Thermoluminescence properties and trap-kinetic analysis of undoped BaZr(BO3)2 for β-radiation dosimetry

Abstract

This study presents the first comprehensive thermoluminescence (TL) and kinetic characterization of BaZr(BO3)2 phosphor. Structural analysis confirms a trigonal R3c phase, while TL measurements reveal intrinsic trapping centers and a dominant dosimetric peak at ~226 ◦C under 365 nm detection. A preheating protocol of 170 ◦C for 13 s effectively suppresses shallow traps and isolates the main peak. The dose–response exhibits linear behaviour up to ~20 Gy, followed by a supralinear trend up to 500 Gy. The material demonstrates good reusability with variations within ~3–5% and a minimum detectable dose in the sub-hundred-mGy range. Kinetic analysis, supported by temperature-lag correction, yields activation energies of ~1.7–1.8 eV, indicating the presence of deep and stable traps. Glow curve deconvolution and Tm–Tstop analysis reveal a hierarchical trap structure. The fading behaviour is non-monotonic, with an initial slight increase within the first few hours followed by a gradual decay; the peak intensity decreases by approximately 20–30% over 1–7 days, while the integrated TL signal shows a slower decay and approaches a quasi-plateau over time. These results indicate that BaZr(BO3)2 is a promising candidate for radiation dosimetry applications.