Browsing by Author "Lawrie E.A."

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    Fine structure in the α decay of 179Hg and 177Au
    (Springer, 2025) Easton, Jayson Lee; Lawrie E.A.; Špaček A.
    The α-decay fine structure of 179Hg and 177Au was studied by means of decay spectroscopy. Two experiments were performed at the Accelerator Laboratory of the University of Jyväskylä (JYFL), Finland, utilizing the recoil separator RITU and a digital data acquisition system. The heavy-ion induced fusion-evaporation reactions 3682Kr + 44100Ru and 3888Kr + 4292Mo were used to produce the 179Hg and 177Au nuclei, respectively. Studying the evaporation residues (ER, recoils)-α1-α2 correlations and α-γ coincidences, a new α decay with Eα = 6156(10) keV was observed from 179Hg. This decay populates the (9/2-) excited state at an excitation energy of 131.3(5) keV in 175Pt. The internal conversion coefficient for the 131.3(5) keV transition de-exciting this state was measured for the first time. Regarding the 177Au nucleus, a new α decay with Eα = 5998(9) keV was observed to populate the 156.1(6) keV excited state in 173Ir. Two de-excitation paths were observed from this excited state. Moreover, a new 215.7(13) keV transition was observed to depopulate the 424.4(13) keV excited state in 173Ir. Properties of the 179Hg and 177Au α decays were examined in a framework of reduced widths and hindrance factors. For clarity and simplicity, the spin and parity assignments (e.g. Jπ) are presented without brackets throughout the text.
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    First observation of rotational bands in the nucleus 231U
    (Springer, 2024) Roux D.G.; Lawrie E.A.; Kheswa B.V.; Khumalo N.A; Noncolela S.P.; Ndayishimye J.; Sharpey-Schafer J.F.
    This work reports the first rotational bands observed in the neutron-deficient nucleus 231U. Excited states were populated in the 232Th(α,5n) reaction at a beam energy of 52 mev. Coincident decay γ-rays were measured with the high-purity germanium detectors of the afrodite spectrometer array, in conjunction with a recoil detector to discriminate against the fission background. The bands are interpreted as the ground-state band ν[633]5/2+, yrast band ν[752]5/2-, and an excited band ν[631]3/2+. Configuration assignments are supported by Cranked Shell Model and B(M1)/B(E2) calculations. The excitation energy of the ν[752]5/2- bandhead is suggested to be 113.0 kev. © The Author(s) 2024.