Table of contents

Special Issue of the Materials of the V International Congress on Energy Fluxes and Radiation Effects (Tomsk, Russia, 2016)

Maksim Trigub, Georgiy Osokin, Alexander Konovod

National Research Tomsk Polytechnic University, 30, Lenin Avenue, Tomsk, Russia

email: geosokin@tpu.ru

The present issue of the journal is based on the materials of the V International Congress on Energy Fluxes and Radiation Effects 2016 (EFRE 2016) that was held on October 2 to 7, 2016 in Tomsk (Russia). This large scientific forum gathers together scientists, developers and representatives of knowledge-intensive enterprises that have relevance to physics and technology. This year, the Congress was dedicated to the 120^th anniversary of the National Research Tomsk Polytechnic University.

The history of the Congress as a joint scientific event dates back to 2000; it traditionally includes three conferences: International Symposium on High-Current Electronics (SHCE), International Conference on Radiation Physics and Chemistry of Condensed Matter (RPC) and International Conference on Modification of Materials with Particle Beams and Plasma Flows (CMM). However, each of these large conferences has its own lasting history.

In 2016, the International Symposium on High-Current Electronics was arranged for the 19^th time. The participants have presented the results of fundamental studies and applied outcomes in the fields of high-power pulsed energy engineering and electronics (Pulsed Power), physics and application of high-power electron and ion beams, high- and low-temperature gas discharge plasma, physics of high-energy treatment and extreme states of matter, electric pulsed technologies. Noteworthy, the symposium took place in the year of the 40^th anniversary of USSR scientific discovery of explosive electron emission. This physical phenomenon—being one of the basics of high-current electronics—determines the processes in pulsed vacuum discharge, enables the operation of high-current electron accelerators, finds application in beam pumping of high-power pulsed gas lasers, switches and other electric pulsed devices.

The 17^th International Conference on Radiation Physics and Chemistry of Condensed Matter is traditionally organised starting from 1969. This conference is the largest both on national and international scale in the fields of radiation physics and chemistry of inorganic substances, investigation of fundamental problems of elementary, nonlinear and catastrophic processes in condensed matter under fluxes of hard radiation.

The International Conference on Modification of Materials with Particle Beams and Plasma Flows was held for the 13^th time beginning from 1988. The high level of this event is due to the participation of the representatives of outstanding scientific schools that stand at the origins of this scientific and technological field.

Regular organisation of EFRE Congress strengthens the interdisciplinary bonds between three grand fields of physics and technology playing increasingly important role in the technological development of society. Pulsed energy generation and high-current electronics provide equipment for electric discharge, plasma beam and radiation technologies that intensely fill and update the technological niches in various branches of industry, defence, chemistry, biology and medicine. The participants of the forums get comprehensive picture of scientific and applied problems and have an opportunity to look at them from the perspective of theoretical and experiment studies and engineering.

The place of the event has been chosen for a reason: Tomsk is a city having strong scientific and educational network including outstanding physical and technological schools. It was Tomsk where many of the scientific topics of the Congress germinated. Each of the forums gathers the representatives of abundant student pool of Tomsk.

The main organisers of the Congress—Tomsk Polytechnic University and Institute of High-Current Electronics of SB RAS, which soon will celebrate its 40^th anniversary—have strong bonds in the field of scientific research, educational activities, management, and represent a splendid example of real integration of academic and university-level science.

In 2016, the Congress gathered leading national and international scientists, manufacturers and consumers of vacuum and electron beam equipment, accelerators and radio-frequency devices, representatives of field-specific organisations and business-structures. The 500 participants of the Congress included specialists from Russia, Republic of Belarus, Brazil, Germany, Israel, Italy, Kazakhstan, People's Republic of China, Republic of Korea, USA, Ukraine, France and Czech Republic.

The conferences were conducted with the financial support of the Russian Foundation for Basic Research (projects nos. 16–02–20530, 16–08–20408, 16–02–20464).

All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

REP DD was suggested as an excitation source of various gas lasers. The efficient lasing was obtained in the IR, UV, and VUV spectral ranges. The ultimate intrinsic efficiency of non-chain chemical lasers on HF(DF) molecules was achieved. REP DD pumped N₂ laser with an ultimate electrical efficiency of 0.2% was developed. Lasing on N₂ molecules with 2 or 3 peaks in successive REP DD current oscillations was obtained for the first time. The laser action on F₂* at 157 nm and rare gas fluorides (KrF*, XeF*) under REP DD pumping was obtained for the first time, as well. It has been shown that the volume stage of REP DD in mixtures with fluorine can last over 50 ns during several current half-cycles. Therewith, the efficiency and the pulse duration of lasers on rare gas fluorides and VUV F₂* laser parameters under REP DD excitation are comparable with those obtained in suitable transverse discharges. The results allow the conclusion that the REP DD homogeneity in mixtures with F₂ and SF₆ is high enough for attaining high laser efficiency.

An experiment on generation and transmission of an intensive electron beam through a magnetic mirror has been carried out at the GOL-3 magnetic trap. An adapted theory and numerical modelling were used to find a maximal beam current for which no beam electrons are reflected. The effect of space charge and magnetic mirror of the reflection were taken into account. A comparison of the computed limiting current with experimental value allowed us to validate a hypothesis that the appearance of reflected electrons is responsible for electric breakdown in the electron gun.

Results of experimental studies of the amplitude-temporal characteristics of a supershort avalanche electron beam (SAEB) with a picosecond time resolution are presented. It is shown that the maximum SAEB current and the voltage drop in the gap are timed to tens of picoseconds and that the use of sharp-ended cathode improves the stability of SAEB generation.

In the present work, the influence of an alternating circularly polarized electric field on the energy spectrum of the He atom is studied. The calculations are performed by the method of the energy matrix diagonalization of an atom in the electric field. This method has allowed us to study the behaviour of the helium energy spectrum from the same numerical procedure under resonant and non-resonant excitations by the electric field. Based on the calculation results, we have found that the resonance effects take place not only in the vicinity of resonance, but they influence the shift directions of the Stark states even under non-resonant excitation. Additionally, we have established that the helium energy spectrum behaves consistently in the electric field. The results obtained have allowed us to clarify mechanisms of the influence of the resonance effects on the radiative characteristics of helium plasma.

A method was developed for building the powerful battery power supplies. Using the method, the battery power supply with a 4 kW max power and up to 93% efficiency was developed to supply the "Yasen" X-ray apparatus. Two 60 A·h series-connected starter lead-acid batteries were used as a primary power supply. A DC output voltage of the source is stable over the entire power range and equals to 310 V. The power supply is based on a 5-phase HF-inverter. There is no difficulty in designing such power supplies with different power outputs. It can be done by the increasing or the decreasing number of phases (of inverter channels). This approach is not limited by the increased number of the inverter channels. The maximum output power will be determined by the battery characteristics only. The power supply is mounted on a mobile trolley, to increase the mobility of the entire set of equipment. The unit dimensions are 410×320×440, the weight is about 40 kg. The unit is forced air-cooled. A power operating mode is short and periodic.

HV solid-state switch control circuit was developed and tested. The switch was made with series connection IGBT-transistors. The distinctive feature of the circuit is an ability to fine-tune the switching time of every transistor. Simultaneous switching provides balancing of the dynamic voltage at all switch elements. A separate control board switches on and off every transistor. On and off signals from the main conductor are sent to the board by current pulses of different polarity. A positive pulse provides the transistor switch-on, while a negative pulse provides their switch-off. The time interval between pulses defines the time when the switch is turned on. The minimum time when the switch is turned on equals to a few microseconds, while the maximum time is not limited. This paper shows the test results of 4 kV switch prototype. The switch was used to produce rectangular pulses of a microsecond range under resistive load. The possibility to generate the damped harmonic oscillations was also tested. On the basis of this approach, positive testing results open up a possibility to design switches under an operating voltage of tens kilovolts.

Parameters of a supershort avalanche electron beam (SAEB) in nitrogen excited by the triangular-shaped voltage pulses with 45kV amplitude in incident wave and full width at half-maximum (FWHM) of ∼ 1 ns were investigated. In experiments, cylindrical-shaped cathodes made of aluminum and stainless steel were used. An interelectrode distance in the gas-filled diode was 3, 5, and 8 mm. It was established that the highest values of SAEB's current were registered with an aluminum cathode. It was shown that, in contrast to the case of 8-mm gap length, when the interelectrode distances were 3 and 5 mm, the amplitude of SAEB current pulse in nitrogen began to decrease with high values of the pressure – 100 and 50 kPa, respectively.

Underground, the pyrolytic conversion of an oil shale in the nearest future may become an alternative source of a fuel gas and a synthetic oil. The main scientific problem in designing this technology is to provide a methodology for determination of the optimal mode of heating the subterranean formation. Such a methodology must allow predicting the composition of the pyrolysis products and the energy consumption at a given heating rate of the subterranean formation. The paper describes the results of heating of the oil shale fragments in conditions similar to the underground. The dynamics of composition of the gaseous products of pyrolysis are presented and analyzed.

The application of the formula, which is used to calculate the maximum field at the tip of the pin-plane electrode system was proposed to describe the process of electrical treeing and treeing breakdown in an oil shale. An analytical expression for the calculation of the treeing breakdown voltage in the oil shale, as a function of the inter-electrode distance, was taken. A high accuracy of the correspondence of the model to the experimental data in the range of inter-electrode distances from 0.03 to 0.5 m was taken.

The respiration of isolated mice liver mitochondria after exposure to nanosecond UWB pulses (0.15 – 36 kV/cm, 0.6 – 1.0 GHz centre frequency, 3 – 20 ns pulse duration) has been investigated. The respiratory control (RC, the ratio of oxygen consumption) was estimated. The possibility of mitochondrial membrane electroporation was detected as the decrease in the electrical resistance, according to the β-dispersion of the electric current. The monotonous decrease of RC after 1000 UWB pulses from 0.15 kV/cm was observed, the ohmic resistance of mitochondria suspension was reduced. The obtained data indicate the inhibitory effect of UWB pulses on a state of irradiated mitochondria and its membrane.

The paper describes the numerical and experimental results of the microwave O-type oscillator based on an oversized slow wave structure (SWS). The feedback is applied to the design scheme, which provides intense modulation of the electron beam in the cathode-anode region and two special cavities before SWS. The selectivity of TM₀₂ operating mode occurs due to increased diffraction loss of parasitic modes in the cathode part. The slow wave structure consists of two identical sections with the phase-shifting region in between. The use of this configuration leads to the formation of a locked TM₀₁ wave, having good conditions for the transformation into the working mode TM₀₂. In the experiments, a stable generation regime with pure TM₀₂ mode at a frequency of 10 GHz with an efficiency of about 30% and the output power of 2.5 GW in the magnetic field below the cyclotron resonance was obtained.

To broaden the spectrum of high-power ultrawideband radiation, it is suggested to synthesize an electromagnetic pulse summing the pulses of different length in free space. On the example of model pulses corresponding to radiation of combined antennas excited by bipolar voltage pulses of the length of 2 and 3 ns, the possibility of twofold broadening of the radiation spectrum was demonstrated. Radiation pulses with the spectrum width exceeding three octaves were obtained. Pattern formation by the arrays of different geometry excited by the pulses having different time shifts was considered. Optimum array structure with the pattern maximum in the main direction was demonstrated on the example of a 2×2 array.

A model is proposed to describe the initial stage of neck formation in an X-pinch that proceeds in three stages: the electrical explosion of metal wires that generates the X-pinch; the expansion of the wire material that occurs due to an excess of the gas-kinetic pressure over the pressure of the magnetic field. The model allows one to predict the minimum rate of current rise at which the formation of a "hot spot" in an X-pinch is possible. The minimum current rise rate is determined by the thermodynamic parameters of the wires at a critical point; it is of the order of 1 kA/ns.

The paper presents experimental and numerical research results on the operation of gas diode at low pressure. A high dispersion in the runaway electron beam current (from 20 to 100 A) with respect to the average one (∼50 A) is observed for a tubular cathode with a working edge radius of 30 μm, nitrogen pressure of 30 Torr, and an interelectrode gap of 6 mm. Numerical simulation data show that the low beam current (∼20 A) is due to the early electron emission from the cathode (at the stage of low-voltage prepulse), in which the runaway electron beam is formed from the boundary of plasma layer developing early in the breakdown. The high beam current (∼100 A) is due to the delayed electron emission from the cathode, which increases the diode voltage and the runaway electron beam current. In the latter case, the runaway electron beam is formed directly at the cathode.

The results of experimental study on the formation of high-current electron beams using three-electrode system are presented. This system enables to create a diffusive obstructed glow discharge in a pulsed regime with an amplitude of applied voltage up to 25 kV. The influence of such experimental parameters as the pressure of plasma forming gas and the amplitude of applied voltage on the obstructed glow discharge duration was investigated. Both the transverse and the longitudinal structure of formed electron beam was determined.

An operation of the thyristor-based switches triggered in impact-ionization wave mode has been investigated. The thyristor switch contained two series connected tablet thyristors having a silicon wafer of 56 mm diameter. Applying across the switch a triggering pulse with a voltage rise rate dU/dt of over 1 kV/ns, the thyristors transition time to a conductive state was reduced to shorter than 1 ns. It is shown that the maximum amplitude of a no-failure current is increased with increasing dU/dt at the triggering stage. A possible mechanism of the dU/dt value effect on the thyristors breakdown current is discussed. Under a safety operation regime at dU/dt = 6 kV/ns (3 kV/ns per a single thyristor), the switch discharged 1-mF capacitor, which was charged to a voltage of 5 kV, to a resistive load of 18 mΩ. The following results were obtained: a peak current was 200 kA, an initial dI/dt was 58 kA/µs, a FWHM was 25 µs, and a switching efficiency was 0.97. It is shown also that a temperature of the silicon wafer is one of the main factors that affects on the thyristor switching process.

The Z-pinch experiments with deuterium gas-puff surrounded by an outer plasma shell were carried out on the GIT-12 generator (Tomsk, Russia) at currents of 2 MA. The plasma shell consisting of hydrogen and carbon ions was formed by 48 plasma guns. The deuterium gas-puff was created by a fast electromagnetic valve. This configuration provides an efficient mode of the neutron production in DD reaction, and the neutron yield reaches a value above 10¹² neutrons per shot. Neutron diagnostics included scintillation TOF detectors for determination of the neutron energy spectrum, bubble detectors BD-PND, a silver activation detector, and several activation samples for determination of the neutron yield analysed by a Sodium Iodide (NaI) and a high-purity Germanium (HPGe) detectors. Using this neutron diagnostic complex, we measured the total neutron yield and amount of high-energy neutrons.

