Effects of low temperature proton irradiation on a large area CCD for astrometric applications

Charge transfer and dark current effects are compared for regions of a large area 4500 × 1966 pixel CCD irradiated with 7.4 MeV protons at -130°C and at room temperature. Post-annealing measurements were also performed. Although there are differences in the concentration of individual defects following warm and cold irradiation and after subsequent annealing steps, these differences were less than a factor 3.5 (and in most cases a factor 2) - with the room temperature irradiation giving a good estimate of the effects except for traps with emission time constant ~4 ms.