Effects of manganese and terbium on the dosimetric properties of CaSO4

Abstract

In this study, a new CaSO4 crystal doped with manganese and terbium is described and its potential for dosimetric applications is evaluated. Crystals were synthesized using the slow evaporation route, and were prepared in pellet form with the addition of Teflon. CaSO4 was doped with manganese and terbium at a concentration of 0.1 mol% in each case. The crystalline structure and optical properties of the crystals were evaluated by X-ray diffraction, Fourier transform infrared spectroscopy and photoluminescence. The suitability of these crystals for thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimetry was also investigated. The material showed adequate OSL and TL characteristics, such as a TL glow curve with two peaks at approximately 205 °C and 325 °C, an adequate OSL decay curve, good reproducibility, and linearity of the luminescent signals, when irradiated with doses of between 200 mGy and 150 Gy. Two trapping centers located at 0.77 and 1.02 eV were revealed. The heating rate dependence was also evaluated. The lowest detectable dose was investigated by the TL and OSL techniques, and the results were presented in mGy for both methods. It was also observed that co-doping with Mn and Tb contributed to a reduction in fading compared to CaSO4:Mn and CaSO4:Tb.