缺中子核99,101Pd的带终结特性研究

项目名称： 缺中子核99,101Pd的带终结特性研究

项目编号： No.10805058

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 郑勇

作者单位： 中国科学院近代物理研究所

项目金额： 22万元

中文摘要： 在本申请的支持下，将研究缺中子核99Pd和101Pd的高自旋态能级结构，重点研究这些核的带终结特性。基于重离子诱发的熔合蒸发反应，利用标准的在束核谱学实验技术建立研究目标核的转动带结构，在这些转动带中寻找可能出现的带终结现象。同时与理论核物理学家合作，确定所发现的带终结结构的单粒子组态成分，并且研究这些带终结结构的组态相关性，例如：不同转动带全顺排角动量的不同，带终结能损的差别，以及从低自旋的集体转动向高自旋的非集体准粒子终结态演化细节的不同等，并分析造成这些不同性的内在物理原因。系统性地研究随中子数的减少Pd同位素链的晕带终结结构的组态变化及形状演变规律。

中文关键词： 过渡核；高自旋态；形变；HPGe探测器

英文摘要： With the support of this research project, we have concentrated on the high-spin level structure of transitional nucleus 101Pd using standard in-beam spectroscopic techniques, and we have also studied the band structures of other deformed neutron-deficient nuclei. Based on the joint in-beam gamma experimental terminal maintained by the Institute of Modern Physics and China Institute of Atomic Energy, and the experimental apparatus at the Japan Atomic Energy Agency(JAEA), the high-spin level schemes of 189Pt, 165Er and 101Pd have been established or greatly revised. The property of the 101Pd's ground-state band which is built on the d5/2 neutron orbital has been studied, the E-GOS curve for this band strongly suggests a structure transition from vibration to rotation while increasing spin. Two dI=2 transition sequences with similar energies in 157Yb have been observed for the first time, and this structure could be interpreted as a pair of pseudospin partners. The level energies in the pseudospin partner bands are well reproduced by the theoretical calculations of the triaxial particle-rotor model if a near-oblate shape is assumed. Electric-dipole transitions linking the 5/2-[523]band and the 5/2+[642] band in 165Er were observed. Relatively large B(E1) values have been extracted experimentally and were attributed to octupole softness. We also performed the gamma-imaging exepriemnt with the array of segmented planar clover-HPGe detectors to test the position sensitivity of this new type of gamma detector. Experimental results suggested a good position resolution for this detector which is 1.28mm at the depth of the detector crystal. All of these results were published in the well-circulated journals.

英文关键词： transitional nuclei; high-spin state; deformed; HPGe detector