习近平深地核天体物理实验 JUNA 的首个成果：92keV 镁（p，γ）铝共振的精确测量。

First result from the Jinping Underground Nuclear Astrophysics experiment JUNA: precise measurement of the 92 keV Mg(p, γ)Al resonance.

机构信息

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.

China Institute of Atomic Energy, P. O. Box 275(10), Beijing 102413, China; School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 101408, China.

出版信息

Sci Bull (Beijing). 2022 Jan 30;67(2):125-132. doi: 10.1016/j.scib.2021.10.018. Epub 2021 Oct 28.

DOI:10.1016/j.scib.2021.10.018

PMID:36546005

Abstract

The Mg(p, γ)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 Mg(p, γ)Al reaction rates are dominated by the 92 keV resonance capture process. We report a precise measurement of the 92 keV Mg(p, γ)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 eV and 0.66±0.04, 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 Mg(p, γ)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 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.

摘要

镁（p，γ）铝反应在研究宇宙 1.809 MeV γ射线作为星系中持续核合成的特征方面起着重要作用。在天体物理温度约为 0.1 GK 时，镁（p，γ）铝反应速率主要由 92 keV 共振俘获过程主导。我们报告了在中国锦屏地下实验室（CJPL）的锦屏深地核天体物理实验（JUNA）设施的首日实验中对 92 keV 镁（p，γ）铝共振的精确测量。确定了共振强度和基态喂养因子分别为 3.8±0.3×10 eV 和 0.66±0.04。结果与以前在直接地下测量中报告的结果在不确定度范围内一致，但不确定度显著降低。因此，我们建议在 0.1 GK 左右的温度下，采用新的镁（p，γ）铝反应速率，比 REACLIB 数据库中的速率大 2.4 倍。新结果表明 Al 和宇宙 1.809 MeV γ射线的产生速率更高。还讨论了新速率对理解其他天体物理情况的影响。