在恒星演化能区对12C(12C,p)23Na反应截面的实验测量以及对恒星碳燃烧天体物理反应率的确定

12C+12C熔合反应，即碳燃烧，在恒星演化中起着关键作用，它对于恒星中的元素核合成过程有着深刻的影响，同时也被普遍认为点燃了Ia型超新星爆发。碳燃烧的伽莫夫窗口能量约为1 MeV≤Ecm≤3 MeV，在此能量区内缺乏足够精确的反应截面测量数据，因此只能依靠理论模型进行拟合再向低能量区做外推计算，而不同理论模型的外推预测值之间也存在着很大的分歧。本项目用伽马谱学方法和带电离子探测相结合，测量12C(12C,p)23Na在天体物理感兴趣能区的反应截面。使用四川大学3MV静电加速器提供的平均约15pμA的强12C束流，配合高纯度的厚碳靶，能够产生足够的反应产额。用伽马射线和带电离子事件做符合的方法，来去除海量的本底干扰。目标是较精确的给出能量为2 MeV≤Ecm≤3 MeV内的12C+12C熔合反应总截面，同时寻找1.8–2.1 MeV内可能存在的强共振结构。

12C+12C fusion reaction in stars, which is known as carbon burning process, is a reaction critical for various astrophysical scenarios, e.g. nucleosynthesis in the interior of massive stars. The carbon burning is also considered to be responsible for igniting the explosions in type Ia supernovae. The Gamow window spans 1 MeV≤Ecm≤3 MeV. There remain large uncertainties in the predicted results that rely primarily on the extrapolation of the data, due to the lack of reliable experimental data. Present work proposes using gamma spectra method and charged particle detection technique to measure the cross sections of 12C(12C, p)23Na at stellar energies. Using high-purity graphite target and high-current 12C beam, which is averagely about 15 pμA and produced by the 3 MV tandetron accelerator in Sichuan University, sufficient reaction yield could be achieved. The massive background can be eliminated by applying particle-gamma coincidence method. The aim is providing accurate cross sections of 12C+12C fusion reaction at energies 2 MeV≤Ecm≤3 MeV, and searching for strong resonances around 1.8 MeV≤Ecm≤2.1 MeV.