^(134)Ba核的高激发态能级结构研究  

Level Structure with High Excitation States in ^(134)Ba

作　　者：车兴来[1] 朱胜江[1] 李明亮[1] 禹英男[1] 陈永静[1] 丁怀博[1] 徐强[1] 竺礼华[2] 吴晓光[2] 李广生[2] 刘颖[2] 贺创业[2] 

机构地区：[1]清华大学物理系,北京100084 [2]中国原子能科学研究院,北京102413

出　　处：《高能物理与核物理》2007年第7期621-624,共4页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金(10375032;10575057);教育部博士点基金(20030003090)资助

摘　　要：在中国原子能科学研究院H-13串列加速器上,通过重离子核反应^(130)Te(~9Be,5n)与在束γ谱的实验技术,对A=130缺中子核区的^(134)Ba核的高自旋态进行了研究,建立了^(134)Ba核的新的能级纲图,最高自旋态扩展到20(?)．除验证了以前报道的大部分能级与跃迁外,将基带的能级扩展到10^+,同时发现了基于10^+同质异能态以上的众多的能级与跃迁．对实验结果的系统学分析表明,10^+同质异能态为yrast陷阱,起源于两中子组态,可能具有γ≈-120°的长椭形状,在其以上的能级表现出很强的单粒子性,具有复杂的结构．基带中观测到明显的集体回弯现象,推转壳模型的计算表明,此集体回弯是由一对中子的顺排所致,TRS计算表明,随着转动频率的增加,核的形状发生明显的变化,基带中在中子顺排后核具有γ≈-60°的扁椭形状．The high spin states in neutron-deficient ^134Ba nucleus have been studied by using heavy ion induced reaction ^130Te（^9Be,5n） and in-beam T-ray spectroscopy carried out at China Institute of Atomic Energy. The level scheme has been updated with spin up to 20h. Most of levels and transitions reported in the previous publications have been confirmed. The levels in the ground state band was expanded to 10^＋ state, and many levels and transitions above the 10^＋ isomer have been identified. Based on the systematical analyzing, the 10^＋ isomer in ^134Ba is a yrast trap of prolate deformation with γ≈ -120° which is originated from two neutron configuration. Above the 10^＋ isomer level, the new levels show strong single-particle motion and complex structural characteristics. The obvious collective back-bending has been observed in the ground state band. The CSM calculations indicate that the back-bending of ^134Ba is caused by alignment of a pair of h11/2 quasi-neutrons. The nuclear shape has obviously changed with rotational frequency increasing according to the TRS calculations, and the nucleus probably has an oblate deformation with γ≈ -60° after the neutron alignment.

关 键 词：核结构 集体回弯 γ-γ 符合测量 同质异能态 

分 类 号：O571.2[理学—粒子物理与原子核物理]