High-light-output scintillator for photodiode readout:: LuI3:Ce3+

In this paper, we investigated the scintillation properties of LuI3:Ce3+. Radioluminescence, light output, energy resolution, and gamma-scintillation decay are reported. We find an extremely high light output of 98 000 +/- 10 000 photons/MeV. LuI3:Ce3+ also gives a very high electron-hole (e-h) pair response when it is coupled with an avalanche photodiode (APD) (92 000 +/- 9000 e-h pairs/MeV). With an APD, a best energy resolution (full width at half maximum over the peak position) of 3.3%+/- 0.3% for 662 keV gamma quanta is observed. A combination of an extremely high light output and a good energy resolution makes LuI3:Ce3+ an ideal scintillator for radiation sensor applications. Some drawbacks due to the hygroscopicity and the difficult growth of LuI3:Ce3+ crystals are also discussed.