Decay of 152Pm to Levels of 152Sm

A spectroscopic study of the decay of 152 Pm to the levels of 152 Sm was performed by using Ge(Li), NaI(Tl) and plastic detectors. The radioactive sources were produced from the (n, p) reaction with 14.8 MeV neutrons on enriched samarium targets. The half-lives of two 152 Pm isomers are 4.30±0.37 and 7.52±0.08 min. One hundred and twenty-nine γ-rays, including 96 new ones, were observed and 108 of them are assigned to the decay schemes for 152 Pm including 22 new levels. An observed Q β value for the 4.30 min 152 Pm was 3.50±0.10 MeV. Most probable spin assignments of 1 + and 4 - are proposed for the 4.30 and 7.52 min 152 Pm, respectively. The results are discussed in terms of the unified model.