基于HIRFL-CSR的原子核质量测量实验进展  

The progress of nuclear mass measurement experiments based on HIRFL-CSR

作　　者：王猛[1,2] 张玉虎 焦红扬[1,2] Meng Wang;Yuhu Zhang;Hongyang Jiao(Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730030,China;School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院近代物理研究所,兰州730030 [2]中国科学院大学核科学与技术学院,北京100049

出　　处：《科学通报》2021年第27期3517-3526,共10页Chinese Science Bulletin

基　　金：国家重点研发计划(2018YFA0404401)资助。

摘　　要：质量是原子核最基本的性质之一,核质量数据被广泛应用于核结构及核天体物理等多个研究领域.短寿命原子核质量的高精度测量是核物理研究的前沿课题.基于兰州重离子加速器装置HIRFL-CSR(cooler storage ring of heavy ion research facility in Lanzhou),我们建设了先进的等时性质谱术,精确测量了一批短寿命原子核的质量,研究了核结构及核天体物理中的前沿科学问题.本文介绍了国际研究现状,回顾了冷却储存实验环(experimental cooler storage ring,CSRe)质量测量发展过程,综述了近期取得的一些代表性成果,并对未来工作进行了展望.As one of the most fundamental properties of nuclei,nuclear mass data are widely used in many research fields such as nuclear structure and nuclear astrophysics.At present,mass measurement of short-lived nuclei is an important research topic in nuclear physics.However,due to their small production rates and short lifetimes,it is technically challenging to measure their masses accurately.Isochronous mass spectrometry(IMS)based on the storage ring is an effective technique for measuring masses of short-lived nuclei.We established the IMS at the experimental cooler-storage ring(CSRe)in Lanzhou and developed the techniques continuously,achieving the highest precision of IMS measurement in the world.Since 2009,10 isochronous mass measurement experiments have been conducted and high-precision mass data were obtained.In the earlier researches,we focused on mass measurements for medium-mass neutron-deficient nuclei.Recently,we have extended the research to heavier and neutron-rich regions.The masses of82 Zr and84 Nb were measured for the first time,and the masses of79 Y,81 Zr,and83 Nb were re-determined with a higher precision.The results do not support the existence of the hypothetical island of pronounced lowαseparation energies for neutron-deficient Mo and Tc isotopes,making the formation of Zr-Nb cycle in the rp-process unlikely.The results also partly remove the overproduction of the pnucleus84 Sr in theνp-process simulations.The masses of the neutron-rich52–54 Sc and54,56 Ti nuclei were measured.The empirical shell gap extracted from the experimental results shows a significant subshell closure at N=32 in scandium.Combined with the theoretical calculations,it turns out that the Sc isotopes are located in the transition region of the shell evolution.Exploiting the high mass resolution of the IMS at CSRe,we also studied the nuclear isomeric states.Masses of52 g,52 mCo were measured for the first time with an accuracy of~10 ke V.Combining the results with the previousβ-γmeasurements of52 Ni,the T=2,Jπ=0+isobari

关 键 词：原子核质量 短寿命核素 等时性质谱术 壳演化 同核异能态 

分 类 号：O571[理学—粒子物理与原子核物理]