http://dspace.nbuv.gov.ua:80/handle/123456789/132698 2026-04-13T04:34:25Z http://dspace.nbuv.gov.ua:80/handle/123456789/140211 The influence of BaF₂ on scintillation properties of PbWO₄ crystal Youbao Wan; Jianxing Zhang; Rurong Wu; Sanfa Xing; Hui Yang PbWO₄ crystals doped with BaF₂ was grown up by using modified temperature-grads technique. The crystal defects were investigated by chemical etching. The XRD of the sample has shown that the peaks were at normal sites, but the lattice parameters was slightly larger than that of pure PbWO₄ crystal. The transmittance spectrum along c axis of the PbWO₄:BaF₂ crystal has evidenced a higher transmittance than that of pure PbWO4 crystal. The luminescence intensity of the 400-450 nm peak in X-ray excited luminescence spectrum of the PbWO₄:BaF₂ crystal is increased significantly, about twice than that of pure PbWO₄ crystal. The light yield of BaF₂ doped PbWO₄ crystal was enhanced up to 2.5 times. These results show that BaF₂ doping of PbWO₄ can improve scintillation properties of the crystal for medium-energy particle detection. 2007-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/137215 Nanoscale Co/C multilayers for "carbon window" Schwarzchild objective Bugayev, Ye.A.; Devizenko, A.Yu.; Zubarev, E.N.; Kondratenko, V.V. The formation features of the Co/C multilayer with ≈2.3 nm period have been studied with aim to form a Schwarzschild objective on a "carbon window" for medical and biological investigations. A sequence of multilayer deposition on curved substrates has been proposed that provides the matched functioning of both objective mirrors. The interaction features of the Co and C layers during deposition, period and reflectivity changes under heating have been considered. 2007-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/136998 Multilayer X-ray mirrors Mo-B₄C- new crystals-analyzers for wavelength range of 5 to 12 A Kopylets, I.A.; Baturin, A.A.; Mikhailov, I.F. Structure and X-ray optical properties of Mo—B₄C multilayer mirrors with period from 13.2 to 33.8 A have been studied. The reflectivity values for the Mo—B₄C mirrors and the traditionally applied RbAP crystal (2d = 26.5 A) have been measured in the 4.7 to 11.9 A range. The interlayer boundary roughness attaining 3 A was found to be the main structure cause of the reflectivity drop with decreasing mirror period. The Mo—B₄C multilayer X-ray mirrors have been shown to provide 2 to 5 times intensity gain as compared to RbAP ones and to be the promising broadband diffraction elements. 2007-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/136996 Preparation of tungsten crucibles starting from tungsten fluoride Gorenko, Yu.V.; Korzh, A.F.; Lytvynov, L.A.; Semyonov, N.A.; Hovansky, N.A.; Shirokov, B.M. The study results are presented on technology development for forming of cylindrical tungsten crucibles starting from tungsten fluoride by reduction WF₆ with hydrogen in horizontal flow-type reaction under reduced pressure. It has been shown, that one way to nonporous with smooth outer surface, heigh surface purity and high strength consist in the deposition process realization in diffusion area at 550°C and the partial pressures ratio in the gas mixture PH₂/PWF₆ = 10/1 2007-01-01T00:00:00Z