[en] Techniques of imaging and SAXS experiments at ultra-fast processes with synchrotron radiation beams are being developed at Siberian Synchrotron and Teraherz Radiation Center (SSTRC) at Budker Institute of Nuclear Physics since the beginning of 2000th. The detector for imaging of explosions, DIMEX, was designed for these purposes. DIMEX is one-dimensional detector that can image the distribution of X-ray flux emitted by single electron bunch and store a series of such images from 100 consecutive bunches. Gaseous version of the detector DIMEX-G has been operating at the VEPP-3 storage ring since 2005 and at the VEPP-4M storage ring since 2015. The main parameters of the detector such as maximum registered X-ray flux and signal measurement precision, frame rate and time resolution can be significantly improved with silicon micro-strip sensor. A dedicated front-end ASIC DMXS6A was developed for such detector. The first ASIC demonstrated high noise that did not allow to get good enough signal to noise ratio. The ASIC was redesigned and the first tests with the prototype with new version of the ASIC DMXS6B have been performed at the SR beam at VEPP-4M. The noise in the new prototype is reduced by a factor of 5 down to 10 equivalent photons. At the same time the detector prototype demonstrates maximum detected photon flux of more than 10000 equivalent photons per bunch per channel (channel pitch 50 um) and maximum frame rate of 40 MFrames/s.

[en] The potential applicability of X-ray fluorescence (XRF) industrial conveyor analyser CON-X series is discussed for thorium (Th) quantitative or semi-quantitative on-line measurement in different types of Th-bearing materials. Laboratory study of several minerals (heavy mineral sands and carbonate rocks as unconventional Th resources; monazite concentrate as Th-associated resources and uranium ore residues after heap-leaching as a waste product) was performed and analyser was tested for on-line quantitative measurements of Th contents along with other major and minor components. The Th concentration range in raw heavy mineral sand is 50–600 ppm; its minimal detection limit (MDL) at this level is estimated at 25–50 ppm in 5-minute measurements depending on the type of material. On-site test of the CON-X analyser for continuous analysis of thorium traces along with other elements in zircon sand showed that accuracy of Th measurements is within 20% relative. When Th content is higher than 1% as in the concentrate of monazite ore (5–8 % ThO₂) accuracy of Th determination is within 1% relative. (author)

[en] Erosion damage due to plasma instabilities such as hard disruptions, edge-localized modes, and vertical displacement events remains a major obstacle to successful realization of the tokamak-reactor concept. As a result of these plasma instabilities, intense plasma energy that is deposited during short periods can cause severe erosion, structural damage, and surface modifications of the plasma-facing materials. Experimental work is being carried out at the high-power VIKA-93 plasma-gun facility in the Efremov Institute, Russia. Interesting results were obtained during preliminary heating of the samples (to 1200 deg. C) and use of maximum plasma gun parameters, i.e., E_in=30 MJ/m², τ=360 μs. In all samples, a large increase in weight loss (up to 80%) was observed during plasma bombardment when preheating was used. Scanning electron microscope investigations have demonstrated a considerable evolution of surface recrystallization processes, especially for preheated CFC materials. Significant differences among various carbon materials are found for specimens with and without preliminary heating

[en] The potential of pulsed laser deposition in an applied uniform electrostatic field was investigated. A flat, positively charged, fine-celled-grid counter electrode was used to provide bias voltage of up to +50 kV with respect to the substrate. This enabled control of the atomic mixing and made it possible to initiate chemical bond formation at the interfaces of the films formed by deposition from the laser-induced plume. As an example, the results of multilayer ⁵⁶Fe/MoS_x/⁵⁷Fe film deposition are presented. At first, a bilayer MoS_x/⁵⁷Fe film was grown in the absence of the electric field. This was followed by ⁵⁶Fe film deposition in an applied field. A relatively sharp interface between the MoS_x and ⁵⁷Fe films was observed. In contrast, after ⁵⁶Fe deposition, effective atom mixing was observed and new chemical bonds between Fe, S and Mo were detected. By penetrating through the interface, accelerated ⁵⁶Fe ions gave rise to the growth of an amorphous layer of up to 50 nm in thickness. It consisted of rather evenly distributed Fe, S and Mo atoms (at total ion dose of 2.5x10¹⁶ cm^-2). The ion flux destroyed Mo-S chemical bonds, and the S atoms released preferably bound Fe atoms, thus forming a FeS₂-type phase. The Mo atoms, as a lower-oxidation-state species (apparently together with S atoms), were localized in the vicinity of Fe atoms and affected the hyperfine magnetic fields. The technique developed has made it possible to study the ion-induced processes occurring at the interfaces of multilayer films. It can also be applied to improve the tribological functionality of thin films

