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 investigated in KBr:In. Measurements of the optical absorption, the magnetic circular dichroism of the optical absorption (MCDA) and the MCDA-detected electron paramagnetic resonance, as well as of the photostimulated In + emission, are utilized. At room temperature, F centres, In 2+ centres and In 0 (1) centres are generated. In 2+ centres are not produced at low temperature and therefore are not primary hole defects. It is shown that the photostimulation process does not occur within F-In 2+ centre pairs, as previously proposed. It involves an aggregate between F centres, In + centres and an unknown, room-temperature-stable hole centre. The photostimulation process, including replenishment effects, seems very similar to the one found earlier for the well known X-ray storage phosphor BaFBr:Eu 2+ .