In-beam -ray spectroscopy of : First observation of a low-lying prolate band in Po isotopesK. Van de Vel1, A.N. Andreyev1, 2, R.D. Page2, H. Kettunen3, P.T. Greenlees3, P. Jones3, R. Julin3, S. Juutinen3, H. Kankaanpää3, A. Keenan3, P. Kuusiniemi3, M. Leino3, M. Muikku3, P. Nieminen3, P. Rahkila3, J. Uusitalo3, K. Eskola4, A. Hürstel5, M. Huyse1, Y. Le Coz5, M.B. Smith6, P. Van Duppen1 and R. Wyss7
1 Instituut voor Kern- en Stralingsfysica, University of Leuven, Belgium
2 Oliver Lodge Laboratory, Department of Physics, University of Liverpool, UK
3 Department of Physics, University of Jyväskylä, Finland
4 Department of Physics, University of Helsinki, Finland
5 DAPNIA/SPhN, CEA Saclay, France
6 Department of Physics and Astronomy, Rutgers University, USA
7 Department of Physics, Royal Institute of Technology, Stockholm, Sweden
(Received: 10 January 2003 / Revised version: 19 February 2003 / Published online: 7 May 2003)
Gamma rays from excited states of 190Po have been observed using the Jurosphere Ge-detector array coupled to the RITU gas-filled separator. They were associated with a collective band which from spin onwards resembles the prolate rotational bands known in the isotones 188Pb and 186Hg. This indicates that in 190Po the prolate configuration becomes yrast above . The experimental results are interpreted in a two-band mixing calculation and are in agreement with -decay data and potential energy surface calculations.
23.20.Lv - Gamma transitions and level energies.
25.70.-z - Low and intermediate energy heavy-ion reactions.
27.80.+w - .
21.60.Ev - Collective models.
© Società Italiana di Fisica, Springer-Verlag 2003