sd壳N=Z-1丰质子核中能库仑激发研究

项目名称： sd壳N=Z-1丰质子核中能库仑激发研究

项目编号： No.11205207

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学II

项目作者： 强赟华

作者单位： 中国科学院近代物理研究所

项目金额： 30万元

中文摘要： 本课题拟在兰州重离子加速器上开展sd壳丰质子奇A核27Si、31S和35Ar的中能库仑激发实验研究。目标核由36Ar弹核碎裂反应产生，利用兰州放射性束流线分离。次级束经过与厚的次级靶Au 或Pb 库仑和核相互作用激发到激发态。探测散射角小于5度的激发产物及其退激γ射线。由效率修正后的γ计数获得小角度库仑激发截面，并与理论计算结果比较提取电磁约化跃迁几率。从电磁跃迁几率推断原子核形变信息，同时结合镜像核已有数据提取基态到第一激发态的质子和中子跃迁矩阵元之比。在sd壳区，N=Z-1核靠近稳定线，蕴含丰富的核结构信息。研究这些核的中能库仑激发，对探索核态的动力学性质，分析原子核形变的微观机制，以及丰富这一核区核结构信息有重要意义。

中文关键词： 中能库仑激发；放射性束；γ 探测阵列；γ射线本底；激发态寿命

英文摘要： The intermediate-energy Coulomb excitation experiments of the sd shell proton-rich nuclei 27Si,31S,and 35Ar will be performed at the Heavy Ion Research Facility in Lanzhou(HIRFL).The second beams will be produced via 36Ar fragmentation reaction,and　separated by using the Radioactive Ion Beam Line in Lanzhou(RIBLL).By the Coulomb and nuclear interactions between the fragments and thick second Au or Pb target, the fragments will be excited.Only the scattering products in the scattering angle less than 5 degree and its de-exciting γ rays will be detected.The small angle Coulomb excitation cross section can be extracted from the counts of γ rays after the efficiency correction. Comparing the expermental results with the theory calculations, we can obtain the electromagnetic reduced transition probabilities and then deduce the nuclear deformation,and extracted the rates of the proton and neutron matrix element combining with the known data in the corresponding mirror nuclei. The sd shell N=Z-1 nuclei located near the stability line could provide rich information of the nuclear structure.Therefore,the study of the intermediate-energy Coulomb excitations in these nuclei is important for analyzing the micromechanism ofthe nuclear deformation and investigating the dynamical properties of the nuclear states as well as ac

英文关键词： intermediate-energy coulomb excitation；Radioactive Ion Beam；γ detector arrays；γ-ray background；lifetime of the excited state