MgO:Li,Ce,Sm as a high-sensitivity material for Optically Stimulated Luminescence dosimetry.

The goal of this work was to investigate the relevant dosimetric and luminescent properties of MgO:Li3%,Ce0.03%,Sm0.03%, a newly-developed, high sensitivity Optically Stimulated Luminescence (OSL) material of low effective atomic number (Zeff = 10.8) and potential interest for medical and personal dosimetry. We characterized the thermoluminescence (TL), OSL, radioluminescence (RL), and OSL emission spectrum of this new material and carried out a preliminary investigation on the OSL signal stability. MgO:Li,Ce,Sm has a main TL peak at ~180 °C (at a heating rate of 5 °C/s) associated with Ce(3+) and Sm(3+) emission. The results indicate that the infrared (870 nm) stimulated OSL from MgO:Li,Ce,Sm has suitable properties for dosimetry, including high sensitivity to ionizing radiation (20 times that of Al2O3:C, under the measurement conditions) and wide dynamic range (7 μGy-30 Gy). The OSL associated with Ce(3+) emission is correlated with a dominant, practically isolated peak at 180 °C. Fading of ~15% was observed in the first hour, probably due to shallow traps, followed by subsequent fading of 6-7% over the next 35 days. These properties, together with the characteristically fast luminescence from Ce(3+), make this material also a strong candidate for 2D OSL dose mapping.