Creation of the indirect-drive cryogenic target with the solid deuterium layer
Creation of the indirect-drive cryogenic target with the solid deuterium layer
E. Yu. Zarubina$^{1,2}$, M. A. Rogozhina$^1$, I. A. Ghugrov$^1$
An indirect-drive cryogenic target is necessary for research in the field of laser thermonuclear fusion at a megajoule energy level facility. Solid fuel layer in the target must meet high requirements: a roughness of the inner cryolayer surface must be less than 1 µm, deviations from the sphericity and the concentricity must be less than 1%. This paper describes the results of the research on meeting these requirements, notably, cryolayer formation and its characterization. Due to the slow crystallization method of the deuterium layer with its simultaneous heating by IR radiation it is possible to obtain deviations from the sphericity and the concentricity of the inner cryolayer surface within limits of 2%, the roughness - within limits of 20 mkm. Theoretical thermal calculations of the target construction are compared with experiment. The program system was developed using the optical shadow method which makes it possible to measure liquid fuel when filling the shell during the performance of the experiment, to perform the characterization of the solid cryogenic layer parameters, to evaluate characterization results robustness.
Show AbstractPlasmon energy losses of electrons in multilayer dielectric structures
Plasmon energy losses of electrons in multilayer dielectric structures
A. N. Vasil'ev
The possibilities of engineering energy losses of electrons created in the cascade process of electron-electron scattering during the interaction of multilayer dielectric structures with ionizing radiation are considered. It is shown that the contribution of surface plasmons associated with layer boundaries to electron energy losses is significant only for nanometer layer thicknesses and increases with increasing electron energy. At the same time, surface states associated with longitudinal optical phonons in ionic crystals significantly change energy losses during electron thermalization and can lead to an increase in the efficiency and growth rate of scintillation in nanostructured systems.
Show AbstractOn activation studies of photonuclear reactions on gamma-beams from backward Compton scattering at Egamma < 40 MeV
On activation studies of photonuclear reactions on gamma-beams from backward Compton scattering at Egamma < 40 MeV
S. S. Belyshev$^1$, V. V. Varlamov$^2$, L. Z. Dzhilavyan$^3$, A. A. Kuznetsov$^{1,2}$, A. M. Lapik$^3$, A. L. Polonski$^3$, A. V. Rusakov$^3$, V. I. Shvedunov$^2$
For the program of studying photonuclear reactions on gamma-beams of the source from backward Compton scattering under developing, when the output energy is Egamma < 40 MeV, activation experiments are proposed as initial ones, which are important both for developing methods for tuning and monitoring gamma-beams, and for studying the excitation of pygmy and giant resonances in atomic nuclei and the multiplicity of photoneutrons from the processes of deexcitation of giant resonances.
Show AbstractTaking into account the distribution of the noise level along the wavelength during broadband control of the deposition process of optical coatings
Taking into account the distribution of the noise level along the wavelength during broadband control of the deposition process of optical coatings
A. N. Sharov, S. A. Sharapova$^2$, A. V. Tikhonravov$^2$, A. G. Yagola$^3$
The paper presents numerical results of simulations of the deposition process of a complex optical coating using broadband monitoring of this process in the case when the noise level in the measured transmittance coefficient has an uneven distribution along the wavelength. The influence on the accuracy of data control at the edges of the measured wavelength range, where the error in the transmittance coefficient is maximum, is investigated. It is shown that when a part of the data is removed at the edges of the range, the self-compensation coefficient of the deposition process errors almost does not change, while the average norm of the error vector of layer thicknesses significantly decreases. Thus, it is shown for the first time that taking into account the effect of self-compensation of errors in broadband control opens up the possibility of a reasonable choice of the optimal spectral range of optical control for practice.
Show AbstractStresses in silicon dioxide films deposited from dielectric targets: results of atomistic modeling
Stresses in silicon dioxide films deposited from dielectric targets: results of atomistic modeling
F. V. Grigoriev, V. B. Sulimov, A. V. Tikhonravov
The previously proposed method of molecular dynamics simulation of the deposition of thin films from metal targets is adapted to the case of dielectric targets and applied to silicon dioxide films. The possibility of not only silicon atoms leaving the target, but also clusters with oxygen atoms was taken into account by adding O=Si=O molecules to the flow of deposited atoms. Atomistic film clusters were obtained by high-energy and low-energy deposition at different percentages of molecules in the flow of deposited atoms. The values of the stress tensor components are calculated. With high-energy deposition, compressive stresses are observed, with low-energy deposition, tensile stresses are observed. The absolute values of the diagonal components of the stress tensor increase with increasing proportion of molecules in the flow of deposited atoms.
