标题： 直接中子捕获对于幻数壳层核 显示英文标题

标题： Direct Neutron Capture for Magic-Shell Nuclei

摘要： 在中子俘获对于幻数壳层核的情况下，直接反应机制可能很重要，甚至可能占主导地位。 作为例子，我们研究了反应 $^{48}$Ca(n,$\gamma)^{49}$Ca 在入射能量低于250 keV时，使用折叠过程计算光学势和束缚态势的直接俘获模型。 得到的理论截面与实验数据一致，表明在此情况下直接反应机制占主导地位。 上述方法也用于计算 $^{50}$Ca(n,$\gamma)^{51}$Ca 的截面。 显示英文摘要

摘要： In neutron capture for magic--shell nuclei the direct reaction mechanism can be important and may even dominate. As an example we investigated the reaction $^{48}$Ca(n,$\gamma)^{49}$Ca for projectile energies below 250\,keV in a direct capture model using the folding procedure for optical and bound state potentials. The obtained theoretical cross sections are in agreement with the experimental data showing the dominance of the direct reaction mechanism in this case. The above method was also used to calculate the cross section for $^{50}$Ca(n,$\gamma)^{51}$Ca.