Performance Evaluation of a Silicon-Based 6U CubeSat Detector for Soft γ-Ray Astronomy

Abstract

The observation of the low-energy γ-ray (0.1 to 30 MeV) sky has been significantly limited since the COMPTEL instrument aboard the Compton Gamma Ray Observatory (CGRO) satellite was decommissioned in 2000. The exploration of γ-ray photons within this energy band, often referred to as the MeV gap, is crucial to address numerous unresolved mysteries in high-energy and multi-messenger astrophysics. Although several large MeV γ-ray missions have been proposed (e.g., e-ASTROGAM, AMEGO, and COSI), most of these are in the planning phase, with launches not expected until the next decade, at the earliest. Recently, there has been a surge in proposed CubeSat missions as cost-effective and rapidly implementable pathfinder alternatives. An MeV CubeSat dedicated to γ-ray astronomy could serve as a valuable demonstrator for large-scale future MeV payloads. This paper proposes a γ-ray payload design with a silicon-based tracker and a cesium iodide-based calorimeter. We report the results of a simulation study to assess the performance of this payload concept and compare the results with those of previous γ-ray instruments. As part of the performance assessment and comparison, we show that with our proposed payload design, a sensitivity better than IBIS can be achieved for energies between 0.1 and 10 MeV, and for energies up to around 1 MeV, the achieved sensitivity is comparable to COMPTEL, therefore opening up a window toward cost-effective observational astronomy with comparable performance to past missions.