缺中子核素101In低位同核异能态的首次观测  

First Observation of the Low-lying Isomer State of ^(101)In

作　　者：刘君豪 张玉虎[1] 邢元明[1] 徐星[1] 帅鹏[1] 王猛[1] 涂小林[1] 张鹏[1,2] 曾奇 陈瑞九 陈相成 付超义 李宏福 孙铭泽 颜鑫亮 高丙水[1] 杨建成[1] 原有进[1] Yu.A.Litvinov[4] K.Blaum S.Naimi 周小红 徐瑚珊[1] LIU Junhao;ZHANG Yuhu;XING Yuanming;XU Xing;SHUAI Peng;WANG Meng;TU Xiaolin;ZHANG Peng;ZENG Qi;CHEN Ruijiu;CHEN Xiangcheng;FU Chaoyi;LI Hongfu;SUN Mingze;YAN Xinliang;GAO Bingshui;YANG Jiancheng;YUAN Youjin;Yu.A.Litvinov;K.Blaum;S.Naimi;ZHOU Xiaohong;XU Hushan(Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China;University of Science and Technology of China,Hefei 230026,China;GSI ttelmholtzzentrum fur Schwerionenforschung GmbH,Darmstadt,64291 Germany;Max-Planck-Institut fiir Kernphysik,Saupfercheckweg 1,Heidelberg,69117 Germany;RIKEN Nishina Center,Wako,Saitama 351-0198,Japan)

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]中国科学院大学,北京100049 [3]东华理工大学,南昌330013 [4]德国GSI重离子研究中心,达姆施塔特64291 [5]德国马克斯普朗克研究所,海德堡69117 [6]日本理化研究所,琦玉351-0198

出　　处：《原子核物理评论》2018年第4期439-444,共6页Nuclear Physics Review

基　　金：国家自然科学基金资助项目(U1232208,U1432125,1160524.8,1160525.2,11605249,11605267);国家重点基础研究发展计划资助项目(2018YFA0404401,2016YFA0400504)欧洲研究理事会资助项目(ERCCG 682841“ASTRUm”).

摘　　要：在兰州重离子加速器冷却储存环(HIRFL-CSR)上,用初级束流112Sn35+轰击了靶厚约10 mm的Be靶,产生了101In的基态和低位同核异能态。这些实验产生的碎片每25 s经过放射性束流线RIBLL2的筛选后注入到实验环CSRe中,利用飞行时间探测器测量离子在CSRe中的回旋周期。在此次实验中,磁场晃动会导致离子在环内的循环周期发生改变,传统的离子鉴别方法难以完成大部分离子的鉴别。通过发展和运用单次注入离子鉴别这一新的离子鉴别方法,有效地消除了磁场晃动对于离子鉴别的影响,并清楚地将101In基态和低位同核异能态鉴别出来,从而首次在实验中观测到101In的低位同核异能态。实验得到的激发能与理论外推值在112 keV的误差范围内一致,其低位同核异能态的寿命大于200μs。Isochronous mass spectrometry has been applied to112 Sn projectile fragments at the HIRFL-CSR facility in Lanzhou. To produce short-lived nuclei of interest, we used projectile fragmentation of112 Sn35+primary beams in a ~10 mm thick9 Be production target. The fragments were selected and analyzed by RIBLL2 and injected into the experimental storage ring(CSRe) every 25 s. To measure revolution times of stored ions,we used a Time-Of-Flight detector installed in CSRe. A new particle identification method was developed to distinguish ions on the measured revolution time spectrum for each injection. Based on this method, the shifts of the revolution time due to instable dipole magnet fields can be corrected and the ground and isomeric states of101 In have been well-resolved. The measured excitation energy is consistent with the theoretical value in the error range of 112 keV. The lifetime of the isomeric states of101 In is more than 200 μs.

关 键 词：HIRFL-CSR 等时性质量谱仪 单次注入离子鉴别 原子核质量测量 

分 类 号：O571.53[理学—粒子物理与原子核物理]