SPECTROSCOPY OF PU-238, PU-239 STUDIED BY QUASI-ELASTIC REACTIONS

The gamma-ray transitions in the ground-state bands of Pu-238 and Pu-2 39 up to spins 26+ and 51/2+, respectively, were observed in the react ion Pu-239 + Sn-117 (E(c.m.) = 422.9 MeV). Another band in Pu-239 was observed, and is tentatively identified as the high-spin continuation of the 0- octupole excitation built on the 1/2+ ground band in Pu-239. The measured gamma-ray multiplicity and total energy provided data on the population of entrance states in both Pu-238 and Pu-239. The one- neutron-transfer cross section, as determined by the yield of the 6+ - -> 4+ transition in Pu-238, was measured to be 65 +/- 25 mb. This tran sition yield is estimated to represent between 80% and 90% of the tota l one-neutron-transfer cross section.