On-orbit calibration of soft X-ray detector on Chang'E-2 satellite*

The X-ray spectrometer is one of the satellite payloads on the Chang'E-2 satellite. The soft X-ray detector is one of the devices on the X-ray spectrometer, designed to detect the major rock-forming elements within the 0.5-10 keV range on the lunar surface. In this paper, energy linearity and energy resolution calibration is done using a weak Fe-55 source. Temperature and time effects are found not to give a large error. The total uncertainty of calibration is estimated to be within 5% after correction.