CCD Radiation Testing at Low Temperatures Using a Laboratory Alpha Particle Source

The performance of a large area 4500times1966 pixel CCD was measured after alpha particle irradiation at -135degC. Trap concentrations (as measured by deferred charge and first pixel response) were a factor ~1.3 higher than after annealing to room temperature or after room temperature irradiation for most trapping defects and for some defects (with emission time ~13 ms) the factor was ~2. Hence it seems that room temperature irradiation cannot be guaranteed to bound the response to displacement damage for applications that use CCDs at low temperatures. Results are also compared with those obtained with room temperature proton irradiations