We present the hybrid MHD/PIC simulations of the time evolution of a deuterium gas puff z pinch. Recent experiments with 3-MA current pinches [6] made in a novel configuration have shown that the neutron yields can reach 3.6×10¹². It was shown that the observed neutron spectra could be explained by a suprathermal distribution of deuterons with a power law fall off in the ion energy distribution function at large energy. In order to perform the numerical simulation of gas puff z pinch a new hybrid model was developed. The described hybrid model treats the electrons as a massless fluid and ions as macroparticles. The macroparticle dynamic is calculated with the use of PIC method. Ion-ion Coulomb collision is considered with the use of MC method. In the model simulation, in the configuration close to described in [6], it was obtained the neutron yields up to 1.2×10¹². Most neutrons are not thermonuclear. This level of the neutron yield is reached only when a strongly nonuniform neck-like constriction of z-pinch plasma occurs. In this case, the obtained deuteron spectra (with energy up to several tens MeV) have suprathermal high energy tail. These simulations demonstrate the utility of the developed hybrid model for the z-pinch simulation.

Results of an experimental research of a rail-type gas switch with preionization by an additional negative corona discharge are presented. The most of measurements were performed for an air insulated two-electrode switch assembled of cylindrical electrodes of 22 mm diameter and 100 mm length, arranged parallel to each other, with a spark gap between them varying from 6 to 15 mm. A set of 1 to 5 needles connected to a negative cylindrical electrode and located aside of them were used for corona discharges. The needle positions, allowing an effecient stabilization of the pulsed breakdown voltage and preventing the a transition of the corona discharge in a spark form, were found. It was shown that the gas preionization by the UV-radiation of the parallel corona discharge provides a stable operation of the switch with low variations of the pulsed breakdown voltage, not exceeding 1% for a given voltage rise-time tested within the range from 40 ns to 5 µs.

Results of creation, operation, and diagnostics of the high power radiators for ultra-short length electromagnetic pulses (USEMPs) with a quasi-unipolar profile, which have been developed in our laboratory, are presented. The radiating module contains: the ultra-wideband (UWB) antenna array, the exciting high voltage pulse semiconductor generator (a pulser), the power source and the control unit. The principles of antenna array with a high efficiency aperture about 0.9 were developed using joint four TEM-horns with shielding electrodes in every TEM-horn. Sizes of the antenna apertures were (16-60) cm. The pulsers produced by "FID Technology" company had the following parameters: 50 Ohm connector impedance, unipolar pulses voltages (10-100) kV, the rise-time (0.04-0.15) ns, and the width (0.2-1) ns. The modules radiate the USEMPs of (0.1-10) GHz spectrum, their repetition rate is (1-100) kHz, and the effective potential is E*R = (20-400) kV, producing the peak E-field into the far-zone of R-distance. Parameters of the USEMP waves were measured by a calibrated sensor with the following characteristics: the sensitivity 0.32V/(kV/m), the rise-time 0.03 ns, the duration up to 7 ns. The measurements were in agreement with the simulation results, which were obtained using the 3-D code "KARAT". The USEMP waves with amplitudes (1-10) kV/m and the pulse repetition rate (0.5-100) kHz were successfully used to examine various electronic devices for an electromagnetic immunity.

A step-up linear pulse transformer and a modular primary powering system were developed for fast (≈350 ns) charging of a pulse forming line (PFL) of a high-current electron accelerator. The linear transformer is assembled of a set of 20 inductors with circular ferromagnetic cores and one–turn primary windings. The secondary turn is formed by housing tube walls and a voltage adder with a film-glycerol insulation installed inside of the inductors. The primary powering system assembles 10 modules, each of them is a low-inductance site of two capacitors of 0,35 µF and one gas switch mounted at the same enclosure. The total stored energy is 5.5 kJ at the charging voltage of 40 kV. According to test results, the equivalent parameters at the output of the transformer are the next: a capacity – 17.5 nF, an inductance – 2 µH, a resistance – 3.2 Ohms.

A new design of triggered spark gas switches with an increased operation life and stable dynamic performances for 2.4 MV, 4 MJ Marx generator of the lightning test complex is developed. An operation mode of switches in the test complex is the following: the total voltage – up to 80 kV, the discharge current – up to 50 kA, the charge flowing – up to 3.5 C/pulse, the working gas – dry air at an atmospheric pressure. An increased operating life is achieved by using the torus-shaped electrodes with an increased working area and by the application of a thick disk with a hole, as a trigger electrode, installed between the two torus-shaped electrodes. A short breakdown time delay and a high stability of the breakdown voltage under dynamic conditions are provided by gas pre-ionization in the spark gap by UV-radiation of an additional corona discharge in the axial region of the switch.

The commutation characteristics of TPI-type pseudospark switches, depending on the parameters of trigger circuits, are studied. An influence of the trigger pulse rise time on the pseudosparks time jitter is explored. It has been shown that the pseudospark switches can be triggered on a pre-ionization electrode with a cathode and a grid, simultaneously grounded. The double and the triple gapped deuterium and hydrogen switches were explored. The time jitter values of 1-2 ns on the deuterium switches triggered on the pre-ionization electrode have been achieved.

The spatio-temporal formation dynamics and basic electrical and optical characteristics of nanosecond discharges with an extended slot cathode in helium are investigated. It is established that electrons ribbon beams are formed in such discharges with an energy of several hundred eV. It is demonstrated that the restriction of the discharge gap in dielectric walls leads to the trapping of electrons in the gap and an increase in the efficiency of excitation and ionization of atoms of beam electrons, which leads to a substantial increase in the current density and intensity of optical radiation of the limited discharge. Experimental data obtained on the relaxation of charge density on the deposited surface of the charge limiter and the value estimates of the electric potential of the dielectric surfaces, were analysed. It is demonstrated that the variation in the discharge structure restricted by the dielectric walls corresponds to the variation in the distribution of the electric field in the gap, as well as under the influence of the surface potential.

Low inertial transition of the field emission into explosive electrons emission at the cathode and related fast-rise-time electron beam formation are of interest in a phase-stable excitation of relativistic high-power microwave oscillators. We present experiments on the cathode activation using emission initiation during specially prepared advance voltage pulse (prepulse) possessing variable amplitude of tens-hundreds kilovolts and the width adjustable from tenths to units of nanosecond. Such a prepulse can be separated in time with a main accelerating pulse as well as adjoined to the fast-rise-time voltage front.

A comprehensive experimental study of the spatio-temporal structure of the fronts of discrete, high-speed ionization waves (HSIW) in shielded discharge tubes filled with inert gases is carried out. It is shown that the ionization wave front at low gas pressures (below 1 Torr) has a volumetric structure, but at gas pressures above 10 Torr assumes a cylindrical form, compressed into the dielectric boundary of the discharge tube. The high-energy electrons generated at the ionization wave front have a significant impact on its structure and their energy relaxation modes. Evaluations of the energies of electrons accelerated at the HSIW front are provided along with an analysis of the influence of the energy relaxation regimes of the high-energy electrons on the structure and dynamics of the development of the ionization wave front in the shielded dielectric discharge tubes.

Results of testing of a generator based on a solid-state drive and the parallel gyromagnetic nonlinear transmission lines with external bias are presented. Stable rf-modulated high-voltage nanosecond pulses were shaped in each of the four channels in 1 s packets with 1000 Hz repetition frequencies. Pulse amplitude reaches -175 kV, at a modulation depth of rf-oscillations to 50 % and the effective frequency ∼4 GHz.

These are the results of research of the oversized (multimode) interference microwave switch at operating mode TE₀₁. The switch was produced from two H-plane T-junctions being connected to each other through straight arms (series connection). Two types of oversized tees were considered. One was based on an oversized waveguide with 25×58 mm² in cross-section and another was a package of regular H-tees operating at TE₁₀ mode with a mutual switched arm. The operating frequency was 9.15 GHz. The conducted simulation showed the conditions of the "proper" TE₀₁ mode at "open" and "close" states of the switch. Moreover, the relations between the arm' lengths and field intensity distribution were compared with the similar relations of a regular cascade microwave plasma switch. In additional, experiments were carried out at low power level.

The paper reports on a magnetohydrodynamic simulation of electrical explosions of conductors in megagauss magnetic fields. It is shown that in a plane geometry, the time of plasma formation at the surface of a metal conductor does not depend on the rate of rise of the magnetic field and is determined by the properties of the metal; the absolute values of the magnetic field at which plasma is formed are 5±0.25 MGs for copper, 4.25±0.2 MGs for tungsten, 3.85±0.15 MGs for aluminum, and 3.6±0.25 MGs for titanium. In cylindrical geometry, the time of plasma formation does depend on the rate of field rise.

This work presents the results of the study of an active microwave pulse compression system capable of forming the rectangular pulses with duration ∼10-100 ns, while its dimensions are several times smaller than the radiated wave train. Such compression system is based on the compact planar-voluminal resonant cavity constructed in the shape of a meander from waveguide sections and H-plane tees. The resonant cavity sections are parallel and are in the same plane with tees. The energy input element is located in the input end of the first section. The output device designed as an H-plane tee interference switch is connected to the output end of the last section. Each end of remaining sections is connected through a straight arm to an H-tee with a short-circuited quarter-wave second straight arm. The side arm of each tee is connected with the side arm of the tee in the next section, thus coupling the sections. The short-circuited arm provides the "open" mode and transmission of the wave from tee to tee. We determined the expressions for wave amplitudes in the components of the meander resonant cavity made of three sections and analyzed the expressions as the functions of the parameters determining the oscillation range and energy distribution in the resonant cavity. Experiments demonstrated that under certain conditions the compressors with such resonant cavity could generate nearly rectangular pulses with duration equal to the time of wave two-way traveling along the resonant cavity, and with the power compatible with that of the wave in the resonant cavity, and the length of the radiated wave train several-fold exceeding the size of the compressor. At pulse duration equal to 25 ns, the gain coefficient was 13 dB and pulse power was 40 MW. The work demonstrates the possibility to change the geometry of the resonant cavity by rearranging its components without changing the output pulse parameters.

Results on studying the angular characteristics of an electron beam, generated in a multi-aperture diode with an arc-discharge plasma emitter are reported. The main beam parameters were as follows: the electron energy up to 120 keV, the emission current up to 100 A, the pulse duration 0.1 - 0.3 ms, and the initial diameter ca. 8 cm. The beam was formed and transported to a metal target in an adiabatically converging magnetic field. The diagnostic technique based on an X-ray imaging of the profiles of individual beamlets passed through the pepperpot-like mask was developed and used to investigate an angular distribution of the beam electrons. The spatial resolution of the diagnostic was evaluated in a special test experiment and found to be not worse than 4 lp/cm at a 10 % contrast level. It was demonstrated that an angular distribution of the beam electrons fits well by the Gaussian function with the RMS width ∼ 0.067 rad. The data on the angular distribution measured with pepperpot diagnostic are in a good agreement with those obtained in the experiments on the beam passage through a magnetic mirror.

The use of plasma emission cathode in the conjunction with a multiple apertured electron optical system (EOS) is promising for the multi-MW class electron beams of a large cross-sectional area. In a multi-aperture source, the beam parameters could be raised simply due to increase of the number of apertures (i.e. an effective emission area), if a uniformity of the electron emission over a large-area plasma cathode is ensured. In the presented paper, the cross-sectional distribution of the emission current density was investigated using the X-ray diagnostic technique for two versions of the diode-type EOS, with electrodes performed as flat molybdenum "grids". The first one had 241 apertures arranged hexagonally inside a circle with a diameter of 8.3 cm and the second had 499 apertures within a circle of 11.8cm diameter. The emission plasma is produced using a single arc-discharge plasma generator placed on the axis at 20 cm from the EOS. It was demonstrated that multi-aperture systems with a single on-axis plasma generator can be effectively employed to obtain large-area beams, even in the presence of the guiding magnetic field. All apertures are emitting in the 499-apertured EOS. The beam current density is quite uniform up to the radius 2.5cm and gradually decreases to the periphery.

An experiment with Al, Cu and Ni exploding foils was carried out at a current density of (0.5-1) ×10⁸ A/cm² through the 6-μm foil with a current density rate of about (0.5-1) ×10⁸ A/cm²·s. To record the metal foil effervescence during the foil explosions, a two-frame radiographic system was used. It was shown that the duration of the explosion resistive phase was considerably lower than the metal boiling time. The foil energy deposition is equal to 30-70% of the sublimation energy.

We present the results of rf oscillations growth dynamics as the high voltage pulse propagates through the gyromagnetic nonlinear transmission line (NLTL). Several equidistant electrical probes were placed inside the NLTL in order to examine the oscillatory wave formation and the role of higher order modes in this process. RF pulses are generated at 2 GHz frequency with nonaveraged peak power of 100 MW. Azimuthal asymmetry of the wave propagating through NLTL is detected.

Si_xC_yO_z composite nanopowder with an average size of particles about 10-50 nm was produced using the pulsed plasma chemical method. The experiments on the synthesis of nanosized composite were carried out using a TEA-500 pulsed electron accelerator. To produce a composite, SiCl₄, O₂, and CH₄ were used. The major part of experiments was conducted using a plasma chemical reactor (quartz, 140 mm diameter, 6 l volume). The initial reagents were injected into the reactor, then a pulsed electron beam was injected which initiated the chemical reactions whose products were the Si_xC_yO_z composite nanopowder. To define the morphology of the particles, the JEOL-II-100 transmission electron microscope (TEM) with an accelerating voltage of 100 kV was used. The substances in the composition of the composite nanopowder were identified using the infrared absorption optical spectrum. To conduct this analysis, the Nicolet 5700 FT-IR spectrometer was used.

An electron and phonon spectra dynamics, features of structural phase transitions, and melting of sodium under the pressure ranging from 0 to 100 GPa are investigated. The electron and the phonon spectra of crystal sodium are calculated ab initio within the density functional theory by means of the software package LmtART-7 (see [1-3] and references herein), allowing the fully potential method of linear muffin-tin orbitals (FP-LMTO method). Earlier, this method was used in papers [4-6] for the calculation of a metals band structure within an atomic-spheres approximation (LMTO-ASA method). Using the Lindemann measure and the calculated phonon spectra, the theoretical values of melting points corresponding to the experimental data are obtained. Features of the electron and the phonon spectra dynamics in the melting curve maximum vicinity and within the structural transition range are discussed cI2 → cF4.

The mode convertor design of fundamental coaxial TEM to the lowest asymmetric TE11-mode of a circular waveguide was proposed and optimized with ANSYS HFSS software. It includes axially aligned parts: the input coaxial line with the high voltage insulator, conical coaxial matching line, wave-coax transition section and output circular waveguide. The most losses in this type of convertor caused by the wave of coaxial TE11-mode running back to the microwave source. To minimize these losses, there is the matching conical coaxial line with the cut-off insertion for coaxial TE11-mode. Characteristics of the convertor are as follows: the maximum input peak power – 3GW, the input impedance – 28Ohm, the central operating frequency – 1.14GHz. The power conversion efficiency to the output mode is from 90% upto 100% in the frequency band of 20%.

