Optically stimulable transparent KCl:Eu crystal as a storage material for two-dimensional UV-ray or x-ray imaging sensors

Intense optically stimulated luminescence (OSL) with a peak at about 420 nm is observed in ultraviolet (UV)-ray or x-ray irradiated europium-doped potassium chloride (KCl:Eu) crystals. The OSL intensity is increased with increasing UV-ray or x-ray irradiation dose. This suggests that KCl:Eu crystal is useful as a material for two-dimensional UV-ray or x-ray imaging sensor utilizing OSL phenomenon. The results obtained are consistent with the proposed emission mechanisms of the 420 nm OSL peak, based on the recombination of electrons released from the F centers with Eu3 ions. The excitation mechanism for the OSL in UV-ray irradiated KCl:Eu crystals is also discussed.