High spin states in Pm139

Abstract

The odd mass nucleus Pm139 has been studied to high spins through the Cd116(Al27,4n)Pm139 reaction at an incident beam energy of 120 MeV. The de-exciting γ-rays were detected using an array of 12 Compton suppressed Ge detectors. A total of 46 new levels have been proposed in the present work as a result of the observation of 60 new γ-rays. Four new bands including a ΔJ=1 sequence have been identified and all the earlier reported bands, other than the yrast band, have been extended to higher spins and excitation energy. The spin assignments for most of the newly reported levels have been made using the observed coincidence angular anisotropy. Tilted axis cranking calculations support the interpretation of two of the observed magnetic dipole sequences as examples of magnetic rotational bands. © 2009 The American Physical Society.