Eur. Phys. J. A (2007) 34: 275-281
https://doi.org/10.1140/epja/i2007-10507-2

Regular Article - Experimental Physics

In-beam gamma-ray spectroscopy of ^{190, 197}Po

¹ Department of Physics, Oliver Lodge Laboratory, University of Liverpool, L69 7ZE, Liverpool, UK
² TRIUMF, 4004 Wesbrook Mall, V6T 2A3, Vancouver, BC, Canada
³ Department of Physics, University of Jyväskylä, FIN-40014, Jyväskylä, Finland
⁴ Department of Physics, Royal Institute of Technology, SE-106 91, Stockholm, Sweden

^* e-mail: rdp@ns.ph.liv.ac.uk

Received: 13 July 2007
Accepted: 6 December 2007
Published online: 20 December 2007

Abstract

γ -ray transitions in the neutron-deficient nuclei ^{190, 197}Po have been identified using the JUROGAM Ge detector array coupled to the RITU gas-filled separator and the GREAT spectrometer. The yrast band of ¹⁹⁰Po has been firmly established through γ -γ coincidences and extended up to a spin and parity of 14⁺. It displays similar behaviour to its isotones ¹⁸⁶Hg and ¹⁸⁸Pb above the 4⁺ level, thus confirming its prolate nature. In ¹⁹⁷Po the band built upon the 13/2⁺ isomer has been extended up to a spin and parity of 33/2⁺, while the non-yrast band has been observed for the first time. The behaviour of ¹⁹⁷Po is found to be similar to that of the nearby even-mass isotopes, which is consistent with the model in which the i _13/2 neutron is weakly coupled to the states in the even-even core.