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A comprehensive study of the electronic structure of trinuclear molybdenum complexes (NH4)2[Mo3S13] and [Mo3S7(dtc)3]Br with cluster core {Mo3S7} and [Mo3S4(tu)8H2O]Cl4 complexes with cluster core {Mo3S4} is conducted by X-ray emission spectroscopy (XES), X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) spectroscopy, and quantum chemistry methods. Data were obtained on the partial atomic composition of the highest occupied molecular orbitals and unoccupied molecular orbitals and the nature of atomic interactions within cluster cores.

The monochromator of the Kosmos synchrotron radiation metrology station is discussed. The results of testing the monochromator in the energy range 2000–6000 eV using Si (111) crystals are presented. A spectral resolution ΔE/E = 10−4 was obtained. A technique for checking the spectral purity of the monochromatic radiation is described. It is shown that the monochromator can be used for spectroscopic measurements in the indicated energy range.

The study of the valence state, local environment structure and magnetic properties of novel type CuCr0.99Ln0.01S2 (Ln = La, Ce) solid solutions was carried out using X-ray absorption spectroscopy, finite difference method simulations and static magnetic susceptibility measurements. The good agreement between experimental and calculated data indicates that cationic substitution does not lead to significant changes in the copper, chromium and sulfur local environment character and electronic density distribution. The copper atoms were found to be in Cu+ oxidation state, the sulfur atoms—in S2− oxidation state and the chromium atoms—in Cr3+ state. The cationic substitution of chromium by lanthanum and cerium in CuCrS2 does not significantly affect the effective magnetic moment and exchange interactions character. The lanthanum-doped CuCr0.99Ln0.01S2 solid solution demonstrates the Seebeck coefficient value 4 times greater than for CuCrS2-matrix at 500 K.

A set of multilayer X-ray mirrors for an upgraded version of the double-mirror monochromator installed on the VEPP-5 synchrotron of the Budker Institute of Nuclear Physics is fabricated, its constituent parts are optimized, and its X-ray optical characteristics are studied. Due to the use of seven subbands, for each of which an optimal pair of materials is chosen, the mirror set ensures high reflection coefficients—ranging from 10 to 75%— for a wide range of photon energies from 80 to 3000 eV and wavelengths from 0.413 to 15.48 nm. The principles of optimization of material pairs are reported. For the first time, multilayer mirrors based on the W/Be pair of materials are fabricated and studied.

We have employed VEPP-4 synchrotron radiation to measure CCD detector absolute responsivity in vacuum ultraviolet (115-310 nm) spectral range. The detector is designed in the form of a stainless steel enclosure containing a backside-illuminated CCD to protect the CCD from contamination. The entrance window of the enclosure is a round MgF2 spectral filter transparent for ultraviolet radiation with wavelengths longer than 112 nm. The measurements were carried out at Kosmos Metrological Station at the operating temperature of -100°C on the sensitive surface of the CCD. We utilized SPD calibrated silicon photodiode with 1 cm2 sensitive area and a known spectral sensitivity profile as a reference detector. The resultant measurements show a clear CCD responsivity dip near 280 nm, and a great potential to improve the CCD responsivity values using specially designed anti-reflection coatings.

The comprehensive experimental and theoretical study of the cation-substituted disulfides CuCr0.99Ln0.01S2 (Ln=La, Ce, Gd) XANES spectra was carried out. The cationic substitution with lanthanide atoms affect to the conduction band structure was studied using the finite difference method, DFT calculations of conduction band structure and the experimental spectra interpretation. The conduction band bottom of CuCrS2 is formed mainly with the contribution of the mixed copper s-, p- and d-states, chromium d-states and sulfur p-states. After the cationic substitution the unoccupied lanthanide f-states localize near the conduction band bottom area replacing the chromium d-states. The unoccupied copper, chromium and sulfur states distribution character is preserved after cationic substitution. In the case of solid solutions CuCr1-xLaxS2 the lanthanum f−states main contribution is shifted into the high energy area from the conduction band bottom.

The main techniques used at the COSMOS synchrotron radiation station to study the radiation hardness of semiconductor detectors are described. The spectral region around the photon energy of 100 eV is singled out from the white SR beam. A small area on the receiving detector’s surface is irradiated with a focused SR beam, and the sensitivity of the exposed and unexposed areas is investigated. The optics comprise full external reflection mirrors and thin-film filters. The techniques for calculating the surface dose are presented along with the results from measurements.

This work presents the results of long-term observation of the silicon photodiodes spatial profile response and the silicon photodiodes dark current after their exposure to 10.2 eV quanta and in the spectral range of 150–300 eV. Exposure of the photodiodes to quanta of an energy of 10.2 eV was repeated. Several other photodiodes have been irradiated in the spectral range of 700-1800 eV with a dose of 8 J/cm 2 . The spatial profile of the irradiated photodiodes was studied with 3.49 eV, 10.2 eV and 100 eV quanta. The effect of the recovery of the response spatial profile has been proved for the p + -n diode. An additional useful method of visualization of irradiated photodiode area is also presented.