Gamma transitions from the beta- decay of 155Sm

Abstract

The purpose of this work is to investigate the states in 155Eu by beta decay of 155Sm to obtain complementary experimental information to elucidate the population of low energy levels (below 2MeV) in this nucleus. This includes an extensive gamma-ray measurement, using high resolution detectors, with high statistics in the region from 30 keV to 1.5 MeV. According to the last compilation by Firestone [1] basically, the results of two studies [2,3] established the features of the beta (-) decay scheme of 155Sm. Analyzing these works, some controversy, regarding the presence and subsequent placement, of gamma transitions in the level scheme were not solved when the data from beta decay are compared with nuclear reactions studies [1]. Besides a number of gamma transitions must be confirmed and nuclear parameters such as energy , spin and parity of excited levels as well as energy and intensity of gamma transition still need verification. In an attempt to propose a well established decay schema of 155Sm motivated us to perform an investigation of excited levels in 155Eu. The energies of 80 gamma rays have been determined, several for the first time. These results were compared with those published [1] and our gamma-rays energies are given more accurate values.