitals) are aligned predominantly along the short and the long axes of the nucleus respectively, whereas the collective rotation occurs predominantly...
For decades now, the low-lying first excited 0+ bands have been attributed to โฮฒ -vibrationsโ, following the seminal works of Bohr and Mottelson [1, 2]. Recent discoveries have demonstrated that these bands could arise due to other modes excitations, such as quadrupole pairing [3] and shape-coexistence [4].
The current work performs a systematics review of low-lying structures in the 160...
The lepton flavor universality ratios $R(D)$ and $R(D^{*})$, defined as $R_{D^{(*)}} \equiv \mathcal{B}(\bar{B}\to D^{(*)} \tau^{-} \bar{\nu}_{\tau})/\mathcal{B}(\bar{B} \to D^{(*)} \ell^{-} \bar{\nu}_{\ell})$ where$(\ell = e, \mu)$, are measured in semi-leptonic $B$ decays and serve as sensitive probes of new physics beyond the Standard Model (SM). Recent experimental averages, $R(D) = 0.342...
The ATLAS and CMS collaborations have jointly reported the first evidence of the Higgs boson ($h$) decay into a $Z$ boson and a photon, with a statistical significance of $3.4\sigma$. The observed signal strength, $2.2 \pm 0.7$ times the Standard Model (SM) expectation, exceeds the SM prediction even when next-to-leading order (NLO) QCD corrections and signal-background interference are taken...
Building on the ATLAS and CMS discovery of the Higgs boson decaying into a $Z$-boson and a photon (with a 3.4$\sigma$ significance), the current Standard Model (SM) predictions for the $h \to Z\gamma$ signal rate exceed the measured value by $2.4 \pm 0.9$, indicating possible new physics effects or systematic uncertainties that warrant further investigation. This analysis investigates this...
Monte Carlo (MC) simulated data are essential for modeling events in the ATLAS Inner Detector. However, full Geant4-based simulations have become increasingly computationally demanding, with approximately 80% of the processing time attributed to shower simulation and detailed ATLAS detector geometry modeling. To address this, the new ATLAS Fast Simulation (AF3) framework provides a...
The hidden abelian Higgs model is used for a search for an additional scalar decaying to two Z-dark bosons (Zd) to two leptons, two neutrinos (2l2v) . The search uses ๐๐ collision data collected with the ATLAS detector at the LHC with an integrated luminosity of 139 fbโปยน at a centre-of-mass energy โs= 13 TeV . This is a follow up to the study of the 4l final states [1]. In our 2l2v channel...
An excited state in 12C close to the 3-alpha breakup was predicted by Fred Hoyle in 1954 and was identified in 1962 by Cook et al. as the 0+ state lying at an excitation energy of 7.65 MeV. It was the key to understanding the production of 12C and heavier elements in the Sun (stars) up to iron. In the Sunโs core, fusion of two alpha-particles leads to the production of excited 8Be* and then...
Unlike axially symmetric nuclei, triaxial nuclei give rise to exotic collective phenomena, such as nuclear wobbling and chiralityโtopics that have garnered significant attention in recent years. These phenomena not only challenge our understanding of nuclear deformation, but also enrich the landscape of gamma spectroscopy with distinctive signatures that demand both experimental and...
