Growth and scintillation characterization of Ce³⁺-doped Rb₂LiGdBr₆ single crystals

Growth and scintillation characterizations of the newly developed cerium doped Rb₂LiGdBr₆ (RLGB) single crystals were investigated. RLGB, which belongs to bromo-elpasolite crystal family, was grown by the vertical Bridgman technique with nominally 1%, 5%, and 10% Ce³⁺-concentration (mole%). X-ray excited luminescence spectra show typical Ce³⁺ bands between 350 to 460 nm wavelength regions. A good energy resolution of 5.5% (FWHM) and light yield of 25,500±2600 ph/MeV for 662 keV γ-rays were observed at 5% Ce³⁺-concentration. Under γ-ray excitation, RLGB:Ce³⁺ crystals display multi-exponential decays with Ce³⁺ like decay components at 23 ns and 29 ns for 1% and 5% Ce-concentrations, respectively. From the results, it is expected that this scintillator could be used as a thermal neutron detector because of Li and Gd ions in the host lattice. Also, like other inorganic halide scintillators, it is very hygroscopic.