Gamma-ray induced thermoluminescence kinetic analysis of La³⁺-doped SrMnO₃ phosphor using multi method glow curve...

The thermoluminescence (TL) kinetic study of La³⁺-doped SrMnO₃ (LSMO) phosphors was conducted to characterize their trapping behavior under gamma irradiation. LSMO phosphors were synthesized via a sol-gel method, followed by calcination at 800 ^°C for 4 h. The structural and morphological characteristics were examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. Gamma-induced TL measurements were performed after irradiation with 50 Gy of ¹³⁷Cs gamma radiation under controlled experimental conditions. The glow curve measured at 5 K s^-1 was resolved into seven overlapping components using computerized glow-curve deconvolution (CGCD). The kinetic parameters were determined using the Peak Fit Procedure (PFP), Peak Shape Method (PSM), and Variable Heating Rate (VHR) methods. The calculated activation energies ranged from 0.86 to 2.31 eV for PFP, 0.83-2.25 eV for PSM, and 1.003-2.69 eV for VHR, reflecting the different kinetic assumptions and calculation procedures of the three methods. The deconvolution showed good agreement between the experimental and fitted glow curves, with R² = 0.99936, adjusted R² = 0.99917, FOM = 2.3%, and p < 0.00001. These results provide a detailed characterization of the trapping structure and TL kinetic behavior of LSMO under the investigated gamma irradiation dose and measurement conditions.