Conveners
Nuclear Structure Studies
- TAOFIQ IBRAHIM (FEDERAL UNIVERSITY LOKOJA, LOKOJA NIGERIA)
Nuclear Structure Studies
- Luna Pellegri (University of the Witwatersrand and iThemba LABS)
Nuclear Structure Studies
- Zsolt Podolyak (University of Surrey)
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 iThemba Laboratory for Accelerator Based Sciences is based around a K=200 Separated Sector Cyclotron (SSC) which is used for radionuclide production and for research in nuclear physics and radiobiology. It plans to build the “South African Isotope Facility”, comprising two phases; the first is the Accelerator Centre for Exotic Isotopes (ACE Isotopes) and the second is the Accelerator...
