摘要
The ^(25)Mg(p,γ)^(26)Al reaction plays an important role in the study of cosmic 1.809 MeV γ-ray as a signature of ongoing nucleosynthesis in the Galaxy.At astrophysical temperature around 0.1 GK,the ^(25)Mg(p,γ)^(26)Al reaction rates are dominated by the 92 keV resonance capture process.We report a precise measurement of the 92 keV ^(25)Mg(p,γ)^(26)Al resonance in the day-one experiment at Jinping Underground Nuclear Astrophysics experiment(JUNA)facility in the China Jinping Underground Laboratory(CJPL).The resonance strength and ground state feeding factor are determined to be 3.8±0.3×10^(-10) eV and 0:660:04,respectively.The results are in agreement with those reported in the previous direct underground measurement within uncertainty,but with significantly reduced uncertainties.Consequently,we recommend new ^(25)Mg(p,γ)^(26)Al reaction rates which are by a factor of 2.4 larger than those adopted in REACLIB database at the temperature around 0.1 GK.The new results indicate higher production rates of ^(26g)Al and the cosmic 1.809 MeV γ-ray.The implication of the new rates for the understanding of other astrophysical situations is also discussed.
银河系星际介质中的^(26)Al衰变发射的1.809 MeVγ射线是γ天文学的主要观测对象之一,是银河系中正在进行核合成的关键证据,也为核合成理论与天文观测进行比较提供一个重要基准.在大质量恒星氢燃烧中,^(26)Al主要通过^(25)Mg(p,γ)^(26)Al反应产生,因此该反应在1.809 MeVγ射线研究中起着重要的作用.在天体环境温度为0.1 GK左右时,^(25)Mg(p,γ)^(26)Al天体物理反应率主要由92 keV共振俘获过程决定.作为在中国锦屏地下实验室(CJPL)中锦屏核天体物理实验(JUNA)装置上进行的首个实验,本工作对^(25)Mg(p,γ)^(26)Al反应的92 keV共振进行了精确的实验测量,得到了该共振的共振强度为ωγ=(3.80.3)10^(-10) eV,基态分支比为f0=0.660.04.与之前的工作相比,本工作大大提高了92 keV共振数据的精度.基于测量的92 keV共振参数和以前的间接测量结果,得到了精度最高的^(25)Mg(p,γ)^(26)Al天体物理反应率.结果表明,在0.1 GK左右时,新的反应率比REACLIB数据库中采用的反应率大2.4倍,这将导致^(26)Al和宇宙1.809 MeVγ射线的产额提高.同时,新反应率也将对理解太阳系的形成、球状星团的元素丰度反相关等问题提供重要的数据支撑.
作者
Jun Su
Hao Zhang
Zhihong Li
Paolo Ventura
Yunju Li
Ertao Li
Chen Chen
Yangping Shen
Gang Lian
Bing Guo
Xinyue Li
Liyong Zhang
Jianjun He
Yaode Sheng
Yinji Chen
Luohuan Wang
Long Zhang
Fuqiang Cao
Wei Nan
Weike Nan
Gexing Li
Na Song
Baoqun Cui
Lihua Chen
Ruigang Ma
Zhicheng Zhang
Taoyu Jiao
Bingshui Gao
Xiaodong Tang
Qi Wu
Jiaqing Li
Liangting Sun
Shuo Wang
Shengquan Yan
Junhui Liao
Youbao Wang
Sheng Zeng
Ding Nan
Qiwen Fan
Ningchun Qi
Wenliang Sun
Xuyuan Guo
Peng Zhang
Yunhua Chen
Yong Zhou
Jifang Zhou
Jinrong He
Changsong Shang
Mingchuan Li
Jianping Cheng
Weiping Liu
JUNA Collaboration
苏俊;张昊;李志宏;Paolo Ventura;李云居;李二涛;陈晨;谌阳平;连钢;郭冰;李鑫悦;张立勇;何建军;盛耀德;陈银吉;王泺欢;张龙;曹富强;南巍;南威克;李歌星;宋娜;崔保群;陈立华;马瑞刚;张智程;焦韬瑜;高丙水;唐晓东;吴启;李家庆;孙良亭;王硕;颜胜权;廖俊辉;王友宝;曾晟;南丁;樊启文;祁宁春;孙文良;郭绪元;张鹏;陈云华;周永;周济芳;何金荣;商长松;李名川;程建平;柳卫平;锦屏深地核天体物理合作组(China Institute of Atomic Energy,P.O.Box 275(10),Beijing 102413,China;Key Laboratory of Beam Technology of Ministry of Education,College of Nuclear Science and Technology,Beijing Normal University,Beijing 100875,China;School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Beijing 101408,China;INAF,Osservatorio Astronomico di Roma,Via Frascati 33,Monte Porzio Catone(RM)00077,Italy;College of Physics and Optoelectronic Engineering,Shenzhen University,Shenzhen 518060,China;Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China;Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment,Institute of Space Sciences,Shandong University,Weihai 264209,China;Yalong River Hydropower Development Company,Chengdu 610051,China;不详)
基金
supported by the National Natural Science Foundation of China(1149056312125509U18672111196114100311775133and 12175152)
the Continuous Basic Scientific Research Project No.WDJC-2019-13
the Equipment Research and Development Project of Chinese Academy of Sciences(28Y531040)
research fund of CNNC。
