Levels and lifetimes in Pm149 and Sm149

摘要: Abstract An investigation of the decay Nd 149 has been made with scintillation counters and fast coinncidence techniques. Eighteen γ-rays have observed directly, seven them delayed. By delayed gating methods genetical relationships among most established unambiguously definite levels (with mean lives in nsec) are proposed for Pm at 114 (3.64±0.05), 189 (5.0±0.2), 210 (≦ 0.5), 267 (3.72±0.06), 530 0.55), 537 0.7) 652 0.26) keV. The resulting scheme, which includesthree other possible levels, is rather different from that recently by Gopinathan Joshi 9 but still quite consistent their data on β-spectra. In addition to measurements life 286 keV level Sm measured as (2.63±0.10) × 10 −10 sec. transition (both largely M1 probably l forbidden) slower than Weisskopf estimates factors 370 230, respectively, some rates appear be anomalous.