Thermoluminescence response of a BeO ceramic dosimeter in therapeutic proton beam

BeO ceramics (Thermalox & REG; 995, Materion Corp.) can function as thermoluminescent dosimeters (TLDs) with a tissue-equivalent effective atomic number and sufficient high solidity which can be used as postal dosimeters. To evaluate the feasibility of employing BeO ceramic in proton dosimetry, we investigated the dose-response and the linear energy transfer (LET) dependence of a BeO ceramic TLD. As the BeO ceramic TLDs exhibit two glow peaks, the dose-responses of the integral thermoluminescence (TL) signals for the low-temperature (G(L)) and high-temperature (G(H)) glow peaks, as well as those for entire TL signal (G(T)), were all investigated in this study. The irradiation doses were 0.5, 1.0, 2.0, and 5.0 Gy, and the LET dependence of the TL efficiency was investigated between 0.53 and 7.42 keV & mu;m(-1). All experiments were performed using a 160 MeV proton beam at NIRS-HIMAC in Japan. The TL intensities of G(L), G(H), and G(T) increased with increasing irradiation dose. The relation between the TL intensity and irradiation dose could be expressed as a function of a quadratic polynomial equation. The TL efficiencies of glow peaks (G(H) and G(T)) decreased with decreasing LET, while no significant correlation was observed between G(L) and LET. The shape of the glow curve of the BeO ceramic depends on the irradiation dose and LET.