Recoil-β tagging study of the N=Z nucleus 66As

Abstract

An in-beam study has been performed to further investigate the known isomeric decays and to identify T=1 excited states in the medium-heavy N=Z=33 nucleus 66As. The fusion-evaporation reaction 40Ca(28Si,pn)66As was employed at beam energies of 75 and 83 MeV. The half-lives and ordering of two known isomeric states in 66As have been determined with improved accuracy. In addition, several prompt γ-ray transitions from excited states, both bypassing and decaying to the isomeric states in 66As, have been observed. Most importantly, candidates for the 4+→2+ and 6 +→4+ transitions in the T=1 band have been identified. The results are compared with shell-model calculations using the modern JUN45 interaction in the pf5/2g9/2 model space. © 2013 American Physical Society.