形变双奇核^(180)Ir的高自旋态实验研究  

Experimental Study of High-Spin States in Deformed Odd-Odd ^(180) Ir

作　　者：张玉虎[1] T.Hayakawa M.Oshima J.Katakura Y.Hatsukawa M.Matsuda H.Kusakari M.Sugawara T.Komatsubara K.Furuno 

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]Japan Atomic Energy Research Institute [3]Chiba University,Inageku [4]Chiba Institute of Technology [5]Institute of Physics and Tandem Accelerator Center,University of Tsukuba

出　　处：《高能物理与核物理》2002年第6期582-588,共7页High Energy Physics and Nuclear Physics

基　　金：国家杰出青年科学基金 (1 0 0 2 5 5 2 5 ) ;国家自然科学基金 (1 960 5 0 0 8) ;日本科学技术厅 (STA)科学家交流项目(1 998- 2 1 ) ;日本学术振兴会invitationfellowship(L0 0 5 1 5 );国家重大基础研究发展规划 (G2 0 0 0 0 7740 0 )资助~~

摘　　要：利用15 4 Sm( 31P ,5nγ) 180 Ir反应产生并研究了双奇核180 Ir的高自旋态 .实验中进行了180 Ir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180 Ir由 5个转动带构成的能级纲图 .依据从实验数据中提取出的带内B(M1 ) /B(E2 )值与理论计算值的比较 ,以及相邻双奇核的带结构特征 ,给出了转动带的准粒子组态 .在推转壳模型的理论框架中 。High spin states in deformed odd odd 180 Ir have been investigated using the 154 Sm ( 31 P, 5nγ) 180 Ir reaction through the measurements of excitation functions at 150, 155, 160, 165 and 170 MeV beam energies, K X γ and γ γ coincidences at 160 MeV. A new level scheme composed of 5 rotational bands has been established. According to the band structure characteristics and the deduced in band B (M1)/ B (E2) ratios, the quasiparticle configurations and spin and parity have been proposed to the observed bands. The neutron AB crossing is observed at ω c≈0.26 MeV for the π1/2 -ν1/2 - and π1/2 -ν5/2 - bands. This AB crossing frequency is close to that in the ν5/2 - band of 179 Os indicating the loss of intruder nature of the π1/2 - orbit. Gradual alignment gain in both the π9/2 -ν7/2 + and π9/2 -? ? 5/2 - bands is observed which is similar to the low spin anomaly in alignment in the π h 11/2 ,π d 5/2 and π i 13/2 bands of neighboring Ir and Re isotopes. Different alignment properties have been discussed in the framework of cranked shell model, and a larger quadrupole deformation is suggested for the bands with π9/2 - orbit involved.

关 键 词：高自旋态 实验研究 在束Γ谱学 形变双奇核^180Ir 转动带 准粒子顺排 铱180 原子核 

分 类 号：O571.2[理学—粒子物理与原子核物理]