摘要:
15O(
α,γ)
19Ne(p,γ)
20Na反应链是高温CNO循环向快速质子俘获过程突破的一条关键路径,相关的反应率输入量可通过
20Mg的β衰变可布居
19Ne共振态并测量其衰变性质来获得。通过高效率高精度地测量
20Mg β衰变中产生的质子与γ射线得到了
20Mg衰变的详细信息,并构建了完整的衰变纲图,还进行了
19Ne 4 033 keV共振态衰变性质的探索,获得了该态在
20Mg β衰变中被布居的分支比上限。通过比
20Mg和
20O镜像能级跃迁的结果确认了同位旋非对称性,为检验相关理论模型提供了精确的实验数据。对于突破路径中有重要影响的
19Ne 4 033 keV共振态的性质,有待更高统计的实验进一步研究。
The breakout from the hot CNO cycle to the rapid proton capture process can occur via the
15O(α,γ)
19Ne(p,γ)
20Na reaction sequence, and the β decay of
20Mg can be used as an alternative method to characterize some specific resonances, which will provide detailed nuclear structure input for reaction rate calculations. The reliable information on the decay properties and structure of
20Mg was obtained by measuring the emitted particles and γ-rays in the β decay with high efficiency and high resolution. Attempt was also made to search for the decay channels associated with the 4 033 keV resonance in
19Ne. To test fundamental symmetries, the transitions in the mirror decays of
20Mg and
20O were compared. The precise experimental data presented here would be important to constrain the theoretical calculations. It is desirable to clarify the astrophysically relevant problem by further experiments with improved statistics on the basis of the present work.