Investigation of the physical nature of ion-irradiation-induced сascade-forming processes by optical spectroscopy, X-ray photoelectron spectroscopy, and field ion microscopy

Projeto: Award Project

Detalhes do projeto

Description

Direct experiments to determine of the energy and geometric parameters of nanoscale zones of dense cascades of atomic displacements (thermalized for a time of about 10^(-12) s) in metals depending on the grade and energy of the bombarding ions were conducted. Computer programs were developed: 1) HT-1D for calculation of heating curves of thin plane targets T(t) during their irradiation by ion beams on the basis of numerical solution of the one-dimensional equation of thermal conductivity in the conditions of heat removal only at the expense of thermal radiation; 2) KB-03 for calculation of profiles of alloying, and also electronic and nuclear losses of energy by inhibiting ions on the depth of the target on the basis of the solution of Boltzmann kinetic equations. The theoretical and experimental concentration profiles of impurities along the depth of the irradiated targets were obtained. The calculations used the above-mentioned program KB-03, as well as the program TRIM, based on the Monte Carlo method. The experimental distribution profiles of heavy ions of inert gases and chemically active ions N^+ and O^+ were measured by x-ray photoelectron spectroscopy. Comparative analysis of theoretical and experimental data showed their good agreement. The emission spectra of metal targets (Al, Ti, Fe, W, Zr and Ta) during their irradiation (in situ) with heavy inert gas ions Ar^+ and Xe^+ with energy in the range of 5-20 keV were measured. Visual and computer analysis of the measured luminescence spectra was carried out. The approximation of the visible band and the "tail" of the infrared band in the visible region by Planck curves of thermal radiation was performed. The position of the maximum of the visible band in nanometers (related to temperature by Wien’s displacement law) were defined the temperature of the areas of experimental atomic displacement cascades (thermal peaks thermal spikes). On the basis of experimentally measured values of temperatures of thermal peaks and data of numerical calculations by means of programs KB-03 and TRIM of the linear sizes of cascades thermal pressures in the thermalized areas of cascades of atomic displacements at irradiation by various ions for the specified pure metals were calculated. These pressures are in range from 5 to 40 GPa. The dependences of the peak values of temperature T(E, A) and pressure P(E, A) in the regions of thermal peaks for pure metals on the atomic mass and energy of ions were constructed. For the analysis of field ion images, a program has been created that allows to recognize the coordinates, geometric dimensions and brightness of images of individual atoms on the field ion microcharts, as well as to build the distribution functions of these parameters in order to identify and analyze the structure of radiation defects. The program was successfully tested in the analysis of atomic layers of pure platinum in the initial state and after ion irradiation. A study by field ion microscopy (FIM) with atomic resolution of radiation defects and radiation-induced processes under ion irradiation in pure platinum and Cu_3Au alloy was carried out. Including the study of structural features of the surviving defects in the nanoscale zones of explosive energy release (areas of dense cascades of atomic displacements-thermal spikes). Quantitative estimates of the size, shape and volume fraction of depleted zones in the near-surface layers of pure Pt and Cu_3Au alloy formed as a result of implantation of gas ions were obtained. Their comparison with the defects formed during the interaction of metals with neutron irradiation as a result of the collision stage and the stage of intra-cascade diffusion is carried out. Comparative analysis of the defect structure of the cascade areas in platinum, initiated by the irradiation by fast neutrons (E > 0.1 MeV) fluences F = 6,7*10^21 m^(-2), f = 3,5*10^22 m^(-2) and ion irradiation (Ar^+, E = 30 keV, F = 10^16 cm^(-2)) was allowed to establish its similarity (close to linear dimensions and structure of depleted zones – areas of the passage of dense cascades of atomic displacements). In platinum after irradiation with ions defects are observed at a depth of about 1.5-2 nm from the irradiated surface. By the FIM method it was established that during irradiation of pure platinum by beams of accelerated argon ions in certain modes: E=30 keV, j = 150 µA/cm^2 and 200 µA/cm^2, F = 10^16 and 10^17 cm^(-2), on the surface of the samples, as well as in the near-surface volume of platinum (in the layer up to 20 nm at F=10^17 cm^(-2)), nanoblocks of size 1-5 nm were formed. By increasing the fluence of argon ions to 10^18 cm^(-2), there is almost complete amorphization of the near-surface areas of platinum to a depth of ~ 12 nm. Separate amorphous region of the phases in the metal at a depth of not less than 60 nm were observed. The results of the work were reported at 7 International and Russian scientific conferences, as well as the results of research prepared and published the scientific articles.
EstadoTerminado
Data de início/fim efetiva01/01/201631/12/2018

GRNTI

  • 29.19.21

Type of Financial Sources

  • RFFI

UrFU Research Division section that handles this grant (Kuibyshev, Mira)

  • Mira Research Division

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