Non-Destructive Determination of Qualitative and Quantitative Parameters of Coatings Based on Reflected Electron Spectroscopy

The most important condition for the stable operation of controlled thermonuclear fusion facilities is solving the "first wall" problems, which include the analysis of the interaction between thermonuclear plasma and in-vessel materials. Within this framework, the most pressing issue is the analysis of depth profiles of structural materials interacting with the plasma. This task is related to the fact that to reduce the average atomic number of the elements entering the plasma discharge, coatings made of low atomic number materials, such as lithium and boron, are used on plasma-facing components. This work presents a methodology for reflected electron spectroscopy that enables the depth profile analysis of targets with complex composition based on the interpretation of differential energy and angle spectra of reflected electrons. A method for calculating the energy spectra of electrons reflected from multi-component heterogeneous targets is introduced, based on the method of partial intensities, which has been repeatedly tested in numerous studies. Path length distribution function, which is the basis for the method of partial intensities and previously determined only within the framework of Monte Carlo simulations, has been established within an analytical approach. It is noted that to identify the depth profile of the distribution of components in the investigated target, a fitting procedure is employed, which is based on repeatedly solving the forward problem of calculating spectra of electrons reflected from a target of complex composition. A good agreement between the calculations and experimental results has been demonstrated. The simplicity of the experimental implementation of the reflected electron spectroscopy method is emphasized, as it does not require high-energy resolution equipment, since information about the target is extracted from the dome part of the reflected electron spectrum.

energy spectra of reflected electrons, boronization of the first wall, deuterium implantation in beryllium