Two-dimensional intensity profiles of effective satellites

The observation of a new X-ray scattering process with synchrotron radiation is reported. The phenomenon is analogous to three-beam diffraction in a single crystal; however, the features in the azimuthal scans are provided by superlattice-satellite reflections instead of bulk reflections. These features were named effective satellites and they are observed over the ordinary satellite reflections as a function of the azimuthal angle. Their occurrences have been monitored in completely different superlattices by mapping the incidence and azimuthal angles of the incident X-ray beam. Effects of structural parameters of the superlattices on the effective satellites as well as the information that can be extracted by measuring their positions are discussed.