Some thermoluminescence properties of an α-Al2O3 sample. Sensitization effects†

The thermoluminescence (TL) properties of an α-Al2O3 sample are studied from 77 to 1000 K after X-irradiation and UV-excitation. Nine trapping centres and three emission centres, namely F, F+, and Cr3+, are detected. The UV-253.7 nm TL response is sensitized by previous X-irradiations followed by various thermal annealings. All TL properties of the virgin crystal are found again by heating up to 910 K, i.e. after the annealing of the TL peak at 910 K. Charge transfers, by UV-excitation (PITL) or in darkness (“dark transfer”), are involved in α-Al2O3. Les proprietes de thermoluminescence (TL) d'une alumine α sont etudiees de 77 a 1000 K apres irradiation X et excitation UV. Neuf centres de piegeage sont mis en evidence ainsi que trois centres d'emission: F, F+ et Cr3+. La reponse aux UV-253,7 nm est sensibilisee par des irradiations prealables suivies par divers recuits thermiques. Toutes les proprietes du cristal vierge sont retrouvees apres recuit de l'echantillon au dela de 910 K, c'est-a-dire apres vidage du pic de TL a 910 K. Des processus de transfert de charges, soit par excitation UV (PITL), soit a l'obscurite (“dark transfer”) sont impliques.