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Information × Registration Number 0218U002325, 0115U003279 , R & D reports Title Scintillators based on the complex oxide compounds: peculiarities of luminescence and energy transfer processes popup.stage_title Head Zorenko Yuriy, Registration Date 14-02-2018 Organization Ivan Franko National University of Lviv popup.description2 In this work, the luminescent and scintillation properties of scintillators on the basis of single crystalline films (SCF) of garnets and orthosilicates were investigated in comparison with their analogues in the form of single crystals (SC) and ceramics. The differences in properties are mainly due to the difference in the concentrations of the main types of defects of the oxides studied (antisites defects, oxygen vacancies and their aggregates) due to significant differences in the composition of the gas atmosphere and the crystallization temperatures of these materials from the melt by Czochralsky (1750-2100 оС), melt- solution by a method of liquid-phase epitaxy (1000-1100 оС) and solid phase reactions (1000-1750 оС). The defects of the structure of garnets and orthosilicates form in the SC, SCF and ceramics of these compounds the centers of capture of charge carriers of both signs and significantly slow down the processes of transferring the excitation energy from the matrix to the centers of luminescence (Pr3 + and Ce3 + ions), and also reduce the light output of scintillations. When performing this research, new methods of reducing the influence of defects and impurities of flux components on the scintillation properties of garnet and orthosilicate crystallized in the forms of SC, SCF and ceramics were tested. In particular, as the latest methodological approach to achieve this goal, a combination of engineering band gap and the position of radiation levels of Ce3+ and Pr3+ ions as well as the energy levels of other impurities in the forbidden zone of the studied oxides Y3Al5O12 and Lu3Al5O12 doped with doped C3+ and Pr3+ by replacing part of Al3+ cations in different crystallographic positions of garnets on Ga3+ ions and orthosilicates Y2SiO5 and Lu2SiO5 by replacing part of cations Y3+ / Lu3+ with Gd3+ ions. The purpose of such engineering of the energy structure of the matrices of the investigated materials and impurities of Ce3 + and Pr3 + as well as of other ions and defects was: (i) to reduce the influence of defects in the structure of garnets and orthosilicates on the processes of transferring the energy of excitation from the matrix to the centers of luminescence by burning their energy levels by the levels of zones allowed energies; (ii) optimization of the width of the band gap of these oxides; (iii) the optimization of the distances, respectively, between the main and radiation levels of the Ce3+ and Pr3+ ions and the edge of the valence band and the bottom of the conduction band. For this purpose, the LPE method was used to growth Ce3 + and Pr3+ doped SCF doped solid solutions of A3Al5-xGaxO12 garnet and A2-xGdxSiO5 (A = Lu, Y) orthosilicates with different concentrations of gallium and gadolinium ions in their composition from melt- solutions based on PbO- B2O3 and BaO-B2O3-BaF2 fluxs, as well as their optical and scintillation properties was studied. The X-ray microanalysis method was used for measured the composition of SCFs and established the Ce3+ and Pr3+ and Ga3+ and Gd3+ cation segregation coefficients under using YAG and Gd3Al2.5Ga2.5O12 (GAGG) and Y2SiO5 substrates for the crystallization of these SCFs. The study of morphology and surface structure of the obtained SCFs by the method of electron microscopy was performed. The X-ray diffraction method has been used to study the structural perfection of the SCF and the values of the film-substrate mismatch. The influence of growth conditions on the luminescence and scintillation properties of Ce3+ and Pr3+ doped SCF garnets A3B5O12 (A = Lu, Gd, Y; B = Al, Ga) and orthosilicates A2SiO5 (A = Lu, Y, Gd) with different cations ratio in their matrix was investigated. The study of the peculiarities of luminescence and the processes of transferring the excitation energy in the SCFs of these garnets and otrosilsilicates in comparison with their SC analogues by traditional methods of optical spectroscopy with the involvement of the results obtained using synchrotron radiation to excite the luminescence of these compounds was carried out. According to the results of the work published 26 articles in journals from the list of JCR and one monograph. The results were presented in 34 reports at international conferences, 3 patents of Ukraine were received on the utility model. Product Description popup.authors Горбенко Віталій Іванович popup.nrat_date 2020-04-02 Close