Fast and Ultrafast Energy-Dispersive X-Ray Reflectrometry Based on Prism Optics

Interference spectra of X-ray reflection from thin films have been obtained for the first time by the decomposition of the spectrum of a polychromatic beam by means of a diamond prism. The measurements of film nanostructures and reference absorption spectra have been performed at the ESRF synchrotron. The proposed spectrometric scheme allows obtaining the interference pattern in a wide range of the scattering vector length q without angular scanning. This makes it possible to study ultrafast processes in layered nanostructures at an intense external action of laser pulses or charged particles with a time resolution of about the duration of an X-ray pulse. © 2017, Pleiades Publishing, Inc

Fast and Ultrafast Energy-Dispersive X-Ray Reflectrometry Based on Prism Optics

Interference spectra of X-ray reflection from thin films have been obtained for the first time by the decomposition of the spectrum of a polychromatic beam by means of a diamond prism. The measurements of film nanostructures and reference absorption spectra have been performed at the ESRF synchrotron. The proposed spectrometric scheme allows obtaining the interference pattern in a wide range of the scattering vector length q without angular scanning. This makes it possible to study ultrafast processes in layered nanostructures at an intense external action of laser pulses or charged particles with a time resolution of about the duration of an X-ray pulse. © 2017, Pleiades Publishing, Inc

The energy dispersive scheme of X-ray fluorescence analysis with a crystal polarizer and polycapillary optics

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. Copyright © 2017 John Wiley & Sons, Ltd

Energy-Dispersive Scheme with a Bandpass Filter for Determining Heavy Element Content from X-Ray Absorption Spectra

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. © 2018, Allerton Press, Inc

Desulfurization of Brown Coal in Water under Supercritical Conditions

A method for the desulfurization of brown coal by treatment in supercritical water (T = 673.15 K, P = 30 MPa) with the subsequent deposition of gaseous sulfur compounds on a copper substrate was proposed. The products were refined fuel with a low heat value of 24 MJ/kg and Cu2S films with a thickness of 0.1 mm. The semiconductor Cu2S films can be used for the preparation of thin-film photoelectric energy converters. The greatest degree of the removal of sulfur from the brown coal was observed after an hour. The main sulfur-containing gas formed upon the autoclave treatment of brown coal in supercritical water was H2S. © 2018, Allerton Press, Inc

The energy dispersive scheme of X-ray fluorescence analysis with a crystal polarizer and polycapillary optics

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. Copyright © 2017 John Wiley & Sons, Ltd

Desulfurization of Brown Coal in Water under Supercritical Conditions

A method for the desulfurization of brown coal by treatment in supercritical water (T = 673.15 K, P = 30 MPa) with the subsequent deposition of gaseous sulfur compounds on a copper substrate was proposed. The products were refined fuel with a low heat value of 24 MJ/kg and Cu2S films with a thickness of 0.1 mm. The semiconductor Cu2S films can be used for the preparation of thin-film photoelectric energy converters. The greatest degree of the removal of sulfur from the brown coal was observed after an hour. The main sulfur-containing gas formed upon the autoclave treatment of brown coal in supercritical water was H2S. © 2018, Allerton Press, Inc

Energy-Dispersive Scheme with a Bandpass Filter for Determining Heavy Element Content from X-Ray Absorption Spectra

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. © 2018, Allerton Press, Inc

Band reject filtration of the excitation spectrum at energy dispersive X-ray spectroscopy of weak signals

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. © 2016, Pleiades Publishing, Inc

Band reject filtration of the excitation spectrum at energy dispersive X-ray spectroscopy of weak signals

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. © 2016, Pleiades Publishing, Inc