Melt processing of alumina in graphite ambient for dosimetric applications

Carbon-doped alumina samples were prepared by a simple process involving melting of polycrystalline alumina powder in graphite environment. The melting was carried out using an electron gun of a vacuum deposition system meant for deposition of thin films. The samples showed excellent thermoluminescence (TL) and optically stimulated luminescence (OSL) response in the dose range 3 mGy to 1 Gy. Defect centers in the prepared material, as determined by excitation spectra, were found to be similar to those of commercial α-Al2O3:C single crystals. Samples were found to be suitable for radiation dosimetry, with a detection threshold of 50-μGy. Fading in the dark has been found to be<2% for a period of 2 months at room temperature. The variation in OSL response among the samples processed under similar conditions was found to be within ±14%.