Comparing hadronic models of GEANT4 for the neutron monitor response function

The NM64 neutron monitor is the most popular instrument that measures the number of highenergy particles impacting the Earth from space. A simulation of the NM64 neutron monitor response function with the GEANT4 toolkit is conducted, and the result is processed to compare low- and high-energy hadronic models provided by this Monte Carlo code. Results shows that the thermal interaction for hydrogen in polyethlene for neutron energies less than 4 eV has a great influence. G4NeutronHP and G4LEND models are compared for low-energy neutrons in this study. At energies from 20 MeV to 10 GeV, the Bertini Cascade and the Binary Cascade models are used and evaluated as applicable physics lists. At energies above 10 GeV, the FTFP and the QGSP physics models are applied to calculate the response function, and the results are a few percents higher than the FLUKA results found in the literature.