Abstract:

Polycrystalline samples of (Gd_1-xY_x)₂Si₂O₇: Ce(x=0.1, 0.2, ...0.7, 1) were prepared through solid state reaction method. The serial samples were screened through scintillation luminescent efficiency i.e. X-ray excited luminescence spectra. The luminescence efficiency of (Gd_0.5Y_0.5)₂Si₂O₇: 0.1%Ce sample was found to be the highest among all samples. The single crystal with this composition was grown by floating zone method. The structure, photoluminescence and scintillation luminescence properties of as grown sample were measured and discussed. The structure of the as grown single crystal was determined by XRD spectrum. Photoluminescence properties were evaluated in terms of photoluminescence excitation and emission spectra and photoluminescence decay curves. The X-ray excited luminescence spectrum, γ-ray multi-channel energy spectrum and scintillation decay curve were measured. According to the measurement result, the as-grown single crystal had orthorhombic structure. The main luminescence peak is around 362 nm. Two-exponential decay curve with fast component of 30 ns and slow component of 211 ns occurs in the PL process due to the Gd(⁶I_J)→Ce(5d₃) nonradiative energy transfer. Slow component accounts for 87% of the total during the scintillation luminescence, which is resulted from the energy transfer and relative low Ce doping concentration. Light output of the as-grown single crystal sample is 90% of the cerium doped lutetium yttrium silicate scintillator.

Key words: scintillator, scintillation performance, mixing crystal, (Gd0.5Y0.5)2Si2O7: 0.1%Ce