The results of experiments on a soft x-ray radiography (≈ 1-2 keV) of a bismuth plasma formed by the high-current vacuum arc discharge are represented. The plasma gun with the arc current ≈ 60 kA and the current rise time ≈ 7 μs was used to produce the Bi plasma jet. The compact pulsed radiograph XPG-1 (250 kA, 220 ns) with an X-pinch load consisting of four Mo wires with a diameter 25 μm was used as a source of the soft X-ray radiation. The X-ray backlighting images of the researched plasma jet and the Bi step-wedge with a step thickness of ≈ 100 nm were recorded simultaneously in the course of the experiment. A comparison of the plasma jet x-ray image with the current trace has enabled to estimate dependencies of the linear mass on the arc current. The experiments have shown that when the arc current density reaches ≈ 3·10⁵ A/cm², the evaporation rate of the electrode material reaches ≈ 100 μg/μs, that under the plasma velocity ≈ 0.5 cm/μs, provides a plasma jet linear mass ≈ 200 μg/cm. At a distance of ≈ 1-2 mm from the arc cathode surface, the sharp increase of the jet linear mass (up to ≈ 500 μg/cm) occurred.

The report presents the design of an electron and an ion pulsed accelerator. The powerful high-voltage pulse generator of the accelerator and the vacuum bushing insulator is able to change the polarity of the output voltage. The low-inductance matching transformer provides an increase in the DFL output impedance by 4 times. The generator based on a high voltage pulse transformer and a pseudo spark switch is applied for DFL charging. The high-impedance magnetically insulated focusing diode with Br magnetic field and the "passive" anode was used to realize the ion beam generation mode. The plasma is formed on the surface of the anode caused by an electrical breakdown at the voltage edge pulse; as a result, the carbon ion and proton beam is generated. This beam has the following parameters: the current density is about 400 A/cm2 (in focus): the applied voltage is up to 450 kV. The accelerator is designed for the research on the interaction of the charged particle pulsed beams with materials and for the development of technological processes of a material modification.

We present the results of the investigation of the initial stage of volume discharge formation in helium of atmospheric pressure. The investigation of the non-locality of energy distribution influence on the ionization wave parameters in the front area is carried out on the basis of a two-dimensional axial-symmetry drift-diffusion model. The results of numerical calculations are in a satisfactory agreement with the experimental data.

In an electro-blasting technology for the solid destruction, the pulse power generators with different types of switches is used. One of them is a triggered vacuum switch, that for an easy operation, has a suitable lifetime of 10⁴–10⁵ commutations in average and can pass about 100 coulombs of charge. However, in most cases it passes only a half-cycle of the current in the ringing mode operation. In this paper, the influence of the ringing current pulse duration on the stress-strained state formation is investigated. Simulation results of the energy release modes in a discharge channel are given. The crowbar mode of operation is also investigated and a comparison with the ringing mode are presented. It is shown that in a dumping oscillations mode with a damping factor of about 7, the second and the subsequent oscillations contribute only about 5 % of a total energy into the shock-wave.

A low-inductance module of a high-current capacitive energy storage with an operating voltage of 40 kV is developed. The design of the module is based on the application of capacitive sections of the industrial condenser IK50-3. The module includes two capacitors of 0.35 μF each, one common low-jitter triggered gas switch and 2 groups of output cables of 4 from each capacitor. A bus bars topology developed for the switch and cables connections provides a small total inductance of the discharge circuit, for the module with the output cables KVIM of 0.5 m long, it is lower than 40 nH. The set of 10 modules is now used for driving the 20 stages linear transformer for a fast charging of the pulse forming line of the high-current nanosecond accelerator. A design of the module and the results of tests of a single module and a set of 10 are presented.

The numerical simulation results on fracture of a concrete block due to dynamic explosive loads applied to the walls of a blast hole are presented. The influence of the pulse shape on the shock-wave dynamics is considered. A comparison of mechanical stresses in direct and reflected pressure waves induced in the concrete block by explosion pulses of various durations and amplitudes shows that the shorter pulses with higher amplitudes and steeper rise times provide a higher blasting efficiency. The wire application for the discharge initiation enables the operating voltage of the generator to decrease, the discharge gap to increase, and hence, the channel energy to lead to the demolition build-up at electro burst. The significant dependence of the stress-wave profile on the pressure pulse wave shape at the borehole wall, which is determined by the rate of electrical energy release in the plasma channel, has been shown. An analysis of the stress-wave dynamics has shown that the rapid power deposition into a plasma channel tends to shift an amplitude of the tangential stresses in a reflected wave to the higher values and to extend the region of tensile tangential stresses initiating the main crack propagation from the borehole walls to a free material surface.

This work describes the operating principle and test results of the diagnostics for measuring the pulsed electron beam parameters under repetitive operation mode. The diagnostics is based on a PIN-diode, which is used as a bremsstrahlung detector. The signal from a PIN-diode was converted to a pseudo constant voltage signal which can be measured by a conventional voltmeter. Then the signal acquired by the voltmeter was compared with a reference signal indicating the normal operating regime of the accelerator, thus information about the shot-to-shot reproducibility of the electron beam parameters was given. The system was developed and tested for the ASTRA-M accelerator with the following operating parameters: 470 kV accelerating voltage, 120 ns beam duration and up to 50 pulses per second repetition rate.

To study a response of tumor cells and macrophages to the repetitive pulsed low-dose X-ray radiation. Methods. Tumor growth and lung metastasis of mice with an injected Lewis lung carcinoma were analysed, using C57Bl6. Monocytes were isolated from a human blood, using CD14+ magnetic beads. IL6, IL1-betta, and TNF-alpha were determined by ELISA. For macrophage phenotyping, a confocal microscopy was applied. "Sinus-150" was used for the generation of pulsed X-ray radiation (the absorbed dose was below 0.1 Gy, the pulse repetition frequency was 10 pulse/sec). The irradiation of mice by 0.1 Gy pulsed X-rays significantly inhibited the growth of primary tumor and reduced the number of metastatic colonies in the lung. Furthermore, the changes in macrophage phenotype and cytokine secretion were observed after repetitive pulsed X-ray radiation. Conclusion. Macrophages and tumor cells had a different response to a low-dose pulsed X-ray radiation. An activation of the immune system through changes of a macrophage phenotype can result in a significant antitumor effect of the low-dose repetitive pulsed X-ray radiation.

The application of an electrical discharge technology for destructive recycling of the reinforced concrete is considered. Its main advantages, in comparison with the mechanical methods, are that the electrical discharge channel acting as a rock-breaking tool has an unlimited service life, and a lifetime of the electrode systems is much higher. The physical and mathematical model of the discharge development is described. The simulation results have shown that the discharge channel propagation velocity and the trajectory depend on the reinforcement locality and the voltage amplitude. The voltage affects the average speed of the discharge structure development which can reach the value of up to υ=5·10³ m/s. It is also shown that the reinforcing elements located between the electrodes attract the growing discharge structure. The lower the distance between the vertical axis of the high voltage electrode and the metal reinforcement position, the more probability of the discharge channel orientation towards this element.

The paper presents a design and the results of testing of the liquid resistive load for a repetitive high-voltage generator (200 kV, 0.5 ms). The load uses a sealed dielectric case, which is to be placed into a vacuum volume (5×10^-4 Torr) for electrical strength ensuring. Repetitive testing of the generator with the load (10 pps) caused the electrolyte heating, the load resistance decreasing, and the changing of a generator mode. An expansion tank is used to compensate thermal expansion of the electrolyte, which makes it possible to absorb up to 1 MJ of energy in the load without seals breaking. A generator load curve can be obtained for one experiment with a help of the fluid load without any additional depressurization of the vacuum volume.

A new high-current electron gun with plasma anode and explosive-emission cathode integrated with planar pulsed powered magnetron is described. Five hundred twelve copper wires 1 mm in diameter and 15 mm in height serve as emitters. These emitters are installed on stainless steel disc (substrate) with 3-mm distance between them. Magnetron discharge plasma provides increased ion density on the periphery of plasma anode formed by high-current Penning discharge ignited within several milliseconds after starting of the magnetron discharge. The increased on the periphery ion density improves the uniformity of high-current electron beam produced in such an electron gun.

The paper presents the results of mathematical modeling of physical processes in electronic devices such as helicon discharge and coaxial pulsed plasma thruster. A mathematical model of coaxial magneto-plasma accelerator (with a preionization helicon discharge), which allows estimating the transformation of one form of energy to another, as well as to evaluate the level of the contribution of different types of energy, the increase in mass of the accelerated plasmoid in the process of changing the speed. Main plasma parameters with experimental data were compared.

In the course of the long-term performance (during 5 years) of a high-power source of gas ions (25 keV, 0.2 A, 600 cm²) with a plasma emitter based on cold cathode discharge, the character and rate of key constructive elements faults were determined, which allowed to calculate the inter-repair time, complexity and cost of the repair. The peculiarities of the gas-discharge system and the ion beam forming system limiting the effectiveness of ion beam treatment were revealed as well. Conditions favorable for the decrease in the discharge voltage by 50–200 V and igniting voltage up to 1.5-2 times are determined. The possibilities of lowering the minimal flow of working gas are demonstrated. The design of the discharge system with reduced sputtering rate of local areas of the hollow cathode is offered. The changes added to ion source design aimed to enhance the lifetime of the plasma chamber that is exposed to cyclic heating by the back electron beam leading to the development of through cracks, and to enlarge the rupture life of glow discharge hollow cathode by optimizing its configuration and the conditions of discharge ignition and burning, are described. The upgraded design of a multislit ion-optical system with enhanced performance ensures uniform surface distribution of ion fluence.

This work investigates the characteristics of the gas discharge system used to create an atmospheric pressure plasma flow. The plasma jet design with a cylindrical graphite cathode and an anode rod located on the axis of the system allows to realize regularly reproducible spark breakdowns mode with a frequency ∼ 5 kHz and a duration ∼ 40 μs. The device generates a cold atmospheric plasma flame with 1 cm in diameter in the flow of various plasma forming gases including nitrogen and air at about 100 mA average discharge current. In the described construction the cathode spots of individual spark channels randomly move along the inner surface of the graphite electrode creating the secondary plasma stream time-average distributed throughout the whole exit aperture area after the decay of numerous filamentary discharge channels. The results of the spectral diagnostics of plasma in the discharge gap and in the stream coming out of the source are presented. Despite the low temperature of atoms and molecules in plasma stream the cathode spots operation with temperature of ∼ 4000 °C at a graphite electrode inside a discharge system enables to saturate the plasma by CN-radicals and atomic carbon in the case of using nitrogen as the working gas.

Plasma technologies of material modification and deposition of coatings with different functional properties can be implemented if the efficient sources of plasma flows are available. These sources are the electric-arc generators of thermal plasma (plasmatrons). The effect of different plasmatron schemes on distribution of temperature and velocity of plasma flows is considered in the current study. For example, it is shown that a partitioned interelectrode insert and gas injection between the sections ensure a plateau in temperature distribution T(r). A similar result was obtained for the plasma flow at the exit of the plasmatron with a stepped output electrode.

The results of tests of a self-heated hollow cathode made by magnet-pulse pressing of the mixture of TiN (90 %) and Ti (10 %) powders with further high-temperature annealing and fusing during operation of the compact as a cathode in high-current (10 - 45 A) discharge are presented. It was found that the rate of the cathode mass loss during operation in Ar/N₂ mixture made 2.3*10^-7 g/C. The possibility of the cathode use for oxygen-argon plasma generation at separated gas feeding (argon – through cathode cavity, and O₂ – to anode area of discharge) was shown. Testing of massive tubular cathodes with the increased thickness of the wall (up to 2.5 mm) and large inner diameter (up to 12 mm) possessing an enhanced resource (300 - 500 h) was carried out.

Electrophysical characteristics of a low–frequency (100 kHz) low–pressure (10–100 Pa) argon inductive discharge with ferrite cores have been investigated for discharge currents of 1–50 A, discharge chamber diameter of 230 mm. The dependencies of electric field strength on the argon pressure and discharge current were measured. Radial profiles of electron density and temperature were determined with double electric probes. Experimental results were compared with numerical results obtained by a self-consistent kinetic model of the low-frequency ICP, based on the simultaneous solution of a non-local Boltzmann equation for electron energy distribution function and balance equations for the metastable argon atoms density and gas temperature. Comparison of numerical and experimental results is presented.

Influence of temperature distribution of thermal and fast electrons on the distribution of the ion current density in the electrode gap diode has been studied. Studies on the phase planes, especially in the plane of the plasma density – ion current density have been carried out. It is shown that the generation of ions in the electrode gap is specified by the fast electron temperature.

The method of some reflecting discharge (Penning discharge) characteristics computation, based on the one-particle approximation is proposed. This discharge is widely used in ion sources aimed at surface modification. However, only the steady state of this discharge is sufficiently described, whereas pulsed modes are preferable in many cases. In fact, the proposed method is similar to the approach used in the early times of first glow discharge investigations and crossed fields ion sources. It may be applied for the early discharge stages (the Townsend regime) description. It is somehow simpler than the diffusion-drift approximation used as a rule for the stationary state description, because plasma does not exist yet. On the other hand, one need not use most of usual diffusion-drift simplifications e.g. 1 or 2D models, uniform magnetic field etc. So the process of discharge formation may be described exactly for different kinds of Penning cells geometries and fields configurations. The discharge ignition condition for the Penning cell, analogous to the Townsend law is evaluated. It allows one to appreciate the discharge formation time as a function of cell geometric parameters, field configurations, anode voltage and Townsend's coefficients α and γ. This time, or exactly the trajectory length during this time, plays the role of the Townsend parameter d – the distance between electrodes. The calculated values of such times show good agreement with experimental data.

The paper presents research results on the capabilities of an unbalanced magnetron sputtering (UMS) system with a coefficient of geometrical unbalance K_G=0.3 to produce gas discharge plasma far from its target. Using argon as the working gas and silicon as the target material, it is shown that the proposed UMS system provides the generation of plasma with an ion current density of ≈ 0.2 mA/cm² in the region of treated material at 440 mm from the Si target. The research data on the maximum power at which the UMS system produces high-density plasma without melting the Si target are also presented.

The method of material near-surface layers doping by mixing of alloying elements films with ion beam is widely used in science and technology. Three magnetrons with independent power systems, integrated in installation for ion-beam treatment of long-range products ILUR-03, were used as deposition systems. Targets for magnetrons were in the form of disks 60 mm diameter and 5 mm thickness and consisted of the following elements: Al, Fe, Mo, Zr, Cr of purity better than 99.99 at.%. Deposition was performed in argon atmosphere at 1-5 Pa pressure and room temperature in stable current mode at 30-100 mA. Analysis of the obtained films on the surface of cylindrical specimens from zirconium alloys with the outer diameter of 9.15 mm showed high uniformity of coating on length of 300 mm, good adhesion and absence of discontinuities in the films body.

