The results of experimental investigation of the combined action of 500-keV protons and ~20-eV oxygen plasma on thin polyimide films are presented. The samples are irradiated with a proton fluence of 1014–1016 cm–2 and an oxygen plasma fluence of ~1020 cm–2. The transmission and Raman spectra of the films, which are measured at different stages of sample irradiation, are compared. Data on the mass loss of the samples as a result of surface erosion are presented.
The effect of 40-keV electron and proton radiation with a flux density of 5 × 10 cm−2 s−1 on the deposition of products of thermostimulated gas release from a polymer composite on a substrate made from protective K-208 glass used for the protection of spacecraft solar panels is experimentally investigated. Analysis of the obtained results shows that, unlike proton radiation, electron radiation results in an increase in the optical density of the glass and stimulates the deposition of gas-release products. It is established that the majority of effects generated as a result of exposure of the substrate to electron radiation are neutralized by protons upon combined irradiation with electrons and protons.
USB15 boronmixed graphite samples subjected to bombardment with 90eV ions of an accelerated oxygen plasma flow are investigated via scanning electron microscopy, Xray microanalysis, Xray diffraction analysis, and mass spectrometry of the thermaldesorption kinetics and volatile compounds. It is revealed that the surface is enriched with oxygen and irradiation is not accompanied by structural changes. The material possesses an imperfect finegrained structure with a very low graphitization level. Thermaldes orption mass spectrometry indicates that spectral lines of boron oxide appear at temperatures of greater than 150°C and reach their maximum at 320–410°C. This corroborates the assumption that an inert boronoxide film is formed on a cold USB15 surface under the action of oxygen ions and evaporates with increasing temperature. The latter leads to a loss in the protective properties of the boron dopant.
The effect of spherical quantum objects (scatterers) embedded into semiconductor barriers on the tunnel current flowing through them has been studied. For this purpose, the problem of the scattering of incident and reflected wave functions (damping if their energy is less than the barrier potential) of the electron by the stepwise spherically symmetric scattering potential has been solved.
C, Cu and W element profiles in films deposited using Plasma Focus facility (PF-4, FIAN) were studied by the method of Rutherford backscattering of 2 MeV He+ ions. The films were deposited on glass substrates in the Ar orifice gas. The element profiles were found to depend significantly on the particle kinetic energy. The penetration depth of particles with ~105 m/s speed was about 1.5 μm. The corresponding glass thickness element profiles were non-linear. For each element, there was the maximum layer depth under the glass surface. The formation of Cu, W and C layers under the glass surface and their overlapping was the feature of the films deposited using the PF-4 facility. Such an arrangement of layers told significantly this method of film deposition from the conventional methods used low deposition atom rates, as well the diffusion. Because of mentioned characteristics of deposition, the obtained films were dielectrics.
We present the results of the simulation tests of samples of polymer nanocomposites based on carbon nanotubes for resistance to oxygen plasma in the Earth’s upper atmosphere. Data on the weight loss of the samples, the results of analysis of their surface structure after irradiation, and data on arrays of carbon nanotubes damaged under the effect of oxygen plasma are given. Possible mechanisms of destruction of the nanotubes are discussed.
The transmission, reflection, and luminescence spectra of two types of samples of a cholesteric photonic crystal are measured: with the orientation of the n director specified by the surface of the optical cell, and when the n director is disoriented on the cell surface. In samples with surface orientation, a perfect helical structure is formed with characteristic features of the luminescence spectra in the photonic band gap due to the density of photonic states. The density of photonic states is restored. The lower threshold value of the surface-anchoring potential W is estimated when the director deviates from the orientation direction given by the surface. The transformation of the luminescence spectra and the temperature dependence of the position of the bands during the transition from surface-oriented structures to disordered ones are observed.
Using methods of X-ray fluorescence analysis (XRFA), the Rutherford backscattering of ions (RBS) and spectral X-ray microanalysis (SXRM) in combination with scanning electron microscopy (SEM), we study the elemental composition and structure of contaminants on the surface of a metallic panel with samples of different materials exposed to outer space for 12 years. It turns out that the main elements of the contaminants are C, O, Si, S, Ca, Fe, and Zn. Since these elements are the constituents of materials located on the panel, they are present as a result of destruction of the materials under the action of outer-space factors. X-ray phase analysis (XRPA) of the contaminants shows that carbon is present in the form of an amorphous graphite phase with a small addition of crystalline graphite, while the other components are in an amorphous state. Crystalline silicium dioxide and other silicium compounds are not found.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
Assemblies made of Ta|CD2|Ta, Ta|Ta|CD2|Ta|Ta and Nb|CD2|Nb foils are irradiated with pulses of high-temperature argon plasma created by means of a “Plasma Focus” setup. The irradiated foil samples are investigated by recording the recoil nuclei of hydrogen and deuterium. It is found that hydrogen and deuterium are redistributed in foil stacks. The ultradeep penetration of light gas impurities (hydrogen and deuterium) can be explained by the influence of shock waves on the foils and accelerated diffusion under an external force.
The method of Rutherford back scattering of He + ions with 2 MeV studied the distribution profiles of the elements C, Cu and W in the films deposited on the discharge installation type "plasma focus". The films are deposited on glass substrates in Ar plasma-forming gas. It is found that the element distribution profiles vary significantly from the kinetic energy of the particles. Particles having a velocity about 105 m / s, penetrates to a depth of about 1.5 microns. Appropriate distribution profiles elements for glass thickness are nonlinear. For each element, there is a maximum depth of the layer under the surface of the glass. A feature of the films obtained on the setting of "plasma-focus" is the formation of layers of the elements Cu, W and C at the glass surface and their mutual overlap. This arrangement of layers distinguishes described film deposition method of the commonly used methods of application at low speeds the deposition of atoms, as well as by diffusion. It is found that the obtained film are insulators.