To clarify the efficiency of irradiation resistance, investigation of body-centered cubic concentrated HfNbTiZr and dilute V-4Cr-4Ti alloys, irradiated by 40 keV He ions up to 5 x 10(16), 1 x 10(17) and 5 x 10(17) cm(-2) fluences at room temperature, was carried out. Similar to V-4Cr-4Ti, HfNbTiZr possesses high phase stability and surface erosion resistance to irradiation with He ions up to 5 x 10(17) cm(-2) . Using transmission electron microscopy, a more than 2-fold increase in overall swelling, as well as its intensification with increasing fluence was observed for HfNbTiZr compared to V-4Cr-4Ti. Combining atomistic calculations and simulations based on the Modified Embedded Atom Method interatomic potential and Density Functional Theory, the energetics of defects and helium-vacancy complexes, as well as their dynamics, were studied for alloys. It was shown that in the HfNbTiZr and dilute vanadium alloys the number of radiation-induced vacancies (v) can be comparable. According to the binding energy curves, there is a tendency for higher He accumulation in helium-vacancy complexes due to the increased He/v ratio in HfNbTiZr compared to V-4Cr-4Ti (similar to 1.5 versus similar to 1.1). It was found that the kick-out of lattice atoms is enhanced in HfNbTiZr and is suppressed in V-4Cr-4Ti. Therefore, the more intense He bubble growth in HfNbTiZr may be due to the kick-out mechanism, which leads to a decrease in the He/v ratio and stimulates helium-vacancy complexes to trap additional He atoms. Our results can be used to improve the bubble swelling resistance in the design of new multicomponent concentrated alloys.

The Zr-1%Nb alloy is widely used as a structural material for nuclear fuel assemblies of light water reactors. One of its key properties is the behavior upon a possible loss-of-coolant accident (LOCA) that can be changed by the surface modification procedures. This paper presents the research results on the effects of both high-intense pulsed ion beam (HIPIB) irradiation and high-current pulsed electron beam (HCPEB) processing on the kinetics of its oxidation at 1200 degrees C in air and steam, similar to the LOCA conditions. HIPIB irradiation led to more uniform reliefs on the sample surfaces but did not change their phase composition. However, both a and c lattice parameters decreased slightly with a simultaneous increase in microstrains. After HCPEB processing, the general patterns of changes in the modified surface layers were similar, but microcracks were found in some areas. In all studied cases, weight gains were greater after oxidation in air than those in steam. Nevertheless, diffusion of oxygen and the formation of scales occurred more slowly in the modified surface layers due to their distorted crystal lattices. The main reason for the variations was different physical processes that had occurred when the surfaces had been modified with charged ions and electrons.

The paper compares the collective acceleration of ions in a Luce diode in residual atmospheres of air, argon and krypton at pressures of 6-156 mPa, evaluating the efficiency of capture of Ar and Kr ions into collective acceleration from their residual atmospheres. At a diode voltage of similar to 232 kV, proton energies were 510 +/- 38, 619 +/- 62 and 567 +/- 59 keV for air, argon, and krypton atmospheres, respectively, while the number of protons per shot was approximately 2 and 3 times higher in the argon and krypton residual atmosphere compared to the normal residual atmosphere. This increase in energy also led to a significant increase in the proportion of protons with energies greater than 3.02 MeV - to 10(10) per shot on average. It was found that with increasing argon pressure, the diode current noticeably decreases, and with increasing krypton pressure, on the contrary, the diode current noticeably increases, which can be explained by the fact that argon is more neutral than krypton. The efficiency of capture of Ar and Kr ions into collective acceleration from their residual atmospheres was estimated as 0.06 % and 0.19 %, respectively.

The influence of spark discharges on the surface morphology and chemical composition of resistive diamond-like carbon (DLC) coatings designed to prevent breakdowns in gas electron multipliers (GEMs) has been studied. DLC coatings with thicknesses of approximately 200 nm and 66 nm were deposited in an inert argon atmosphere on polyimide substrates by high current pulsed magnetron sputtering and on silica (silicon oxide) substrates by vacuum arc method. Based on the analysis of images of optical and scanning electron microscopy, it was established that, the region of interaction between the gas discharge channel and the coating surface presents an accumulation of erosion craters with a characteristic linear size in the range of 20-40 mu m. The value of current density passing in the region of interaction between the plasma in spark discharges and the sample is estimated to be of the order of 10(5) A/cm(2), which is sufficient to ablate the coating and create thermal stresses of magnitude 4 GPa at the interface between the coating and the substrate. Thus, pulsed surface erosion, insufficient adhesive strength of the coating to the substrate, and poor thermal conductivity should be considered as the key reasons for destruction of the DLC coating.

