NMISA supports the South African industry with measurement traceability and measurement solutions. The ionising radiation division has dosimetry and radioactivity laboratories and recently has introduced capabilities for performing measurement audits at radiotherapy centres. The presentation will look at different programmes and projects currently running at these laboratories.
Targeted alpha therapy is a rapidly evolving discipline, referring to an emerging class of revolutionary cancer agents delivering alpha-particle-emitting radiopharmaceuticals selectively to cancerous lesions via attachment to appropriate ligands and carriers.
Clinically effective alpha particle–emitting radionuclides for cancer therapy exhibit short half-lives, (limiting long-term radiation...
A new fast neutron facility has been established within the Metrological Applied Sciences University Research Unit (MeASURe) located in the Department of Physics at the University of Cape Town. The facility features a D-T sealed tube neutron generator within a bunker which can produce a well-collimated beam of 14 MeV neutrons suitable for a wide variety of applications, including cross section...
We use advanced nuclear measurement techniques to study the fundamental physics of material flows and the dynamics of physical systems. At the previous ANSTT meeting we presented a research strategy broadly aligned to the scientific programme. We now present developments over the past year, including new high speed data acquisition systems, machine learning explorations, and novel radioisotope...
Results are presented from the first in-beam experiment using the NuBALL hybrid HPGe-LaBr3 gamma-ray spectrometer at IPN, Orsay, performed in November 2017, with the physics aim of determining the electromagnetic transition rates to the ground state of the N=100 nucleus 166Dy. In this first configuration, the NuBALL spectrometer comprised 24 Compton suppressed HPGe Clover detectors, 10 coaxial...
The Environmental Radioactivity Laboratory of iThemba LABS, in the Department of Subatomic Physics has been using radiation detectors for measurements of anthropogenic (man-made) and natural radionuclides present in our environment. The radiation detectors consist of a laboratory-based HPGe detector, field-based MEDUSA detector systems and a flexible radon monitor, RAD7. To assist in the...
In environmental gamma-ray spectroscopy, it is essential that the detectors employed have high efficiency and excellent energy resolution in order to give accurate assessment, identification and quantification of radionuclides present in the sample being measured.
As part of a joint project with the Environmental Radioactivity Research Centre at the University of Liverpool a Mirion...
The activity concentrations of $^{238}$U and $^{232}$Th series radionuclides in beach sand were measured using a gamma-ray spectrometer comprising four LaBr$_3$:Ce (2" x 2") detectors without background shielding. The sample was placed 10 cm equidistant from the detectors and counted for 48 hours. This spectrometer allowed for measurement in singles and coincidence (gamma-gamma) modes....
Soil samples were obtained from Ijero, Nigeria where the chemical and radiotoxicity of soil is under question due to ongoing and unprofessional mining activities. The soil samples were crushed, sieved, dried and sealed in identical cylindrical containers. The activity concentration of primordial radionuclides 238U, 232Th and 40K was measured using a High-Purity Germanium (HPGe) detector...
High concentrations of radionuclides and toxic elements in abandoned gold mine facilities present a potential health hazard to the people living around these former mining areas and lead to a degradation of the environment. Environmental measurements were performed around the areas designated as gold mines, coal mines, coal power stations, mine dumps and abandoned mines. Soil and water samples...
Radon 222Rn is a natural radioactive gas directly produced from the decay of Radium, 226Ra found in rocks and soil. Since radon is a gas, it can move freely through the soil allowing it to escape into the atmosphere or flow into buildings. Elevated radon-in-air levels are associated with an increased risk of developing lung cancer. Over the years comprehensive surveys of indoor radon levels...
Abstract:
Radioactivity has existed since the beginning of time and is part of our planet Earth. Several studies have been well documented to monitor natural radioactivity as a source of radiation exposure to the environment and to human beings. In order to determine the effects of natural radioactivity in around areas of former uranium mines in the West-Rand area, an investigation of...
