Feasibility of using oxyorthosilicates as optically stimulated luminescence detectors

Abstract

Abstract The goal of this study is to determine if cerium-doped oxyorthosilicate scintillators can be used as Optically Stimulated Luminescence (OSL) detectors, possibly offering alternative OSL materials as well as allowing the design of instruments combining passive (OSL) and active (scintillation) detection. The OSL of three common scintillators, Y 2 SiO 5 :Ce (YSO), Gd 2 SiO 5 :Ce (GSO), and Lu 2 SiO 5 :Ce (LSO), were tested. The property which makes these compounds good scintillators, efficient recombination of electron-hole pairs created by ionizing radiation, should make them poor candidates for OSL materials, since OSL requires the creation of electron-hole pairs trapped separately in defects in the crystal lattice. However, defects in the crystal structure can provide a pathway for the OSL phenomenon to take place. Based on the stimulation and emission OSL spectra of the oxyorthosilicates, a CW-OSL reader was built and used to test the samples' OSL capabilities. The results showed that YSO showed promising OSL, characterized by a strong initial OSL intensity and fast OSL decay, while GSO and LSO were impractical for OSL applications due to low response and high background signal, respectively. Further characterization of YSO included the determination of the OSL dose response and the characteristics of OSL decay curves. The results are compared to carbon-doped aluminum oxide (Al 2 O 3 :C), a common OSL dosimetric material.