Feasibility study of CaSO4:Tb,Yb as a thermoluminescent dosimeter

A new composite based on CaSO4, using terbium as dopant and ytterbium as co-dopant (CaSO4:Tb,Yb), was developed for employment as a thermoluminescent (TL) dosimeter. The crystals used in this work were grown using a production route based on the Yamashita method (Yamashita et al., 1968). Crystal powder was calcined at 600°C for 1h. Pellets were made by adding commercial and colorless glass to improve physical resistance and sintered at 700°C for 6h. All samples were irradiated by a beta source (90Sr/90Y) and received doses from 1Gy to 5Gy. TL analyses have been performed and characteristics such as sensitivity, reproducibility, linearity, and fading have been studied. The CaSO4:Tb,Yb pellets glow curves presented two peaks, the first at around 115°C, and the second at around 200°C. The highest intensity was shown for CaSO4:Tb,Yb with a concentration of 0.1mol% of Tb and Yb together. In all the samples the TL response was proportional to the absorbed dose. Therefore, the CaSO4:Tb,Yb has potential to be used as a thermoluminescent dosimeter.