在低温核天体物理环境下,如静态核稳定燃烧阶段的核反应都发生较低的能区,其伽莫夫窗口内的核反应截面非常小,这就需要加速器提供较强束流才能完成核反应截面的直接测量。最近在中国科学院近代物理的320 k V高压平台上建立了低能核天体...在低温核天体物理环境下,如静态核稳定燃烧阶段的核反应都发生较低的能区,其伽莫夫窗口内的核反应截面非常小,这就需要加速器提供较强束流才能完成核反应截面的直接测量。最近在中国科学院近代物理的320 k V高压平台上建立了低能核天体物理实验室以及相应的研究平台。驱动该平台的是一个14.5 GHz的永磁铁型ECR离子源,它能够提供非常强的束流离子。对于质子和氦离子,离子源出口的最大流强可以达到100 eμA,在实验终端上可以获得大约30 eμA的流强。基于此强流加速器装置,我们建立了核天体物理实验测量装置,包括靶室以及带电粒子和伽玛射线探测器等设备。利用已知的核反应对探测器性能和实验方法进行了一系列测试。同时,展示了近年来取得的一些主要实验结果。最后,对该平台上开展工作的前景进行了展望,并指出基于该地面装置的低能核反应研究所积累的技术及经验对于我国锦屏深地核天体物理JUNA项目的重要意义。展开更多
The asymptotic normalization coefficients （ANCs） of the virtual decay 16N -- 15N ＋ n are extracted from the 15N（7Li, 6Li）16N reaction populating the ground and first three excited states in 16N. The root-mean-squ...The asymptotic normalization coefficients （ANCs） of the virtual decay 16N -- 15N ＋ n are extracted from the 15N（7Li, 6Li）16N reaction populating the ground and first three excited states in 16N. The root-mean-square （rms） radii of the valence neutron in these four low-lying 16N states are then derived by using the ANCs. The probabilities of the valence neutron staying out of the core potentials are found to be 31%± 8%, 58%± 12%, 3270 ± 8%, and 60% ± 12%. The present results support the conclusion that a one-neutron halo may be formed in the 16N first and third excited states, while the ground and second excited states do not have a one-neutron halo structure. However, the core excitation effect has a strong influence on the one-neutron halo structure of the ground and first excited states in 16N.展开更多
基金Supported by National Natural Science Foundation of China(11505117,11490560,11475264,11321064,11375269)Natural Science Foundation of Guangdong Province(2015A030310012)+1 种基金973 program of China(2013CB834406)National key Research and Development Province(2016YFA0400502)
文摘The asymptotic normalization coefficients （ANCs） of the virtual decay 16N -- 15N ＋ n are extracted from the 15N（7Li, 6Li）16N reaction populating the ground and first three excited states in 16N. The root-mean-square （rms） radii of the valence neutron in these four low-lying 16N states are then derived by using the ANCs. The probabilities of the valence neutron staying out of the core potentials are found to be 31%± 8%, 58%± 12%, 3270 ± 8%, and 60% ± 12%. The present results support the conclusion that a one-neutron halo may be formed in the 16N first and third excited states, while the ground and second excited states do not have a one-neutron halo structure. However, the core excitation effect has a strong influence on the one-neutron halo structure of the ground and first excited states in 16N.
