Afterglow and Thermoluminescence Response of Europium-Doped Alkali Halides Dosemeters

It is well known that Eu2+-doped alkali halides show a persistent luminescence, often referred to as afterglow, after being subjected to ionising radiation. Several mechanisms responsible for the observed afterglow and thermoluminescence have been proposed which are dependent on the type of alkali halide crystal, of radiation used and the aggregation - precipitation state of the impurity. We have carried out detailed afterglow and thermoluminescence measurements in europium-doped KC1, irradiated with X rays. Our conclusions support the occurrence of at least two main mechanisms originating in the existence of impurity vacancy dipoles and the recombination of F centres and other defects with interstitial halogen ions.