Dual electrical and optical detection of ionizing radiation: Radiation-induced currents and radioluminescence in NaMgF3:Sm

Abstract Simultaneous optical and electrical detection of ionizing radiation was achieved using near tissue-equivalent NaMgF3:Sm. The electrical characteristics of the system were capacitive and ohmic and the resistivity of the compound was on the order of 1013 Ω cm. During exposure to X-rays, the compound exhibited both radiation-induced electrical conductivity and radioluminescence from Sm2+ and Sm3+. Initially, strong dose history dependences were observed for both detection methods. The radiation-induced current stabilized after a priming dose and increased with dose rate according to a power law with an exponent Δ = 0.73, and the radioluminescence intensities increased linearly with dose rate. The mobility-lifetime product of the dominant charge carriers was high and estimated to be 1.6 × 10-4 cm2/V. Our results show that dual detection of ionizing radiation is possible using NaMgF3:Sm where the minimum detectable dose rates were 46 μGys-1 and 1.5 mGys-1 for the electrical and optical detection techniques, respectively.