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, In²⁺ centres and In⁰(1) centres are generated. In²⁺ 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-In²⁺ 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:Eu²⁺.