编号 2 (2025)

The effect of exposure to pulsed megawatt submillimeter (0.1–0.4 THz) radiation fluxes on the spectral characteristics of some thin-film polymer materials in the frequency range from 0.2 to 2 THz has been registered. The polymer samples have been characterized using technical solutions within the framework of time-domain-spectroscopy and BWO spectroscopy. For the exposure, a radiation flux in the submillimeter wavelength range with duration of about 4 μs generated during beam-plasma interaction at the GOL–PET facility (BINP SB RAS) has been used. Relative changes in the real part of the permittivity of individual polyvinylidene fluoride samples is found to reach a level of 0.5 with an initial value of about 3.0, while for polyvinyl chloride samples no changes in this parameter have been registered. At the same time, for polyurea individual samples, both significant changes in this parameter and its insignificant changes as a result of exposure have been observed. The results of the experiments provide a basis for using thin-film polymeric materials as substrates for samples of supramolecular complexes, which during research will be exposed to powerful pulsed radiation fluxes in the submillimeter wavelength range.

The influence of high-temperature annealing on the composition of surface layers of rapidly solidified Al–Mg–Li–Sc–Zr alloy foils of 1421 grade obtained by centrifugal quenching from the melt has been studied when heated to 380°C in air depending on the holding time. Surface elemental mapping of the foils annealed for 1 h was carried out by scanning electron microscopy with energy dispersive X-ray microanalysis. The depth distribution of lithium after annealing the samples for 1, 2 and 8 h was studied by nuclear reaction analysis. After short-term annealing for 1 h, the formation of a gradient composition with an increased content of the main alloying elements in the surface layers of annealed foils was found. The thickness of the diffusion layer enriched with lithium is about 3.3 μm. In the 0.3 μm thick near-surface layer, the average lithium concentration is 30 at.%. In contrast to the contact surface, the non-monotonic character of the lithium concentration profiles of the foils near the free surface includes the presence of a sharp maximum at a depth of 0.3 μm: the lithium content increases from 20 at. % in the thin surface layer (0.1 μm) up to 40 at. %. During the annealing process, with increasing holding time, an intensive mass transfer of lithium atoms to the depth of the foils is observed. The thickness of the diffusion layer increases 4 times.

Low-k dielectrics are applied as interlayer isolators between metallic (cuprum) interconnects in very large integrated circuits. Diffusion of Cu atoms can lead to their degradation, and the most efficient way to solve this problem is the fabrication of ultra-thin metal barrier layers. However, this process is complicated by the non-flatness of low-k surface and the presence of hydrophobic CH₃-groups preventing the metal deposition. Therefore, before the barrier coating it is necessary to perform preliminary surface functionalization aimed at removing methyl groups. In this work the dynamic density functional theory-based simulation of radical and ion irradiation of low-k surface for plasma of various composition (noble gases, molecular nitrogen and oxygen) was carried out to study the mechanisms of methyl group removal. The results obtained showed the possibility of this process for low-energy range (10–15 eV) of incident particles. In this work the detailed analysis of the calculated trajectories is presented, the interactions of CH₃-groups with noble gas atoms (Ne, He) and with more chemically active N and O atoms were compared, the peculiarities of methyl group removal under molecule and molecular ion irradiation were described.

Electrostatic discharges and radiation-stimulated leakage currents were studied under separate and combined action of 10–40 keV electrons and solar electromagnetic radiation on K-208 glass samples used as cover glass for solar batteries and reflective elements for spacecraft thermal radiators. The values of the electron flux density (φ) were changed in the range of (5 × 10⁸–1 × 10¹¹) cm^–2 · s^–1, the electromagnetic radiation flux corresponded to one equivalent of solar illumination. Irradiation was carried out in a vacuum of 10^–4 Pa. During irradiation, two types of discharges were observed: the first type is a discharge from a cone-shaped microprotrusion on the glass surface into the surrounding ionized medium; the second type of discharge developed along the irradiated surface leaving about 100 nm wide and up to 2 nm deep discharge channels on it. Discharges of both types were accompanied by plasma emissions and generation of electromagnetic pulses. The dependences of the discharge frequency and leakage currents on the parameter φ for electron and combined irradiation were obtained. It was found that for fixed electron energy, discharges of the second type on the samples surface in the case of combined irradiation occur at a lower φ value than in the case of electron irradiation. It was also found that with combined action the share of breakdowns of cover glass samples on the conductive substrate in the events recorded in the experiments increases significantly. The share of breakdowns of glass samples also increases with increasing energy of the impacting electrons.

The results of solving the problem of describing the dependence of the charge state of the ion beam on their velocity for all atoms of the periodic system of elements are presented. The values of the basic parameters that are necessary for calculating the charge state of the ion beam are determined and tested by comparing the calculations of the stopping power with an array of experimentally measured values.

The effect of grain size and texture of polycrystalline tungsten on the sputtering yield and surface morphology under high-dose irradiation with 30 keV Ar⁺ ions has been studied. Samples with an average grain size from 300 nm to 7 μm, without texture and with a [001] texture have been used in the experiment. It is shown that the ion-induced surface morphology strongly depends on the grain size and irradiation fluence. The grain size has little (less than 10%) effect on the sputtering yield, while the texture can reduce the sputtering yield by a factor of two. An experiment with varying the angle has shown that the channeling effect is the reason for the two-fold decrease in the sputtering yield for textured samples. The influence of the surface relief on the sputtering yield has been analyzed. An expression taking into account atomic redeposition and ion reflection is proposed to predict the sputtering yield of a surface with ion-induced relief.

The results of a study of the microstructure and structure of plates made of tungsten metal powder (group of companies “Specmetalmaster”, GC “SMM”) used as protective tiles in the lower divertor of the tokamak Globus-M and subjected to additional treatment with hydrogen plasma of a coaxial accelerator from distances of 50 and 260 mm at 5, 10 and 20 irradiation cycles are presented. The microstructure and elemental composition of the plate surface were determined by scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. The microstructure of the irradiated surface layer of the plates at a penetration depth of X-rays up to ~1.4 μm was analyzed from X-ray diffraction data using graphical methods of Williamson–Hall plot and crystallite size — microstrain plot adapted to take into account the observed pseudo-Voigt type of X-ray reflections. The structure of this layer was refined using the Rietveld method. The asymmetry of tungsten (W) reflections after plasma treatment was described by a model with 2 (for samples irradiated from a distance of 260 mm) and 3 (for a distance of 50 mm) crystalline W phases of the same cubic symmetry, but with slightly different parameters of the cubic unit cell and with different values of the mean size of crystallites and the absolute value of mean microstrain in them.

Personalized medicine is a modern concept aimed at individualization of patient therapy. The relevance of the search and identification of new highly sensitive and specific prognostic markers in patients with hemoblastoses is due to the leading positions in the incidence and mortality rate among young working-age population, which gives the problem special socio-economic significance. The study is aimed at studying the content of trace elements in biopsy material (red bone marrow) of patients with hemoblastoses at the onset of the disease and after chemoradiation therapy. Using the method of X-ray fluorescence analysis and synchrotron radiation, it is possible to simultaneously determine more than 25 chemical elements in a low-mass sample with non-destructive sample preparation. Difference in the concentrations of 10 elements (S, K, Ca, Cu, Zn, Fe, Se, Br, Rb, Cd) in patients with two pathologies, lymphoma and leukemia, is considered.