COMPARATIVE-STUDY OF ROUGH SUBSTRATES FOR X-RAY MIRRORS BY THE METHODS OF X-RAY REFLECTIVITY AND SCANNING PROBE MICROSCOPY

The relation between the root-mean-square heights of rough quartz subs trates determined from the X-ray reflectivity and scanning probe micro scopy data has been studied. The underestimated values of the roughnes s parameter sigma obtained from X-ray reflectivity data are explained by the presence of relatively narrow high peaks of roughness relief ag ainst the background of lower uniformly distributed peaks. The scannin g probe microscope data are used for the experimental verification of the well-known theoretical statement that a decrease of reflectivity o f the rough surface is independent of its fractal dimension.