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Eu 2+ :CeBr 3 crystals were grown by vertical Bridgman growth method and slight aliovalent doping of Eu 2+ in the CeBr 3 crystal did not change the crystal structure. The X-ray stimulated luminescence, photoluminescence, decay kinetics and scintillation properties were investigated at room temperature. The X-ray stimulated luminescence spectra exhibited wide broad emission bands from 3.54 eV to 2.95 eV in the Eu 2+ :CeBr 3 crystal with high content of 620 ppm of Eu 2+ , which were the overlap of the emission bands ascribed to 5d → 4f transition of Ce 3+ and 4f 6 5 d 1 → 4f 7 transition of Eu 2+ , respectively. When the content of Eu 2+ was decreased to 70 ppm, another emission band centered at 2.29 eV was observed. The photoluminescence spectra showed the energy transfer from Ce 3+ to Eu 2+ . This decreased the Ce 3+ emission intensity but enhanced the Eu 2+ emission intensity. The photoluminescence decay time of Ce 3+ emission decreased from 14 ns to 10 ns when the content of Eu 2+ increased from 70 ppm to 620 ppm. The decay time of the emission of 525 nm did not change with the excitation wavelength and Eu 2+ content, which could be assigned to the excitons that were bound on Eu 2+ related centers. The light output of the Eu:CeBr 3 crystal under the excitation of 241 Am radioactive source was less than 20.2% of Tl:NaI crystal. [ABSTRACT FROM AUTHOR]

Multicomponent garnets, due to their excellent light yield and energy resolution, become one of the most promising scintillators used for homeland security and nuclear non-proliferation applications. This work focuses on the optimization of Ce-doped (Gd,Y) 3 (Ga,Al) 5 O 12 scintillators using a combination strategy of pre-screening and scale-up. Ce-doped Gd x Y 1− x Ga y Al 5− y O 12 ( x =1, 2 and y =2, 2.2, 2.5, 2.7, 3) polycrystalline powders were prepared by high-temperature solid state reaction method. The desired garnet phase in all the samples was confirmed using X-ray diffraction measurement. By comparing the radioluminescence intensity, the highest scintillation efficiency was achieved at a component of Gd 2 Y 1 Ga 2.7 Al 2.3 O 12 :Ce powders. A (Gd 2 Y 1 )Ga 2.7 Al 2.3 O 12 doped with 1% Ce single crystal with dimensions of Ø35×40 mm was grown by Czochralski method using a <111> oriented seed. Luminescence and scintillation properties were measured. An optical transmittance of 84% was achieved in the concerned wavelength from 500 to 800 nm. Its 5d–4f emission of Ce 3+ is at 530 nm. The light yield of a Ce1%: Gd 2 Y 1 Ga 2.7 Al 2.3 O 12 single crystal slab at a size of 5×5×1 mm 3 can reach about 65,000±3000 Ph/MeV along with two decay components of 94 and 615 ns under 137 Cs source irradiation. [ABSTRACT FROM AUTHOR]

LiCaAlF 6 single crystals doped with different Eu concentrations varied from 1 at% to 5 at%, and LiCaAlF 6 :Eu single crystals co-doped with 3 at%Cu+, 2 at%Mg2+, 2 at%Ba2+ were grown by the Bridgman method in non-vacuum atmosphere. Their optical and scintillation performances were studied. The optimal scintillation efficiency was achieved in the LiCaAlF 6 :Eu single crystals with Eu concentrations between 2 and 2.5 at%. The influences of Cu+, Mg2+ and Ba2+ co-doping on optical properties, scintillation yield, scintillation decay and defect structures were studied. It was found that the Cu+ co-doping can improve the scintillation efficiency. The Mg2+ and Ba2+ co-doping have negligible effects on light yield. • Bridgman method in non-vacuum atmosphere were used to grow LiCaAlF 6 :Eu crystals. • The optimal scintillation efficiency obtained between 2 and 2.5 at%Eu concentration. • The Eu–Cu co-doping improve the scintillation efficiency than Eu doped LiCaAlF 6. • The Eu–Cu co-doping changed the defect structure than Eu doped LiCaAlF 6. [ABSTRACT FROM AUTHOR]