锦屏深地核天体物理实验(JUNA)地面实验进展

Progress of the Ground Experiments of Jinping Underground Nuclear Astrophysics Experiment

锦屏深地核天体物理(JUNA)实验项目将利用中国锦屏深地实验室(CJPL)的良好条件,在天体物理伽莫夫能量窗口开展核天体关键反应^(25)Mg(p,γ)^(26)Al、^(19)F(p,α)^(16)O、^(13)C(α,n)^(16)O和^(12)C(α,γ)^(16)O的直接测量,为理解恒星演化和元素起源提供新的数据。目前,已经在地面上对加速器装置、束流稳定性、靶、探测器以及电子学进行了系统的测试。地面实验内容包括高纯锗探测器效率刻度,^(25)Mg(p,γ)^(26)Al在304 keV的共振强度测量,^(19)F(p,δ)^(16)O的截面测量,聚乙烯作为慢化体的中子探测器的设计、加工和效率刻度,靶的设计和稳定性检测等。JUNA项目整体进展顺利,地面实验已取得一系列关键进展和初步成果。在不远的将来,JUNA项目将有序开展地下实验,完成设定目标,也将促进更广泛的国际合作,助力于天体演化中的若干重大科学问题的解决。

A number of nuclear reactions such as^(25)Mg(p,γ)^(26)Al,^(13)C(α,n)^(16)O,^(12)C(α,β)^(16)O and ^(19 )F(p,α)^(16)O will be measured directly down to the Gamow window energy range in Jinping Underground Nuclear Astrophysics(JUNA)Experiment,taking the advantage of the ultra-low background in China Jinping Unerground Laboratory(CJPL).The measurements can provide updated data for understanding the evolution of stars and the origin of elements.Up to now,tests of accelerator,beam,targets,detectors,and electronics have been performed systematically on the ground.The high-purity germanium detectors efficiency calibration,304 keV resonance strengths measurement in^(25)Mg(p,γ)^(26)Al,^(19) F(p,α)^(16)O cross section measurement,neutron detector design,production and efficiency calibrationas as well as target design and stability test are included as overground experiments.The Whole JUNA project is going smoothly in general.A series of key progresses and primary results have been reached on the ground.Underground experiments in the JUNA project will be carried out in order and reach the prospected goals in the near future.Broader international cooperation will also be promoted,supporting the solution of several major scientific problems in the evolution of cosmogony.