THE PHOTOSTIMULATION PROCESS IN THE X-RAY STORAGE PHOSPHOR KBR-IN

The nature of the radiation damage centres generated by x-irradiation at 300 K, 100 K and 10 K and the photostimulation process are investig ated in KBr:In. Measurements of the optical absorption, the magnetic c ircular dichroism of the optical absorption (MCDA) and the MCDA-detect ed electron paramagnetic resonance, as well as of the photostimulated In+ emission, are utilized. At room temperature, F centres, In2+ centr es and In-0(1) centres are generated. In2+ centres are not produced at low temperature and therefore are not primary hole defects. It is sho wn that the photostimulation process does not occur within F-In2+ cent re pairs, as previously proposed. It involves an aggregate between F c entres, Int centres and an unknown, room-temperature-stable hole centr e. The photostimulation process, including replenishment effects, seem s very similar to the one found earlier for the well known x-ray stora ge phosphor BaFBr:Eu2+.