First observation of high-spin states in Se83

The level structure of Se-83 was studied via prompt gamma-ray spectroscopy of fragments following the fission of the compound nucleus Th-226 formed in the O-18 (91 MeV) + Pb-208 fusion-evaporation reaction. The first four high-spin states above the 9/2(+) ground state were established. The coupling of the neutron hole in the g(9/2) orbital to the yrast states in the Se-84 core can account for these states. The experimentally observed high-spin states are compared with predictions of shell-model calculations.