A Lunar CubeSat mission for high-sensitivity nuclear astrophysics

MeV astronomy provides unique and direct diagnostics of cosmic explosions and chemical evolution. Gamma-ray lines provide detailed information on nuclear physics processes throughout the universe. New instruments sensitive to MeV gamma-ray lines are needed. A new instrument concept with high energy and angular resolution is proposed to study nuclear astrophysics in the medium gamma-ray energy range. The system consists of a 12U CubeSat carrying onboard CdZnTe detectors that will be placed in orbit around the moon. The Lunar Occultation Technique will be used to analyze the changes in counting rate during occultations of the moon to pinpoint the location of gamma-ray line flux at precise locations in the sky. The lack of lunar atmosphere, stable background, and low-mass spacecraft provides the perfect environment for high sensitivity gamma-ray spectroscopy and good angular resolution. Simulation studies using MCNP6 were used to determine the expected instrument efficiency and lunar gamma-ray background environment. An initial simulation study indicates that the proposed instrument can achieve sensitivity to gamma-ray lines comparable to much larger proposed Compton Telescopes.