INFLUENCE OF THERMAL TREATMENTS ON GLOW CURVE AND THERMOLUMINESCENCE EMISSION-SPECTRA OF LIF-MG,CU,P

LiF:Mg,Cu,P is a highly sensitive thermoluminescence material, but los es its sensitivity if annealed at temperatures above 513 K. In this pa per, the effects of these annealing temperatures on GR-200A samples ar e investigated and quantified. The changes in the glow curve and the e mission spectrum are investigated as a function of annealing temperatu re and cooling rate. The return of up to 79% of its sensitivity (after a 633 K for 10 min treatment) is found with a special thermal treatme nt including a cooling at 40 K min(-1) down to 513 K and a dwell time at that temperature for 10 min. Treatments above 513 K lead to both ir reversible and reversible processes in the material. A return of TL in the main glow peak is coupled with a decrease of the TL in the high t emperature region, which is the main source of the residual signal. An alysis of the emission spectrum shows two emission bands at 347 and 37 7 nm, of which the latter is influenced by the annealing procedure and can be correlated with the main glow peak, and the other with the res idual signal. A comparison with X-ray induced emission spectra indicat es that the luminescence processes in LiF:Mg,Cu,P materials may be exp lained by centre-to-centre recombination.