Surface correlation function analysis of high resolution scattering data from mirrored surfaces obtained using a triple-axis X-ray diffractometer

Within various X-ray programs there exists a need for a detailed investigation of the surface roughness of mirrored surfaces over a wide spatial wavelength bandwidth, ranging from large scale figure error to microroughness. A number of methods exist to measure the surface roughness. Common to all methods is that they are bandwidth-limited. A crucial point in the analysis of data is, therefore, to specify accurately the wavelength bandwidth limitation and to determine the surface autocorrelation function within this bandwidth. The authors present a number of scattering measurements obtained using a triple-axis perfect-crystal X-ray diffractometer and the results of an autocorrelation function analysis. Furthermore, they present some measurements of integrated reflectivity, which they believe provide evidence for microroughness in the range from a few angstroms to tens of microns