Browsing by Author "Orce, J.N"

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    Modern African nuclear detector laboratory: Development of state-of-the-art in-house detector facility at the University of the Western Cape
    (SpringerLink, 2021) Kapoor, K.; Orce, J.N; Abrahams, K; Akakpo, E; Bester, Z; Jenkins, D.G; Jordaan, K.L; Jones, M.Y.; Kamedien, M.A.; Lindsay, R.; Lomberg, B; Masango, S.; Ngwetsheni, C.; Ntshangase, S.S.; Radebe, N.; Triambak, S; Zyl, J.J. van,
    The upcoming detector facility aims at developing new state-of-the-art particle detectors as well as providing hands-on training to postgraduate students using both analog and digital signal processing from nuclear radiation detectors. The project is two-fold and aims at developing: 1) ancillary detectors to be coupled with the new GAMKA array at iThemba LABS. Of particular interest to our group is the determination of nuclear shapes, which depend on the hyperfine splitting of magnetic substates; 2) PET scanners for cancer imaging using a cheaper technology. Performance of NaI(Tl) inorganic scintillator detectors has been evaluated using PIXIE-16 modules from XIA digital electronics. Gamma-ray energy spectra were acquired from 60Co and 137Cs radioactive sources to calculate the detector resolution as well as to optimize the digital parameters. The present study focuses on improving and optimizing the slow and fast filter parameters for NaI(Tl) detectors which can eventually be used in the list mode of data aquisition.
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    Observation of the 0+ 2 and γ bands in 98Ru, and shape coexistence in the Ru isotopes
    (Elsevier, 2020) Garrett, P.E; Makhathini, L.; Bark, R.A; Rodríguez, T.R.; Valbuena, S.; Wirth, H.F.; Vyfers, E.C.; Triambak, S.; Singh, B.; Rebeiro, B.; Orce, J.N; Nzobadila Ondze, J.C.; Ntshangase, S.S.; Ngwetsheni, C.; Mukwevho, N.J.; Mthembu, S.H.; Mehl, C.; Lawrie, E.A; MacLean, A.D.; Leach, K.G; Lawrie, E.A.; R., Kamil; R. Dubey; T. Faestermann; C. Burbadge; T.D. Bucher
    Excited states in 98Ru were investigated using γ-ray spectroscopy following the β-decay of 98Rh, and via the 100Ru(p,t) reaction. Combining the results from the two experiments, two states were revised to have spin-parity of 4+ and subsequently assigned to the 02+ and “γ” bands, respectively. The observed structures in 98Ru are suggested to be deformed and rotational, rather than spherical and vibrational, and fit well into the systematics of these excitations in the Ru isotopes. The 02+ excitation is suggested as a shape coexisting configuration. This observation eliminates some of the last remaining candidates for nearly harmonic vibrational nuclei in the Z≈50 region. Beyond-mean-field calculations are presented that support shape coexistence throughout the Ru isotopes with N=52–62, and suggest a smooth evolution of the shapes