丰中子Ru奇A核能级结构的进一步研究

Further Research on Level Structures of Neutron-Rich Odd-A Ru Nuclei

通过对重核2 52 Cf自发裂变产生的瞬发γ谱的高精度测量数据的分析 ,扩展了丰中子奇A核10 9,111Ru的高自旋态 ,对不同延迟符合矩阵的数据分析 ,得到了10 7,10 9,111,113Ru低激发态多个能级的寿命 ,发现10 9Ru核中的 96 .4keV的能级为一寿命约为 130 0ns的同质异能态 .对10 9,111Ru转动带的转动惯量随转动频率变化的分析表明 ,在相邻偶偶核110 Ru中观测到的集体回弯现象确实起源于一对h11/ 2 中子的角动量顺排 .用粒子 转子模型对10 7,10 9,111,113Ru的集体带的部分能级及跃迁几率进行了计算 ,得到与实验较为满意的符合 ,指出在这几个核中的中子h11/ 2 闯入带尼尔逊轨道的起源 .

Through analyzing the data with high statistics from measuring high-fold prompt γ-ray coincidence events following the spontaneous fission of 252Cf with the Gammasphere detector array, the level schemes in neutron-rich odd-A109,111Ru nuclei have been extended up to higher spin states. Based on the data analysis of the coincidence matrices with different delay times, the life times for many low excited levels have been obtained in 107,109,111,113Ru nuclei, among them, the 96.4 keV level in 109Ru is an isomer with life time value 1300 ns. It is shows that the observed backbending in the yrast band of the neighboring even-even Ru is indeed originated from the alignment of a pair of neutrons through analyzing the moments of inertia J(1)vs. rotational frequencies Plank constant/2πω of the observed collective bands in 107, 109Ru nuclei. Triaxial rotor plus particle model has been employed to calculate some levels of the collective bands as well as the B(M1)/B(E2) values. The calculated results basically accord with the experimental ones.