Investigation of the properties of Bragg-Fresnel gratings

摘要

Systematic experimental investigations of Bragg-Fresnel gratings are discussed. Gold and nickel masks with periods of 0.4 μm n 5 μm were evaporated on the surfaces of Si [111] symmetric and asymmetric crystals. These have been used to obtain x-ray diffraction in the energy range of 8000 eV n 8500 eV. A theoretically calculated maximum of diffraction efficiency of the order of 30 % was measured experimentally for gratings with grooves parallel to the beam direction (sagittal gratings). Diffraction effects in the crystalline substrate for the gratings with grooves perpendicular to the beam direction (meridional gratings) limit the diffraction efficiency on the order of a few percent. Experimental data are compared with the theoretical calculations dispersion and efficiency of Bragg-Fresnel gratings.