Show AbstractMultibit failures of the spacecraft's onboard electronics from a single particle of cosmic radiation
Multibit failures of the spacecraft's onboard electronics from a single particle of cosmic radiation
N. G. Chechenin, N. V. Novikov, A. A. Shirokova
The analysis of the effect of high-energy protons of space radiation on the onboard electronics of the spacecraft is carried out. It is shown that protons can cause nuclear reactions with atomic nuclei of electronics material. The residual nuclei formed as a result of a nuclear reaction have sufficiently high energy to cross the sensitive areas of several bits of electronics, and the high ionizing ability of nuclear fragments allows generating an excess charge of carriers exceeding the critical charge for the failure to occur simultaneously in several bits of the electronic device
Show AbstractAnomalous band bending in the (K$_{0.8}$Na$_{0.2}$)$_{0.8}$Fe$_{1.8}$Se$_2$ superconductor
Anomalous band bending in the (K$_{0.8}$Na$_{0.2}$)$_{0.8}$Fe$_{1.8}$Se$_2$ superconductor
L. L. Lev$^{1,2,3}$, T. E. Kuzmicheva$^{2,3}$, S. A. Kuzmichev$^{2,3}$, A. M. Lebedev$^5$, V. G. Nazin$^5$, R. G. Chumakov$^5$, A. I. Shilov$^3$, E. O. Rahmanov$^{3,4}$, I. V. Morozov$^4$
Iron dichalcogenides intercalated with alkali metal atoms attract the attention of physicists due to their unusual natural phase separation, in which superconducting clusters are formed at the boundaries of the antiferromagnetic phase. In this work, using photoelectron spectroscopy technique, we discovered an unusual effect that presumably arises due to this phase separation. We studied the temperature dependences of the photoelectron spectra of Se 3d, Fe 3p and the valence band at temperatures above and below $T_c \approx 27$~К of the compound (K$_{0.8}$Na$_{0.2}$)$_{0.8}$Fe$_{1.8}$Se$_2$ with a unique substitution of alkali metal atoms. A strong temperature dependence of both the valence band and core levels was discovered: we observed a strong broadening of the spectra, which monotonically decreased with increasing sample temperature, while the temperature changes were cyclic. We believe that this broadening is associated with the appearance of space charges in the dielectric matrix, which leads to band bending. Moreover, the shape of the potential arising inside a given compound was reconstructed, and an estimate was obtained for the relative amounts of dielectric and superconducting phases. The results obtained will help to better understand the physical processes occurring in this compound.
Show AbstractDetermination presence of packaging defects in palladium-based alloys by X-ray diffraction method.
Determination presence of packaging defects in palladium-based alloys by X-ray diffraction method.
O. V. Akimova
Alloys studied in this work are of interest for the needs of hydrogen energy, electronics, pharmacology. The aim of the research is to reveal regularities of defect subsystems development, which is necessary for development of processes to improve performance of metallic systems. Probability of the presence in palladium-based membrane alloys of two-dimensional lattice defects affecting the structure-sensitive properties of materials - packing defects (PD) - are assessed. The analysis of lattice imperfections of Pd93.5In6.0Ru0.5 (numerical indices-mass.%), Pd100-xPbx (x=5, 8, 12, 16, 20 mass.%) alloys was performed according to the results of X-ray diffraction using synchrotron radiation (SR) of the Kurchatov Research Center. The dependence of probability of PD formation on the concentration and grade of the palladium doping element has been established.
Show AbstractThe tardigrade radioprotective protein Dsup (damage suppressor) is resistant\\ to~high doses of ionizing radiation
The tardigrade radioprotective protein Dsup (damage suppressor) is resistant\\ to~high doses of ionizing radiation
M. P. Zarubin$^1$, A. F. Nizamieva$^{1,2}$, S. I. Alexeev$^1$, S. V. Mitrofanov$^1$, Yu. E. Gorshkova$^{1,2}$, E. V. Kravchenko$^1$
The unique Dsup protein of the tardigrade Ramazzottius varieornatus increases resistance to radiation and oxidative stress in various species of organisms and in human cell culture. According to modeling data, Dsup forms a complex with DNA with an intermolecular distance of ~4 Å, as a result of which DNA is less damaged by reactive oxygen species formed during exposure to radiation. However, the stability of the Dsup protein itself under the influence of ionizing radiation remains unclear, which is important for assessing its radioprotective potential and understanding the molecular mechanisms of the action of this protein under conditions of high doses of radiation. In this work, the radiation degradation of the Dsup protein after γ-ray irradiation by small-angle X-ray scattering (SAXS) and protein electrophoresis in polyacrylamide gel under denaturing conditions (SDS-PAGE) was studied for the first time. It has been shown that, in contrast to the control bovine serum albumin, the spatial and structural characteristics of the Dsup protein remain almost unchanged even when exposed to high doses of radiation (5 and 10 kGy), which suggests its high radiation stability.
Show AbstractA model of surface nanorelief formation under gas cluster ion beam irradiation
A model of surface nanorelief formation under gas cluster ion beam irradiation
D. R. Bessmertniy, A. E. Ieshkin
A model for the evolution of surface nanorelief under irradiation with gas cluster ions is proposed. The model is based on consideration of individual collisions of clusters with a surface. The amount of substance sputtered from the collision area and the efficiency of its redeposition onto other surface elements are determined. The performance of the model is shown when compared with experimental data. The stages of smoothing of a harmonic relief are studied. A new measure of the effectiveness of surface smoothing is proposed.
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