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Low temperature thermoluminescence of GAGG:Ce and LuAG:Pr scintillator crystals has been studied by means of the Tmax-Tstop method. It is shown that the glow curves of both materials are superpositions of discrete glow peaks and broad bands due to quasi-continuous Gaussian distributions of trapping levels. A model function has been built and trap parameters have been evaluated. [ABSTRACT FROM AUTHOR]

Eu doped SrI2 [Eu:SrI2] bulk single crystals with 1 in. diameter were grown using a special-shaped carbon crucible and a modified micro-pulling-down furnace and their scintillation properties were investigated. As-grown Eu:SrI2 bulk crystals indicated high transparency while they included several cracks in the crystals. Grown crystals indicated a single phase of SrI2 structure in the powder X-ray diffraction measurement. In the X-ray radioluminescence spectrum, there was a sharp emission peak around 435 nm which originated from 5d-4f transition of Eu2+ ion. Light yields of Eu5% and 7.5%:SrI2 crystals under γ-ray irradiation from 137Cs radiation source were 83,000 and 85,000 ph/MeV, respectively. Their decay times under γ-ray irradiation were approximately 2 μs. [ABSTRACT FROM AUTHOR]

Eu:SrI2 and La, Gd or Lu co-doped Eu:SrI2 single crystals were grown by a modified micro-pulling-down method and the effects of rare-earth (RE) co-doping on the crystal growth and scintillation properties were investigated. RE-free Eu7.5 mol%:SrI2 and La, Gd or Lu 1 mol% co-doped Eu7.5 mol:SrI2 single crystals with high transparency were obtained. The powder X-ray diffraction measurements revealed that all the grown crystals had a single phase of SrI2 structure. In the X-ray radioluminescence spectra, emission peaks around 435 nm were observed for the Eu:SrI2 and La co-doped Eu:SrI2 specimens. The light yield of the La co-doped Eu7.5%:SrI2 specimens were lower than that of the RE-free Eu7.5%:SrI2 specimen due to the generation of some defects by La co-doping. [ABSTRACT FROM AUTHOR]

Al-doped Ca3TaGa3Si2O14 single crystals with various Al concentrations were grown by the micro-pulling-down method and their structure and chemical composition were investigated. Ca3Ta(Ga1-xAlx)3Si2O14 crystals with x=0, 0.2, 0.4, 0.6, 0.8 and 1 were grown. They were highly transparent and a single phase of langasite-type structure was confirmed in the powder X-ray diffraction measurement. Their lattice parameters related to the a- and c-axes systematically decreased with increase in Al concentration. It followed from the EPMA analysis that the real Al concentration in the crystals almost corresponded to the nominal compositions. [ABSTRACT FROM AUTHOR]

Single crystals of orthorhombic and monoclinic BaLu2F8 doped with Nd and Tm were grown by micro-pulling-down method. The monoclinic (low temperature modification) was grown using LiF flux, while the orthorhombic (high temperature modification) was grown with special hot-zone with shallow gradient and employing quenching process. Reasonable scintillation efficiency was achieved for the crystals of the former modification, while no rare-earth ion emission was observed in the latter due to preferential energy transfer to defects. The orthorhombic (low temperature) modification of ErF3 was grown using LiF flux and hot zone with steep gradient. Quite low scintillation efficiency was found for the Nd-doped sample due to energy migration over the Er3+ levels. Possibility of using pure ErF3 as an infra-red scintillator is discussed. [ABSTRACT FROM AUTHOR]