The surface of monocrystalline silicon irradiated with a high-power pulsed beam of carbon ions and protons is studied using optical and scanning electron microscopy. The surface is irradiated using a TEMP-2 accelerator in a vacuum of 10–3 Pa. The ion beam consists of 70

The surface of single-crystal silicon irradiated with a powerful pulsed beam of carbon ions and protons was studied using optical and scanning electron microscopy. The surface was irradiated using a TEMP-2 accelerator in a vacuum of ~10–3 Pa. The ion beam consisted of 70 % carbon ions (C+ + C+2) and 30 % protons. The sample was irradiated with one pulse with a dose of 1.5 × 1013 ions/cm2. Craters characterized by a hexagonal shape were obtained on the silicon surface. X-ray phase analysis showed the presence of carbon content inside the crater.

— The optical properties of Al–Si–N nanocomposite coatings deposited by reactive magnetron sputtering on substrates of stainless steel 12H18N10T and zirconium alloy E110 are studied. The absorption and luminescence characteristics are determined by growth defects and also depend on the type of substrate and its treatment with a powerful ion beam. Absorption and luminescence centers are identified with intrinsic defects in c -Al and a -SiN x and their simplest complexes. The effect of hydrogen absorption and 420-keV proton irradiation on the optical properties of the coatings is established. The dose dependences of the optical characteristics indicate the radiation resistance of the coatings. The radiation resistance of the coatings on zirconium alloy is slightly higher due to the stabilizing effect of silicon-containing defects.

The collective acceleration of helium ions from its residual atmosphere in the Luce diode was studied at helium pressures from 0.13 to 0.23 Pa. The energy of accelerated ions was determined from the drift velocity of the virtual cathode accelerating the ions. The number of 4He was determined by radioactivities of 13N and 30P induced in h-BN and Al targets via the nuclear reactions 10B(α,n)13N and 27Al(α,n)30P. The efficiency of capturing 4He ions in collective acceleration from the residual helium atmosphere was estimated as 0.25%. With increasing helium pressure above 0.15 Pa, the energy of the main ion group noticeably decreased to 0.46 MeV/amu compared to the acceleration from a usual residual atmosphere (~0.6 MeV/amu); however, the probability of ion acceleration to a specific energy of up to 1.57 MeV/amu increased significantly. Such increases in the ion energy were accompanied by the appearance of the signal of the second virtual cathode 7–9 ns after the appearance of the first virtual cathode.

Intense pulsed ion beam (IPIB) technology has made remarkable progress in surface modification, mixing, polishing, film deposition, and nano powder synthesis in recent years. However, the surface properties of materials under IPIB irradiation are highly sensitive to beam intensity variations. Deviations from acceptable parameter range can change the surface characteristics and increase prevalence of defects. Consequently, the real-time online monitoring of beam stability during irradiation experiments and promptly identifying of pulses exhibiting significant parameter jitter are of significance in accurately analyzing results and optimizing surface modification. This study presents a fast-response pulse X-ray diagnostic system by employing EJ-200 plastic scintillator, 9266FLB photomultiplier tube, and Tektronic TDS 2024 four-channel oscilloscope. Single particle test demonstrates that the system achieves a time resolution of 6 ns, meeting the requirements for temporal response to detecting pulse X-ray signals with a half-width of ~80 ns. By adjusting the insulation magnetic field strength of the ion diode, the IPIB output level is regulated. The diagnostic system successfully captures X-rays emitted by the external magnetic insulated ion diode operating at different output levels. Simultaneously, the ion beam energy density is measured by using an infrared camera. To mitigate diagnostic errors stemming from target ablation, the maximum energy density is controlled to be below 1.32 J/cm2. Analysis results establish a positive correlation between X-ray intensity and ion beam energy density. This relationship arises from the influence of the insulating magnetic field adjustment on the diode's operating voltage, which subsequently affects the bremsstrahlung radiant intensity and ion beam emission intensity. This correlation offers the potential for the real-time monitoring of IPIB beam output stability by utilizing X-ray signals. To further corroborate the synchronized changes in pulse X-ray intensity and ion beam intensity, Faraday cup is employed as an alternative to infrared imaging method for measuring ion current density. Results demonstrate that the amplitude of the X-ray signal changes synchronously with fluctuations of ion current density. It is worth noting that when the output intensity of ion beam deviates significantly (more than 10% of the preset value), the diagnostic system will respond quickly. These findings validate the efficacy of the proposed non-interceptive diagnostic method of real-time monitoring the intense pulsed ion beam output stability.

