Проведено исследование структуры поликристаллической алмазной плёнки (ПКАП), полученной методом газофазного осаждения из активированной СВЧ-разрядом смеси водорода и пентана, и её сенсорных свойств по отношению к синхротронному излучению. Результаты исследования поперечного сечения плёнки методом спектроскопии комбинационного рассеяния света (КРС) показали присутствие sp2-гибридизованных включений. При удалении от ростовой поверхности ПКАП доля неалмазной фазы увеличивается, а её морфология изменяется из аморфизованного до кристаллического sp2-гибридизованного углерода. Исследование фотоэлектрического отклика ПКАП на рентгеновское излучение проводилось на станции «Космос» с использование синхротронного излучения из накопителя ВЭПП-4М. При низких полях смещения показана максимальная чувствительность ПКАП-детектора. Данный эффект был связан с повышением эффективности сбора индуцированных носителей заряда за счет их оттока из алмаза в sp2-гибридизованные включения с последующим транспортом по проводящим путям вдоль границ кристаллитов.

We present a study of the structural features of polycrystalline a diamond film (PCDF) synthesized by the microwave plasma-enhanced chemical vapor deposition method from a hydrogen/pentane mixture and consider its photoelectric response to synchrotron radiation. Raman spectroscopy analysis of the PCDF cross-section revealed the presence of sp2-hybridized inclusions. As the distance from the PCDF growth surface increases, the amount of the non-diamond phase also increases, while its morphology changes from amorphous to crystalline graphite-like carbon. The investigation of the photoelectric response of PCDF was carried out at the “Cosmos” station using synchrotron radiation from the VEPP-4M storage ring. The PCDF detector exhibited maximum sensitivity at low bias voltage. This effect was attributed to the increased efficiency of collecting photo-induced charge carriers from the diamond to the sp2-hybridized inclusions followed by their subsequent transport through conductive paths along the boundaries between diamond crystallites.

A high-resolution monochromator with a broad spectral range of 125-4200 Angstrem is designed for a measuring beamline of the projected synchrotron radiation source "SKIF" (Novosibirsk). The optical configuration of the monochromator comprises a grazing-incidence concave mirror, a plane VLS grating, and an exit slit. It is planned to use two replaceable VLS gratings with central groove frequencies of 600 and 150 mm-1 intended for subranges of 125-1000 Angstrem and 900-4200 Angstrem, respectively. Wavelength tuning in each of the two subranges is carried out by solely the rotation of the VLS-gratings. Due to the proper choice of p1 VLS-grating coefficients, the focal distance varies only slightly over the entire spectral range, and the p2 VLS-grating coefficients are used to suppress the aberrations of the mirror and the gratings. The resolving power of the configuration obtained by numerical ray tracing exceeds 1000 in the 125-1000 Angstrem range and 2000 in the 900-4200 Angstrem range. Keywords: VUV, spectroscopy, VLS-grating, synchrotron radiation.

Cl K-edges of a set of chlorides of 4d- and 5d-transition metals {MCl6}n– (M = Rh, Pd, Re, Os, Ir, Pt) were obtained using the “Cosmos” station of the VEPP-4 synchrotron. The combined use of experimental X-ray and theoretical methods made it possible to determine the magnitude of the spin-orbit interaction (SOC) depending on the transition metal. The features of the Cl K-edge are analyzed with and without SOC, as well as stretched and compressed complexes.

