Design and technology review of the solar X-ray detector onboard the Macao Science Satellite-1B

On May 21, 2023, the Macao Science Satellite-1B (MSS-1B), a low-inclination, low-latitude, and high-precision scientific exploration satellite for geomagnetic fields and space environments, was successfully launched. The solar X-ray detector (SXD), one of the two major scientific payloads onboard the MSS-1B, has obtained a large amount of solar X-ray radiation data, which reveals the distribution law of the magnetic field in the low Earth orbit, as well as the coupling law of the Earth’s magnetic field and the solar radiation and energy particle distributions. First, the overall design of the multi-detection-unit, broad-energy-range, small-volume, and low-power SXD was implemented to achieve the scientific objectives of the mission. Second, the technical indicators of the instrument were decomposed into various components, and the key technologies, such as collimator, processing circuit, thermal, and payload dataset designs, were reviewed. Third, the backgrounds, including electronic noise, cosmic diffuse X-ray background, and high-energy background in the Earth’s radiation belts in and out of the field of view, were analyzed for the instrument. Then, the ground calibrations of the energy response, detection efficiency, and temperature-dependent peak drift of the SXD flight model were conducted. Finally, the in-orbit temperature, energy spectrum data, background, and solar flare process observation of the instrument in the in-orbit test stage are presented, verifying the instrument design, analysis, and ground calibration, providing a foundation for obtaining accurate solar X-ray radiation data, and achieving the scientific objectives of the satellite.