Thermoluminescence of LiF:Mg,Cu,P (GR-200A) TLD after annealing between 200 and 400 degrees C

For LiF:Mg,Cu,P TL material when the pre-irradiation annealing temperature is above 245 degrees C the shape of the glow curves changes remarkably and the TL intensity clearly decreases. TL glow curves and the emission spectra of LiF:Mg,Cu,P (GR-200A) have been studied under different thermal treatments. After a standard annealing regime recommended by the manufacturer (240 degrees C for 10 min), the samples have been annealed at 200, 240, 260, 280, 300 and 400 degrees C for 30 min and 120 min. The experimental results of the glow curves have shown that the T-max of the glow peaks moved towards higher temperatures and the TL intensity decreased remarkably with the increase of annealing temperature. There is an exception that after annealing at 300 degrees C for 120 min the glow peak T-max is in the same position as the original one. The emission spectra can be deconvoluted into two components, 3.25545 eV (band 1) and 3.54330 eV (band 2). With the increase of the annealing temperature, the area ratio of the two components changes. A concept of 'thermal damage to trap' (TDT) is being put forward to explain the loss of TL intensity of the phosphor