The interest in recent years in quasi-free scattering (QFS) originates from its util-
ity as a tool to investigate single particle properties of unstable nuclei. However, the
difference in quenched spectroscopic behaviour as a function of proton-neutron asym-
metry observed between nucleon removal reactions on light nuclei e.g. 9Be(28S,27P),
transfer reactions, and (p,pN) reactions in...
Neutron-rich beams are being developed at iThemba LABS to study nuclear structure away from stability. This is also the opportunity of deepening our understanding of astrophysical origin of elements. The interest of using (p,xp) reactions in the production of exotic nuclei, lies in the fact that proton beams have a large penetrating power and can be produced with high intensity. Some...
iThemba LABS, South Africa, is a suitable laboratory for the experimental study of the E1 strength in nuclei. The K600 magnetic spectrometer is one of the few spectrometers in the region of 30-200 MeV with high-energy resolution and the ability to perform measurements at zero degrees. This capability enabled the study of fine structure in giant resonances and the role of deformation in these...
Describing rapidly evolving nuclear deformation is important for determining the true behaviour of the strong force and to create accurate macroscopic-microscopic models of the nucleus. Current models suggest a change from soft shapes through triaxial deformation in $^{66}$Ge. This nucleus lies in a particularly interesting region of the nuclear chart, with neutron numbers between the two...
It is now well established that atomic nuclei composed of certain combinations of protons and neutrons can adopt reflection-asymmetric, or octupole-deformed, shapes at low excitation energy. These nuclei show promise in the search for a permanent atomic electric dipole moment, the existence of which has implications for physics beyond the Standard Model. Theoretical studies have suggested that...
The region of the nuclear chart around neutron-rich A~100 nuclei is one where prolate and oblate nuclear shapes are predicted to be in close competition. An indirect measurement of the shape of the nucleus can be obtained from measuring level lifetimes which relate, via transition rates, to beta_2 deformation. In order to make measurements of level lifetimes in the sub nanosecond range an...
The two rp-reactions $^{34}$S(p,$\gamma$)$^{35}$Cl and $^{34g,m}$Cl(p,$\gamma$)$^{35}$Ar were studied via a shell-model approach. At energies in the resonance region near the proton-emission threshold many negative parity states appear. We present results of calculations in a full (0$+$1)$ \hbar \omega $ model space which addresses this problem. Energies, spectroscopic factors and...
The properties of excited states in the neutron-rich nucleus 194Os have been investigated using the 192Os(18O, 16O)194Os 2 neutron transfer reaction using a 80 MeV 18O heavy-ion beam provided by the tandem van de Graaff accelerator at the IFIN-HH laboratory Bucharest. Discrete γ-ray decays from excited states have been measured using the hybrid HPGe-LaBr3 (Ce) γ-ray spectroscopic array...
A. A. Avaa1,2, P. Jones2, T. Kibédi3, J. T. H. Dowie3, I. T. Usman1, A. E. Stuchbery3,
M.V. Chisapi2,4, A. Akber3, L. J. Bignell3, B. J. Coombes3, M. S. M. Gerathy3, T. J. Gray3, G. J. Lane3, B. P. McCormick3, A. J. Mitchell3, H.T. Hoang5, E. Ideguchi5,
M. Kumar Raju5, and B. P. E. Tee3
1 School of Physics, University of the Witwatersrand, Johannesburg, South Africa
2 iThemba...
Spectroscopy of $^{50}$Ti through internal-pair formation
The excited states of atomic nuclei predominantly de-excite via 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 greater than 1022 keV). In...
Fine structure has been studied on the region of the Isoscalar Giant Quadrupole Resonance (ISGQR), for stable even-even nuclei of neodymium isotopes. The 200 MeV proton beams were delivered by the Separated Sector Cyclotron (SSC) facility of iThemba LABS. Measurements were made using the state-of-the-art K600 magnetic spectrometer, where unique high energy-resolution ($\Delta$E ≈ 42 -...