The Hard X-ray Imager (HXI) on the Advanced Space-based Solar Observatory (ASO-S)

The Hard X-ray Imager (HXI) instrument is one of the three payloads on board the Advanced Space-based Solar Observatory (ASO-S) that will be launched into a 720 km Sun-synchronous orbit by a Chinese CZ-2D rocket in 2022. HXI is being developed by a team led by the Purple Mountain Observatory. HXI will provide images and spectra of solar X-rays between ∼30 and 200 keV with a spatial resolution of 3.1 arsec within a 40 arcmin field of view. Together with the other two instruments on ASO-S, the mission will study the relation among the solar magnetic field, solar flares, and coronal mass ejections. HXI will investigate how electrons are rapidly accelerated and how energy is released in solar flares. Here, we provide a description of the instrument, its performance, and present the preliminary results of ground calibrations.