The decay of 76Br

Abstract

The radiations of 16.1±0.2 hour 76Br have been studied with single-crystal and coincidence scintillation spectrometers; beta-gamma coincidences were also studied with a proportional counter-scintillation crystal coincidence spectrometer. Three positon groups of maximum energies (and relative intensities) of 3.68±0.10 (45 +), 3.15±0.10(100 + and 1.9±0.2 MeV(< 40 +) were resolved; the ratio of electron capture to positon emission was determined as 0.6±0.2 MeV. The 3.68 MeV positon group is a ground state transition, since it is not in coincidence with the 0.56 MeV gamma ray. A total number of 15 gamma rays with energies ranging from 0.56 to 4.42 MeV were resolved (see table 1). For a few selected gamma rays coincidence measurements performed with the proportional counter yielded the relative amount of positons feeding these gamma transitions. In view of the complexity of the gamma ray spectrum no unambiguous decay scheme for 76Br can be proposed. Some features of the level scheme of 76Se are discussed especially in relation to the results obtained from a separate study of the decay of 76As.