光子穿透系数及同质异能态俘获截面的研究

Study on Photon Transmission Coefficient and Capture Cross Section of Isomeric State

合理地给出了复合核反应光子穿透系数及同质异能态俘获截面的计算公式，其中包括统计和非统计过程．通过求解级联γ退激过程计算光子穿透系数，既合理地扣除（ｎ，γｎ）过程，又包括首次γ跃迁至中子分离能Ｂｎ以上能级的贡献．以４ＭｅＶ以下中子和５９Ｃｏ及１０３Ｒｈ的反应为例，比较用不同方法计算的光子穿透系数，计算同质异能态俘获截面并和实验数据进行比较，最后对结果进行了分析和讨论．

The formulas for calculating the photon transmission coefficient and the capture cross section of the isomeric state for the compound nucleus reaction are presented,in which statistical and non-statistical processes are all contained.Calculating the photon transmission coefficient by solving the cascade deexcitation processes,the (n,γn)processes are deducted reasonably,and the contribution of the first transitions to the levels distributed above the neutron separating energy Bn can be included.The numerical calculations for 59Co and 103Rh in the energy below 4MeV are made.The different calculation methods for the photon transmission coefficients are compared with other and the calculation results of the isomeric capture cross sections are compared with the experimental data.Analysis and discusions,especially the dependence of calculated results on energy level distributions are presented.