The thermoluminescence (TL), induced in LiF:Mg, Ti by Xo r r-rays, is widely used in dosimetric measurements, but its mechanism is very complex and not yet well understood. In particular, various models have been proposed /1 to 5/ t o explain the TL sensitization in LiF:Mg, Ti, that is the enhancement of T L after h q h X-o r r-exposure and partial annealing, but none of them have been completely accepted. Presently the model that seems to receive the greatest consent was proposed by Nink and Kos /4/. According to this model, the Z2 centers, that arise from Z3 centers by capturing an electron, are responsible for peak 5 in the glow curve of T L in LiF. During the heating