Galenin E. Obtaining of BGO-BSO scintillation crystals with the eulitine structure from melt.

The work is devoted to the development of technological approaches to increase the obtaining efficiency of scintillation crystals with the eulitine structure from the melt. Bi4(GexSi1-x)3O12 crystals with the enhanced parameters were obtained due to improving of optical transparency in luminescence band of crystals. The developed optimized growth atmosphere composition О2:Ar=3:97 provided the enhancement of transmission in the luminescence band and improvement by 0,5% the energy resolution at irradiation with 662 keV γ-quanta by 137Cs). The growth conditions of Bi4Ge3O12 (BGO) crystals with the diameter up to 82 mm by the conventional Czochralski method were determined. This enabled the production of Ø76x76 mm scintillation detectors without increasing the size of the platinum crucible and crystallizer. Minimizing the residual raw material amount in the crucible up to 5% from the initial raw material weight, combining the crucible loading with melt and crystal growth in one heating cycle provides the increase of the platinum crucible lifetime by more than 3 times. For the first time, shaped BGO crystals were obtained in the form of rods with the diameter up to 20 mm and plates with the cross section up to 3x40 mm2 and the length up to 100 mm. The results of this work are implemented in BGO crystals production in ISMA NAS of Ukraine. Keywords: crystals with the eulitine structure, gaseous inclusions, Czochralski method, EFG method, crucible lifetime, large-size crystals.