Optical and scintillation properties of Ti-doped α-Al₂O₃ single crystals

Ti-doped α-Al 2 O 3 single crystals with different Ti concentrations were grown using the floating zone method, and their optical and scintillation properties were systematically investigated. The synthesized samples exhibited photoluminescence spectra related to charge-transfer transitions of Ti 4+ ions and d-d transition of Ti 3+ ions. Photoluminescence decay times on the order of several tens of microseconds were obtained due to charge-transfer transitions of Ti 4+ ions. In terms of scintillation performance, both the emission peaks and decay times due to charge-transfer transitions of Ti 4+ ions and d–d transitions of Ti 3+ ions were observed. Pulse height spectra under α-ray excitation using a 241 Am source were evaluated. Among all the samples, the 0.5 % Ti-doped sample showed the highest light yield (approximately 880 photons/5.5 MeV-α) and good energy resolution (20 %).