Monte Carlo Simulation of Proton-induced Cosimc Ray Cascades in the Atmosphere

We have developed a Monte Carlo model of the Earth's atmosphere and implemented it in three different codes (GEANT4, MCNPX, and FLUKA). Primary protons in the energy range of 1 GeV-100 TeV are injected at the top of the atmosphere. The codes follow the tracks of all relevant secondary particles (neutrons, muons, gammas, electrons, and pions) and tally their fluxes at selectable altitudes. Comparisons with cosmic ray data at sea level show good agreement.