We demonstrate a possibility of a radical reduction in an effective radiation dose when monitoring the content of a contrast agent in an object with X-ray absorption spectroscopy (XAS) using survey data from multispiral computed tomography (CT). A directional beam passes through the region of interest, the 3D coordinates of which are determined with CT, and the transmission spectrum is recorded in the range of the K-jump in the X-ray photoabsorption of the contrast agent. The unambiguity of the obtained results is confirmed by independent measurements of the xenon content in the phantom using CT and XAS methods, as well as by direct manometric control of gas volumes.

The paper presents some results of experimental studies of Mo/Si multilayer degradation under UV exposure from compressed plasma jets in air. Such high current plasma flows generate broadband powerful UV radiation fluxes. A single exposure caused a slight decrease of reflectivity from 0.54 to 0.47 due to the coating contamination by the debris from the plasma light emitter.

It is shown that combined diffraction and absorption filtration of a polychromatic X-ray spectrum allows spectral bands tunable in energy and relative width to be separated. In the energy range E < 30–35 keV, the spectral valley is formed by passing a polychromatic beam through a plate of the highly oriented pyrolytic graphite mosaic crystal ≈0.5–1 mm thick under the Bragg condition of diffraction. The filtration band width is extended by placing two or more plates at different diffraction angles. In the energy range E > 35–40 keV, filtration is performed by a selectively absorbing filter that contains a chemical element with the photoabsorption K-jump energy in this region of the spectrum. The results can be used in medical X-ray diagnostics and X-ray spectrometry.

This study discusses the main features of the irradiation of prospective multilayer coatings by VUV/UV radiation from compressed plasma flows. Such radiation is characterized by a broadband spectrum and high brightness fluxes. Oxide and Mo/Si bilayers were used as the basis of the reflective multilayers for the visible and UV ranges. A gas-dynamic response from the irradiated surfaces was studied with schlieren photography. The properties of original and irradiated multilayers were described with ultra violet visible infrared spectroscopy (UV-Vis-IR), X-ray diffraction (XRD), X-ray reflectometry, scanning electron microscopy (SEM) and other techniques. Data on the degradation of optical properties and surface morphology were obtained.

The possibility of stable generation of intense characteristic Cs radiation upon electronic excitation of a Mo anode target heat treated in Cs and O2 vapors is demonstrated. The radiation source is a microfocus transmission type X-ray tube with a beryllium window and an S20 photocathode. A Cs-Mo-O layer is formed on the initial target in the form of a 1-µm-thick Mo film during heat treatment. The L and K spectral series are measured in an anode—cathode voltage range of 10—47 kV. A stable generation mode is observed at an electron flux power density up to 600 W/cm2. The energy of the Cs Kβ spectral line is in the region of photoabsorption peaks of the I and Xe atoms, which are widely used in the composition of contrast agents for medical diagnostics. This allows obtaining two- and three-dimensional images with the maximum contrast.

The possibility of forming deep spectral valleys in the polychromatic spectrum of X rays with an energy of E ≥ 15 keV using diffraction band rejection is demonstrated. The rejection has been carried out by passing the radiation beam through plates of highly oriented pyrolytic graphite (HOPG) with a thickness of 0.73 and 0.58 mm at the diffraction angle θ in the interval of 3.26°–6.98°. The average values of the mosaic spread angles Δω of HOPG samples are equal to 0.72° and 0.3°. For HOPG with Δω = 0.72°, a five- and threefold attenuation of the radiation intensity due to diffraction extinction has been obtained upon the rejection of the spectral band with minima near 15.2 and 22.5 keV, respectively, and the full width at half depth of the valley is 1.4 and 3.1 keV. The proposed diffraction filtration scheme can be used in X-ray spectrometry and in medical diagnostics to reduce radiation loads.

A point source of X-ray radiation with an energy range of up to 40 keV has been developed on the basis of a specially designed image converter tube. The source is capable of operating in pulsed and continuous modes. The main purpose of this is to use the source for testing X-ray streak cameras. The device can also be used in X-ray microscopy and spectroscopy as a reference radiation source, in biomedical research, and in other fields.

Phase formation and transitions in platinum silicide films on polycrystalline Si in the process of Pt magnetron sputtering and heat treatments at different temperatures are studied using X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and X-ray diffractometry. Phases of amorphous and polycrystalline Pt$_3$Si and Pt$_2$Si are shown to form during the room-temperature Pt deposition on poly-Si beneath the Pt layer. The relaxation of the interfacial film and partial transformation of Pt$_3$Si into Pt$_2$Si occurs as a result of the thermal treatment for 30 minutes in the temperature range from 125 to 300$^{\circ}$C. The Pt$_3$Si and Pt$_2$Si phases crystallize to PtSi due to annealing at the temperatures from 320 to 480$^{\circ}$C for the same time period.

