Detecting X-ray refraction in weakly absorbing thin films of beryllium and carbon

Features of X-ray refraction (XR) in thin, weakly absorbing films of beryllium and carbon are considered for radiation with a wavelength of λ ～ 0.1 nm incident at a small grazing angle. It is established that an interference modulation of the angular diagram of XR appears due to the elastic wave scattering on defects of the film surface and the subsequent specular reflection from the film-substrate interface. The proposed experimental scheme of XR observation and the corresponding calculation model ensure determination of the film thickness at the sample edge to within ～1%.