Preliminary study of lithium tetraborate doped with Cu and in for external dosimetry.

A potentially tissue-equivalent dosimeter based on lithium tetraborate co-doped with Cu and In was successfully synthesized in two steps melting process. Basic material properties were characterized using Differential scanning calorimetry, X-ray diffraction, and Fourier Transform Infrared Spectroscopy, the dosimetric properties using Thermoluminescence. The highest sensitivity was observed for dopant concentrations of 0.1% Cu and 0.5% In. Tmax-Tstop analysis revealed the existence of eight individual peaks in the composite TL glow curve, which was confirmed by computerized glow curve deconvolution. A linear dose-response was seen up to about 30 Gy, for higher doses saturation effects occurred. The minimum detectable dose was estimated at about 670 μGy. TL peaks, with peak temperature above 150 °C faded to values between 3.3 and 14.9% of the respective of initial values after 70 days storage.