g factors near the first backbend in 82Sr and 84Sr

Abstract

The transient-field technique has been used to measure g factors of excited states in 82Sr and 84Sr populated in the reactions 12C(72,74Ge, 2n) at 215 MeV. The nuclei recoiled through a 6 mu m iron foil and the nuclear precessions were deduced from the rotations of the gamma -ray angular distributions observed by four Ge(Li) detectors. The feeding time to discrete states in the vicinity of the first backbend, determined by lineshape analysis of some of the gamma -ray transitions was sufficiently short to allow g-factor determinations for these states. Large positive g factors of the 82+ and 10 2+ states in both 82Sr and 84Sr indicate proton g9/2 quasiparticle alignment. The lifetime of the 81+ state in 82Sr was measured as tau m=1.1(2) ps.