A comparative study on the thermal stability of LiF:Mg,Ti and LiF:Mg,Cu,P detectors for environmental monitoring

The results obtained in an investigation on the thermal stability of LiF:Mg,Cu,P (GR-200) compared to the more traditional LiF:Mg,Ti (TLD-100) at 40 degrees C and 70 degrees C are presented. Samples of both varieties of dosemeters were stored irradiated or unirradiated in order to evaluate the relative importance of the temperature/storage induced effects on either traps or trapped charges. The measured glow curves were analysed using the deconvolution programs developed at CIEMAT. These techniques allow the detailed characterisation of the evolution pattern followed by each individual peak during the experiment. The results obtained confirm that, for both varieties of LiF phosphor, the process affecting their respective main dosimetric peaks is not fading, understood as the spontaneous release of trapped charges. On the contrary, the observed variations in the TL response should be addressed to the modifications experienced by the trap system during storage. However, some slight differences between the evolution of TLD-100 and GR-200 have been found in this comparison and are analysed.