The role of F-centres in the thermoluminescence of LiF:Mg,Ti

The aim of the present work was to investigate the relation of F-centres and thermoluminescence (TL) peaks of differently doped LiF:Mg, Ti samples in a wide dose range. A direct experimental approach was applied: thermal bleaching of the 250 nm optical absorption (F-band) was measured during slow linear heating, and the TL emission intensity was simultaneously recorded. The results clearly indicate that although the F-centre absorption curve shows bleaching steps at almost every TL peak temperature, the size of the bleaching steps are far from being proportional to the corresponding TL peak intensities. This suggests that the role of the F-centres in the TL process is very different at the low and high temperature parts of the TL glow curve. (author)