Photo-, thermo- and optically stimulated emission spectra in KCl : Eu2+

Photoluminescence (PL), thermostimulated (TL) and optically stimulated lumi nescence (OSL) emission spectra in quenched KCl:Eu2+ single crystals have b een measured. The PL spectra consist of an emission band with maximum at 42 0 nm (at RT) related with isolated Eu2+-cation-vacancy dipoles and first ag gregates and a weak (about 100 times lower) additional band at 350 nm. The TL and OSL spectra coincide fully with the PL spectra at short wavelengths but exhibit additional bands with maxima at 437 an 453 nm (at RT) for X-ray s and UV irradiated crystals, respectively. The relative contribution of th e additional bands increases as temperature rises (especially for UV irradi ated crystals), but this increasing is monotonous and does not display some features near TL peaks. It is concluded that the mechanism of recombinatio n after destroying TL and OSL traps by heat or light stimulation includes a t least two different recombination centers.