Research on the degradation of resolution in cameras based on CMOS image sensor under γ- and X-rays irradiation

Remote control engineering in industry usually requires cameras to assist target identification and detection, but the cameras working in nuclear environments face the threat of radiation-induced degradation. Both γ- and X-rays in nuclear environments will cause ionizing radiation damage, but the difference in degradation of camera's performance induced by ionizing radiation damage with equivalent total ionizing dose (TID) of these two rays is unclear, which is crucial for the evaluation of camera performance in a nuclear radiation environment. In order to figure out the degradation of CMOS cameras by ionization radiation damage under different rays, this study conducted irradiation experiments on CMOS image sensors under X-ray with 10 keV and 60Co-γ ray with 1.25 MeV, respectively, and then tested and calculated the resolution of camera based on this CMOS image sensor. After comparing and analyzing the results, it was found that the dark current and full well capacity of the CIS, as well as the resolution of the camera, were more severely degraded after X-ray irradiation. Further analysis found that the interface dose enhancement effect of X-ray, as well as the generation of high-density oxide trapped charges in the gate oxide, aggravated the degradation of full well capacity on the CIS after X-ray irradiation, resulting in more severe degradation in the resolution of the CMOS camera. This study provides theoretical basis for the safety and reliability evaluation of cameras in strong nuclear radiation environments.