AstroPix: A Pixelated HVCMOS Silicon Sensor for Astrophysics and Nuclear Physics

Addressing the "MeV gap" in astrophysical sensitivity with a singular instrument is challenging - the system must be sensitive to photons over four decades of energy interacting through three unique energy-dependent mechanisms. In order to accurately measure and reconstruct medium-energy gamma rays in this band, a particle tracking system with a low noise floor of 5 keV and precise energy resolution of 9.7% FWHM at 122 keV is required. The component must also draw relatively low power (<1mW/cm^2) to effectively scale into a large instrument. AstroPix is a CMOS monolithic active pixel silicon (APS) sensor being designed for such use in space-based gamma-ray telescopes. A high voltage applied individually to all pixels will allow for depletion into the bulk up to 500um, enabling a dynamic range of 25-700 keV per 500x500um pixel. Drawing from heritage in high-energy particle physics, AstroPix can be implemented in a range of instruments from future gamma-ray telescopes to nuclear physics experiments. This talk will outline the scientific drivers from gamma-ray astronomy that shape AstroPix’s benchmark characteristics and overview its development process. Special attention will be paid to the first flight version of AstroPix, version 3, to be flown in late 2024 and future implementations in nuclear physics.