Abstract
A study has been made of the rays emitted by the 8.9- and 9.5-Mev levels of using the reaction at the 1.47- and 2.11-Mev resonances. The decay schemes of these levels were reinvestigated using a three-crystal pair spectrometer, NaI(Tl) single-crystal measurements, and standard coincidence techniques. The anisotropies relative to the bombarding beam of most of the observed transitions were measured using the three-crystal pair spectrometer. The angular distributions of some of the transitions were measured using a single NaI(Tl) crystal. Measurements were made of the Doppler shifts of the ground state decay of the 5.10-Mev level and the cascade from the 5.83-Mev level to the 5.10-Mev level. From these Doppler shift measurements the mean lifetime of the 5.83-Mev level was found to be in the range (5.65)× sec; while an upper limit of 3× sec was set on the mean life of the 5.10-Mev level. The results of the study of the decay of the 9.5- and 8.9-Mev levels combined with the results of earlier measurements give conclusive assignments of , , 3, and 2 for the levels at 9.50, 8.90, 5.83, and 5.10 Mev. The 5.83-Mev level most probably has odd parity. A tentative assignment of is given to the 7.02-Mev level. Evidence is presented, from this and previous investigations, that indicates the 8.06-, 8.70-, 8.90-, and 9.50-Mev levels arise from the and configurations with the largest contribution being from the () configuration for the 8.06- and 8.70-Mev levels and from the () configuration for the 8.90- and 9.50-Mev levels. The analogs of these levels in are almost certainly the 6.09-, 6.89-, 6.72-, and 7.35-Mev levels, respectively. The , and states of are also discussed. It is proposed that the 4.91-, 5.69-, 5.10-, and 5.83-Mev levels of are and , and and , states, respectively.
- Received 11 November 1958
DOI:https://doi.org/10.1103/PhysRev.114.214
©1959 American Physical Society