原子核质量的高精度测量

Precise mass measurement of nuclides

原子核的质量直接反映了核内强相互作用、电磁相互作用和弱相互作用的结果.文章简要阐述了原子核质量测量的意义、现状和主要方法,介绍了基于兰州重离子冷却储存环的原子核质量测量实验,比较了首次得到的63Ge,65As,67Se和71Kr核质量测量值与理论计算结果,探讨了65As质量对天体物理快质子俘获过程的影响,文章最后给出了今后的研究内容.中国科学院近代物理研究所在轻质量丰中子区,系统测量了从Ne到Ca核素的质量,研究了N=20和28幻数随中子数和质子数变化的演化;在丰质子区,精确测量了快质子俘获路径上关键核素的质量,为解释X射线暴等爆发性天体过程提供重要的质量数据;在中重丰中子区,系统地测量丰中子核质量,通过天体网络计算模拟超新星爆发中的快中子俘获过程.

The mass of atomic nuclides reflects directly the sum effect of the strong, weak and electro- magnetic interactions among the participating nucleons. A brief description of the importance, history and current status of nuclear mass measurements is given. With the recent commissioning of a cooler storage ring at the Heavy Ion Research Facility in Lanzhou, the masses of ^63Ge, ^65As, ^67Se and ^71Kr have been measured for the first time. The values have been compared with the theoretical predictions, and the implication of the ^65As mass in the astrophysical rapid proton capture process has been addressed. Future research plans are presented. In the light mass region, precise mass measurements of the neutron-rich isotopes from Ne to Ca will be carried out, and the evolution of the N=20 and 28 shell closures studied while changing the neutron or proton numbers. In the proton-rich mass region, measurements will focus on the nuclei located in the path of the rapid proton capture process in stellar nucleosynthesis, and this can improve our understanding of explosive astrophysical phenomena, such as Type I X-ray bursts. In the medium-heavy neutron-rich mass region, systematic mass measurements will be performed, and the experimental data willserve as important input in the theoretical simulation of the rapid neutron capture process in the explosion of supernova.