부산대학교 도서관

A TOC scintillator material, lanthanum yttrium oxide ((La,Y)2O3) has been investigated at RMD. The X-ray excited emission shows a broad band that peaks at ∼ 415 nm, originating from the host lattice. Under gamma-ray excitation the emission decays with a fast time constant of ∼ 17 ns, and multiple slower components. The temperature dependence of LYO was studied in the −30°C to +50°C range. The relative light output decreases with the increase in the temperature, whereas, the energy resolution was observed to be fairly constant. The scintillation light yield of the material estimated by a comparison with a BGO single crystal is ∼21,000 photons/MeV. Energy resolution of 4.9% at 662keV (FWHM) was also measured. The composition shows good proportionality in the 60 keV to 1275 keV energy range, with only ∼ 2% deviation from the linear response at 60 keV. The scintillation properties will be further improved by optimization of La concentration and optical quality of the ceramics. The material is not hygroscopic and scale up to large sizes is possible due to cubic structure of Y2O3. Overall, LYO seems to be a very promising material for gamma-ray spectroscopy.