http://dspace.nbuv.gov.ua:80/handle/123456789/114618 Wed, 22 Apr 2026 16:00:57 GMT 2026-04-22T16:00:57Z http://dspace.nbuv.gov.ua:80/bitstream/id/341309/ http://dspace.nbuv.gov.ua:80/handle/123456789/114618 http://dspace.nbuv.gov.ua:80/handle/123456789/119261 IR spectroscopy of KBr salt and crystals Goriletsky, V.I.; Mitichkin, A.I.; Belenko, L.E.; Rebrova, T.P. The IR absorption spectra of the KBr salt pellets of different purity and crystals grown of them were investigated in the region of 400…4000 cm⁻¹. It was found that by the IR spectra of the KBr salt pellets suitable for growing optically pure crystals one can evaluate the KBr salt quality. Revealed in the IR spectra are not only the impurity oxygen-containing molecular anions and the adsorption water but also, indirectly through them, the most dominating cations of sodium, barium and calcium. Determined was the concentration, beginning from which sodium ions are observed in the IR spectra of the KBr salt pellets. The coefficient of proportionality between the concentration of sulfates in the KBr salt and the absorption coefficient of SO₄²⁻ ions at the frequency of deformation vibration n₄ was found. The latter allows to estimate quantitatively the sulfates in the KBr salt. Mon, 01 Jan 2001 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119261 2001-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/119260 Photoluminescence of pentacene solutions in n-pentyl-n-cyanobiphenyl Piryatinskiy, Yu.; Furier, M.; Nazarenko, V. We investigated photoluminescence (PL) spectra of pentacene (Pc) in the liquid- and solid-crystalline n-pentyl-n´-cyanobiphenyl (5CB) matrices. It was shown that the liquid-crystalline matrix behaves as a polar solvent relatively to Pc. Pc and 5CB molecules can form loosely bound donor-acceptor complexes. These complexes may be characterized with their PL spectrum and lifetime that are different from those of molecular Pc. Being heated up to 343 K these complexes are broken down, and Pc molecular radiation is observed in the PL spectra of solutions. Mon, 01 Jan 2001 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119260 2001-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/119259 Spectral properties of reflective interference filters Pervak, V.Yu.; Poperenko, L.V.; Pervak, Yu.A. The spectral properties of band reflective interference filters are investigated. The operation of the filter is based on the method of residual rays. Angular dependences of the filter transmission bandshape on the parameters of multilayer coating, such as the thickness, refractive indexes, the number of the layers, are analyzed. Mon, 01 Jan 2001 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119259 2001-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/119258 GSO: Ce³⁺ scintillator with a high energy resolution Bondar, V.G.; Gavrilyuk, V.P.; Konevskii, V.S.; Krivonosov, E.V.; Martynov, V.P.; Savvin, Yu.N. It is known that in case of registration of the scintillation light using photomultiplier energy resolution of the scintillation detector can be written as sum of three components, each of them is statistically independent of others: Rin - the value describing the dispersion of the light quantity which is formed in the process of radioluminescence and depends on the scintillator material; Rph - the value describing statistic variations of the number of photoelectrons knocked out from the photocathode by the scintillation photons, it is reversely proportional to the scintillator light output; Rt - the value corresponding to the non-uniformity of the light collection coefficient in different parts of the scintillator volume. In this paper the authors made an attempt to improve energy resolution of GSO(Ce) detector owing to lowering the latter two terms by varying the bulk optical properties and reflection characteristics of the surface by means of annealing. Energy resolution 8.5% by γ-line 662 keV from ¹³⁷Cs was achieved due to improvement of transparency and especially selected surface roughness of the cylindrical Gd₂SiO₅:Ce scintillator 27 mm in diameter and 90 mm long. Mon, 01 Jan 2001 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119258 2001-01-01T00:00:00Z