In-orbit monitoring for dynamic detector-oriented containment of TID-induced degradation in CMOS-TDI sensor systems

Abstract Space-borne CMOS-based sensor systems with time delay and integration (TDI) functionality are susceptible to the radiation environment in orbit. Total ionizing dose (TID) impacts CMOS detector structures and considerably deteriorates performance and image quality. We investigated dynamic detector-oriented methods to counteract TID-induced degradation effects. We equipped the CMOS-TDI detector system with in-orbit monitoring capabilities applying charge injection and subsampling to reveal inherent detector operation feedback and enable system adaptation during operation. Thus, the impact of radiation was significantly contained. The charge transfer efficiency (CTE) accordingly reached the pre-radiation level. The relative charge loss was reduced by a factor of 8.1, yielding a substantial improvement in CTE, and hence, in the geometric resolution. We further applied device compact modeling, aiming for a comprehensive system model to facilitate adequate prediction of performance degradation caused by TID, which could be generally applied to upcoming designs of the CMOS-TDI detector family after external validation.