Diffused vacuum arc, which is characterized by the absence of microparticles in cathode erosion products and by the irregular voltage oscillations, is considered to be a perspective plasma source for plasma reprocessing technology of spent nuclear fuel (SNF). The development of this technology requires data on ions energy in plasma jet. In this work parameters of plasma jet in diffused vacuum arc with a gadolinium cathode were studied by a retarding field analyzer, Langmuir and condensation probes. Gadolinium is regarded as a substance simulating SNF plasma. Ion energy spectrum was studied at arc currents of 30-75 A and voltages of 4-15 V at the distance of 20 cm above the arc anode. Dependencies of spectrum widths and most possible ion energies on arc voltages were obtained. The measured electron temperature was 2 eV, the maximum ion energy reached 70 eV. Experimental data were used to calculate adiabatic plasma expansion through the anode outlet.

The formation of an atmospheric pressure plasma jet (APPJ) in a gas flow passing through the discharge gap depends on both gas-dynamic properties and electrophysical parameters of the plasma jet generator. The paper presents the results of experimental and numerical study of the propagation of the APPJ in a laminar flow of helium. A dielectric-barrier discharge (DBD) generated inside a quartz tube equipped with a coaxial electrode system, which provided gas passing through it, served as a plasma source. The transition of the laminar regime of gas flow into turbulent one was controlled by the photography of a formed plasma jet. The corresponding gas outlet velocity and Reynolds numbers were revealed experimentally and were used to simulate gas dynamics with OpenFOAM software. The data of the numerical simulation suggest that the length of plasma jet at the unvarying electrophysical parameters of DBD strongly depends on the mole fraction of ambient air in a helium flow, which is established along the direction of gas flow.

Laser-induced plasma has been considered for multiple applications by the moment, and its characteristics strongly depend on laser radiation parameters. Reaching demanded values for the latter might be rather costly, but, in certain cases, similar or even better results could be reached in case of additional impact (optical, electric, magnetic, corpuscular, mechanical etc.). Combined impact effects are mainly based on target properties or interaction mechanism change, and found to decrease plasma generation thresholds by orders of magnitude, improve energy efficiency significantly, and also broaden the range of plasma parameters. Application area, efficiency and optimal regimes for laser plasma generation at such combined impact have been considered. Analysis based on published data and own experiments was performed for both target material and induced plasma flows. Criterial parameters have been suggested to characterize both combined impact and response to it. The data on plasma generation thresholds, controlled parameters, working media supply systems and recovery rate of droplets are very important for technology setups, including those for material modification.

The investigations of dynamics and macrostructure (spatial and temporal distributions of charged particles) of optic-plasmadynamic discharges with light erosion mechanism of plasma formation and generation of accelerated gas–plasma flows of various chemical composition in the wide range of dynamic and energy & power characteristics are presented. The plasma was heated as a result of the thermalization due to shock interaction of high kinetic energy plasma flows with a gas medium, which works as a stopping barrier for such discharges. It was shown that the deceleration of the radially inhomogeneous flow at a deformable gas barrier has an essentially two-dimensional nature: a complex system of conical shock wave forms in a hypersonic plasma flow.

The optimization of hydrogen Penning sources used, in particular, in plasma chemical processing of materials and DLC deposition, is still very important. Investigations of mass-charge composition of these ion source emitted beams are particular relevant for miniature linear accelerators (neutron flux generators) nowadays. The Penning ion source energy and mass-charge ion distributions are presented. The relation between the discharge current abrupt jumps with increasing plasma density in the discharge center and increasing potential whipping (up to 50% of the anode voltage) is shown. Also the energy spectra in the discharge different modes as the pressure and anode potential functions are presented. It has been revealed that the atomic hydrogen ion concentration is about 5-10%, and it weakly depends on the pressure and the discharge current (in the investigated range from 1 to 10 mTorr and from 50 to 1000 μA) and increases with the anode voltage (up 1 to 3,5 kV).

Ion fluxes on the surface of sample embedded in inductively coupled plasma have been studied in conditions typical for titanium alloy nitriding: total pressure 0.44 Pa, Ar/N₂ = 70%/30%, and RF power 1500 W. The gas composition was independently monitored by the quadrupole analyser. The ion fluxes were sampled using a specially designed electrostatic extractor and then analysed with a magnetic sector mass-separator. The extractor design allowed us to apply a bias voltage to the plasma facing electrode thus imitating interaction of ions with the surface during the plasma processing. The ion fluxes of Ar⁺, ${{\rm{N}}}_{2}{}^{+}$, and N⁺ on the surface were measured. The mass spectroscopy diagnostics unit is suitable for extensive ion content studies in the plasma technology facilities.

The prosperity of plasma technologies stimulates making of a facility generating compressive plasma flows at the South Ural State University. The facility is a compact-geometry magnetoplasma compressor with the following parameters: stored energy up to 15 kJ, voltage of a bank from 3 to 5 kV; nitrogen, air, and other gases can serve as its operating gas. The investigation of parameters of the facility showed the following parameters of compressive plasma flows: impulse duration of up to 120 μs, discharge current of 50-120 kA, speed of plasma flow of 15-30 km/s. By contrast to the available facilities, the parameters of the developed facility can be adjusted in a wide range of voltage from 2 kV to 10 kV, its design permits generating CPF in horizontal and vertical positions.

The paper presents the results of nitriding the titanium alloy VT6 (Ti-6Al-4V) in a non-self-maintained high-current discharge and in a glow discharge in different regimes. Nitriding was conducted in pure nitrogen and in the mixture of nitrogen and argon. It is shown that microhardness of the samples increased; however, the efficiency of surface modification depends on the modification conditions.

The evolution of atomic displacement cascades initiated near free surfaces with different crystallographic orientations in bcc iron specimens was studied on the base of the molecular dynamics approach. The craters surrounded by adatom mounds were formed in the case of the (111) surface irradiation. The dislocation loops consisted of vacancies were generated after the (110) surface irradiation. The dislocation Burgers vector was a/2 <111> or a <100>. It was shown that the type of structural damage is determined by the anisotropy of propagation of shock waves generated by atomic displacement cascades. For energies of the atomic displacement cascade lower than 20 keV the number of adatoms and survived point defects was higher for specimen with the (110) free surface due to the different character of surface damage. The increase in the cascade energy up to 20 keV results in formation of almost the equal number of survived point defects for the (110) and (111) free surfaces as displacement cascades were developed on larger distance from the irradiated surfaces.

The simulation of peculiarities of the surface layer reconstruction in the crystallites of aluminum after the ion bombardment and the copper film irradiated by the electron beam is carried out. The performed calculations are based on the molecular dynamics method. It is shown that the orientation of the irradiated surface and preliminary elastic deformation have a significant impact on features of atomic structure formation in the ion-modified layer in aluminum. Weak structural changes in the surface layer are observed at the irradiation of the {100} surfaces. Sufficiently great number of stacking faults is formed under irradiation of the {111} and {110} surfaces. It is shown that heating by the electron beam of the {110} surface in the copper film leads to the formation of stacking faults. It is shown that the preliminary elastic deformation of the material lowers the energy of the irradiation, at which formation of structural defects and fragmentation of crystallites of aluminum and copper will take place.

Numerical simulations of heat and evaporation processes of quartz particles in Ar radio frequency inductively coupled plasma (ICP) are investigated. The quartz particles are supplied by the carrier gas into the ICP within gas-cooling. It is shown that with the increase of amplitude of discharge current above critical value there is a toroidal vortex in the ICP torch at the first coil. The conditions for the formation of vortex and the parameters of the vortex tube have been evaluated and determined. The influence of vortex, discharge current, coil numbers and feed rate of carrier gas on the evaporation efficiency of quartz particles have been demonstrated. It was found that the optimal discharge current is close to the critical value when the quartz particles with initial sizes up to 130 μm can be fully vaporized in the ICP torch with thermal power of 10kW. The heat and evaporation processes of quartz particles in the ICP torch have significant importance for the study of one-step plasma chemical reaction method directly producing silicon from silicide (SiO₂) in the argon-hydrogen plasma.

This paper reviews the conditions of iron borides formation and simulation of surface layers saturation depending on the stoichiometry of original components. Temperature fields have been investigated as well, which form certain phases in accordance with the pressure in the chamber and the power of the electron beam. A thermodynamic study of phase equilibria in Fe-B-C-O systems has been performed. This was done in order to optimize conditions for forming functional layers on the surface of iron-carbon alloys as a result of electron beam boriding in vacuum. Furthermore, strength characteristics of iron boride layers have been determined. Then these layers obtained by different methods and using various source components have been thoroughly compared with each other during the analysis.

The paper presents the mechanisms of mass transfer in a material under compressive plasma flows. The work contains numerical studies on mass loss from the surface of a sample treated by Compressive Plasma Flow, in the first case, and by High-Current Electron Beam, in the second case. The mass ablated from the material surface was computed with BETAIN software. The effects of plasma flow pressure on mass transfer of the material and processes of formation of the molten layer and erosion of mass from the material surface were investigated. It was revealed that plasma flow pressure formed a shock-compressed layer on the sample, and molten liquid was displaced from the center to peripheral regions. If sample size is less than the diameter of plasma spot, the melt is displaced out of the sample. This approach can explain experimental values of molten thickness and mass loss.

We present our models of the tensile fracture of metals in the solid and molten states, the melting and the plastic deformation of the solid metals. Also we discuss implementation of these models for simulation of the high current electron beam impact on metals. The models are constructed in the following way: the atomistic simulations are used at the first stage for investigation of dynamics and kinetics of structural defects in material (voids, dislocations, melting cites); equations describing evolution of such defects are constructed, verified, and their parameters are identified by means of comparison with the atomistic simulation result; finally, the defects evolution equations are incorporated into the continuum model of the substance behaviour on the macroscopic scale. The obtained continuum models with accounting of defects subsystems are tested in comparison with the experimental results known from literature. The proposed models not only allow one to describe the metal behaviour under the conditions of intensive electron irradiation, but they also allow one to determine the structural changes in the irradiated material.

The paper presents the results of computer calculations of glow discharge plasma parameters in a hollow cathode zone and modeling of thermal and diffusion processes at local ion nitriding with a hollow cathode. The proposed model of a glow discharge with a hollow cathode with sufficient accuracy allowed to describe the distribution of plasma parameters in a cathode void. Values of plasma parameters in a cathode void formed by a mesh screen and cathode surface were obtained via the probe method. It was found that the use of hollow cathode effect allows to increase the concentration of ions near the treated surface by 1.5 times. The suggested computer model allows to predict the distribution of the temperature field and depth of a diffusion layer at local ion nitriding with a hollow cathode for various configurations and sizes.

The paper presents research results on the influence of martensitic steel ultrafine-grained (UFG) structure on diffusion processes at low-temperature ion nitriding. UFG structure was obtained through severe plastic deformation by torsion (SPDT) of coarse-grained (CG) steel samples. Ion nitriding was performed under the constant voltage mode during 4 hours at a temperature of 420 °C. Optical microscope was used to study the microstructure of a sample. Thickness of a modified layer was defined according to measurements of microhardness by depth. The analysis of research results showed that UFG steel structure enhances effective intensification of diffusion processes by 1.7 times, which in its turn contributes to low-temperature modification of a surface. At the same time, surface microhardness of UFG steel after treatment amounted to 1,200 HV and 525 HV of CG steel correspondingly.

In the modern technics there is a requirement in micro- and macrorough surfaces of products for improvement of their operational characteristics (improvement of adhesive properties of various coverings, decrease in deterioration of rubbing details because of the best deduction of greasing, increase of the heat exchanging coefficient from a surface, stimulation of adhesive processes on sites of contact to a bone fabric of medical implants in stomatology and orthopedy etc.). In the given work the modes of reception regulated micro- and macrorough surfaces on samples from a titanic alloy and stainless steel by electrothermal influence of moving cathodic stains in the vacuum arc discharge are investigated. Chaotically moving stains, possessing high specific power allocation (∼ 10⁷ W/cm²), "scan" the difficult design of a product, including "shadow" sites, doing rough its blanket. The sizes of roughnesses are regulated by a current and time of influence of the discharge, pressure in the vacuum chamber and a number of other parameters. The scheme of experimental device, photo and the characteristic of rough surfaces and technological modes of their reception are resulted.

The experimental results prove the ability to realize technology of chemical heat treatment of some materials by surface microalloying using a wide-aperture low-energy high-current electron beam. Such layers were produced due to initiating exothermic chemical self-propagating high-temperature reactions in the thermal explosion mode between the base and the thin film covered on the base. New phase compounds in reaction products were found.

Thin films of tin oxide were deposited on the glass substrates at a room temperature using reactive magnetron sputtering. The ratio between O₂/Ar and the discharge voltage is maintained in such a mode when the deposited films are dielectrics. After the deposition, the films were irradiated with an argon ions beam. The modification of the optical and electrical properties of the films depending on the irradiation time was studied. Optical properties of the films were analyzed in the range of 300-1100 nm using photometry and structural X-ray diffraction. The diffractometric research showed that the films, deposited on a substrate, had a crystal structure, and after argon ions irradiation they became quasi-crystalline (amorphous). It was found that the modification in the transmittance was correlated with modifications in the meaning of surface resistance. The dielectrics films SnO₂ with increasing exposure time became conductive and then the electrical resistance decreased and reached a minimum at 13.2 seconds. Then resistance films began to increase.

An experimental investigation of ion-plasma nitriding of austenitic stainless steel AISI 321 in a low-frequency (100 kHz) nitrogen inductive discharge has been performed for the nitrogen pressure of 7 Pa, nitrogen ion densities of 10¹⁰–10¹¹ cm^-3, sample temperatures of 440–590 °C, the densities of current on the sample surface of 1.2–3.3 mA/cm², sample biases of -500 and -750 V. The time of ion-plasma treatment was 20 and 60 min. It is shown that even for the short (20 min.) ion-plasma treatment in the low-frequency inductive discharge, formation of nitrided layers with the thickness of up to 40 μm and microhardness of up to 9 GPa is observed.

Intense pulsed ion beam (IPIB) has been extensively used in the surface strengthening of metal materials in the past decades. Quite a lot of these materials need to be operated in the corrosive environment. Therefore, it is of significance to research the corrosion behavior of metal materials after IPIB irradiation. In this work, the corrosion behavior of Ni-based superalloy irradiated by IPIB in NaCl solution was studied. Compared to the original samples, after IPIB irradiation the corrosion resistance of samples were improved, and craters were formed on the surface of Ni-based super alloys. It is found that micro-areas with craters would be eroded prior to other areas in caustic solutions. The analysis revealed that craters play an important role in the corrosion process of the metal after irradiation. This research would help understand the influence of craters induce by IPIB on the operational performance of metal materials.

