25Mg(p,γ)26Al反应58 keV共振的间接测量

25Mg(p,γ)26Al is one of the key reactions for Mg-Al cycle in explosive hydrogen burning of stars. Its cross sections at star energies are essential to understand the problem of 26Al and 26Mg abundances. It is very difficult to direct measure the 58 keV resonance in 25Mg(p,γ)26Al reaction, and the indirect measurement results deviate by a factor of about 2 up to now. In order to clarify this discrepancy, an independent indirect measurement is highly needed. We plan to precisely measure the angular distribution of 25Mg(α, t)26Al*6.364 reaction with the Q3D magnetic spectrometer of the HI-13 tandem accelerator, and derive the proton spectroscopic factor of 26Al*6.364, and then the proton width and resonance strength for the corresponding 58 keV resonance. Finally the astrophysical S factors and reaction rates can be extracted.

25Mg(p,γ)26Al反应是恒星爆发性氢燃烧镁铝循环中的关键反应，精确测量其在恒星能量的反应截面是解决26Al、26Mg等核素超丰疑难问题的关键。由于该反应的58 keV共振难以直接测量，而且目前间接测量结果的分歧将近两倍，很有必要采用一个可靠的新实验方案对该共振进行独立的间接测量。我们计划在串列加速器Q3D 磁谱仪上精确测量25Mg(α, t)26Al反应布居对应58keV共振的6.364 MeV激发态的角分布，并提取质子谱因子，进而计算出该共振的质子宽度与共振强度，并结合已有其它共振的实验数据导出更可靠的恒星能量下25Mg(p,γ)26Al天体物理S 因子和反应率。本实验的束流申请已获得串列加速器束流评审委员会的批准。

25Mg(p, γ)26Al反应是恒星爆发性氢燃烧镁铝循环中的关键反应，精确测量其在恒星能量的反应截面是解决26Al、26Mg等核素超丰疑难问题的关键。由于该反应的58 keV共振难以直接测量，而且目前间接测量结果的分歧将近两倍，很有必要采用一个可靠的新实验方案对该共振进行独立的间接测量。我们在串列加速器Q3D 磁谱仪上精确测量了25Mg(7Li, 6He)26Al反应布居对应58keV共振的6.364 MeV激发态的角分布，同时测得了布居基态和前10个激发态的角分布，通过DWBA计算提取了质子谱因子，计算出该共振的质子宽度与共振强度，并结合已有其它共振的实验数据更新了恒星能量下25Mg(p,γ)26Al天体物理反应率。