Thermally and optically stimulated luminescence correlated processes in X-ray irradiated KCl : Eu2+

The effect of optical bleaching on thermoluminescence (TL) and thermal blea ching on optically stimulated luminescence (OSL) outputs in X-ray irradiate d KCl : EU2+ have been investigated. The X-ray induced glow curves reveal t hree main peaks located at 370, 410 and 470 K. Illumination with 560 nm lig ht leads to a drastic change of the TL glow curve. The 470 K peak is destro yed during bleaching. The other peaks initially increase in intensity and o nly after sufficiently long bleaching begin to decrease. After long-time bl eaching, the TL peaks in X-ray irradiated crystals look like the TL peaks f ound in UV irradiated crystals. The effect of thermal bleaching on OSL is also very pronounced. The tempera ture dependencies show a step-by-step decrease of the OSL intensity correla ted with the positions of the TL peaks. The result obtained shows that cent ers responsible for the TL peaks participate in OSL, but this participation seems not to be direct and is complicated by processes accompanying the F center bleaching. (C) 2001 Elsevier Science Ltd. All rights reserved.