Optical and radioluminescence properties of Ce-doped Sr2RE8(SiO4)6O2 (REÂ =Â Y, Gd, Lu)

Ce-doped Sr2Y8(SiO4)6O2, Sr2Gd8(SiO4)6O2 and Sr2Lu8(SiO4)6O2 (SrYS, SrGS and SrLuS, respectively) apatite crystals were grown by the Floating Zone method, and their optical and radioluminescence (RL) properties were characterized. In the photoluminescence (PL) and RL spectra, we observed an emission band between 400 and 500 nm for all the samples, which were due to the 5d-4f transition of Ce3+. The RL decay time profiles were approximated by a sum of two exponential decay functions, and the origin of faster decay component was due to the 5d-4f transition of Ce3+. Among all the samples, SrGS sample showed the lowest afterglow level. In the pulse height spectrum, all the samples showed a full energy absorption peak under 241Am 5.5 MeV α-ray irradiation. The absolute scintillation light yields of SrYS, SrGS and SrLuS were around 31, 76 and 940 ph/5.5 MeV-α, respectively.