Undoped and Eu doped LaCa₄O(BO₃)₃ phosphors: Thermoluminescence characteristics with a focus on kinetic parameters, anomalous heating rate, and dose response

• Published in: Ceramics international 2024-11
• Main Authors: Bulcar, K., Portakal-Uçar, Z.G., Zelai, T., Souadi, G., Hakami, O., Kaynar, U.H., Madkhali, O., Topaksu, M., Can, N.
• Format: Article
• Language: English
• Subjects: Anomalous heating rate; Dose response; Glow curve deconvolution; Kinetic parameters; LaCa₄O(BO₃); Thermoluminescence
• ISSN: 0272-8842
• DOI: 10.1016/j.ceramint.2024.11.094

The thermoluminescence (TL) properties of LaCa₄O(BO₃)₃ (LACOB) phosphors, both undoped and doped with 0.5 % Eu³⁺, were synthesized using a microwave-assisted sol-gel method and analysed under beta irradiation doses ranging from 0.1 Gy to 700 Gy. The TL glow curves revealed prominent peaks at 100 °C and 285 °C for the Eu-doped sample. Activation energy values were calculated using the Hoogenstraaten and Booth-Bohun-Parfianovitch methods, yielding 1.52 eV and 1.48 eV for the undoped sample, and 2.07 eV and 2.01 eV for the Eu-doped sample, respectively. Eu³⁺ ions introduced deeper traps and enhanced the thermal stability of the material. Anomalous increases in TL intensity with rising heating rates were observed, deviating from typical thermal quenching behaviour; this phenomenon was explained using a semi-localized transition (SLT) model. The TL reusability measurements demonstrated a standard deviation of less than 5 %, indicating consistent and reliable performance across multiple cycles. The TL glow curve deconvolution identified six distinct peaks in the undoped sample, while the Eu-doped sample showed a more complex trap structure with eight peaks, indicating the introduction of additional or modified trapping sites by Eu doping. The figure of merit (FOM) values obtained from the deconvolution analysis were all below 2.5 %, indicating a good fit between the observed and fitted TL signals. These findings suggest that Eu³⁺-doped LACOB is a robust material for radiation dosimetry, with its enhanced sensitivity, stability, and versatility across various dosimetric applications.