进一步指认近质子滴线核^(129)Pm的衰变  

Further Identification of the Decay of ^(129) Pm Near the Proton Drip Line 

作　　者：徐树威[1] 谢元祥[1] 许甫荣[2] 李占奎[1] 王旭东[1] 邢烨炳[1] 

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]北京大学技术物理系,北京100087

出　　处：《高能物理与核物理》2005年第3期237-239,共3页High Energy Physics and Nuclear Physics

基　　金：国家自然科学基金 (10 3 75 0 78;10 175 0 0 2 ) ;中国科学院综合计划局 ;国家重点基础研究发展规划项目 (G2 0 0 0 0 7740 2 )资助~~

摘　　要：20 0 4年曾报道过利用4 0 Ca + 92 Mo融合蒸发反应产生了近质子滴线新核素12 9Pm ,并首次观测到它 (EC + β+)衰变产生的能量为 99keV的γ射线 .为了进一步确认上述指认 ,以下提供了三方面的新证据 :1)在 16 4— 190MeV能量范围内测量了 99keV衰变γ射线的激发函数 ;2 )进行了交叉反应36 Ar + 96 Ru的实验 ,观察到了相同的 99keV衰变γ射线 ;3)用Woods SaxonStrutinsky方法计算了12 9Pm的核势能面 ,其基态自旋宇称被预言为 5 / 2 - ,所以12 9Pm的 (EC + β+)衰变有利于馈送到子核12 9Nd的 5 / 2 - 的低位态 ,这也与前期报道相符 .It was reported in our previous paper in 2004 that the unknown isotope 129Pm near the proton drip line was produced via the fusion-evaporation reaction 40Ca + 92Mo, and a 99 keV γ line was assigned to the (EC + β+) decay of 129Pm for the first time. In order to confirm the assignment, following three new evidences are provided in this paper. 1) The excitation function of the 99 keV γ line was made from 164 MeV to 190 MeV of the incident energy. 2) A cross bombardment 36Ar + 96Ru was carried out, from which the same 99 keV y transition was observed. 3) The nuclear potential-energy-surface (PES) of 129Pm was calculated by using the Woods-Saxon Strutinsky method. The ground state spin and parity of 129Pm was then predicted to be 5/2-.. This prediction leads to a 5/2- low-lying state in the daughter nucleus 129Nd via the (EC + β+) decay of 129Pm favorably.

关 键 词：质子滴线 激发函数 交叉反应 Woods-Saxon Strutinsky方法 核势能面 γ射线 

分 类 号：O571[理学—粒子物理与原子核物理]