We investigated the effect of magnetic field in the anode and cathode gap (A-C gap) of a radial focusing (Br) external magnetically insulated diode on the emission behavior of IPIB. The magnetic field distribution between the A-C gap was analyzed by finite element method. The non-uniform magnetic field distribution induced the stronger ion emission at the outer ring area of the anode. It revealed the reason for the more serious depletion of the anode outer ring. Within the magnetic induction intensity less than 1.37 Bcrit, it was found experimentally that the diode voltage and ion beam density reached a higher value with the increase of magnetic field. A smoother surface of Al2O3 ceramic was observed after the irradiation of IPIB generated by the Br diode. The study provides guidance for optimizing ion emission uniformity and efficiency of Br diode, promoting the effective application of IPIB technology in materials science.

The unique flash heating characteristics of intense pulsed ion beams (IPIB) offer potential advantages to fabricate high-performance coatings with non-equilibrium structures. In this study, titanium-chromium (Ti-Cr) alloy coatings are prepared through magnetron sputtering and successive IPIB irradiation, and the feasibility of IPIB melt mixing (IPIBMM) for a film-substrate system is verified via finite elements analysis. The experimental results reveal that the melting depth is 1.15 μm under IPIB irradiation, which is in close agreement with the calculation value (1.18 μm). The film and substrate form a Ti-Cr alloy coating by IPIBMM. The coating has a continuous gradient composition distribution, metallurgically bonding on the Ti substrate via IPIBMM. Increasing the IPIB pulse number leads to more complete element mixing and the elimination of surface cracks and craters. Additionally, the IPIB irradiation induces the formation of supersaturated solid solutions, lattice transition, and preferred orientation change, contributing to an increase in hardness and a decrease in elastic modulus with continuous irradiation. Notably, the coating treated with 20 pulses demonstrates a remarkable hardness (4.8 GPa), more than twice that of pure Ti, and a lower elastic modulus (100.3 GPa), 20% less than that of pure Ti. The analysis of the load-displacement curves and H-E ratios indicates that the Ti-Cr alloy coated samples exhibit better plasticity and wear resistance compared to pure Ti. Specifically, the coating formed after 20 pulses exhibits exceptional wear resistance, as demonstrated by its H3/E2 value being 14 times higher than that of pure Ti. This development provides an efficient and eco-friendly method for designing robust-adhesion coatings with specific structures, which can be extended to various bi- or multi-element material systems.

The tungsten surface was processed by high power pulsed ion beam at the TEMP accelerator (Cn+ ions, accelerating voltage 200 ± 10 kV, energy density of a single pulse 2.6 – 3.0 J/cm2). Changes in the relief and structure of the surface of tungsten samples were studied by scanning electron microscopy. After treatment with a powerful pulsed ion beam (MIIP), defects in the form of craters form on the surface of tungsten. The number of craters decreases with an increase in the number of impact pulses. After exposure to 3 pulses, microcraters are forms in the surface layer along the grain boundaries. After 10 pulses, there are practically no cracks on the irradiated surface. An increase in the number of pulses leads to the formation of a more equiaxed ultrafine-grained structure in the near-surface layer of tungsten.

The surface microstructure and phase structure of zirconia (ZrO2) ceramics under intense pulsed ion beam (IPIB) irradiation were investigated in this work. Experiments were carried out on TEMP-4M accelerator with peak accelerating voltage, current density, and pulse duration of 220 kV, 150 A/cm2, and 80 ns. Micro-cracks with a height of up to 150 nm above the surface were observed and were deduced to be formed by the tensile stress during the shrinking process. The cross-sectional observation indicates that columnar structure thin layer with thickness about 1.23 & mu;m was produced after IPIB irradiation. The GIXRD pattern indicates that obvious preferred orientation in (1 1 0) and (200) of t-ZrO2 was occurred in near-surface region after IPIB irradiation. Opposite micro-stress in bulk and near-surface region was revealed by W-H plot after Rietveld refinement. The evolution of mass loss and surface roughness of samples with pulse number was also investigated.

