The $(n,\alpha )$ reactions play an important role for the energy generation and the synthesis of chemical elements in the stars, as well as for nuclear engineering and medical applications. The aim of this study is to explore the evolution of $(n,\alpha )$ reactions in Fe and Sn isotope chains in order to assess the cross section properties with the increase of neutron number in target nucleus, and to make a comparison with other relevant neutron induced reactions. The cross section calculations are based on the statistical Hauser-Feshbach and exciton models in TALYS nuclear reaction code, using global optical model potential that is additionally adjusted by the $(n,\alpha )$ cross section data for ⁵⁴Fe and ¹¹⁸Sn. The calculations of $(n,\alpha )$ reactions in Fe and Sn isotopes provide the insight into their isotopic dependence and properties over the complete relevant range of neutron energies. The cross sections result in pronounced maxima at lower-mass isotopes, and rather strong decrease for neutron-rich nuclei consistent with the reduction of the reaction Q-value and increased contributions from other exit channels from compound nucleus. The analysis of the Maxwellian averaged cross sections at temperatures in stellar environment shows that the $(n,\alpha )$ reactions have significant contributions for low-mass Fe isotopes, that is opposite than for Sn isotopes. For both neutron rich isotopes γ and neutron emissions dominate, with their interplay depending on the temperature involved.

这$（n,\alpha ）$反应对于恒星中的能量产生和化学元素的合成以及核工程和医学应用发挥着重要作用。本研究的目的是探索进化$（n,\alpha ）$Fe和Sn同位素链反应，以评估随靶核中子数增加的截面特性，并与其他相关中子诱导反应进行比较。横截面计算基于 TALYS 核反应代码中的统计 Hauser-Feshbach 和激子模型，使用全局光学模型势，并通过$（n,\alpha ）$⁵⁴ Fe 和¹¹⁸ Sn的横截面数据。的计算$（n,\alpha ）$Fe 和 Sn 同位素的反应可以深入了解它们在整个相关中子能量范围内的同位素依赖性和特性。横截面导致较低质量同位素处的明显最大值，并且富中子核的显着下降与反应Q值的降低以及来自复合核的其他出口通道的贡献增加一致。对恒星环境温度下麦克斯韦平均截面的分析表明：$（n,\alpha ）$反应对低质量 Fe 同位素有显着贡献，这与 Sn 同位素相反。对于富中子同位素γ和中子发射来说，它们的相互作用取决于所涉及的温度。