Determination of the Relative Concentration of Deuterium Implanted into Beryllium by Elastic Peak Electron Spectroscopy

Abstract

The relative concentration of deuterium implanted into a beryllium sample is determined by elastic peak electron spectroscopy (EPES). The method of partial intensities based on solution of the boundary value problem for the transport equation by the invariant embedding method is used for subsequent determination of the energy spectra of reflected electrons. The differential inverse inelastic mean free paths (DIIMFPs) and the differential surface excitation probability (DSEP) are retrieved using a fitting procedure based on numerous solutions of the direct problem with fitting parameters. The high efficiency of the fitting procedure is based on the technique of numerical solution of equations for the partial intensities, which combines precision and a record-high calculation speed. In the work DIIMFP and DSEP are obtained for both the surface region and for a homogeneous array in the bulk. Calculations of DIIMFP and DSEP are carried out for pure beryllium and for beryllium samples implanted with deuterium. The relative concentrations of deuterium into beryllium were determined at a different fluence. The obtained values of the relative deuterium concentrations are n_D/n_Be = 0.12 ± 0.02 and 0.15 ± 0.03 for an irradiation dose of 5.5 × 10²¹ and 20.1 × 10²¹ m^–2, respectively. The results indicate that, in comparison with the methods used earlier, the developed method allows an order of magnitude in of the sensitivity of determining the relative hydrogen-isotope concentration in compounds to be attained.