Effect of Ce doping on scintillation characteristics of LiYF4 single crystals for γ-ray detection

Effect of Ce content on the γ-ray response of LiYF4 single crystals with four different Ce concentrations is reported. The LiYF4 crystals were grown by the micro-pulling down method (μ-PD) with Ce content ranged from 0.1 to 10 mol%. The emission spectra of all samples under α-ray (241Am) excitation are due to the Ce3+ 5d–4f transition and are characterized by a band at about 320 nm. The pulse height spectra under γ-quanta (137Cs) were successfully observed and light yields were evaluated to be about 2800±280 (2 mol%), 3000±300 (5 mol%), and 3700±370 (10 mol%) phs/MeV, respectively. The energy resolution decreased with increasing of Ce concentration as follows: 12±3 (2 mol%), 19±3 (5 mol%), and 30±22 (10 mol%) %, respectively. The α/γ ratio were evaluated to be about 0.18 (2 mol%), 0.175 (5 mol%), and 0.15 (10 mol%), respectively. The non-proportionality curve of specimen with Ce 5 mol% doping exhibited good proportionality. Furthermore, the decay time examined with pulsed X-ray irradiation, detected using a streak camera, decreased with increasing of Ce concentration.