[en] Between 1986 and 1991, steam generator damage occurred in some VVER-1000 nuclear power plants. For that reason, these SGs have been replaced before their estimated and of life. The degradation of the ''cold'' collector material was a very new problem, not encountered before. Several factors considered jointly could explain the collector damage whereas each factor separately cannot lead to the observed damage. A detailed analysis of this problem has shown its technical and scientific complexity, thus requiring numerous studies and long term tests in the fields of metallurgy, corrosion and fracture mechanics. When designing SGs, it was not possible to predict the phenomenon as the data required to explain its occurrence were lacking. Remedial measures have now been taken, from technical and organisational points of view, to improve safety and lifetime which must be at least equal to the expected one for new and future SGs. (authors)

No abstract available

[en] Thorium (Th) as nuclear fuel is clean and safe and offers significant advantages over uranium. The technology for several types of thorium reactors is proven but still must be developed on a commercial scale. In the case of commercialization of thorium nuclear reactor thorium raw materials will be on demand. With this, mining and processing companies producing Th and rare earth elements will require prompt and reliable methods and instrumentation for Th quantitative on-line analysis. Potential applicability of X-ray fluorescence conveyor analyzer CON-X series is discussed for Th quantitative or semi-quantitative on-line measurement in several types of Th-bearing materials. Laboratory study of several minerals (zircon sands and limestone as unconventional Th resources; monazite concentrate as Th associated resources and uranium ore residues after extraction as a waste product) was performed and analyzer was tested for on-line quantitative measurements of Th contents along with other major and minor components. Th concentration range in zircon sand is 50-350 ppm; its detection limit at this level is estimated at 25- 50 ppm in 5 minute measurements depending on the type of material. On-site test of the CON-X analyzer for continuous analysis of thorium traces along with other elements in zircon sand showed that accuracy of Th measurements is within 20% relative. When Th content is higher than 1% as in the concentrate of monazite ore (5-8% ThO_2) accuracy of Th determination is within 1% relative. Although preliminary on-site test is recommended in order to address system feasibility at a large scale, provided results show that industrial conveyor XRF analyzer CON-X series can be effectively used for analytical control of mining and processing streams of Th-bearing materials. (author)

[en] A wear-resistant steel is developed not requiring chemical-heat treatment (CHT) (carburizing, carbonitriding) used for aircraft engineering units. The new steel has double the level of wear resistance than that with CHT. The cast steel optimum phase composition is determined guaranteeing good wear resistance. It is established that the amount of carbide phase in solid solution may be ≥ 8.5 wt.%, and 90% of carbide is based on vanadium. In order to obtain the required level of steel properties not less than 0.35 wt.% chromium, and 0.5 wt.% vanadium should be in solid solution. The amount of residual austenite is not more than 15%.

[en] Exact solutions of the resistive magnetohydrodynamics (MHD) equations for a stationary and incompressible plasma are presented. These solutions describe a particular kind of magnetic reconnection known as magnetic reconnective annihilation. The two dimensional (2D) case in polar coordinates is described first. Subsequently two ansatzs for 3D solutions in cylindrical and cartesian coordinates are presented. The former consists of a generalization of the previously described form for 2D solutions in curvilinear coordinates. The latter is its analogous counterpart in cartesian coordinates and it allows to derive new 3D solutions for fan reconnection

[en] The emission spectra and the plasma parameters of discharges were investigated. Water solutions of copper and nickel chlorides with additions of sodium chloride were used as electrolyte cathodes. The change of the relative intensities of the emission lines of the elements (Cu and Ni) with increasing NaCl concentrations in the solution is shown. The gas temperature and the reduced electric field strength in the plasma were founded. The electron energy distribution function and the excitation rate coefficients for emitting states of copper and nickel atoms by the numerical solution of the Boltzmann equation were obtained. It was shown that in plasma emission spectroscopy measuring it is necessaryto considerthe correlation between rates of excitation and composition of the sample solution in order to determine the concentration of metal ions in the water solutions. (paper)