Improving the accuracy of W 182 , 184 , 186 ( n , n ′ γ ) cross-section calculations

Evaluated nuclear databases currently in use for numerical simulations to develop new nuclear technology and design advanced nuclear reactors still present large uncertainties. Their improvement is necessary, in particular through better reaction models and experimental nuclear data. Among the reactions of interest, (n, xn) reactions are of great importance for the operation of a reactor as they modify the neutron spectrum, the neutron population, and produce radioactive species. Providing new data on inelastic scattering reactions can be done in several ways, direct or indirect. Here, we present experimental data on (n, xngamma) reactions that provide strong constraints on the mechanism of inelastic scattering. Tungsten isotopes, being deformed like actinides but free of the fission channel, are of interest to test the models. We report on 182, 184, 186W(n, n'gamma) cross-section measurements. 63 Gamma production cross sections were measured. This large set of new experimental data offers a valuable opportunity to probe modeling of direct, pre-equilibrium and compound nucleus reaction mechanisms. The choice of major reaction ingredients and parameters can be refined thanks to comparison to partial (n, n'gamma) cross sections, which allows to provide recommendations and highlight modeling aspects that may require further work.