Very sensitive α-AlO:C polycrystals for thermoluminescent dosimetry.

New materials have been widely investigated for ionizing radiation dosimetry for medical procedures. Carbon-doped alumina (α-AlO:C) have been reported to be excellent thermoluminescent (TL) and optically stimulated luminescence (OSL) radiation dosimeters. In the present study, we have synthetized nano and micro-sized α-AlO:C polycrystals, doped with different percentages of carbon atoms aiming to compare their efficiency as TL dosimeters. The dosimetric characteristics for X ray and gamma fields were investigated. Samples doped with different amounts of carbon atoms were sintered under different atmosphere conditions, at temperatures ranging from 1300 °C to 1750 °C. Among the investigated samples, the micro-sized alumina doped with 0.01% of carbon and sintered at 1700 °C under reducing atmosphere, has presented a very high TL output. The main TL peak is centered at 250 °C and has a linear behavior with photon dose in the dose range of 0.02-to-5000 mGy, with correlation coefficient very close to one (0.99991). Samples produced by using nanosized alumina have shown much lower TL output when compared to the samples with microsized alumina. The micro-sized alumina obtained by the methodology used in this work is a suitable candidate to be explored for application in X and Gamma radiation dosimetry.