Exploring the luminescence properties and dosimetric characteristics of CaSO4:Tb, CaSO4:Mn, and CaSO4:Mn,Tb phosphors synthesized by slow evaporation route

Abstract

This work aimed to investigate and compare the luminescence properties of CaSO4:Tb, CaSO4:Mn, and CaSO4:Mn,Tb synthesized by slow evaporation route. The crystalline structure, morphology, and optical properties of the phosphors were characterized by X-ray diffraction analysis (XRD), photoluminescence (PL), radioluminescence (RL), and scanning electron microscopy (SEM). In addition, thermoluminescence (TL) and optically stimulated luminescence (OSL) were used to comprehensively investigate the dosimetric properties of the phosphors, such as the TL glow curve and continuous wave OSL (CW-OSL) curves, dose-response and its reproducibility, fading, and sensitivity. For dosimetric analyses, the samples were irradiated with beta radiation. PL and RL emission spectra confirmed the presence of Tb3+ and Mn2+ ions in crystalline matrices. The samples showed a typical exponential OSL decay curve, indicating that the charge traps have a high photoionization cross-section for blue LEDs. The synthesized pellets exhibited good luminescent and dosimetric properties, with linear luminescent response over a wide dose range (169 mGy–100 Gy) and reproducibility of both OSL and TL signals. Furthermore, the incorporation of terbium as a co-dopant in the CaSO4:Mn matrix reduced its fading from 75% to only 17%. The phosphors had high TL and OSL sensitivities in comparison to some commercially available dosimeters.