Measurement of the isotope composition of hydrogen in carbon materials using elastically scattered electron peak spectroscopy

The quantitative composition of hydrogen and helium isotopes in the surface layers of structural materials is reconstructed using the developed technique for processing the energy spectra of electrons scattered from plane-parallel layers of solids into a preset solid angle element. These are the spectra measured with a high energy resolution $\Delta E\simeq$ 0.2–0.4 eV. The change in the shape of peaks for elastically scattered electrons is analyzed depending on the probe electron beam energy and experimental geometry. The theory of electrons scattered from plane-parallel layers of solids is constructed using the solution of the boundary value problem for the transfer equation by invariant immersion methods. The analytic solution to the system of equations is found in the small-angle approximation for the reflection and transmission functions. The results of calculations are compared with experimental data on electron scattering from polyethylene. The shape of the energy spectra of electron scattering from deuterium and tritium is predicted. The sensitivity threshold of the method relative to percentage concentration of hydrogen isotopes in hydrocarbons is analyzed.