Studying the X-ray absorption near-edge structure shows that cation substitution of a MnS matrix with lanthanide atoms does not significantly affect the character of the local environment of metal (manganese, dysprosium, thulium and ytterbium) and sulfur atoms in lanthanide-doped Ln 0.05 Mn 0.95 S ( Ln = Dy, Tm, Yb) solid solutions. Comparison of the experimental and theoretical data obtained by the finite-difference method has revealed that the main contributions of the unoccupied p- and d -states of manganese and p -states of sulfur are localized at the conduction-band bottom, both in the case of the initial MnS matrix and in the case of lanthanide-substituted Ln 0.05 Mn 0.95 S solid solutions. The main contributions of unoccupied f ‑states of ytterbium and thulium in Ln 0.05 Mn 0.95 S ( Ln = Tm, Yb) solid solutions are shifted to the high-energy region of the conduction band, while the f -states of dysprosium in dysprosium-doped Dy 0.05 Mn 0.95 S solid solutions are localized near the conduction-band bottom. According to the calculated model spectra, it is found that the contributions of the free lanthanide d -states in Ln 0.05 Mn 0.95 S ( Ln = Dy, Tm, Yb) solid solutions are shifted to the region of the conduction-band bottom with an increase of the atomic number of the lanthanide atom.

The paper presents the results of studies of W/B4C multilayer structures with small periods for their use as the first mirror in a two-mirror soft X-ray monochromator at the KOSMOS station of the VEPP-4M synchrotron. It is shown that even if the periods of the mirror and the RbAP crystal coincide, when operating in a wide wavelength range, the Bragg angle must be adjusted due to the stronger refraction in the W/B4C multilayer mirror.

The Center for Collective Use “Siberian Center for Synchrotron and Terahertz Radiation” provides users from various organizations with the opportunity to use modern analytical techniques using synchrotron radiation beams for a wide range of research work. At present, the general direction of the development of new techniques is focused on the development of new original approaches to the use of synchrotron radiation.

Cl K -edges of a wide range of chlorides of 4 d and 5 d transition metals {MCl 6 } n − (M = Rh, Pd, Re, Os, Ir, Pt) are obtained using the Kosmos station of the VEPP-4 synchrotron. The combined use of experimental X-ray and theoretical means allows determination of the magnitude of spin–orbit coupling (SOC), depending on the transition metal. The features of the Cl K -edge are analyzed with and without SOC, and upon stretching and compression of the complexes.

An Erratum to this paper has been published: https://doi.org/10.3103/S106287382301001X

The project of the station of synchrotron radiation of the second stage Plamya-2 for the Siberian ring photon source SKIF is based on the experience gained during the development of the station "Plamya" on the storage ring VÉPP-4 at the Siberian Center for Synchrotron Radiation (SR). The station is designed to study the processes of combustion and thermal decomposition of various organic compounds by the method of photoionization mass spectrometry using vacuum ultraviolet (VUV) synchrotron radiation. The use of selective photoionization by VUV radiation in the molecular beam method of sampling from the reaction zone in flames or pyrolyzers makes it possible to identify and quantify the concentrations of atoms, radicals, and other labile and short-lived compounds, which provides key information on chemical transformations under conditions of high-speed combustion and thermal decomposition. The paper considers the possibility of using various SR generators available on the SKIF storage ring, as well as the optical scheme of the station and the conceptual design of its front-end. The experimental results of measuring photon fluxes for the Plamya station and the calculated photon fluxes on the sample for the Plamya-2 station are also presented.

The main technical solutions chosen to implement the project of fourth-generation synchrotron radiation (SR) source Synchrotron Radiation Facility "Siberian Circular Photon Source" (SRF SKIF), which is currently being built in Novosibirsk, are presented. The choice of the configuration and parameters of the synchrotron radiation source is described; the principles of the scientific program compilation are considered; and the radiation generation devices, the frontend design, and the engineering infrastructure are discussed.

A high-resolution monochromator with a broad spectral range of 125 – 4200 Angstrem is designed for the measuring beamline for the projected synchrotron radiation source "SKIF" (Novosibirsk). The optical configuration of the monochromator comprises a grazing-incidence concave mirror, a plane VLS grating, and an exit slit. It is planned to use two replaceable VLS gratings with central line frequencies of 600 mm-1 and 150 mm-1 intended for subranges of 125 – 1000 Angstrem and 900 – 4200 Angstrem , respectively. Wavelength tuning in each of the two subranges is effected by only the rotation of the VLS-gratings. Due to the proper choice of p_1 VLS-grating coefficients, the focal distance varies only slightly over the entire spectral range, and the p_2 VLS-grating coefficients are used to suppress the aberrations of the mirror and the gratings. The resolving power of the configuration obtained by numerical ray tracing exceeds 1000 in the 125 – 1000 Angstrem range and 2000 in the 900 – 4200 Angstrem range.

