Speaker
Dr
Mark Looper
(The Aerospace Corporation)
Description
Geant4 is a vital tool for understanding and calibrating the response of space-borne radiation sensors at The Aerospace Corporation. For the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) sensor aboard the Lunar Reconnaissance Orbiter (LRO), we have found Geant4 to be particularly critical in modeling the effects of delta rays (energetic secondary or "knock-on" electrons), which are generated in the large amount of inert material (A-150 Tissue Equivalent Plastic) in the detector stack and which cause significant out-of-aperture sensor response. We have also used it to calculate the distribution of secondary particles coming up to the spacecraft from galactic cosmic ray (GCR) interactions with the moon's surface. The Relativistic Proton Spectrometer (RPS) aboard the Van Allen Probes uses a combination of silicon solid-state detectors and a Cherenkov radiator to make energy-resolved measurements of relativistic protons among the GCRs and in the heart of the inner Van Allen belt. We have particularly used Geant4 to hone our understanding of the behavior (Cherenkov light production, scintillation, internal reflection, etc.) of the Cherenkov optical subsystem; the code also proved crucial to our understanding of the laboratory environment when testing at the TRIUMF particle accelerator in British Columbia. Finally, we will discuss work in progress to model the detailed response of the Magnetic Electron Ion Spectrometer (MagEIS) sensor heads aboard the Van Allen Probes. These are a set of magnetic electron spectrometers, using a combination of rigidity filtering and pulse-height analysis to reject background events and obtain a clean signal in the intense electron environment encountered in the active outer Van Allen belt.
Primary author
Dr
Mark Looper
(The Aerospace Corporation)
Co-authors
Dr
J. Bernard Blake
(The Aerospace Corporation)
Dr
Joseph Mazur
(The Aerospace Corporation)
Dr
T. Paul O'Brien
(The Aerospace Corporation)