The National Nuclear Regulator is funding a project to plan a residential radon survey in South Africa. This is a very large project and we are looking at ways to decide if different areas are likely to be radon prone. Two of the important parameters to predict the radon levels in houses is the radium concentration in the soil and the emanation coefficient. This project aims to measure the...
In order to monitor future environmental pollution and to enforce uranium mining regulations during and after mining, several efforts have been made to establish pre-mining baseline data at proposed uranium mines in Tanzania1-6. However, these attempts did not produce the desired baseline data because there was no clearly defined sampling area. The basis of the methods used for selection and...
Prompt Gamma Imaging (PGI) focuses on the detection of secondary (prompt) gammas during a proton therapy treatment. With the use of a Compton camera, PGI is working to create an in-vivo image of the dose deposited within the patient as a dose verification system. I will present the UCT PGI detection system and the current work being performed. I will also discuss the next steps towards the...
Direct monitoring of targets for isotope production implies harsh conditions with large neutron and gamma fields. These have implications on the type of instrument to use and how to extract information. Micro fission pocket detectors for nuclear power generation applications, for example, can sustain neutron fluxes in the order of 1014n/cm2/s or more. This makes them suitable to quantify...
PEPT Cape Town is a dedicated research centre focused on measuring the underlying
physics of opaque multiphase flow systems. The basis of this nuclear
measurement technique hinges on how accurate and representative the
tracer particle is of the media of interest in these dynamic applications.
This presentation will report the current state of tracer particle
techniques and the areas of...
National Metrology Institutes (NMIs) involved in Radionuclide Metrology play an important role in enabling societal benefits from nuclear physics research (1). NMIs are responsible for the development and maintenance of primary measurement standards, distributed to end users to calibrate their own instruments in an uninterrupted ‘traceability chain’ of calibrations. NMIs compare their primary...
Concrete is extensively within just about all nuclear facilities for its structural and shielding properties. In a re used actor facility, for example, the concrete will be subjected to high neutron and gamma-ray fluxes for the lifetime of the reactor (60+ years), and must retain is mechanical integrity and shielding properties at an acceptable level until decommissioning. Beyond the typical...
Reactions induced by beams of light ions such as protons, deuterons, $^{3}$He and ⍺ particles have been the main tool for investigating nuclear properties for almost a century. In recent years such reactions have been used to measure the nuclear level density (NLD) and the 𝛾-ray strength function (𝛾SF) [1]. These quantities have been identified as one of the key quantities in proper...
The progressive development of the scintillator detectors has made it possible to do direct electronic lifetime determination. The 2” x 2” LaBr3:Ce detectors provide a combination of excellent time resolution and good energy resolution. With these detectors it is possible to perform direct lifetime measurements of excited nuclear states up to a few hundred picoseconds. Six 2” x 2”...
A new position sensitive detector system for the focal plane of the K600 magnetic spectrometer is currently being developed. The existing focal plane detectors (FPDs) were designed to detect Z≤2 ions with kinetic energies 30 MeV/u or higher. A new low-pressure gas-filled tracker combined with a stopping scintillator detector is required to allow for the efficient detection of heavier particles...
The African LaBr Array (ALBA) consists of 23 large volume LaBr3:Ce. The characteristics of these crystals, such as the good energy resolution and the high efficiency, make this array very useful for the detection of high-energy gamma rays. The ALBA project foresees the use of the gamma spectrometer in stand-alone mode and coupled to the K600 spectrometer or to silicon-detector arrays for the...
Information gained on neutron-rich N~126 nuclei is essential for the understanding of nuclear structure in heavy nuclei. Studies around doubly magic systems allow direct tests of the purity of shell model wave functions. In the case of the beta decay of N~126 nuclei there is strong competition between allowed and first-forbidden transitions. This is the mass region where first-forbidden...
