Geant4 validation of neutron production on thick targets bombarded with 120 GeV protons

Neutron energy spectra and angular distributions are calculated for 120 GeV protons on thick graphite, aluminum, copper, and tungsten targets using relevant physics models within the Monte-Carlo simulation package Geant4. The calculations are compared to data from recent experiment. Discrepancies are observed between experimental data and Geant4 models, and suggest that improvements of the intra-(INC) and inter-nuclear cascade processes employed by the models are required.