The work was aimed to study the influence of plasma nitriding on electrical and mechanical properties of structural steels and their durability in pulsed high magnetic field. The plates and cylindrical magnetic flux concentrators were made of several steel grades (30KhGS, 40Kh, 50KhGA, 38Kh2MYuA, and U8A), heat-treated, and subjected to the low-temperature (400, 500°C) plasma nitriding. Electrical and mechanical properties of materials, phase composition of steel surface layer, microstructure and microhardness profiles were investigated on the plates before and after plasma treatment. Microstructure and microhardness profiles across the subsurface layer of plasma treated and untreated concentrators applied for high magnetic field generation were also studied. Magnetic field of 50 T under tens of microseconds in duration inside the flux concentrators was generated by long-life outer coil.

The effect of ion implantation of boron ions with an energy of 100 keV and a dose of (1-6)×10¹⁵ cm^-2 in the MBE HgCdTe films on the characteristics of the MIS structures based on these films was investigated. The changes of the conductivity type in the near-surface layer of HgCdTe after ion implantation of boron and etching by ions of argon were detected. The concentrations of the major charge carriers in the near-surface layer of the epitaxial films after ion implantation and after ion etching were close to 5.88×10¹⁶ cm^-3 and 2.47×10¹⁷ cm^-3, respectively.

The effect of a high-frequency nanosecond volume discharge forming in an inhomogeneous electrical field at atmospheric pressure on the CdHgTe (CMT) epitaxial films is studied. The measurement of the electrophysical parameters of the CMT specimens upon irradiation shows that that the action of pulses of nanosecond volume discharge leads to changes in the electrophysical properties of CMT epitaxial films due to formation of a near-surface high-conductivity layer of the n-type conduction. The preliminary results show that it is possible to use such actions in the development of technologies for the controlled change of the properties of CMT narrow-band solid solutions and production of structures heterogeneous with respect to conduction.

In this work we studied the characteristics of MBE MCT films after the introduction of different energies As+ with different doses of irradiation. Some of the samples were subjected to post-implantation annealing. Electrical characteristics of the samples were determined from Hall measurements. Voltage-current characteristics of the structures were also measured. Activation As and modification of the characteristics of MCT outside the implanted layer after annealing have been detected. Also we found differences in the p-n junction depths and electrically active defects profiles.

The paper describes the solutions of the building materials heat conduction problems – heating source power and size definition based on temperature measurements on a material surface and on layers, heating source characteristics and surface temperature identification by temperature measurements on a treated area. The basic problem of the building concrete block heating by mobile Gauss type thermal source are addressed. As a result there are given formulae for an estimation of the plasmatron useful power and maximal temperature on the depth z ≥ 1 mm with accuracy enough for a practical appliance. Also values of the main technological parameters during the treatment are recommended and the technology of concrete block finish is shown.

The possibility to obtain barrier layers during the surface modification by ion-plasma to decrease the oxidation and hydrogenation rate of fuel claddings from zirconium alloys at various operation conditions is studied in this paper. Fuel claddings from the alloy E110 obtained on the outer surface of fuel elements after ion polishing are determined on the basis of calculations and experiments performed: the average ion energy in a beam is 3-4 keV, the ion current is 0.4-0.7 mA cm^-2, and the total irradiation dose is 5×10¹⁸ ion cm^-2. Cleaning and polishing of samples from the alloy E110 were carried out on the installation ILUR-03 by a radial beam of argon ions with a wide energy spectrum. Thin films (up to 100 nm) of alloying elements – Fe, Al, Mo, Y, Mg, and Cr were obtained on the polished surface by magnetron deposition and then implanted into the near-surface layer under the influence of a radial beam of argon ions. Study of the element composition of cleaned and modified near-surface layers was performed by X-ray microanalysis. A part of the samples was preliminarily autoclaved in distilled water at the temperature of 350 °C and the pressure of 17 MPa for 500 h to obtain a protective layer from an oxide film enriched by implanted elements. It is shown that alloying elements are mostly located at the oxide-metal boundary and in the oxide.

A multiple increase in the atom mobility in metastable supersaturated (quenched from 850 °C) Fe-8.16 at % Mn solid solution is detected at temperatures less than 250°C under irradiation with 5-keV Ar⁺ and Xe⁺ ions of different masses. The irradiation-induced atom redistribution in the entire volume of foils 30 μm thick at a projected Ar⁺ and Xe⁺ ion ranges as much as 20-30 nm only is found and studied by the transmission Mössbauer spectroscopy. Long-range effects at low irradiation doses and anomalously low temperatures are attributed to "radiation shaking" of metastable media with post-cascade solitary waves in contrast to thermally stimulated radiation-enhanced processes in the narrow nanoscale near-surface layers of the alloy. It has been shown that heavier Xe⁺ ions at higher irradiation doses have a stronger impact on the solid solution than Ar⁺ ions.

Composites based on copper matrix are of a great interest in various applications. Copper-tin alloys are intensively investigated due to their thermal and chemical stability in combination with good mechanical properties. This work shows the possibility to obtain Cu-Sn ceramics by spark plasma sintering using nanoscale powders consisting of copper and tin, synthesized by plasma dynamic method. This method is implemented by using a coaxial magnetoplasma accelerator with copper electrodes and adding the solid precursor (tin) in the accelerator before carrying out the synthesis process. The synthesized Cu-Sn powders were investigated by X-Ray diffractometry and transmission electron microscopy. It was determined that the final material consists of phase Cu41Sn11. Using this product, the bulk ceramics samples were obtained by spark plasma sintering at different temperatures (150 °C, 250 °C and 500 °C). The changes in microstructure of copper-tin ceramics in dependence on the sintering temperature were also studied. After analyzing all ceramics samples by X-Ray diffractometry and scanning electron microscopy methods, it was found that the optimal temperature for sintering Cu-Sn ceramics, which was made of the powder synthesized by a plasma dynamic method, was equal to 250 °C at pressure 60 MPa. At these conditions, the ceramics sample had the lowest porosity with the smallest grain size.

The work presents the field ion microscopy images of the surface atomic layers of irradiated platinum (layer-by-layer from 1st to 5th and more distant). A specially developed algorithm and software were used for image analysis to study the effect of Ar⁺ ions (E = 30 keV) on the subsurface atomic structure of pure platinum. The coordinates of atoms, the brightness of their images, and their sizes were determined. The curves of the distribution of the brightness and atomic radii were built. It is shown that the width of the distributions significantly decreases when moving from the damaged surface deep into the platinum bulk, whereas the number of atoms in the field ion microscopy images increases. Field ion microscopy images with only those atoms whose brightness (or radius) is in certain range were synthesized (these atoms can be highlighted in the ionic field microscopy images). It has been established that damaged zones include the images of atoms with both abnormally low and abnormally high radii. The principal possibility of reconstruction of the 3D-picture of the irradiated metal at a temperature of liquid nitrogen (T ∼ 77 K) is shown.

The effect of continuous Ar⁺ ion beams (E = 30 keV, j = 400 μA/cm²; F = 5·10¹⁶ cm^-2) on the hardness and microstructure of the Gr2-titanium-based and Ti-6Al-4V alloys after cold working and subsequent recrystallization annealing is studied. It has been found that the initial microstructure of the annealed alloys in the equilibrium state, which consisted of recrystallized equiaxed grains, does not change after irradiation; thus the hardness of the irradiated samples is comparable with that of the initial samples. The initial fine fiber structure of the deformed Ti-6Al-4V alloy changes insignificantly after both annealing (T = 790°C, 30 min) and ion irradiation under used conditions. In contrast to that, the effect of rapid radiation annealing of the cold-worked titanium Gr2 alloy with beams of accelerated ions of inert gas at low temperatures (lower by 130°C than the conventional annealing temperature of these alloys at 680°C) and for a shorter time (9 min instead of 35 min, τ_irr ∼ 20 s) has been revealed. The result is the formation of a uniform recrystallized structure with equiaxed fine grains 5-10 μm in size in the entire volume of the 3-mm-thick samples, despite the fact that the average projected range of 30-keV Ar⁺ ions in titanium is only 20 nm.

Ageing changes of the elementary composition of titanium surface (VT-1) treated by runaway electron preionized diffuse discharge in nitrogen at atmospheric pressure have been studied. Dependence of the elementary composition of titanium surface layers on surface free energy has been shown.

Modeling a TiN-Cu layers deposition process on a fused silica substrate under given conditions is carried out in this work. Calculation formulas which allow to determine the films thickness and their uniformity, with a substrate holder being located at an angle of 45 degrees to the normals of mutually perpendicular planes of the evaporated titanium cathode and the magnetron sputtering copper cathode, are given. The results of this work will be used to analyze the distribution velocity of the substance condensation flow and the character of the formed composite layers depending on the geometry of the cathode-substrate system.

This work studies the mathematical model of plasma channel. We consider the beam current in the range of 100-400 A and the external magnetic field in the range of 100-1500 G. It is shown that plasma channel expands under the influence of diffusion. The channel expansion is inversely proportional to the external magnetic field magnitude.

Studying and comparing microstructure and microhardness of boride layers formed on die D2 steel by using different methods – electron beam borating with continuous and pulsed beams under vacuum. The created layers have a heterogeneous structure combining hard and plastic components resulting in decrease of boride layer embrittlement.

The paper presents research results of VT3-1 titanium alloy samples subjected to nitriding in glow discharge with a hollow cathode. The influence of working gas composition on the thickness of a hardened layer at nitriding in glow discharge with a hollow cathode was studied. It was found that the increase of argon up to 80-90% in gaseous mixture during nitriding in glow discharge with a hollow cathode leads to the increase of the hardened layer thickness to ∼ 90 microns and surface microhardness to ∼ 850 HV_0,1, and contributes to a smaller gradient of the surface layer microhardness. The hardened layer on the surface of VT3-1 titanium alloy obtained upon nitriding in glow discharge with a hollow cathode is less fragile and resists plastic deformation more efficiently in comparison with the hardened layer obtained via traditional ion nitriding.

The wear of the surface layer of rolls after ion nitriding in glow discharge, followed by a coating of TiN -TiAlN plasma arc are studied and simulated. stress-strain state of the material rolls under asymmetric rolling with ultra-high shear deformations is simulated. The effect of thermal fields, formed upon contact of the tool and a deformable sheet, the structure of aluminum alloys, are considered.

The NiTi shape memory alloy has been modified by ion implantation with Ta to improve the surface and biological properties. The elemental and phase composition and structure of the surface and near-surface layers of NiTi specimens after the Ta ion implantation with the fluency D = 3 × 10¹⁷ cm^-2 and D = 6 × 10¹⁷ cm^-2 are examined. The methods of Auger electron spectroscopy (AES), transmission electron microscopy (TEM), and electron dispersion analysis (EDS) are used. It is found that a nonuniform distribution of elements along the depth of the surface layer after the ion implantation of NiTi specimens, regardless of the regime, is accompanied by the formation of a number of sublayer structures.

TiNi shape memory alloys (SMAs) are unique metallic biomaterials due to combination of superelastisity and high corrosion resistance. Important factors limiting biomedical applications of TiNi SMAs are a danger of toxic Ni release into the adjacent tissues, as well as insufficient level of X-ray visibility. In this paper, the method for fabrication of protective Ni-free surface alloy of thickness ∼1 μm of near Ti₇₀Ta₃₀ composition on TiNi SMA substrate has been successfully realized. The method is based on multiple alternation of magnetron co-deposition of Ti₇₀Ta₃₀ thin (50 nm) films and their liquid-phase mixing with the TiNi substrate by microsecond low-energy, high current electron beam (≤15 keV, ∼2 J/cm²) using setup RITM-SP (Microsplav, Russia). It was found by AES, XRD, SEM/EDS and HRTEM/EDS examinations, that Ti-Ta surface alloy has an increased X-ray visibility and gradient multiphase amorphous-nanocrystalline structure containing nanopores.

Titanium nitride and aluminum nitride coatings have been deposited on glass and aluminum oxide substrates in a flow of metal atoms accompanied by high-energy gas atoms. The metal atoms are produced due to sputtering of a flat rectangular magnetron target. The gas atoms with energy up to 25 keV are produced due to charge exchange collisions of ions extracted from the magnetron discharge plasma and accelerated by high-voltage pulses applied to a flat grid parallel to the target. The metal atoms pass through the grid and deposit on the substrate. Conjunction of their trajectories with those of gas atoms bombarding the growing coating enables the coating synthesis on complex-shape dielectric products planetary rotating inside the vacuum chamber. Mixing high-energy gas atoms of the coating and substrate atoms substantially improves the coating adhesion.

Comparative study of titanium nitride deposition has been carried out, the growing coating being uninterruptedly bombarded by 100-eV ions or ions accelerated by high-voltage pulses applied to the substrate. The study revealed that microhardness of coatings synthesized using 25-kV pulses rises from 21 GPa to 29 GPa when percentage of nitrogen in the mixture with argon increases from 15% to 20%. With a further increase of nitrogen percentage to 30%, the microhardness slightly diminishes to 27 GPa. In contrast to golden coatings synthesized at low-voltage substrate biasing, the color of titanium nitride coating produced using high-voltage pulses is brown. The most striking difference of coating deposited using high-voltage pulses applied to the substrate is its perfect adhesion despite the interface formation at the room temperature without any preheating and activation. The adhesion characterization using a scratch-tester has revealed that critical loads of coatings synthesized using 25-kV pulses are several times higher than those of conventional nitride coatings synthesized at uninterrupted substrate biasing of 100 V. When the pulse amplitude diminishes to 5 kV, the critical loads and microhardness of the coating decrease to conventional values.

Before the synthesis of superhard coating, the product surface is hardened by means of plasma nitriding, which prevents the surface deformations and the coating brittle rupture. The product heating by ions accelerated from plasma by applied to the product bias voltage leads to overheating and blunting of the product sharp edges. To prevent the blunting, it is proposed to heat the products with a broad beam of fast nitrogen molecules. The beam injection into a working vacuum chamber results in filling of the chamber with quite homogeneous plasma suitable for nitriding. Immersion in the plasma of the electrode and heightening of its potential up to 50–100 V initiate a non-self-sustained glow discharge between the electrode and the chamber. It enhances the plasma density by an order of magnitude and reduces its spatial nonuniformity down to 5–10%. When a cutting tool is isolated from the chamber, it is bombarded by plasma ions with an energy corresponding to its floating potential, which is lower than the sputtering threshold. Hence, the sharp edges are sputtered only by fast nitrogen molecules with the same rate as other parts of the tool surface. This leads to sharpening of the cutting tools instead of blunting.

