The effect of fast electrons with energy of 0.5–6.2 MeV at a fluence of 1018 electrons/cm2 and γ sources of 60Со (Е = 1.25 МeV) at the absorbed dose of 0.1–25 MGy on the radiation-protective composites based on a magnetite matrix used for biological protection of nuclear reactors is calculated and studied experimentally. The depth of penetration of the electron beam and the nature of distribution of the absorbed dose of fast electrons on thickness of the protective composite are studied. The processes promoting change in the oxidation and coordination states of iron atoms and structural-phase and magnetic states in the composite under the influence of fast electrons and γ radiation are determined.
We study experimentally how optical, electrical, and physical properties of spacecraft surface elements (optical glasses, "metal-insulator-metal" structures, and solar arrays) change upon bombardment by high-speed particles of submicron and micron size. For particle acceleration, we use an electrodynamic accelerator. В© Pleiades Publishing, Ltd., 2013.
A method based on the spectral analysis of thermowave oscillations formed under the effect of radiation of lasers operated in a periodic pulsed mode is developed for investigating the state of the interface of multilayered systems. The method is based on high sensitivity of the shape of the oscillating component of the pyrometric signal to adhesion characteristics of the phase interface. The shape of the signal is quantitatively estimated using the correlation coefficient (for a film–interface system) and the transfer function (for multilayered specimens).
In work researches of structural features of mineral crystal phases and deficiency of crystals of an organosilikonate of bismuth are conducted at various temperature of its processing (from 100 to 5000C). According to x-ray diffraction ranges in СuКα - radiation the periods of a crystal lattice of a crystal are estimated, the analysis of broadening of the most intensive diffraction line for this crystal taking into account crystallographic indexes h, k, l by an approximation method for determination of the size of areas of coherent dispersion and microdistortions of a crystal lattice Δа/а is made. On the basis of the conducted researches it is revealed that at heat treatment of the Na2O-Vi2O3-SiO2 system (NBS material) in a temperature interval 300-5000C there was a decrease in amorphy, microdistortions and density of dislocations of defects in a crystal lattice of a sillenit of structure of Bi12SiO20. Formation of more dense structure of a crystal of a sillenit with the increased x-ray density (9,210 g/cm3) and increase in parameters of a cubic lattice of a crystal is recorded (and =10,1335 Å). The developed material of structure Bi12SiO20 can be used as a gamma and protective filler of radiation protective polymers, and also for creation of electro-and magneto-optical modulators of laser radiation.
A combined method for synthesizing a highly dispersed (0.8–2.5 μm) hydrophobic Na2O– Bi2O3–SiO2 powder (NBS powder) based on solutions of sodium methyl siliconate and bismuth nitrate is studied. The powder is synthesized at a reduced temperature (100°C). The microstructure and the phase composition of the resulting compounds in the Na2O–Bi2O3–SiO2 system at different processing temperatures are investigated. The structural phase transformations in the mineral phases of NBS powder are revealed in the temperature range of 100–500°C. The metastable bismuth silicate Bi2SiO5 at 400°C is transformed into stable sillenite with composition Bi12SiO20 having a cubic crystal structure (a = 10.1050 Å). The synthesized NBS powder can be used as a filler to fabricate highly effective constructional radiation-shielding polymer composites with tailored properties.
The effect of a high-power pulsed flow of deuterium ions and deuterium plasma generated in a plasma focus setup on the surface structure of a Ti plate was investigated. It was established that, depending on the radiation-thermal conditions on the surface, three zones with different surface morphology, structure, and defects were formed in the surface layer irradiated. The peculiarities of the surface damage in the center of the irradiated region of the Ti target exposed to the most severe radiation (power density of the ion and plasma flows of qi ≈ 1011–1012 and qp ≈ 109–1010 W/cm2, respectively) were studied, as well as those for the peripheral region exposed to softer radiation.
The kinetics of growth of a nanosized germanium film deposited by magnetron sputtering on the Si(001) surface is studied using a developed experimental X-ray reflectometry technique distinguished by the joint recording of specularly reflected and diffusely scattered radiation. By using this technique, it is possible to perform in situ both the analysis of the morphology of the growing film and the control of its thickness with an accuracy to 1 nm. Dependences of the intensity of specular reflection, diffuse scattering, rate of growth, and mean square roughness and density of the film on the deposition time are obtained. According to the results of the measurement of specularly reflected radiation, the film roughness increases with time according to a power law. However, at a thickness of the film of 4 nm, a clearly defined maximum of diffuse scattering is observed, the angular position of which corresponds to the critical angle of total external reflection of germanium of 0.31°. This pattern of distribution of scattered radiation is explained by the manifestation of the Yoneda effect that consists in the anomalous X-ray scattering, the maximum of which corresponds to the critical angle θC of total external reflection from the film. It is established experimentally that, at the initial stage of growth, the film is formed by the Volmer–Weber mechanism. It is found using in situ X-ray reflectometry that the formation of a continuous layer of a germanium film occurs at its thickness of 7 nm; the subsequent growth of the film proceeds according to the power law σf ~ tβ, where β = 0.23.
In the article possibility of use of a neutron-protective polymeric cover for transport packing sets (containers) of the fulfilled nuclear fuel has been considered. Possibility of synthesis of high-disperse hydrophobic metalloorganosiloksan powders has been achieved. In oligomerny volume of siloksan chain of the powder chemically connected gadolinium with high concentration of atoms of gadolinium was contained. On the basis of this investigation its have been developed the scientific fundamentals of modifying of both structure and properties of polymeric composites. This modifying provides the directed regulation of their supramolecular structure by injection of both plasticizing and modifying additives. Settlement and experimental investigations of neutron-protective properties of the developed polymeric composite were conducted.