Analysis of neutron spectra from thick targets bombarded with 710-MeV alpha particles by quantum molecular dynamics plus statistical decay model

The spectra of neutrons produced from thick targets (water, carbon, iron an d lead) bombarded with 710-MeV alpha-particles were calculated by using qua ntum molecular dynamics (QMD) plus statistical decay model (SDM). The calcu lation was compared with experiments. For all targets, the calculated resul ts reproduced the experimental data much better than those calculated with the intra-nuclear cascade-evaporation (INCE) code HETC-KFA1. It was found t hat the neutron transport effect was important for the prediction of spectr a of neutrons produced at backward angles for targets thicker than the mean free path of the neutrons observed with the lowest energy in the experimen t.