Tinkova V. Obtaining micro- and nanopowders ZnWO4 for composite scintillators

Thesis is devoted to the development of technological approaches for obtaining scintillation micro- and nanopowders of ZnWO4, composite materials based on them, also to the study of its functional characteristics. The conditions for obtaining nanocrystals with controlled morphology (obtained “grains” 30-50 nm in length and “rods” up to 250 nm in length) by the method of hydrothermal synthesis with microwave heating were determined. It was shown that the X-ray luminescence intensity of “nanorods” exceeds that for “grains” by almost an order of magnitude. The X-ray luminescence intensity of the obtained “nanorods” is 20% relatively to the crushed ZnWO4 single crystal. By the method of solid-phase synthesis using LiNO3 as a mineralizer, a single-phase ZnWO4 micropowder was obtained, which in terms of X-ray luminescence intensity can be compared with a crashed ZnWO4 single crystal. It is shown that the composite scintillator based on the obtained micropowder in light output was at the level of the composite of crushed ZnWO4 single crystal, and could be compared with single crystal CdWO4. The resulting composite scintillators are promising in computed tomography, nuclear safety systems and non-destructive testing. Key words: luminescent nanopowders, luminescent micropowders, zinc tungstate, mixed nanocrystals, composite scintillators.