Scintillation spectrometry study of the 73Se isomeric pair

Abstract

The position and the gamma ray spectra of the two 73Se isomers have been studied with a scintillation spectrometer. No new gamma rays have been observed in the decay of the (7.1 ± 0.2) hour activity. The (42 ± 3) min activity shows a position group of (1.72 ± 0.10) MeV and the three gamma rays of 88, 251 and 580 keV and possibly one of 1080 keV. The relative position of the two isomers cannot be deduced from the results of these measurements; no isomeric transition has been identified with certainty. If an isomeric transition occurs, it might be associated with the gamma ray of 88 keV which then should be of M3 or E3 character, but this interpretation is not very attractive in view of shell model predictions for 73Se.