摘要
利用152Sm(31P,5nγ)178Ir反应产生并研究了双奇核178Ir的高自旋态.实验中进行了178Ir核的在束 γ测量,包括γ射线的激发函数测量、X-γ和γ-γ符合测量.首次建立了双奇核178Ir基于πh9/2νi13/2和πh11/2νi13/2准粒子组态上的转动带能级纲图.发现在低自旋区,两个转动带能级均出现旋称反转.对此核区半退耦带的旋称反转作了简要的分析和讨论.
High-spin states in 178Ir have been produced and studied via the 152Sm(30p,5nγ) 178 Ir reaction. In-beam γ rays were measured including the excitation functions at 150 , 155, 160, 165 and 170 MeV beam energies,K X-γ and γ-γ coincidences at 160 MeV. According to the band structure characteristics and the deduced intra-band B (M1)/B (E2) ratios, two rotational bands are identified for the first time and assigned to be associated with the πh9/2νi13/2 and the πh11/2νi13/2 quasiparticle configurations respectively. Low-spin signature inversion in bob bands has been confirmed hased on the observation of signature crossing at Ic = 21 h for the πh9/2νi13/2, semidecoupled band and at Ic = 16 h for the πh11/2νi13/2 strongly coupled band, respectively. Systematics of the signature inversion has been discussed for the semidecoupled bands in the A= 160-180 mass region and some regularities are proposed concerning the crossing spins with variation of mass. The signature splitting in the πh11/2νi13/2 band of 178Ir is smaller than that in the similar band of 176Re; this trend is opposite to the predictions based on the projected shell model.
出处
《高能物理与核物理》
EI
CSCD
北大核心
2000年第12期1123-1130,共8页
High Energy Physics and Nuclear Physics
基金
国家自然科学基金(19605008)
国家重点基础研究发展规划(G2000077400)
日本STA科学家交流项目(1998-21)支持
关键词
在束Γ谱学
形变双奇核
转动带
旋称反转
in-beam γ-ray spectroscopy,deformed odd-odd nucleus, rotational band, signature invers?