Dosimetric properties of germanium doped calcium borate glass for use as photon dosimeter

Abstract

Borate glasses have been widely studied due to their features as glass formers and present a very useful material for radiation dosimetry applications. The fundamental properties of germanium doped calcium borate glass; (30 -x)CaO 70B2O3: xGeO2 ( x = 0.1, 0.2, 0.3, 0.4 and 0.5 mol%) prepared using melt-quenching method were investigated. The physical properties including the amorphous state, density and molar volume were measured. The structural analyses were carried out using infrared transmission spectra and optical properties were determined from ultraviolet-visible optical spectra. Weight fraction obtained from energy dispersive X-ray spectrometry analysis leads to the determination of the effective atomic number of the sample. The total mass attenuation coefficients at photon energies of 0.662 MeV and 1.25 MeV were also calculated by using WinXCom software. Thermoluminescence properties measurements were performed by irradiating the glasses with 60Co gamma ray, 6 MV and 10 MV photon beam with doses ranging from 0.5 Gy to 4.0 Gy. The amorphous phases of the glass samples were identified from this study. The effective atomic number of glass sample was found to be between 11.70 to 12.52 for GeO2 concentration of 0.1 to 0.5 mol%. The values are quite close to the effective atomic number of the bone, which is 14. The densities, , molar volumes, optical band gap and refractive index indicate that GeO2 acts differently on the glass structure over their compositions. The glow curves were analysed to determine various thermoluminescence characteristics of the glass samples. The glass sample with GeO2 concentration of 0.1 mol% has the best thermoluminescence characteristics such as linearity, sensitivity, fading and reproducibility. In conclusion, germanium doped calcium borate glass has potential to be considered as thermoluminescence dosimeter.