AbstractThe efficiency of broadband filtering of a polychromatic X-ray spectrum by a polycapillary structure in the region of photon energies E > 10 keV was demonstrated. A polycapillary 40.5-mm-long rod made of borosilicate glass and containing 10^6 parallel hexagonal capillaries was used as a filter. Filtering was performed by introducing a misalignment of 0–4 mrad between the axis of this capillary structure and the primary beam direction. The relative attenuation of spectral density observed at energies ranging from 12 to 23 keV was as high as 17 dB.

An energy-dispersive scheme using a bandpass filter based on pyrolytic graphite is proposed for determining the content of heavy elements from X-ray absorption spectra. The detected excitation spectrum is corrected to increase the accuracy of measurement. The initial shape of the photoabsorption jump is reconstructed in the approximation of an isolated atom by numerically solving the convolution equation.

The efficiency of broadband filtering of a polychromatic X-ray spectrum by a polycapillary structure in the region of photon energies E > 10 keV was demonstrated. A polycapillary 40.5-mm-long rod made of borosilicate glass and containing 106 parallel hexagonal capillaries was used as a filter. Filtering was performed by introducing a misalignment of 0–4 mrad between the axis of this capillary structure and the primary beam direction. The relative attenuation of spectral density observed at energies ranging from 12 to 23 keV was as high as 17 dB.

The efficiency of the polarization scheme based on polycapillary optics and a diamond crystal polarizer was demonstrated. The scheme provides suppression of the background of scattered radiation in measuring X‐ray fluorescence spectra. A quasi‐parallel X‐ray beam with an angular divergence of 4.2 mrad was formed by a microfocus source with a copper anode and polycapillary half‐lens. Simultaneous polarization and monochromatization of radiation was obtained with a crystal of natural diamond, which was set at the diffraction reflection (113). The degree of polarization of CuKα1 spectral line and the maximum radiation flux were respectively equal to 99.86% and 5 · 106 photon/s. In the direction orthogonal to the plane of diffraction, the maximum attenuation of the background was up to 19 dB.

An energy-dispersion scheme for determining the conсentrations of impurities of heavy elements from the absorption spectra in the regions of X-ray photoabsorption jumps is described. A semiconductor X-ray spectrometer and a pyrolytic graphite monochromator were used to record data in a spectral band of width up to 1 keV. The initial shape of the absorption spectrum in the approximation of an isolated atom was reconstructed by means of a numerical solution of the convolution equation. The scheme provides a sharp increase in the data acquisition and measurement sensitivity. The results of measurements of the Bi and Pb contents in samples with organic matrices and determination of the thicknesses of thin Mo films on diamond substrates are presented.

The possibility of the efficient band reject filtration of the continuous X-ray excitation spectrum in the energy range E ≥ 8 keV is demonstrated. This makes it possible to strongly increase the sensitivity of energy dispersive X-ray spectroscopy at detecting of weak fluorescence lines. Spectral rejection is implemented by transmitting a primary beam through highly oriented pyrolytic graphite with given structural parameters. Diffraction extinction in pyrolytic graphite ensures the possibility of reducing the intensity by more than 20 dB and rejecting the spectral band with a width of ~1 keV. The reduction of statistical fluctuations of the background of elastically scattered radiation is achieved when the bottom of the formed spectral valley is adjusted to the analyzed fluorescence line. The proposed scheme of band reject filtration also allows the suppression of intense characteristic lines in the primary and scattered radiation spectra.

The morphology of low-temperature (growth temperature 360 °C) multilayer Ge/Si heterostructures with Ge quantum dots was investigated by means of transmitting electron microscopy, scanning tunneling microscopy and X-ray optics. The possibility to determine integral morphological characteristics of heterostructures’ layers using X-ray optics method is shown. The results of X-ray optics are in a good agreement with TEM measurements and we discover the cross-correlation between Ge layers in heterostructures containing thin Si spacers. The spectral sensitive region of structures under investigation is estimated by measuring photo-emf spectra at the temperature of 78 K and 300 K. The possibility of controlled forming of spectral sensitive region of Ge/Si heterostructures in the range of 1.5 – 2.8 μm is verified.