University of Jyväskylä

Dissertation: 19.12 Spectroscopic Studies of 173Pt and 175Pt (Peura)

Start date: Dec 19, 2014 12:00 AM

End date: Dec 19, 2014 03:00 PM

Location: Ylistönrinne, FYS 1

Pauli Peura. Kuvaaja: Jan SarénM.Sc. Pauli Peura defends his doctoral dissertation in Physics. Opponent Professor Philip Walker (University of Surrey, UK) and custos University Researcher Dr. Catherine Scholey (University of Jyväskylä). The event is in English.


Neutron-deficient 173Pt and 175Pt were studied using heavy-ion fusion-evaporation reactions. The JUROGAM Ge array and the GREAT spectrometer, in conjunction with the RITU gas-filled separator, were used for prompt-gamma-ray and decay spectroscopy, respectively. The prompt gamma rays of 173,175Pt were selected using the recoil-gating and recoil-decay tagging techniques. For both nuclei, the known positive-parity bands were extended, and negative-parity bands were observed. An i13/2 quasineutron alignment was observed for the positive and negative-parity bands of 173Pt and 175Pt, based on a cranked shell-model analysis. Observed low-frequency alignment irregularities of 175Pt suggest a change of deformation within the rotational structure. Based on unhindered alpha decays of 173Pt and 175Pt, and the observation of subsequent M1 transitions in 169Os and 171Os, respectively, the ground-states of 173,175Pt were assigned to have Ip = (7/2-). An isomeric state with a half-life of 9.0(5) us was observed in 173Pt. This isomeric state was assigned to have Ip = (13/2+), based on the observation of coincident M2 and M1 transitions following the decay of the isomeric state.

The dissertation is published in the series Department of Physics, University of Jyväskylä, Research Reports number 13/2014, Jyväskylä 2014, ISSN: 0075-465X, ISBN: 978-951-39-5922-7 (paper), ISBN: 978-951-39-5923-4 (online).

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