The Lunar Radiation Environment: Comparisons between PHITS, HETC-HEDS, and the CRaTER Instrument

Understanding the radiation environment near lunar surface is a key step towards planning for future missions to Moon. However, complex variety of energies and particle types constituting space makes process replicating such very difficult in Earth-based laboratories. Radiation transport codes provide practical alternative covering wider range energy, angle, type than can be experimentally attainable. Comparing actual measurements with simulation results help validating flux input models, collision models databases involving nuclear electromagnetic interactions. Thus, this work, we compare LET spectra simulated using Monte Carlo code PHITS made by CRaTER instrument that currently orbiting Moon studying its environment. In addition, utilize feature allows user run simulations without Vavilov energy straggling test whether it root cause erroneous phenomena exhibited similar studies literature. The herein show good agreement between instrument. They also confirm distribution correction would ultimately better previous from HETC-HEDS HZETRN.