Czochralski growth of 4-inch diameter Ce:Gd3Al2Ga3O12 single crystals for scintillator applications

Ce-doped Gd3Al2Ga3O12 single crystals 4 in. in diameter were grown by the Czochralski technique. Three main growth problems were identified: formation of Ir particles on the surface of the melt, Ga oxide evaporation and crystal cracking during the cooling stage. These problems were solved by careful selection of the ceramic hot zone, shift of the growth atmosphere from Ar + O-2 to N-2 + CO2 and application of an original post-growth cooling technique. It was found possible to grow up to five sequential 4-inch crystals from the same melt without any notable decrease in the scintillation properties. The optimal solidification fraction (0.23) was found. Additionally, a 4-inch Mg,Ce co-doped Gd3Al2Ga3O12 crystal was grown under the same conditions.