The results of studying the intense ion beam propagation with peak energy up to 330 keV are presented. The ion beam was injected into the metal tube made from stainless steel in the form of a hollow cone. It was found that the ion beam focused due to neutralizing the space charge and reducing the divergence of ions. Neutralization of the beam space charge was investigated by measuring its electric potential. The average energy density of a beam increased up to 2.9 J/cm2 over the beam cross-section in the focal plane. The ion beam current density in the tube rose by a factor of 3 in comparison with geometric focusing. The analysis of the surface structure of the ion beam spot obtained on the stainless steel AISI 304 plate was done.

Поверхность тантала облучали мощным импульсным ионным пучком на ускорителе ТЕМП Томского политехнического университета (Cn+, ускоряющее напряжение 200±10 kV, плотность энергии в импульсе 2.6–3 Дж/cм2). Изменение топографии поверхности тантала после воздействия мощного импульсного ионного пучка исследовали с помощью растровой электронной микроскопии. Изменения рельефа и структуры поверхности образцов Та изучали методом сканирующей электронной микроскопии.

The effect of short-pulsed irradiation with 220 keV carbon ions for fluences of 2.2 x 10(13) - 2.1 x 10(15) cm(-2 )on the optical and electrical properties of titanium nitride films deposited by reactive magnetron sputtering on silicon and steel substrates has been studied. Relationships are obtained between the irradiation conditions and the parameters of interband absorption. A relationship has been established between the concentration of defects before and after irradiation, the degree of overlap of their levels and changes in the optical and electrical properties of the films. Reasons of high radiation resistance of the films are discussed. The optical and electrical properties of the films change during irradiation in two stages. The first stage is related to the annihilation of defects, the second stage is associated with their accumulation. Irradiation of films significantly slows down the rate of oxidation of their surface layers and stabilizes the electrical properties.

Today, the concept of single-phase concentrated solid solutions offers an alternative strategy for increasing the radiation resistance of materials, namely, a multi-element composition with equiatomic or nearly equiatomic concentrations. It is highly desirable to understand the relationship between the chemical complexity of alloys and the thermal effects associated with irradiation in order to increase the radiation resistance of such materials. We present an analysis of the radiation heating, the thermoelastic stresses and the density of growth dislocations in the family of Ni-based alloys: NiCo–NiFe–NiCoFe–NiCoCr–NiCoFeCr–NiCoFeMnCr exposed to high-energy irradiation with 145 MeV Kr ions performed by numerical modeling. The results show that the composition complexity of the alloys, especially that of NiCoFeMnCr, favors the radiation annealing of defects, decreases the level of hazardous thermoelastic stresses relative to the ultimate strength, and reduces the growth dislocation density compared to that in Ni.

The effect of short-pulse irradiation with 200-keV carbon ions on the optical and electrical properties of aluminum-nitride films and Al–Si–N coatings with variable atomic composition deposited by reactive magnetron sputtering on a silicon substrate is investigated. Absorption and luminescence centers are associated with growth and radiation-induced defects in nitrides and their simplest complexes. A change in the properties during irradiation occurs due to the accumulation of radiation defects and their association into complexes. Ion irradiation is accompanied by intense radiation and the thermal annealing of unstable defects. The dose dependences of the coating characteristics indicate their high radiation resistance, which are slightly inferior to coatings on steel substrates. The radiation resistance of the coatings is due to the limiting effect of growth defects on defect formation, the wide band gap of nitrides and the interaction of defects.

Explosive electron emission cathodes provide a high current density without auxiliary systems and, therefore, have long been the subject of research for high-power pulsed accelerators. The paper summarizes the results of studies on the operation of an explosive-emission cathode based on carbon fiber in operating modes with a pulse repetition rate of 5-15 pps, at a voltage rise rate of asymptotic to 2.5 x 10(12) V/s. The change in current and voltage as a function of the number of pulses and the diode impedance in the pulsed-periodic mode with a voltage pulse duration of 200 ns at full width half maximum (FWHM) are studied. During testing, the total diode current reduced by 25%. The change in the characteristics of the cathode at different pulse repetition rates is given up to 3.2 x 10(5 )pulses. Changes in characteristics are correlated with changes in the microstructure of the cathode surface, presented in the enlarged images of the cathode surface.