Simulation study of neutron production in thick beryllium targets by 35MeV and 50.5MeV proton beams

A data-driven nuclear model dedicated to an accurate description of neutron productions in beryllium targets bombarded by proton beams is developed as a custom development that can be used as an add-on to GEANT4 code. The developed model, G4Data(Endf7.1), takes as inputs the total and differential cross section data of ENDF/B-VII.1 for not only the charge-exchange ⁹Be(p,n)⁹B reaction which produces discrete neutrons but also the nuclear reactions relevant for the production of continuum neutrons such as ⁹Be(p,pn)⁸Be and ${}^9\text{Be}\left(\text{p,n}\alpha \right){}^5\text{Li}$. In our benchmarking simulations for two experiments with 35 MeV and 50.5 MeV proton beams impinged on 1.16 and 1.05 cm thick beryllium targets, respectively, we find that the G4Data(Endf7.1) model can reproduce both the total amounts and the spectral shapes of the measured neutron yield data in a satisfactory manner, while all the considered hadronic models of GEANT4 cannot.