Comparative Study of Cryogenic Versus Room-Temperature Proton Irradiation of N-Channel CCDs and Subsequent Annealing

Abstract

Two PLATO Teledyne-e2v CCD280 have been proton irradiated: one whilst operating at cold and the other unbiased at room temperature. We report on differences in the postirradiation hot pixel population, trap species, and charge transfer inefficiency (CTI), including after annealing. We demonstrate once more that proton irradiation performed at the charge-coupled device temperature of operation can show significant differences to the traditional room-temperature irradiation. The cold-irradiated detector shows a factor 2 greater radiation induced increase in dark current and a factor 3 to 4 greater increase in hot pixel numbers, however, the parallel CTI measured in the PLATO operating conditions is a factor 1.5 lower. Using the trap pumping technique, we provide distributions of radiation-induced trap release time constants at different temperatures, which can be used to identify the type of defects and estimate CTI in other operating conditions.