Observation of high spin levels in 131Cs from 131Ba decay

[摘要] The 𝛾- and conversion electron spectra following 131Ba 𝜖-decay are investigated, using HPGe detector and mini-orange electron spectrometer. Attention is particularly focussed on identifying weak transitions associated with low energy high spin levels in 131Cs level scheme earlier inferred in reaction studies but not yet observed in 131Ba decay. Our experiment identifies 15 new gammas and 6 new conversion lines in this decay. Internal conversion coefficients and multipolarities of several transitions are determined. Five new levels (3 with 𝐼𝜋=7/2+ and one each with 𝐼𝜋=9/2+ and 11/2-) are introduced in the 131Cs level scheme based on our observations taken together with the results from reaction studies. Spin-parity assignments to a few other levels are also suggested.

[学科分类] 物理（综合）

[关键词] Radioactivity;131Ba beta decay;𝛾 and ce measured HPGe;miniorange;internal conversion coefficient;multipolarities;131Cs level scheme.