The influence of the microarc oxidation parameters and electrolyte composition on the structure, properties and composition of CaP coatings modified with Zn– or Cu– incorporation on the Ti–40mas.%Nb (Ti–40Nb) alloy was investigated. The linear growth of thickness, roughness, and size of structural elements with process voltage increasing has been revealed. It was shown that the CaP coatings have the low contact angles with liquids and, consequently, high free surface energy. This indicates a high hydrophilicity of the coatings. X–ray diffraction analysis showed that the coatings have X–ray amorphous structure. The increase of the process voltage leads to the formation of such crystalline phases as CaHPO₄ and β–Ca₂P₂O₇ in the coatings. The maximum Ca/P atomic ratio was equal to 0.4, and Zn or Cu contents was equal to 0.3 or 0.2 at.%, respectively.

Polycrystalline diamond films were fabricated on copper substrates by a multi-step process comprised of physical vapor deposition of Al-based composite interlayer on Cu substrate and depositing continuous diamond film on composite interlayer by plasma assisted chemical vapor deposition (PACVD). The interface characteristics and adhesion strength were investigated by Auger electron spectroscopy, Raman analysis, calotest and indentation test. The results show that the continuous film without cracks is successfully obtained. The improved adhesion between diamond film and substrate results from the low residual stress in the film due to their compensation by Al interlayer in the sample cooling process.

Application of high frequency short pulse plasma immersion low energy ion implantation for titanium nitride coating deposition using vacuum arc metal plasma and hot-cathode gas-discharge plasma on R6M5 alloy was investigated. Implementation of negative repetitively pulsed bias with bias amplitude 2 kV, pulse duration 5 μs and pulse frequency 10⁵ Hz leads to 6.2-fold decrease of vacuum arc macroparticle surface density for macroparticles with diameter less than 0.5 μm. Ion sputtering due coating deposition reduces the production rate approximately by 30%. It was found that with bias amplitude range from 1.1 to 1.4 kV and pulse duration 5 μs yields to formation of coatings with local hardness up to 40 GPa. This paper presents the results of experimental studies of adhesion strength, tribological properties and surface morphology of deposited TiN coatings.

The aim of this work was to research the possibility of using coaxial magneto plasma accelerator for TiC-coatings deposition on steel substrates. As a result, coatings with 0.01 m² area was deposited. They were researched using XRD, SEM; also, the nanohardness on cross section of coating was measured. The influence of energy and carbon load on phase content, average hardness and microstructure is shown. It is established that the finest microstructure and average nanohardness is 15.3 GPa are achieved at energy W = 46.7 kJ and carbon load of 2.0 grams.

The paper presents research results on the adhesion of Si coatings deposited by magnetron sputtering on NiTi substrates after preliminary surface treatment (cleaning and activation) with low-energy ion beams and gas discharge plasma. The adhesion properties of the coatings obtained by two methods are analyzed and compared using data of scratch and spherical abrasion tests.

NiO/ZrO₂-Y₂O₃ (NiO/YSZ) anode functional layers (AFL) with 16-60 vol.% of NiO were deposited onto NiO/YSZ anode substrates by magnetron sputtering, followed by annealing in air at 1200 °C. The optimal deposition conditions for NiO/YSZ were determined. NiO content in the films was varied by changing the oxygen flow rate during the sputtering process. The microstructure and phase composition of NiO/YSZ anode functional layer were studied by SEM and XRD methods. Anode functional layers were fully crystallized and comprised of grains up to 500 nm in diameter after reduction in hydrogen. Anode-supported solid oxide fuel cells (SOFC) with the diameter of 20 mm including the magnetron sputtered AFL, 4-microns thick YSZ electrolyte and La_0.6Sr_0.4Co_0.2Fe_0.8O₃/Ce_0.9Gd_0.1O₂ (LSCF/CGO) cathode were fabricated and tested. Electrochemical properties of the single fuel cells were investigated as a function of NiO volume content in AFL and AFL thickness.

The paper is devoted to the experimental study of the generation of the weakly ionized high velocity heterophasic flows by gas detonation in acetylene-oxygen mixtures. Such flow can contain fine hydroxyapapite (HOA) particles with an average diameter of d_p≤100 μm for spraying of biocompatible coatings. The characteristic velocity (≈2.3...2.5 km/s) and pressure (≈3.1...3.8 MPa) of the detonation waves were defined and the attenuation dependences of those parameters were stated. The structure of the detonation flows was visualized and the chemical composition was estimated. The samples of the HOA coatings (with a thickness of 80...100 μm) were prepared on the carbon nanocomposites and their properties were characterized by SEM, EDX and XRD. The possibility of the using of such flow as a working fluid for electromagnetic acceleration of HOA was offered by the two-stage pulsed plasma set.

The paper has investigated conditions and parameters of argon trapping in molybdenum, tantalum and tungsten layers during their deposition on tungsten substrate by the atoms sputtered from the respective targets in argon plasma. The substrate temperature during deposition was 1273 K. The rate of deposition was 1 μm/h. It was shown that electron irradiation of the deposited layer with the beam intensity of 4 mA/cm² initiated argon trapping in tungsten and tantalum coating with approx. 2 x 10²⁷ at/m³ and 8 x 10²⁶ at/cm³, respectively, but did not stimulate argon trapping in the molybdenum layers. Features of argon trapping in the tungsten coating and its release are investigated in detail.

In the current study, the effect of corundum particle sizes (50 and 250–320 μm) used for sand–blasting on the structure, roughness, wettability, mechanical properties, and adhesion of radio frequency magnetron hydroxyapatite coating deposited on treated titanium substrate is studied. Morphology analysis revealed that pretreatment uniformly deforms the surface and induces the formation of pits, which size depends linearly on the grit size. The deposited coatings (Ca/P was in a range of 1.75-1.79) are homogeneous and repeat the relief of the substrate (mean roughness Ra is 1.9±0.1 (250–320 μm) and 0.8±0.1 μm (50 μm)). Texture coefficient calculations revealed the predominant (002) growth texture of hydroxyapatite coatings. The resistance of the coating to plastic deformation and the surface hardening were significantly higher for coatings formed on sand blasted with particle size of 50 μm. Scratch test have shown the significant improvement of wear resistance and lower friction coefficient of coatings for smoother samples. Dynamic contact angle measurements revealed the hydrophilic properties of the hydroxyapatite coating. Thus, sand–blasting of titanium with corundum powder having the size of 50 μm prior to the deposition of RF magnetron coating is recommended for the medical applications intended to improve the bonding between the substrate and coating.

Composite layers on the basis of carbides and borides the titan and silicon on titanic alloy VТ-1 are generated at diffused saturation by electron beam treatment in vacuum. Formation in a composite of MAX phase Ti₃SiC₂ is shown. Thermodynamic research of phase equilibrium in systems Ti-Si-C and Ti-B-C in the conditions of high vacuum is executed. The thermodynamics, formation mechanisms of superfirm layers borides and carbides of the titan and silicon are investigated.

This paper presents results of the research in influence of preliminary surface treatment on adhesion of film to substrate (St8 or brass-target, CU, Ni-film). The preliminary treatment has been conducted by two methods: first, by compressive plasma flow with charge duration ∼100μs, plasma formation rate (15-20)×10³ m/s; second, by low-energy high-current electron beams with pulse duration 2-3 μs and electron energy up to 30 keV. The investigation shows the strong influence of preliminary sample treatment and processing parameters on adhesion of film to substrate and final roughness. Experimental investigations have revealed the best adhesion of film to substrate, and the smoothest film is corresponding to the mode with preliminary LEHCEB irradiation with electron energy of 25, 30 keV. It was shown that the alternation of deposition with LEHCEB irradiation has resulted in large-scale surface smoothing: the surface has become glassy whereas craters of 10-20 μm have formed. It was shown that the magnetron-covered samples can withstand the saline mist for twice as long as samples with galvanic coatings.

Conductive thin films formation by copper and silver magnetron sputtering is one of high technological areas for industrial production of solar energy converters, energy–saving coatings, flat panel displays and touch control panels because of their high electrical and optical properties. Surface roughness and porosity, average grain size, internal stresses, orientation and crystal lattice type, the crystallinity degree are the main physical properties of metal films affecting their electrical resistivity and conductivity. Depending on the film thickness, the dominant conduction mechanism can affect bulk conductivity due to the flow of electron gas, and grain boundary conductivity. The present investigation assesses the effect of microstructure and surface topography on the electrical conductivity of magnetron sputtered Cu and Ag thin films using X–ray diffraction analysis, scanning electron and laser interference microscopy. The highest specific conductivity (78.3 MS m^–1 and 84.2 MS m^–1, respectively, for copper and silver films at the thickness of 350 nm) were obtained with the minimum values of roughness and grain size as well as a high degree of lattice structuredness.

This paper presents the study of the influence of a substrate structure on the adhesion behavior of monolayer coatings TiN and multilayer coatings TiAl₃ / TiAlN deposited by vacuum arc plasma. Martensitic steel with a coarse-grained (CG) and ultrafine-grained (UFG) structure was used for samples. The samples were subjected to ion nitriding in a glow discharge before coating deposition. Adhesion of the coatings was examined with CSM ScratchTEST. For samples with different structures, critical load was defined at which microcracks are formed in the coatings.

The paper considers several approaches to protect martensitic steels with ultrafine-grain (UFG) structure in aggressive environments. Scanning electron microscopy was used to study the microstructure and composition of steel substrates and coatings. The samples were also subjected to corrosion tests. Regularities of corrosion behavior were specified for the UFG steels. The samples were subjected to ion nitriding in a glow discharge and deposition of protective TiAl₃/TiAlN coatings in vacuum arc discharge plasma. Corrosion rates were identified for different treatments.

Synchronous electric explosion of metal wires and synthesis of bicomponent nanoparticles were investigated on the base of molecular dynamics method. Copper and nickel nanosized crystallites of cylindrical shape were chosen as conductors for explosion. The embedded atom approximation was used for calculation of the interatomic interactions. The agglomeration process after explosion metal wires was the main mechanism for particle synthesis. The distribution of chemical elements was non-uniform over the cross section of the bicomponent particles. The copper concentration in the surface region was higher than in the bulk of the synthesized particle. By varying the loading parameters (heating temperature, the distance between the wires) one can control the size and internal structure of the synthesized bicomponent nanoparticles. The obtained results showed that the method of molecular dynamics can be effectively used to determine the optimal technological mode of nanoparticle synthesis on the base of electric explosion of metal wires.

Magnetite Fe₃O₄ and epsilon iron oxide -Fe₂O₃, having excellent frequency characteristics and high electrical resistivity, are considered as the most promising phases among all iron oxides for high-frequency equipment in order to increase the working frequency of the data transmission. Despite the large number of existing methods for synthesizing these materials, many of them do not provide both of these phases. In opposite to these methods, the plasma dynamic synthesis can provide the synthesis of necessary phases in a one-step process. The process is implemented in an electrodischarge iron-containing plasma jet, which interacts with gaseous precursor (oxygen). The use of plasma jet allows obtaining nanoscale powdered products. This work shows the results of the experiment series, where the influence of initial energy parameters on the final phase composition was studied. It is found that the plasma dynamic synthesis allows obtaining both magnetite Fe₃O₄ and epsilon phase -Fe₂O₃ during one short-term process (less than 1 ms). It is also established that the final phase composition strongly depends on the initial parameters of the system. The increased energy parameters lead to the formation of the product with predominant content of epsilon phase, while lower parameters allow synthesizing magnetite phase. Thus, by changing energy parameters, it is possible to control the final composition in the considered system.

Zinc oxide is a well-known semiconductor material having good electrical, optical and catalytic properties. It can be used in different areas from cosmetics to drug delivery and biosensors. The synthesis of nanosized zinc oxide is an urgent task for obtaining ZnO-based ceramics with enhanced physical properties. This work shows the possibility to implement the plasma dynamic synthesis of zinc oxide in one short-term process (less than 1 ms) using an electrodischarge zinc-containing plasma jet, flowing into oxygen atmosphere. It allows synthesizing a mono-crystalline powder with particle size distribution from tens to hundred nanometers. The synthesized powdered product is investigated using by X-Ray diffractometry (XRD), scanning electron microscopy and high-resolution transmission electron microscopy. According to XRD, the obtained product consists of hexagonal zinc oxide with lattice parameters a = b = 3.24982 Å, c = 5.20661 Å that is clearly confirmed by microscopy data. This powder was used to produce a bulk ceramics sample on its basis by spark plasma sintering. The influence of sintering parameters on the structure of the resulting sample was studied. The optimal parameters were found which allows obtaining the more dense ceramics with a better microstructure. It was also found that the absence of exposure time after reaching the working temperature and pressure allows decreasing the porosity of ceramics.

We report about the features of polycrystalline diamond coatings CVD synthesis in repetitively-pulsed plasma of abnormal glow discharge. The discharge burning time was varied from 0.5 to 10 ms with proportional pauses. The dependences of deposited diamond films growth rate on the durations of the discharge burning and pauses are presented. The mutual influence of two plasma filaments on each other and onto the substrate has unequivocally established. Raman spectroscopy, X-ray diffractometry and SEM were used for identification of phase composition and microstructure of deposited films. Implementation simplicity and reliability of the proposed discharge system may find application in diamond film deposition industries.

An interest in WC_1-x cubic tungsten carbide results from its catalytic properties similar to those of platinum group metals and the synergistic effect between WC_1-x and Pt in reactions of hydrogen evolution and hydrogen oxidation. However, according to the phase diagram of the W–C system, the cubic phase WC_1-x only exists in a narrow range of temperature stability (about 2798–3058 K), which makes it difficult for being obtained. To date, there are different methods for synthesizing tungsten carbide powder with a low content of cubic phase that complicates the study of WC_1-x properties. A direct plasma dynamic synthesis is known as one of the promising methods to produce WC_1-x. The aim of this work is to find the optimal amount of tungsten precursor to obtain cubic tungsten carbide with a high purity by plasma dynamic method. The synthesized products were examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns showed that the main phase was cubic tungsten carbide with negligible content of hexagonal tungsten carbide W₂C and pure tungsten W. According to a quantitative analysis of synthesized products, which were obtained using masses of initial tungsten equal to 1.0, 0.7, 0.6 and 0.5 gram, the yield of WC_1-x phase was 84, 89, 95 and 92 wt%, respectively. The results of TEM displayed that the synthesized powders consist of crystallites, having the size less than 100 nm (WC_1-x), and a carbon matrix. This carbon was not detected in XRD due to its presence as an amorphous phase.

Silicon carbide (SiC) nanopowders were produced by the synthesis in an electrodischarge plasma jet generated by a high-current pulsed coaxial magnetoplasma accelerator. The present work focuses on the experiments where the obtained hypersonic plasma jet flew into space of the reactor chamber without impact on a target. The energy level of experiments was changed from ∼10.0 to ∼30.0 kJ. Four experiments were carried out at different energy levels. The powder products synthesized by the plasmadynamic method were studied by such well-known methods: X-ray diffraction (XRD), transmission electron microscopy (TEM). All the powders mainly contain cubic silicon carbide (β-SiC) particles with clear crystal structures and triangular shapes. SiC content reaches its maximum value 95% at the energy level 21.0 kJ, then SiC content is decreased to 70% the energy level 27.8 kJ. The powder crystallites in different experiments have approximately the same average crystallite size because quasistationary time, which allows growing powder crystallites, is absent.

