【作者】 柳敏良； 张玉虎； 周小红； 郭应祥； 刘忠； 雷相国； 何建军； 郑勇； 竺礼华； 温书贤；

【Author】 LIU Min-Liang ZHANG Yu-Hu ZHOU Xiao-Hong GUO Ying-Xiang Liu Zhong LEI Xiang-Guo HE Jian-Jun ZHENG Yong (Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 730000, China)ZHU Li-Hua WEN Shu-Xian (China Institute of Atomic Energy, Beijing 102413, China)

【机构】 中国科学院近代物理研究所； 中国原子能科学研究院；

【摘要】 利用能量为75-95 MeV19F束流,通过反应128Te(19F,5n)142Pm研究了双奇核142Pm的高自旋态能级结构。实验中进行了射线激发函数和γ-γ符合测量。建立了142Pm核高自旋态能级纲图,位于前人建议的一个2毫秒、8-同质异能态之上。由测量的γ射线激发函数和γ-γ符合关系,澄清了一个67微秒同质异能态及其衰变混乱的指定,本论文把67微秒同质异能态及其衰变指定给了142Pm,建议此同质异能态的激发能为2828.5 keV,推断此同质异能态的自旋宇称为13-。根据能级结构的系统性,识别了四个两准粒子态,一个为g7/2质子空穴耦合h11/2中子空穴激发,另外三个质子h11/2耦合h11/2中子空穴多重态成员。根据经验壳模型计算建议了几个新建的关键能级的组态。67微秒同质异能态的组态被建议为一个四空穴态(πg7/2-1d5/2-2vh11/2-1)13-。更多还原

【Abstract】 In-beam γ-ray spectroscopy experiment for odd-odd nucleus 142 Pm has been performed via the 128Te(19F, 5n ) 142Pm reaction at beam energies of 75 MeV through 95 MeV. Excitation functions and γ-γcoincidences have been measured. Detailed analysis of γ-γ coincidence relationships leads to a revised high-spin level scheme for 142Pm above the previously known 2 ms 8- isomer. The experimental results clarify a confusion existing in the literature related to anassignment of a 67-μs isomeric state and the associated decay γ rays,which were definitely assigned to 142Pm in this work. The 67-μs isomeric state has been placed at an excitation energy of 2828.5 keV in the level scheme and the spin-parity was deduced to be 13-. During the course of this investigation, someone reported on a level scheme built on the 2-ms isomer via the 133Cs(13C, 4n)142Pm reaction;the present level scheme above the 67-μs isomer is almost consistent with the previous one built up from the 2-ms isomer except for themultipolarity assignments for the corresponding γ radiations. Theπh11/2(?)vh11/2-1 multiplet and the (πg7/2-1vh11/2-1)9- state in this nucleus have been identified and discussed based on systematic of corresponding states in neighboring odd-odd nuclei. Configurations of several levels have been suggested from an empirical shell model approach. The above-mentioned 67-μs isomer is proposed to be a 4-hole state with predominantly the (πg7/2-1d5/2-2vh11/2-1)13- configuration.更多还原