Lifetimes of high-spin states in 173Re

Lifetime measurements have been carried out by both recoil-distance and DBLS techniques on high-spin states in 173Re, produced in the reaction 150Sm(27Al,4n) at a bombarding energy of 125 MeV on the HHIRF tandem accelerator. Measurements were made at 23 target-stopper separations ranging from 0 to 2200 μm. Lifetime data were obtained for four bands. The preliminary results for the πh9/2, (1/2)-[541] band (in ps) are: (13/2)-, 116±14; (17/2)-, 12.9±1.6; (21/2)-, 5.0±0.6; (25/2)-, 1.7±0.4; (29/2)-, 1.25±0.14; (33/2)-, 0.76 ±0.12; (37/2)-, 0.90±0.10. These lifetimes are indicative of moderate deformation (β∼0.25) which remains resonably constant up to ℎω∼0.30 MeV, in line with TRS predictions. A preliminary analysis of the (5/2)+[402] band reveals the presence of large deformation increases (from β2∼0.22 to β2∼0.29) in both signatures of this band at low rotational frequencies (ℎω ∼0.16 MeV) as predicted by TRS calculations and offers new insight into the behavior of 173Re and perhaps other light nuclei in this region. The B(M1) values also show an increase at about the same rotational frequency. Particle-rotor calculations can account qualitatively for the observed transition rates in the (5/2)+[402] band