Thermoluminescent properties of CaF2:Dy TLD's

Selected thermoluminescent (TL) properties of CaF2 Dy TLD's have been investigated for a single batch of crystals. These include phosphor response, glow curve structure, long term signal fading, and pre-irradiation annealing effects. Co60 exposures ranged from 0.1 roentgen (r) to 3 × 103 roentgens (r). Comparisons are made with data presently available in the literature and notable discrepancies are identified. These discrepancies are used to demonstrate the necessity of characterizing the TL properties of each batch of CaF2 :Dy crystals prior to use as a radiation detector. Techniques developed during the investigation for improving the accuracy of dosimetry data obtained with the phosphor are discussed.