Li2B4O7 phosphor for beta particle dosimetry: Synthesis, structural and thermoluminescence performance

Abstract

We report the structural and thermoluminescent (TL) properties of Li₂B₄O₇ phosphor synthesized by a solid-state reaction method for radiation dosimetry. The Li₂B₄O₇ was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to determine the crystalline structure and morphology. The Li₂B₄O₇ samples were exposed to beta particle irradiation in a dose range from 1 to 1024 Gy. The TL glow curve showed three emission maxima at ∼ 123, 191 and 290 °C. The TL signal increased with increasing dose, with a linear dependence from 1 to 64 Gy. Remarkable reproducibility of the integrated TL response in 10 irradiation cycles was observed for the TL maximum at 191 °C, suggesting that Li₂B₄O₇ samples are reusable, especially for the dosimetric TL peak. The T_m-T_stop and computerized glow curve deconvolution (CGCD) showed that the TL glow curve of Li₂B₄O₇ consists of seven TL peaks, with five peaks showing a first-order trend (peaks 1, 2, 3, 5 and 6) and two peaks showing a second-order trend (peaks 4 and 7). The mass attenuation and energy absorption coefficients show that Li₂B₄O₇ exhibits similar behavior to human tissue when indirectly exposed to ionizing radiation. Li₂B₄O₇ exhibits a wide linearity range and a reliable response to high doses, positioning it as an optimal dosimeter for dosimetric applications where the dosimetric range of commercial dosimeters, such as the TLD-100, has limitations. This novelty is particularly important as Li₂B₄O₇ has an effective atomic number equivalent to that of human tissue. These results suggest that Li₂B₄O₇ phosphor is a promising candidate for clinical dosimetry applications such as radiotherapy and brachytherapy.