Defect Optical and Scintillation Properties of Lu_2Si_2O_7:Ce Single Crystal Grown by Floating Zone Method

Floating zone(Fz) method was employed to grow the Lu2Si2O7(LPS):0.5%Ce single crystal.The crack,defect,optical and scintillation properties of LPS:Ce were studied.The electron probe microanalysis(EPMA),transmittance spectrum,X-ray excited luminescence(XEL) spectra,photoluminescence spectra and decay curves(from 77 K to 500 K) were recorded.The cleavage and thermal stress cracks are detected in the as-grown crystal.Two kinds of inclusions are found through the EPMA: one is [Si3O9]6-and 2 [SiO 3]n anion radicals and the other is the excess SiO 2.Part of Ce 3+ in the LPS:Ce sample was oxidized into Ce4+ in the air growth atmosphere.Fz grown LPS:0.5%Ce sample presents high luminescence efficiency,which is 32000 ph/MeV.As the temperature increases,the photoluminescence curves move towards the longer wavelength direction and broaden,leading to the increasing self-absorption.The rollover point of the decay time locates at 450 K,indicating that the LPS:Ce scintillator is a kind of high performance scintillator which can be applied in the high temperature environment.