Excited states in 75As

Abstract
The gamma-ray spectrum of 75Se has been studied with a variety of Ge(Li) detectors. The energies and intensities of 15 lines have been accurately measured. Of these a 24.4 and 468.6 keV transition were substantiated for the first time in the gamma-ray spectrum. Ge(Li)–Ge(Li) coincidence measurements established the newly observed 24.4 keV transition. These experiments also substantiated the 80.8 keV transition (observed for the first time) deduced from electron conversion spectra. The accurate intensity values obtained in this work have been combined with proper literature data and conversion coefficients for various transitions have been determined. These data and recent half-life measurements of some excited states by other workers permitted us to calculate the transition rates in 75As. The data obtained indicate that the 198.6, 279.5, and 400.5 keV levels in 75As exhibit strong collective character, in contrast to the 264.6 keV level, which shows little influence of collective effects.