Abstract
The decay of to states of has been studied with Si, Ge(Li), and NaI(Tl) detectors. was produced in the reaction at MeV by bombarding S targets, enriched to 1.93% in . The half-life was measured to be 169.6 ± 0.7 min. The main branch (83 ± 2)% with end-point energy 1005 ± 20 keV proceeds to a previously unidentified level of at 1942 keV. A 1941.7 ± 0.2-keV ray has been observed in coincidence with this branch. The transition is allowed () giving for (1942 keV). The decay of the 1942-keV level proceeds 100% to the ground state, and an upper limit of 0.4% can be set for any other possible decay mode. No rays in coincidence with the 1942-keV ray were observed. The - and -ray measurements determine the value for the reaction as 2947 ± 20 keV. In addition to the main branch a (2.8 ± 0.3)% branch proceeds to the 1746.2 ± 0.4-keV level, which decays predominantly to the ground state. The restricts the 1746-keV level to have ; the reaction establishes the parity as odd. No other rays from were observed, which leads to a value of (14.2 ± 2)% for the ground-state branch and to a unique first-forbidden matrix element, , of 1.53 ± 0.22 , in excellent agreement with theoretical calculations. The Coulomb energy difference between and is determined as 6051 ± 32 keV. The isobaric-multiplet mass equation is used to predict the masses of the lowest , states in , , , and . The predicted mass excess for is + 10.55 ± 0.78 MeV.
- Received 8 September 1970
DOI:https://doi.org/10.1103/PhysRevC.3.180
©1971 American Physical Society