Optical and thermally stimulated emission studies on γ†irradiated SrF<inf>2</inf>: Pb single crystals

Optical absorption (OA), fluorescence, and thermally stimulated emission (TL) studies are made on a Pb‐doped (0.3 wt%) SrF2 crystal. Unirradiated crystals show a prominent OA band around 6.05 eV. This band increases after γ‐irradiation and also a broad band around 4.77 eV appears which can be attributed to Pb3+ ions. Fluorescence emission is observed at 5.35 eV when the crystal is excited in the Pb2+ absorption region which is around 6.05 eV. Thermoluminescence glow shows a very intense broad peak at 653 K. TL emission shows only the characteristic Pb2+ emission at 5.35 eV. Also the OA of heavily irradiated crystals shows the presence of Pb (1)+ centres. The probable TL mechanism is that the trapped electron from a Pb (1)+ centre when thermally released can recombine with Pb3+ ions to give the characteristic Pb2+ emission. All these results are discussed. Copyright © 1994 WILEY‐VCH Verlag GmbH & Co. KGaA