Geant4 Simulations of Space Radiation Sensors and Environment at The Aerospace Corporation
Geant4 is a vital tool for understanding and calibrating the response of space-borne radiation sensors at The Aerospace Corporation, and for understanding the space radiation environment that they measure. In the year and a half since the last Geant4 Space Users’ Workshop, we have used the code to continue to refine our understanding of the response, both foreground and background, of sensors aboard the Van Allen Probes and the Lunar Reconnaissance Orbiter (LRO), and we will show some examples. As part of this, we have begin making use of the extensions to the basic Geant4 code that enable import of CAD geometries and that perform adjoint Monte Carlo simulations, and we will present some initial evaluations of performance relative to our standard use of Geant4 (geometry via CSG with Geant4 primitives, forward Monte Carlo simulations). With regard to the environments measured by our sensors, we have also used Geant4 to conduct an extensive parametric study of the effects of hydrogen in the upper layers of the lunar surface on “albedo” protons coming up to be measured by LRO after production in cosmic-ray interactions with the regolith, and we will present a summary of the results.