Research on Spatial Ionizing Radiation Effects on VOx Uncooled Infrared Focal Plane Arrays

[Background]: Vanadium oxide (VOx) detector plays a crucial role in the fields of space infrared detection and imaging due to their sensitivity to infrared radiation, particularly in the Long-Wave Infrared (LWIR) band, coupled with their advantages of high sensitivity, low noise, uncooled operation, and cost-effectiveness. However, performance degradation caused by space ionizing radiation, particularly the decrease in responsivity and the increase in noise levels, poses a significant threat to the imaging quality and reliability of these detectors. [Purpose]: To bridge the current gap in research on the space radiation effects on VOx detectors and provide input for their radiation hardening, [Methods]: This study aims to present ground-based radiation simulation experiments and analyze the radiation damage to detectors. Both online and offline testing methods were employed to systematically investigate the changes in detector output under varying radiation doses. Furthermore, post-irradiation annealing tests were conducted on the detectors to deeply explore the specific patterns of performance degradation in VOx detectors under space radiation environments. [Results]: The results indicate that space radiation significantly affects the output performance of VOx detectors. When the accumulated dose reaches 31 krad(Si), the non-uniformity of the detector's blackbody temperature response and the number of dead pixels surge. At 39 krad(Si), the non-uniformity of the blackbody response escalates to 88%, the dead pixel rate climbs to 66%, and the output image becomes aberrant. Within 24 hours after the irradiation test, the annealing effect of the VOx infrared array detector is evident, with the average grayscale value of the blackbody response output closely aligning with the pre-irradiation results after 72 hours of annealing, and the number of dead pixels tending towards zero after one week of annealing. [Conclusions]: Space radiation significantly impacts the output of VOx detectors, with the detector's output performance declining as the radiation dose accumulates, reaching a point where the device cannot recognize objects in images at 24 krad(Si). The total ionizing dose effect at lower accumulated dose values does not constitute permanent damage, as the detector's performance can be restored through room-temperature annealing. This study provides valuable insights for the subsequent design of radiation-hardened VOx detectors for space applications.