The results are considered of calibration of semiconductor detectors of the VUSS-E spectro- photometer intended for monitoring the solar ultraviolet radiation flux in the Lyman-alpha line (L, 121.6 nm) on Roshydromet geostationary satellites. The calibration was carried out at the Kosmos metrological station at the Siberian International Center for Synchrotron Radiation in the channel of the VEPP-4 relativistic electron storage ring. The contribution P to the VUSS-E signal from the L line and from the spectral region above ~122 nm is calculated using the model ultraviolet radiation spectra. It is shown that the value of P can vary greatly for different sensors and different levels of solar activity: P ~ 30-60% at a low level and P ~ 50-70% at a high level of solar activity. This result indicates a need to calibrate all channels of each flight instrument and to take into account the dependence of the contribution P to the VUSS-E signal from the L line on the level of solar activity when monitoring space weather.

Методом РСА изучено строение биядерного тиоцианатного комплекса ниобия(IV) — (Bu4N)4[Nb2(μ2-S2)2(NCS)8]·H2O (1·H2O). Соединение 1·H2O кристаллизуется в ромбической сингонии (пространственная группа Pbca) с параметрами элементарной ячейки a = 23.2139(4) Å, b = 25.2962(4) Å, с = 32.5478(6) Å, V = 19112.8(6) Å3, R = 0.0592. Методами рентгеновской спектроскопии изучена электронная структура комплексов (Bu4N)4[Nb2(μ2-S2)2(NCS)8] и (Bu4N)4[Nb2(μ2-Se2)2(NCS)8], проведено сравнение с полимерными халькогалогенидами Nb2S4Br4 и Nb2Se4Br4. Методом РФЭС показано, что эффективные заряды на атомах ядра {Nb2(μ-Q2)2}4+ (Q = S, Se) не изменяются при переходе от Br– к NCS– лигандам. Методами РЭС и XANES изучена структура HOMO и LUMO для (Bu4N)4[Nb2(μ2-S2)2(NCS)8] и (Bu4N)4[Nb2(μ2-Se2)2(NCS)8]. Установлено, что наибольшие вклады состояний S 3p лигандов NCS– в занятые молекулярные орбитали находятся вблизи верхней границы валентной зоны, тогда как вклады от дихалькогенидных мостиковых лигандов имеют более равномерное распределение. В случае зоны проводимости вклады состояний S 3p лигандов NCS– расположены в более глубокой области, а вклады от дихалькогенидных мостиковых лигандов — вблизи нижней границы зоны проводимости. Взаимодействие состояний Nb 4d и S 3p/Se 4p дихалькогенидных мостиков для HOMO имеет разрыхляющий характер, для всех остальных занятых молекулярных орбиталей — связующий, а для всех свободных молекулярных орбиталей — разрыхляющий.

Методами рентгеновской эмиссионной спектроскопии (РЭС), рентгеновской фотоэлектронной спектроскопии (РФЭС), рентгеновской спектроскопии поглощения (XANES) и квантовой химии проведено детальное исследование особенностей электронной структуры трехъядерных комплексов молибдена (NH4)2[Mo3S13] и [Mo3S7(dtc)3]Br с кластерным ядром {Mo3S7}, а также [Mo3S4(tu)8H2O]Cl4 с кластерным ядром {Mo3S4}. Получены данные о парциальном атомном составе высших занятых и свободных молекулярных орбиталей и характере взаимодействий между атомами внутри кластерного ядра.

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.

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 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.

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 coefficientsranging 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.