Development of an FPGA-based Readout System of CMOS Image Sensor toward Future Satellite Missions

We report the preliminary results of development of an FPGA-based fast readout system dedicated to a CMOS image sensor for the future satellite HiZ-GUNDAM observing X-ray transients. Our previous research showed the CMOS image sensor has the low-energy X-ray detection capability and strong radiation tolerance, which satisfies the requirements of the HiZ-GUNDAM mission. However, considering the frame rate of ¿10 fps required from the X-ray mission, the amount of the observation raw image data is extremely large and cannot be stored in the satellite bus system. Thus, it is necessary to extract only X-ray events from the raw image data to reduce the amount of data size. We have developed the FPGA-based image signal processing system that can perform fast on-board X-ray event extraction. In addition, the system board is so compact that it can be equipped with not only HiZ-GUNDAM but also CubeSat missions, which can help early demonstration of in-orbit operation. In this paper, we give the preliminary results of the performance evaluation tests of the new FPGA-based readout system with X-ray irradiation experiments.