Ti-B nanopowders were produced by plasmadynamic synthesis. This method was implemented by the synthesis in an electrodischarge plasma jet generated by a high-current pulsed coaxial magnetoplasma accelerator. Two experiments were carried out using copper and titanium conductors for initiating the plasma jet. The synthesized products were analyzed by several modern techniques including X-ray diffractometry and transmission electron microscopy. The variety of crystalline phases in the products of both Ti-B and Ti-O systems were identified. The most successful results were obtained using titanium conductors. In this case, the product mainly contains titanium boride and titanium diboride. Synthesized powder consists of hexagonal and cubic particles, which were identified as titanium boride and titanium diboride particles, respectively. The method using titanium conductors for initiating the plasma jet is more efficient and simple way for obtaining TiB/TiB₂ nanopowders.

Plasma synthesis of SiO₂ nanoparticles in experimental atmospheric pressure plasma reactor on the basis of DC arc plasma generator was presented in this paper. Solid high-silica raw materials such as diatomite from Kamyshlovskoye deposit in Russia, quartzite from Chupinskoye deposit in Russia and milled window glass were used. The obtained nanoparticles were characterized based on their morphology, chemical composition and size distribution. Scanning electron microscopy, laser diffractometry, nitrogen absorption (Brunauer–Emmett–Teller method), X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy were used to characterize the synthesized products. The obtained silica nanoparticles are agglomerated, have spherical shape and primary diameters between 10-300 nm. All samples of synthesized nanopowders were compared with commercial nanopowders.

This paper considers a method of synthesis fullerenes and carbon nanotubes at atmospheric pressure. Carbon evaporates into the plasma arc. The paper discusses the method of synthesis of helium at a pressure of 10⁵ Pa. We show the dependence yield of fullerenes and carbon nanotubes from the buffer gas pressure. It has been found that the fullerene yield increased with increasing pressure. The obtained fullerenes and nanotubes find their application in the modification of construction materials. The use of carbon nanomodifiers in the modification of the construction is promising since their introduction significantly improves the physico-mechanical properties using a small quantity of additives. With the introduction of the carbon nanomodifier decrease the porosity of cement stone, which leads to high strength and frost-resistant indicators of the modified cement.

Numerical study of the influence of magnetic field on the plasma compressed by powerful source is carried out. Numerical experiments for the magnetized plasma behavior during and after laser pulse are presented. Convective and thermal parts of a model were tested on several tasks. Spatial distribution of the plasma pressure, temperature, velocity, density, magnetic pressure and laser radiation are obtained in the presence of the external magnetic field.

Tungsten oxyfluoride glasses are characterized by low phonon energy. This is due to the presence of fluoride ions that have low phonon energy and formation of low phonon energy WO6 units. Oxyfluoride glasses based on WO3–BaF2–RF, where RF = LiF, NaF or mixed (LiF–NaF) have been prepared by melt quenching technique. The density and molar volume of the prepared glasses show a decrease with the increase of RF instead of WO3 content. The glass transition temperature Tg is found to decrease with increasing RF content. The refractive index increases with the addition of heavy polarizable fluorides. The decrease of the elastic moduli and microhardness of these glasses may be due to the decrease in density and the depolymrization effect. The Poisson's ratio increases with increasing RF content due to the structural changes and formation of (NBOs) and (NBF) units. The aim of this work is to prepare a glass host with low phonon energy to be an efficient host with good luminescence properties, when doped with rare earth ions, and to study its structural, thermal, optical and mechanical properties.

This paper analyzes from a numerical point of view the ignition and propagation of the combustion front during the exothermic TiC combustion synthesis of a material made of pressed titanium and carbide particles when thermophysical properties are either assumed constant or temperature and conversion rate dependent. A two-dimensional cylindrical geometry is considered. The heat supply is prescribed on one, two or three sides of the physical domain. A one-step kinetics is used to describe the reaction Ti+C→TiC in a solid phase and leads to the computation of the conversion rate. A coupling with a non-linear heat equation which takes into account the heat generated by the exothermic kinetics and the two allotropic phase-changes is considered. An explicit finite-volume discretization of the coupled system is constructed and analyzed. Time-step's stability condition is given for a general expression of the thermo-physical characteristics. A discrete maximum principle is reported. Open MP API was used to parallelize the numerical software written in C. An average speedup of three was obtained on an intel quad-core processor i7-2600. The ignition time and the fraction of unreacted material are systematically computed and compared for several heat supply scenario.

Spectra of photoluminescence (PL) in the region of 1.5–5.5 eV, PL excitation spectra (3–22 eV), PL decay kinetics and PL temperature dependence were measured for single crystals and ceramics K₃WO₃F₃ as well as for ceramics K₃WO₃F₃ irradiated by fast electrons. Synchrotron radiation was used for low temperature PL experiments with time resolution. Single crystals are transparent in microwave, visible and near UV range, inter-band transition energy is E_g = 4.3 eV. In K₃WO₃F₃, the wide band luminescence in the region of 2.5 eV with the Stokes shift of 1.5 eV with the microsecond decay kinetics is connected with luminescence of triplet self-trapped excitons (STE). This luminescence is formed by electronic transitions in [WO₃F₃] octahedron. Different distortion of KWOF crystal lattice is manifested in the change of the Stokes shift of the STE luminescence band. The 3.2 eV emission band in low-temperature PL spectrum with decay times of 1.8 ns and 11 ns corresponds to singlet STE luminescence. A new 2.9 eV emission band is discovered in low-temperature PL spectrum in the samples irradiated by fast electrons (E = 10 MeV, D = 160 kGy). This emission band is excited not through the intracenter mechanism but through the creation of excitons bound on the defects. It is suggested that it is F-like centers of anionic sublattice induced by the mechanism of elastic collision.

The dependencies of critical laser initiation energy density of pentaerythritol tetranitrate (PETN) – aluminum nanoparticles, PETN – cobalt nanoparticles and lead azide – lead nanoparticles on pulse duration were calculated in terms of the refined micro hot-spot model. It was shown that the absorption efficiency of the laser irradiation taken into account makes the initiation criterion change. According to the calculation results, the criterion in the limit of short pulses is energy density matching the experimental data. If the neodymium pulses duration is less than 50 ns, the radius of the nanoparticles with highest temperature varies insignificantly. The expression for the critical hot-spot temperature dependence on the pulse duration was derived. The conclusion was made that the model refining with nanoparticles absorption efficiency dependence on their radius is sufficient for the "small particles' paradox" solution.

The procedure for measuring the temporal characteristics and light output of inorganic scintillating materials excited by β-, γ-, and α-particles from radioactive sources is described. Results of measurements of characteristics are presented for ∼30 scintillating compounds including cerium-doped yttrium silicate and scandium borate; europium-doped strontium phosphate; cerium-doped strontium silicate, calcium silicate and magnesium calcium silicate, etc. Upon β- and γ-excitation, cerium-doped scandium borate gives the highest light output with a fluorescent lifetime of 40 ± 4 ns. The highest light output for α-excitation was from cerium-doped yttrium aluminum perovskite, with a fluorescent lifetime of 29 ± 3 ns.

Using the Rouse-Fowler (RF) model this work studies the radiation-induced electrical conductivity of a polymer nanocomposite material with spherical nanoparticles against the intensity and exposure time of gamma-ray, concentration and size of nanoparticles. The research has found the energy distribution of localized statesinduced by nanoparticles. The studies were conducted on polymethylmethacrylate (PMMA) with CdS nanoparticles.

The effect of a constant contactless electric field on the rate of a chemical reaction in silver azide is explored in this paper. The technology of growing and processing silver azide whiskers in the constant contactless electric field (field intensity was varied in the range from 10^-3 V/m to 10⁰ V/m) allows supervising their explosive sensitivity, therefore, the results of experiments can be relevant for purposeful controlling the resistance of explosive materials. This paper is one of the first attempts to develop efficient methods to affect the explosive sensitivity of energy-related materials in a weak electric field (up to 10^-3 V/m).

We have considered the influence of preliminary irradiation by ⁶⁰Co gamma quanta on development of catastrophic failure during long-term operation of IR-LEDs based upon dual AlGaAs heterostructures. Irradiation was realized in passive power mode of the LEDs prior to aging. Two specific doses of irradiation were used. The first irradiation dose corresponded to the first stage of emission power drop of the LEDs irradiated by gamma-quanta, which is attributed to the radiation-stimulated reconstruction of the initial defect structure of the LED crystal. The second dose corresponded to the second stage of emission power drop, which is attributed solely to the introduction of radiation defects. Aging under long operating time conditions was simulated by a step-stress approach. We have established that the preliminary irradiation by gamma-quanta can be used in manufacturing technology of LEDs to improve their operating parameters on condition that irradiation doses are chosen in strictly provide area of the radiation-stimulated reconstruction of the initial defect structure.

The aim of the work is studying the impact of Gunn diodes thermocompression bonding conditions upon their resistance to being radiated with protons of various energies. It was established that the tough conditions of Gunn diodes thermocompression bonding results in local mechanic stresses introduced into the active layer of the device, reduction of electron mobility because of the faults introduction and, subsequently, to reduction of operating current, power of UHF generation, percentage of qualitative units production and general reduction of production efficiency of the devices with required characteristics. Irradiation of Gunn diodes produced under the tough conditions of thermocompression bonding with protons which energy is (40–60) MeV with an absorbed dose of (1–6)·10² Gy does not practically reduce the radiation resistance of Gunn diodes produced with application of the given technique. This technique can be recommended for all semiconductor devices on the base of GaAs, which parameters depend significantly upon the mobility of the electrons, to increase the efficiency of production.

The paper presents the results obtained in the study of the change in the parameters of IR LEDs based on AlGaAs double heterostructures under ⁶⁰Co gamma irradiation with regard to irradiation temperature. The study indicated several consecutive stages of LED emissive power lowering under ionizing radiation. Increased temperature during gamma irradiation enhances radiation resistance at the first stage due to radiation-stimulated defect annealing, which reduces relative contribution of the first stage to the overall emissive power lowering. It was found that in exposure at temperature more than 380 K, the first stage of LED emissive power lowering is completely eliminated. At the second stage, increase in resistance is caused by the decreased relative contribution of the less stable first stage to the overall emissive power lowering. The maximum resistance of LEDs to gamma radiation depends on radiation resistance of metal–semiconductor contacts.

Thermoluminescence (TL) of ultrafine anion-defective magnesium oxide ceramics with a grain size of about 150 nm, which were thermally treated in highly reducing conditions at T=1100–1400 °C, has been studied after high-dose irradiation with a pulse electron beam (130 keV). Thermal treatment was found to cause TL intensity grow, which is associated with an increasing concentration of F-type centers. It was shown that varying occupancy of deep trapping centers changes a yield of the TL peak at 380 K. A hypothesis was made that the traps which are responsible for the TL peak at 380 K mainly have a hole nature in the samples under study.

The main ignition characteristics of high-energy materials are the ignition time and critical heat flux allowing evaluation of the critical conditions for ignition, fire and explosive safety for the test solid propellants. The ignition process is typically studied in stationary conditions of heat input at constant temperature of the heating surface, environment or the radiate heat flux on the sample surface. In real conditions, ignition is usually effected at variable time-dependent values of the heat flux. In this case, the heated layer is formed on the sample surface in dynamic conditions and significantly depends on the heat flux change, i.e. increasing or decreasing falling heat flux in the reaction period of the propellant sample. This paper presents a method for measuring the ignition characteristics of a high-energy material sample in initiation of the dynamic radiant heat flux, which includes the measurement of the ignition time when exposed to a sample time varying radiant heat flux given intensity. In case of pyroxyline containing 1 wt. % of soot, it is shown that the ignition times are reduced by 20–50 % depending on the initial value of the radiant flux density in initiation by increasing or decreasing radiant heat flux compared with the stationary conditions of heat supply in the same ambient conditions.

The use of metal powder (usually aluminum) as a fuel in composite solid propellants (CSPs) for propulsion is the most energy efficient method that allows improvement of combustion characteristics of propellants in the combustion chamber and specific impulse. This paper presents the experimental data of the ignition and combustion processes of CSPs containing Alex aluminum nanopowder and mixtures of Alex/Fe and Alex/B nanopowders. It was found that the introduction of Alex/Fe in CSPs leads to 1.3–1.9 times decrease in the ignition time at q = 55–220 W/cm² and to 1.3–1.4 times increase in the burning rate at p = 2.2–7.5 MPa with respect to that for basic CSP with Alex. When introducing Alex/B in CSP, the ignition times are 1.2–1.4 fold decreased, and the burning rate is practically unchanged. However, the agglomeration is significantly enhanced, which is manifested through the increase in the agglomerate particles content in condensed combustion products by a factor of 1.8–2.2, at 1.6–1.7 fold increase of the agglomerates mean diameter for CSP with Alex/B.

The efficiency of radiation defects formation in alkali halide crystals (AHC) was studied by the method of absorption spectroscopy. However, it is not possible to study the deformation-stimulated processes in detail by the absorption spectrum of radiation defects due to the limited sensitivity compared with luminescent spectroscopy. In this regard, thermally stimulated luminescence (TSL) of radiation defects at elastic and plastic deformation was applied in AHC. In the absence of deformation, the dominant peaks in TSL are $\left( {X_3^ - } \right)_{aca}^0$-centers. After elastic deformation, low temperature peaks of TSL corresponding to F^'-, V_K- and V_F-centers became dominant. After plastic deformation, the peaks of TSL corresponding to $\left( {X_3^ - } \right)_{aca}^0$-centers became dominant. The elastic deformation contributes to the increase in concentration of low-temperature F^'-, V_K- and V_F-centers, and the plastic one contributes to that of high temperature $\left( {X_3^ - } \right)_{aca}^0$-centers (peaks of TSL in KCl at 360K, in KBr at 365K, in KI at 340K), composed by divacancies created by plastic deformation. At elastic deformation, unrelaxed interstitial halogen atoms are converted into V_K- and V_F-centers, and due to this fact the long-range interaction is absent, the result of which are the $X_3^ -$-centers.

