^(139)Pm高自旋态的实验研究

Experimental observation of high spin states in ^(139)Pm nucleus

通过重离子核反应116Cd(27Al,4n)与在束γ谱的实验技术,对A=130~140核区的奇A核139Pm的高自旋态进行了研究.根据γ-γ符合关系、γ射线的相对强度和各向异性度的测量结果,扩展并更新了139Pm的能级纲图.实验观测到基于πh11/2和πg7/2-[πh11/2]2(或者πd5/2-[πh11/2]2)组态的转动带,利用已有的理论计算结果对这些转动带进行了解释.同时还观测到三个具有很强M1跃迁、旋称劈裂很小的-I=1的带.通过简单分析和系统学比较,指认了它们的组态,发现它们具备磁转动带的特性,很可能是磁转动带.

High spin states in ^139Pm nucleus have been studied using in-beam γ-ray spectroscopy technique.The nuclear reaction used is ^116Cd（^27Al,4n） with a beam energy 120 MeV.The level scheme has been updated based on γ-γ coincidence relationships,relative intensities and DCO ratios.Collective bands built on the πh11/2 and πg7/2 [πh11/2]^2 or πd5/2 [πh11/2]^2 configurations were observed and discussed according to the existing knowledge in A=130–140 mass region.In addition,three △I=1 bands with strong M1 transitions and very small signature splitting have been observed.From systematic comparison of the related bands in neighboring nuclei,configuration assignments have been made and a magnetic rotation nature has been proposed for them.