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Galenin E.,Institute for Scintillation Materials of Ukraine | Baumer V.,SSI STC Institute for Single Crystals NAS of Ukraine | Gerasymov I.,Institute for Scintillation Materials of Ukraine | Tkachenko S.,Institute for Scintillation Materials of Ukraine | Sidletskiy O.,Institute for Scintillation Materials of Ukraine
Crystal Research and Technology | Year: 2015

Bismuth germanate shaped crystals have been grown by the EFG (Stepanov) method. The correlation between growth rate, shape of crystals, their optical and scintillation parameters has been analysed. Optical and scintillation characteristics of the EFG crystals are similar to those obtained with Czochralski grown crystals, however, growth rate in EFG is by 2.5 times larger. Also we compare the photochromic effect under UV-irradiation in EFG and Czochralski grown crystals. Material losses at fabrication of plates, pixels, and rods from EFG shaped plates may be reduced by ∼50% compared to large diameter boules. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

Deineka T.G.,Institute for Single Crystals | Doroshenko A.G.,Institute for Single Crystals | Mateychenko P.V.,Institute for Single Crystals | Tolmachev A.V.,Institute for Single Crystals | And 5 more authors.
Journal of Alloys and Compounds | Year: 2010

A new precursor of yttrium aluminum garnet with an approximate composition of NH4AlY0.6(CO3)x(OH) y(SO4)z·nH2O has been synthesized via a reverse strike co-precipitation method with ammonium hydrogen carbonate as the precipitant and ammonium aluminum sulfate as the sulfate ions source. The evolution of phase, chemical composition and morphology of the precursor during calcination has been studied by means of XRD, XPS, DTA-TG, BET methods and FT-IR spectroscopy. The loosely agglomerated powders with narrow size distribution, spherical shapes and diameter of 50-60 nm have been obtained by calcination of the sulfate-containing precursor at 1100 °C for 2 h. The doping by sulfate ions enhances densification of Y3Al 5O12:Nd3+ nanopowders compared to undoped ones. This leads to improved microstructure and optical transmittance of vacuum sintered ceramics prepared from sulfate-doped nanopowders. © 2010 Elsevier B.V. All rights reserved.

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