Currently, strengthening of the intensity of luminescence in alkali halide crystals (AHC) at lattice symmetry lowering is discussed as a promising direction for the development of scintillation detectors [1-3]. In this regard, for the study of anion excitons and radiation defects in the AHC anion sublattice at deformation, the crystals with the same sizes of cations and different sizes of anions were chosen. In the X-ray spectra of KCl at 10 K, the luminescence at 3.88 eV; 3.05 eV and 2.3 eV is clearly visible. The luminescence at 3.05 eV corresponds to the tunneling recharge [F*, H]. Luminescence at 3.88 eV is quenched in the region of thermal destruction of F'-centers and characterizes tunneling recharge of F', V_K-centers. In KCl at 90 K, the luminescence of self-trapped excitons (STE) is completely absent. In KBr at deformation not only STE luminescence, but also deformation stimulated luminescence at 3.58 eV were recorded, the last one corresponds to tunneling recharge of F', V_K-centers. In KI crystal at 10 K and 90 K at deformation, only STE luminescence is enhanced. There are no deformation luminescence bands in KI compares with KBr and KCl crystals.

Stabilization of structure-phase state in a wide temperature range is one of the most important problems of improving properties of oxide compounds. As such, the search of new effective methods for obtaining metal oxides with desired physic-chemical, electro-physical and thermal properties and their control is important and relevant. The aim of this work is identification features state of the oxide films of some metals Be, Al, Fe, Cu, Zr on the metal surface of the polycrystalline samples by infrared spectroscopy. To identify the resonance emission bands the algorithm of IR-spectra processing was developed and realized on the basis of table processor EXCEL-2010, which allow revealing characteristic resonance bands successfully and identification of inorganic chemical compounds. In the frame of simple oscillator model, resonance frequencies of normal vibrations of water and some inorganic compounds: metal oxides – Be, Al, Fe, Cu, Zr were calculated and characteristic frequencies for different states (aggregate, deformation, phase) were specified. By means of IR-spectroscopy fundamental possibility of revealing oxides films on metal substrate features state is shown, that allow development and optimization of the technology for production of the oxide films with desired properties.

Complex experiments were conducted on deformation dependence on time for different static loads and irradiation doses in polyethylene terephthalate. Curves of time (t) dependence of deformation (ε) show a significant change in the behavior of the material after irradiation. The obtained dependence curves of ε on t for both non-irradiated and irradiated materials are satisfactorily described by cascade-probability model.

The possibility of using the explosion energy of condensed explosives in solids analytical spectroscopy was investigated. For the atomization and excitation emission spectra of solids (BaCl₂ and SrCl₂) pressed powders of furazanotetrazinedioxide (FTDO, C₂N₆O₃) were used. Initiation of the explosion was induced by the influence of high-current electron beam. The impurity atoms that are the part of FTDO, as well as atoms and molecules formed by the evaporation of BaCl₂ and SrCl₂ were identified in the spectra of explosion plasma.

The thermally stimulated luminescence (TSL) and exoemission (TSE) in Li and Cu doped NaF and LiF single crystals irradiated with electron high energy electron beams of (10 MeV, doses 0.75 and 2 MGy) have been investigated. The results obtained reveal important properties that suggest that the crystals have a sufficient radiation stability and sensitivity for high energy electron beams and are promising for application as high-dose detectors of electron radiation.

The most objective assessment of radon hazard of build-up area can be the amount of radon released from the underlying rocks. In the Russian Federation, the criterion of radon hazard is the radon flux density, measured by the method of accumulation chambers. The paper presents the results of measurements obtained by the method of accumulation chamber using two measuring complexes and the method of "two depths". The measurements were performed on a testing site of Tomsk (Russia); the type of soil is loam. Studies have shown that the considered assessment methods of radon risk have significant drawbacks, because they do not allow reliable determination of the amount of radon coming from the soil surface.

The paper presents the results of studies of luminescent centers induced by irradiation of LiF crystals with flow of silver ions of a fluence varying in a range of 2×10¹³−5×10¹⁷ ions/cm² and energy about of 150 keV. Two bands with maxima at 250 nm and 420 nm in the absorption spectra of the exposed crystals were observed. The former was due to the absorption of F colour centers and the latter consisted of F₂ (F₃⁺) colour centers band and a plasmon resonance band arose due to the embedded silver ions. The peak of the latter remained stable after annealing the sample at 400 °C unlike the colour centers bands. The luminescence spectra of the crystals under excitation with a laser irradiation of 375 nm wavelength showed a band with a peak at 450 nm along with the bands with peaks at 530 and 680 nm corresponding to F₃⁺ and F₂ colour centers, respectively. The peak of the former reached saturation, while the peaks of the colour centers bands increased with ion fluence increasing. These results show that sub-nanometre sized metal clusters Ag(n+) (n=3-6) are responsible for the observed luminescence, while the Ag particles of a nanometer scale are not luminescent.

Ammonium perchlorate–aluminum compositions taken in stoichiometric ratio were ignited in air and under the cover with 1.06-μm 0.8-ms-long laser pulses. The ignition energy thresholds were measured for samples at various dispersity of Al. The causes of the difference in examined compositions sensitivity to the influence of laser radiation is considered from the perspective of the thermal theory.

Generation of coherent THz Smith-Purcell radiation by single electron bunch or multi-bunched electron beam was simulated for lamellar, sinusoidal and echelette gratings. The dependences of the CSPR intensity of the corrugation gratings depth were investigated. The angular and spectral characteristics of the CSPR for different profiles of diffraction gratings were obtained. It is shown that in the case of femtosecond multi-bunched electron beam with 10 MeV energy sinusoidal grating with period 292 μm and groove depth 60 μm has the uniform angular distribution with high radiation intensity.

The electric discharge and mechanical technology of hard rock breakage was developed on the ground of mechanical and electrical pulse methods and it was tested for purposes of deep drilling. It was demonstrated that, due to breakage of the rock surface by electric discharges, the rock excavation volume (breakage performance) is significantly improved as compared to conventional mechanical methods.

Anion-deficient corundum and TLD-500 detectors on their basis were studied for a possible correlation between the thermoluminescence (TL) yield in the high-temperature TL peak at 830 K and the transformation of intrinsic defects and contents of impurities. Only 40– 60% of TLD-500 detectors were found to have 830 K TL peak. The efficiency of thermally stimulated direct conversion of F and F⁺ centers in the 800–930 K region depends on the presence of TL peak at 830 K. Obtained data point to the quenching role of the Ti impurity in the formation of the 830 K TL peak. Also, these data provide indirect evidence of association of the 830 K TL peak with Cr³⁺ ions.

The aim of this paper is to study some spectral-luminescent properties of sulphates activated by tin ions. The paper presents the photoluminescence excitation spectra of K₂SO₄-Sn²⁺ crystal. In this spectrum, peaks are observed at 240 nm and 260 nm. In the long-wavelength wing, the emission band has a "shoulder" indicating the presence of the second emission band. Thus, the presence of two bands of photoluminescence excitation suggests that K₂SO₄ formed two types of the impurity luminescence center differing in the immediate surroundings.

The paper presents the analysis of the recorded tracks of high-velocity emission in the air-argon plasma flow during breaking up of tungsten microdroplets. This new physical effect of optical emission involves two stages. The first one includes thermionic emission of electrons from the surface of the melted tungsten droplet of 100–200 μm size and formation of the charged sphere of 3–5 mm diameter. After it reaches the breakdown electric potential, it collapses and produces a spherical shock wave and luminous radiation. The second stage includes previously unknown physical phenomenon of narrowly directed energy jet with velocity exceeding 4000 m/s from the surface of the tungsten droplet. The luminous spherical collapse and high-velocity jets were recorded using CMOS photo-array operating in a global shutter charge storage mode. Special features of the CMOS array scanning algorithm affect formation of distinctive signs of the recorded tracks, which stay invariant to trace transform (TT) with specific functional. The series of concentric circles were adopted as primitive object models (patterns) used in TT at the spherical collapse stage and linear segment of fixed thickness – at the high-velocity emission stage. The two invariants of the physical object, motion velocity and optical brightness distribution in the motion front, were adopted as desired identification features of tracks. The analytical expressions of the relation of 2D TT parameters and physical object motion invariants were obtained. The equations for spherical collapse stage correspond to Radon–Nikodym transform.

Different proton irradiation regimes were tested to provide more than 20 kHz-frequency, soft reverse recovery "snap-less" behavior, low forward voltage drop and leakage current for 50 mm diameter 7 kA/400 V welding diode Al/Si/Mo structure. Silicon diode with such parameters is very suitable for high frequency resistance welding machines of new generation for robotic welding.

The mechanism of abnormal photo-thermal effect of laser radiation on nanoparticles of oxide bronzes has been proposed in this paper. The basic features of the observed effect are: a) sub-threshold absorption of laser radiation by the excitation of donor-like levels formed in the energy gap due to superficial defects of the oxide bronze nano-crystals; b) an interband radiationless transition of energy of excitation on deep triplet levels and c) consequent recombination occurring at the plasmon absorption. K or Na atoms thermally intercalated to the octahedral crystal structure of TiO₂ in the wave SHS combustion generate acceptor levels in the gap. The prepared oxide bronzes of the non-stoichiometric composition Na_xTiO₂ and K_xTiO₂ were examined by high resolution TEM, and then grinded in a planetary mill with powerful dispersion energy density up to 4000 J/g. This made it possible to obtain nanoparticles about 50 nm with high surface defect density (10¹⁷–10¹⁹ cm^-2 at a depth of 10 nm). High photo-thermal effect of laser radiation on the defect nanocrystals observed after its impregnation into cartilaginous tissue exceeds 7 times in comparison with the intact ones.

The inactivation of Opisthorchis felineus eggs in the wastewater was demonstrated. The wastewater samples were taken at the bio-filter outlet of district wastewater treatment plant of settlement "Airport" of rural settlement "Mirnenskoe" of Tomsk district of Tomsk region. The UV irradiation of wastewater samples was performed by the combined exposure of UV excilamps at 282 and 222 nm. There was less than 15% of the initial count of Opisthorchis felineus eggs in the wastewater after the UV treatment at the total surface dose of 25 mJ/cm². At the same time, 85% of the eggs lost the shell integrity and destroyed. It is proposed to use UV irradiation by excilamps to wastewater deworming on wastewater treatment plants of small capacity up to 200 m³/day.

Simulation of laser heat absorbing inclusions in a transparent matrix of explosive material is carried out. The inclusions are spherical particles with R₀ radius ranging from 10⁻⁵ to 10⁻² cm. The duration of the laser pulse varies from 10⁻⁹ to 10⁻³ s and allows investigating process in both adiabatic and quasi–stationary heating modes. It has been found that the duration of laser pulse affects the maximum heating temperature for particles with a specific radius. A remarkable thing is that the temperature drastically decreases if the absorption cross section and small size of inclusions are taken into account. It leads to heat reduction in a thermal center, which is formed nearby a small–sized inclusion, and shows strongly decreased reactive capacity of explosive decomposition.

The work presents the results of the study of the luminescence of uranium doped LiF crystals. Introduction of the dopant (U) and the co-dopant (OH) shows the occurrence of additional absorption in the range of 260–320 nm. The IR spectrum in crystals containing OH has distinguished characteristic absorption bands at 3725 cm⁻¹. In crystals doped with (U), the bands 3550–3580 cm⁻¹ are observed, which are responsible for OH ions. The doped crystals with co-dopant contain an additional band at 3342 cm⁻¹. The luminescence is observed in the 470–520 nm spectral range excited by ionizing and UV radiation.

The paper presents the results of the studies of the structure and porosity of the coal cake processed by electric arc plasma. The main limiting factor in processing of coal cakes sorbents is their high water content. As a result of coal washing, the main share of water introduced into the cake falls on hard-hydrate and colloidal components. This makes impossible application of traditional processes of manufacturing from a cake of coal sorbents. Using the electric arc intensifies the processes of thermal activation of coal cakes associated with thermal shock, destruction and vapor-gas reactions occurring at the surfaces of the particles at an exposure temperature of up to 3000 °C, which increases the title product outlet (sorbent) and thereby reduces manufacturing costs and improves environmental performance. The investigation of the thermal activation zone is carried out in the plasma reactor chamber by thermal imaging method followed by mapping-and 3D-modeling of temperature fields. the most important physical and chemical properties of the sorbents from coal cake activated by plasma was studied. The obtained results showed the possibility of coal cake thermal activation by electric arc plasma to change its material composition, the appearance of porosity and associated sorption capacity applied for wastewater treatment.

The modern radiation technology, nuclear engineering, non-linear optics are associated with radiation-resistant optical material study. Evolution of electronic excitations in these materials is a complex multichannel process which currently has no integrated model. A special role belongs to the low-symmetry single crystals, such as beryllium oxide (BeO). We present theoretical results that advance our understanding of exciton-based channel of electronic excitations relaxation. The four possible self-trapped exciton (STE) configurations in beryllia single crystal have been investigated by using a quantum mechanical approach (Hartree-Fock and B3LYP HF-DFT hybrid functional, as implemented in the CRYSTAL09 code). B3LYP DFT functional with 30% of exact exchange was used (B3LYP30). All calculations were performed using periodic boundary conditions and full SC geometry relaxation. The lattice distortion and charge density distribution for considered defect configurations were obtained. STE-A1 luminescence energy was found to be 6.0 eV for HF and 6.5 eV for B3LYP30; STE-A2 luminescence energy was found to be 9.2 eV for HF and 7.8 eV for B3LYP30. STE-B1 luminescence energy was found to be 5.5 eV for HF, 6.2 eV for B3LYP30; STE-B2 luminescence energy was found to be 4.7 eV for HF.

In this paper, the new sensors based on the C(4) or/and C(5) mono(heteroaryl) and di(heteroaryl) substituted pyrimidines are described. The effect of different substituents in pyrimidine ring on the detection limits and selectivity for prepared sensors are explained. The results of detection towards various nitro-explosives and volatile interferents at room temperature with use of the portable detector "Nitroscan" are shown.

Luminescence characteristics of gadolinium co-doped yttrium aluminium garnet doped with cerium phosphors were studied. In this work, powder X-ray diffraction (XRD) spectra, elemental composition analyses, excitation and emission spectra, conversion efficiency of emission phosphor, corresponding (CIE) chromaticity colour coordinates and pulsed photoluminescence decay kinetic curves were investigated, all the measurements were performed at room temperature. The properties of the phosphors were studied by comparing the composition of the phosphors and their luminescent properties.

The dispersion of the characteristic decay times of gadolinium co-doped yttrium aluminum garnet doped with cerium phosphors were studied. In the present work, an ultraviolet semiconductor laser (λ_em=375 nm, τ = 1 ns) was used as excitation source for measuring kinetics characteristics of phosphor groups based on YAG with different content of cerium.

In this paper we investigate the balance of energy in the discharge circuit of a spark discharge generator (SDG) for nanoparticles synthesis. The released energy consists of several parts: the energy in a discharge gap and the energy dissipated in the other elements of the circuit. In turn, in the gap a one part of the energy releases in preanode and precathode regions and the other part in an arc between electrodes. We measured these parts and proposed ways to optimize energy efficiency of the nanoparticles production.