Abstract
The spectrum shape for the 4.12-MeV → allowed positron transition has been measured in the positron energy range greater than 2 MeV. The observed shape deviates markedly from the statistical shape (slope about - 11% per MeV at 3 MeV). The forbidden matrix element is extracted from the data and used to calculate the mean life of . For the latter, the value obtained is (3.3±0.3) × sec. The sign of the allowed matrix element is found to be positive. The value obtained for the 4.12-MeV transition is (2.14±0.03) × sec and the branching fraction is found to be (0.61±0.01)%.
- Received 28 March 1966
DOI:https://doi.org/10.1103/PhysRev.148.1024
©1966 American Physical Society