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Description
This study investigates the thermoluminescence (TL) response of LiMgPO₄:Al dosimeters under different radiation fields. A comparative analysis was performed using two radiation sources with distinct linear energy transfer (LET) characteristics: a ⁹⁰Sr/⁹⁰Y beta source (low LET) and a ²²⁶Ra source emitting α, β, and γ radiation (mixed field with high-LET contribution). For ⁹⁰Sr/⁹⁰Y irradiations, TL detection was performed in the UV region, while for ²²⁶Ra irradiations, it was performed in the visible region. Beta irradiations were carried out in the dose range of 63 – 625 mGy. TL glow curves obtained under UV and beta irradiation exhibited two well-defined peaks at approximately 116 °C and 210 °C. The TL glow curve was deconvoluted using general order kinetic analysis, identifying three peaks with temperatures at 115, 199, and 215 °C. Activation energies of 0.82 and 0.84 eV were determined for shallow traps, and up to ~1.62 eV for deeper traps. The kinetic order parameter (b) was 2.0; 1.0; 1.5, and the frequency factor (s) was 1.316×10¹⁰; 1.748×10⁸; 2.191×10¹⁶ s⁻¹. The figure of merit (FOM ≈ 1.22) demonstrated excellent deconvolution fitting. The dose–response curve showed high linearity (R² > 0.999), indicating homogeneous trap filling under low-LET radiation. Under ²²⁶Ra irradiation, TL peak temperatures shifted to 161 °C and 219 °C, with increased asymmetry and greater contribution from deeper traps. The deconvolution of the TL curves revealed three peaks at 157, 224, and 228 °C, with activation energies of 0.61, 0.97, and 1.17 eV, and FOM ≈ 1.64. These results reflect greater structural complexity under mixed radiation fields. The findings confirm the robustness of the TL response of LiMgPO₄:Al and highlight the dependence of kinetic parameters on radiation quality, expanding its applicability across different dosimetric contexts.