ENERGY-DISPERSIVE METHOD USED FOR NON-SPECULAR X-RAY-SCATTERING FROM MULTILAYER STRUCTURE

The Energy Dispersive method (EDM) is used to study the non-specular diffraction of X-rays by multilayers. The EDM experimental results obtained are compared with those obtained on the same multilayer with the classical Angular Dispersive method (ADM). The ADM is performed with monochromatic X-rays, so that it is necessary to rotate sample or detector in order to obtain the non-specular intensity distribution. Monochromatic X-rays are an advantage to interpret the results because the absorption coefficient and the index of refraction are constant parameters for the used wavelength. The EDM uses the continuum spectrum of an X-ray tube and the scattered photons spectral distribution is analysed with a Si(Li) detector. The multilayer absorption and refractive index change with the energy, but the advantage is that no instrument motion is required and measurements are made easier by a simultaneous registration for all energies. The complementarity of both methods is briefly discussed.