Estimation of the influence of elastic neutron scattering anisotropy on the integral parameters of the model experiment

Abstract

For the vast majority of isotopes presented in modern evaluated data libraries, the quality of description of elastic neutron scattering anisotropy is difficult to assess due to the lack of critical experiments that are sensitive to these data. This results in a large variation in these data, due to both the difference in the models used in the estimation, and the smoothing of the resonance peculiarities in representation of the energy dependence in the evaluated data files. This work estimates the effect of anisotropy of elastically scattered neutrons based on the model of a critical assembly with a reflector from the tested isotope. Direct estimates of the angular distributions in the evaluated data libraries were compared with the angular distributions, which were reconstructed from the resonance parameters by using Blatt-Biedenharn formula. The thickness of the reflector at which an assembly model became critical is used as a comparison value. The obtained integral characteristics of the elastic scattering anisotropy data, together with the performed comparisons of the detailed dependences of the angular distribution parameters, can serve as a basis for setting tasks to improve the quality of the evaluated data.