20MeV以下快中子与 56 Fe非弹性散射截面的分歧研究

56Fe的非弹性散射截面在核装置中子输运计算中扮演着重要的角色，但无论从实验数据还是从评价数据，非弹性散射截面都存在很大分歧，它的数据直接影响到核装置的设计、建造与运行维护。本工作从实验数据本身出发，深入分析了不同实验室测得的847 keV的γ产生截面的分歧，经转化后补充非弹性散射截面的实验空白能区，并同时利用满足全截面、去弹截面等截面自洽关系的评价方法推荐了高精度的快中子与56Fe的非弹反应截面结果。积分检验表明，新的非弹截面的改进使得评价数据与积分实验结果一致，较CENDL-3.1的评价数据结果有显著改善。 Knowledge about the inelastic scattering cross section of 56Fe is very important in neutron transportation calculation. However there are great discrepancies not only between experimental data but also between evaluated data. More detail analysis was performed for inelastic scattering cross section in the fast range up to 20 MeV where there are significant differences among the main evaluated libraries, mainly caused by the different inelastic scattering cross section measurements. The large discrepancies on 56Fe(n, n1'γ) cross section which could fill the neutron energy blank of the 56Fe(n,inl) were clarified and were converted to the inelastic scattering cross section of 56Fe. And the high-quality results were evaluated by using the unitarity constrain among total cross section, noelastic reaction and other reactions. The integral experiment result indicates that the new evaluated result of inelastic cross section brings greater improvement than that of CENDL-3.1.