Pre-launch characterization of the spectrometer of Hard X-ray Imager (HXI) onboard the ASO-S mission

Abstract As one of the three payloads Advanced Space-based Solar Observatory (ASO-S), pre-launch characterization HXI includes collimator and spectrometer. This article focuses on HXI's spectrometer, including detection efficiency, energy resolution, to ADC channel (E-C) relationship. The efficiency necessitates a sufficient number calibrated points in observation range, with refined measurement around absorption edge lanthanum bromide crystal, is an X-ray beam. results are consistent simulations show that difference between detector modules controlled within ±3%. Radioactive sources 133 Ba 137 Cs used calibrate resolution E-C all modules' resolutions better than 26% at 32 keV, meeting design specification. And their relationships vary regularly voltage. All indicate flight model spectrometer meets performance requirements capable performing on-orbit activities.