High resolution gamma-ray spectroscopy of <super>76</super>Aas, <super> 207</super>Bi, and <super>75</super>Se

Abstract

The decay schemes of 76As, 207Bi and 75Se have been studied using Ge(Li) detectors and coincidence techniques with particular emphasis on the weaker modes of gamma decay. The feasibility of detecting weak modes of gamma decay is discussed and supporting electronic systems which have been developed to yield data suitable for reduction and analysis with computer programmes are described.

Low energy gamma transitions in the decay of 75Se were studied using an X-ray Ge(Li) detector. Two previouslyunconfirmed transitions at 24.4 keV and 80.8 keV have beendetected and their positions in the decay scheme of 76As have been established.

In the decay of 207Bi, an upper limit of 0.014 +/- 0.008 relative to the 570 keV transition as 100 has been placed on the intensity of the 'l-forbidden' gamma transition at 328 keV.

The decay scheme of 76As has been shown to include two previously unreported gamma-rays at 220 keV and 316 keV and coincidence experiments have indicated a new energy level at 2006 keV. Several gamma-rays and level energies suggested by previous authors were not confirmed by this work.