Modeling of proton-induced radioactivation background in hard X-ray telescopes: Geant4-based simulation and its demonstration by Hitomi ’s measurement in a low Earth orbit

The ASTRO-H (Hitomi) x-ray astronomy satellite

The ASTRO-H X-ray astronomy satellite ⬇️

The Hard X-ray Imager (HXI) for the ASTRO-H Mission

The hard x-ray imager (HXI) onboard ASTRO-H

The soft gamma-ray detector (SGD) onboard ASTRO-H