Thermoluminescence characteristics, and potential feasibility of a homemade CaSO4: Er phosphor

Abstract

This research introduces a custom-prepared calcium sulfate (CaSO₄):Er thermoluminescent phosphor synthesized using the coprecipitation method. It focuses on its development, analysis, and potential uses. Structural identification was carried out through X-ray diffraction (XRD) and scanning electron microscopy (SEM), while thermoluminescence (TL) analysis investigated the dosimetric characterization such as gamma dose-response, thermal fading, reusability, and minimum detectable dose. This custom phosphor exhibited reasonable sensitivity to ionizing radiation, with a relative sensitivity of 19.4 ± 0.47 % compared to TLD-100. It is capable of detecting very low doses, down to 19.7 mGy. Based on the linearity index, the prepared phosphor exhibits linear-sublinear behavior between 0.5 and 200 Gy and linear-supralinear behavior up to 2 kGy and notable reusability (accuracy within 4 %). Thermal fading of 42 % after 24 h from irradiation followed by 15 % after 3 d with no significant fading during the remaining investigation time of 27 days was observed implying more future investigation and analysis of the recorded glow curve and the effect of thermal treatment of the prepared phosphor. In parallel, Diffuse Reflectance Spectroscopy (DRS) was used to examine pure and erbium-doped calcium sulfate samples. Optical transitions at 5.24 eV and 3.92 eV were observed in the pure samples while doping with Er³⁺ ions introduced additional transitions at 1.88 eV, 2.38 eV, 2.54 eV, and 3.24 eV. Photoluminescence measurements confirmed the successful incorporation of erbium ions, further illustrating the impact of doping on the material's electronic structure and optical properties. The findings enhance the development of radiation dosimeters for dosimetry applications and provide valuable insights into the viability of homemade CaSO₄: Er.