^(22)Ne(α,n)^(25)Mg反应:大质量恒星中的关键中子源  

^(22)Ne(α,n)^(25)Mg:The key neutron source in massive stars

作　　者：南巍 郭冰[1] 谌阳平 李志宏[1] 柳卫平[1] Wei Nan;Bing Guo;Yangping Shen;Zhihong Li;Weiping Liu(China Instituteof Atomic Energy,Bejing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《科学通报》2022年第28期3357-3366,共10页Chinese Science Bulletin

基　　金：国家杰出青年科学基金(12125509);国家自然科学基金重点国际合作项目(11961141003)资助。

摘　　要：宇宙从铁到铀的超铁元素起源是核天体物理领域一个重要的前沿方向,被认为是21世纪“物理学的11个未解之谜”之一,有望孕育出重大科学发现中子俘获反应可以克服库仑势垒,是生成宇宙中超铁元素的关键途径.自由中子的平均寿命只有约15min,因此,中子的来源对理解超铁元素起源是一个热点课题.本文评述了超铁元素起源、大质量恒星中的关键中子源^(22)Ne(α,n)^(25)Mg反应的研究意义、中子源最新研究进展和未来研究计划,特别是深地直接测量实验计划.The origin of heavy elements from iron to uranium in the universe is an important frontier direction for nuclear astrophysics.It is considered to be one of the 11 greatest unanswered questions of physics in this century.The neutron capture reaction can overcome the Coulomb barrier and is the key way to generate heavy elements in the universe.The average life of free neutrons is only about 15 min.Therefore,the neutron source is a hot topic for understanding the origin of heavy elements.There are two main neutron sources in the s-process nucleosynthesis,one is the^13C(α,n)^16O reaction,the other is the^(22)Ne(α,n)^(25)Mg reaction.The^13C(α,n)^16O reaction mainly provides neutrons for the s-process nucleosynthesis of small or medium mass stars,and affects the nucleosynthesis of nuclides with the mass numbers from 90 to 209;while the^(22)Ne(α,n)^(25)Mg reaction mainly provides neutrons for the s-process nucleosynthesis of massive stars and affects the nucleosynthesis of nuclides with the mass number less than 90.The 2Ne(α,n)*"Mg reaction takes place in the core helium burning phase and the subsequent shell carbon burning phase of massive stars.Due to the difficulty of experiment measurement,the data of the 2Ne(a,n)*"Mg reaction rate is stil lacking,which leads to the problem of understanding effective neutron supply in the nucleosynthesis of the heavy elements in massive stars.Limited by cosmic ray backgrounds,a large number of key reactions in hydrostatic nuclear burning phases cannot be accurately measured.Therefore,direct measurement of these reactions has gradually moved from the earth-surface to underground laboratories.The Laboratory for Underground Nuclear Astrophysics(LUNA)experimental platform in Italy is a mature underground nuclear astrophysics laboratory in the world.Since the 199os,direct measurement of many nuclear reactions has been carried out.Jinping Underground Nuclear Astrophysics Laboratory(JUNA)is a new experimental platform.JUNA is located in the world's deepest underground laboratory-China

关 键 词：核天体物理 超铁元素起源 S-过程 中子源 深地实验 

分 类 号：P152[天文地球—天文学]