Light and Current Pulses from X-Rayed Potassium Di-Hydrogen Phosphate Crystals

Short-duration light pulses accompanied by current pulses have been observed on warming KDP crystals x-ray irradiated at 77°K. The pulses start a few degrees above the transition temperature (TC=123°K) and continue until about 200°K. The pulses appear only under ambient gas pressures above about 0.1 Torr. Warming of the irradiated crystal to an intermediate temperature between TC and 200°K causes only a partial exhaustion of the pulses, and after cooling and reheating pulses appear only above the temperature reached in the former cycle. The pulses originate from discharges into the surrounding atmosphere. A simple model is given to account for the experimental results.