Preliminary study on the thermoluminescence properties of CaF2 and Tm2O3 pellets

Abstract This contribution describes a dry physical process to increase luminescence of a mixture of calcium fluoride (CaF2) and thulium oxide (Tm2O3) pellets. Thermoluminescence (TL) technique has been used by means of two different filters (UV-blue and green) for the prepared aliquots irradiated with a  90Sr beta source (10 mGy/s). Many trapping centers were created during the preparation due to new structural defects in the CaF2 matrix, exhibiting a second maximum at 195 °C in the TL glow curve, and having fading of 11% after 1-month storage. Regarding the glow curve structure, first-order kinetics has been reported with a peak-I, around 130 °C, with an activation energy of 1.27(1) eV obtained by the initial rise method using a heating rate of 5 °C/s. Linearity property has been confirmed in the range from 0.1 Gy up to 2.0 Gy. UV-blue TL glow curve shown some changes when a lower heating rate (2 °C/s) was used. Peaks with greater intensity in a factor about 5%, and peaks position at lower temperatures (around 115 °C and 180 °C) were obtained. The results show that this low-cost phosphor can be used at doses higher than 10 mGy, such as in medical and industrial applications. The preparation process parameters used to produce this material are provided.