Monopole transition studies has been of theoretical and experimental interest for over 50 years now. Since gamma decay is forbidden between two 0+ states, the study of nuclear structure through the usual technique of gamma measurement cannot be useful in such a case. Hence, the decay mode of spin zero state is most probable by electron emission. Depending on the probable transition energies,...
Excited nuclei eventually de-excites mainly through electromagnetic transitions, e.g. gamma-ray transitions or electric monopole (E0) transition in an event that the former is forbidden. E0 transitions proceed via conversion electrons and electron-positron pairs (for transition energies > 1022 keV). Compared to gamma-ray transitions that are predominantly studied across the chart of nuclides,...
Metrological difficulties in measurement of lifetimes of nuclear excited states have posed controversies in the quest to answer the fundamental question of whether lifetimes of nuclear states are in variable or not. Although several studies have suggested the possibility of slight variations of lifetimes depending on conditions of the nucleus [1, 2, 3], it is important to note that any claims...
The phenomenon of fine structure of the Isoscalar Giant Quadrupole Resonance (ISGQR) has been studied with high energy-resolution proton inelastic scattering at iThemba LABS, in the chain of stable even-mass Nd isotopes covering the transition from spherical to deformed ground states. A wavelet analysis of the background-subtracted spectra in the deformed $^{146,148,150}$Nd isotopes reveals...
The nuclear dipole polarizability - a second order effect – governed by dynamics of giant dipole resonances was investigated. Along with the resulting effects of recently observed enhancement of photon strength functions at low energies for nuclide in A ≈ 50, 90 mass region. Empirical drops observed in ground-state nuclear polarizabilities indicate deviations from the effect of giant dipole...
Metal-poor stars provide a unique testing ground to investigate the beginnings of star formation and the synthesis of chemical elements in the early Universe. In particular, the abundance patterns seen in these metal-poor stars provide constraints on the nature of first generation of super-massive stars in the universe. These stars are also characterized by unusual abundance patterns of...
Neutron-rich nuclei close to mass A=100 display a variety of intriguing shape phenomena such as exotic triaxial shapes, shape changes and shape coexistence. Recent investigations exploiting Coulomb excitation have helped to shed light on these phenomena [1]. However, as more intense radioactive beams of these refractory isotopes become available it has become evident that some of the key...
A new pipeline for Coulomb-excitation studies has been developed at iThemba LABS with the first particle-gamma coincidence measurements carried out during a two-month campaign in April-May 2016 using an XIA-based digital DAQ. We used the reorientation effect to determine the spectroscopic quadrupole moment of the first high-lying excitation in Tz=0 self-conjugate nuclei (20Ne, 32S, 36Ar) -...
Background and Purpose: Innovations in external beam radiotherapy have been limited to linear accelerators, yet radiotherapy began with cobalt-60 teletherapy. One such technology is called intensity modulated radiotherapy (IMRT), which can be executed with cobalt-60 teletherapy units to yield dosimetric characteristics that are comparable with linear accelerator beams. The lower energy and...
Phenomenological interactions have been successful in the description of the alpha cluster structure of light nuclei. The interactions however lack the required fundamental Nucleon-Nucleon character. This shortcoming is addressed by exploiting the known surface localization of the cluster that is well described by microscopic interactions. The ground-state band properties of 94Mo and 136Te...
The specific activities of 226Ra, 232Th and 40K in some commonly consumed leafy vegetables cultivated through surface water irrigation in Lagos metropolis were determined using High Purity Germanium (HPGe) detector. To assess the radiation hazards associated with the consumption of these vegetables, annual effective dose (AED) and excess lifetime cancer risk (ELCR) were also determined. The...
This work investigated the radioactivity due to some selected radionuclides in the vegetation, soils and waters in an urban settlement around a cement producing factory. Samples of the vegetation, soils and waters of were collected from different locations close the factory and there treated for HPGe gamma spectroscopy to detect and measured the activity concentration of the radionuclides...
