Browsing by Author "Lawrie, E.A"

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    Low- And medium-spin negative-parity bands in the Os 187 nucleus
    (American Physical Society, 2021) Sithole, M. A; Sharpey Schafer, J.F; Lawrie, E.A
    Low- and medium-spin negative-parity bands of Os187 have been studied using the AFRican Omnipurpose Detector for Innovative Techniques and Experiments (AFRODITE) array, following the W186(He4,3n)Os187 reaction at a beam energy of 37 MeV. In the current work, all the previously known bands have been significantly extended and three new bands have been added to the level scheme. The angular distribution ratio (RAD) and polarization measurements have been used to assign spin and parity to the observed new levels. The configurations of some of the bands have been modified. The observed bands are interpreted within the cranked shell model (CSM) and cranked Nilsson-Strutinsky-Bogoliubov (CNSB) formalism. Comparison with experimental data shows good agreements. Systematic comparison with the neighboring Os185 isotope is also discussed.
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    New bands in ¹⁹²Tl using gamma spectroscopy techniques
    (University of the Western Cape, 2011) Easton, Jayson Lee; Lawrie, E.A; Lindsay, R
    High spin excited stats in¹⁹²Tl were studied using gamma-ray spectroscopy. The study included taking an active part in performing the experiment, understanding the experimental procedure, electronics and data acquisition in this experiment. The high spin states in ¹⁹²Tl were produced using a ³⁷Cl beam and ¹⁶⁰Gd target. The nine clovers of the AFRODITE array were placed at 90° and 135°. The target was thin, allowing the residual thallium nuclei to recoil in vacuum. Two weeks of data was acquired and analysed in this work. In addition more data was acquired in order to perform DSAM lifetime measurements, but this is beyond the scope of this work. The preliminary data analysis of the thin target data involved energy and time-gain matching calibrations as well as Doppler shift and gain drift corrections. Then the data were sorted into matrices and spectra for the actual analysis. The known level scheme of ¹⁹²Tl was extended by more than 50 new transitions placed in three new bands. A chiral partner to the yrast band in ¹⁹²92Tl was searched for but not found. But there is still a possibility such a band to be discovered, when the additional three weekends of data (including the DSAM lifetime measurements) undergo such an analysis.
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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