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

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 As-66. The fusion-evaporation reaction Ca-40(Si-28,pn)As-66 was employed at beam energies of 75 and 83 MeV. The half-lives and ordering of two known isomeric states in As-66 have been determined with improved accuracy. In addition, several prompt gamma-ray transitions from excited states, both bypassing and decaying to the isomeric states in As-66, 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 pf(5/2)g(9/2) model space.