EFFICIENCY MEASUREMENTS AT MO SI MULTILAYER GRATINGS AND COMPARISON WITH THE MODEL OF RADIATING DIPOLES/

Diffraction efficiencies of three different laminar multilayer grating s (333 lines/mm) were measured in the soft X-ray region with photon en ergies between 30 and 350 eV. The measurements are compared with calcu lations using a model based on a reasonable assumption for the electri c field in the modulated area of the grating and applying the Ewald-Os een theorem. The gratings differ in the line-width to groove-width rat io. The grating profiles have been characterized accurately by atomic force microscopy measurements. Moving sample and detector according to the grating equation provides continuous efficiency mapping for the d ifferent diffraction orders. These results display structures from whi ch all the important parameters of the gratings can be deduced.