中重核中子辐射俘获γ射线强度函数研究

Study on γ-Ray Strength Function of Neutron Radiative Capture for Middle and Heavy Nuclei

假设退激过程中除包含巨偶极共振模式外还存在6 He,6 Li,6 Be ,7Li和7Be等粒子集团激发态的退激过程 .本文对这一物理假定作了进一步分析 .利用据此建立的包括这些过程在内的γ射线强度函数 ,计算了在核素93Nb ,1 81 Ta和天然元素Ag上入射中子能量在 0 .0 1— 5MeV能区以及在核素1 97Au上入射中子能量在 0 0 1— 10MeV能区的中子辐射俘获反应截面和γ能谱 ,得到了与实验数据较好符合的结果 .特别是可以较好地解释γ能谱中 5 5MeV之后的反常突起 .这表明 ,上述物理假定适用于中重核中子辐射俘获反应 .

Using the hypothesis as well as the γ-ray strength function proposed by us, the neutron radiative capture reaction cross sections and the γ energy spectra have been calculated for 93Nb,natural Ag and 181Ta in the neutron incident energy region from 0 01 to 5MeV as well as for 197Au in the neutron incident energy region from 0 01 to 10MeV. The results which are coincident better with the experimental values were obtained. The comparisons with the experimental values have shown that, not only the abnormal protuberances near and after 5 5MeV of the γ spectra in the nuclear mass regions about 110< A <140 and 180< A <210 are explained better,but also the γ production data can be theoretically calculated for the middle and heavy nuclei by means of this hypothesis and the γ-ray strength function deduced from this hypothesis. = =