Verification of a Monte-Carlo planetary surface radiation environment model using γ-ray data from Lunar Prospector and 2001 Mars Odyssey

Characterising a planetary radiation environment is important to: (1) assess the habitability of a planetary body for indigenous life; (2) assess the risks associated with manned exploration missions to a planetary body and (3) predict/interpret the results that remote sensing instrumentation may obtain from a planetary body (e.g. interpret the γ-ray emissions from a planetary surface produced by radioactive decay or via the interaction of galactic cosmic rays to obtain meaningful estimates of the concentration of certain elements on the surface of a planet). The University of Leicester is developing instrumentation for geophysical applications that include γ-ray spectroscopy, γ-ray densitometry and radiometric dating. This paper describes the verification of a Monte-Carlo planetary radiation environment model developed using the MCNPX code. The model is designed to model the radiation environments of Mars and the Moon, but is applicable to other planetary bodies, and will be used to predict the performance of the instrumentation being developed at Leicester. This study demonstrates that the modelled γ-ray data is in good agreement with γ-ray data obtained by the γ-ray spectrometers on 2001 Mars Odyssey and Lunar Prospector, and can be used to accurately model geophysical instrumentation for planetary science applications.