Resolution functions of powder diffractometers at a synchrotron-radiation source

The resolution functions for various powder diffractometers using parallel-beam geometry are calculated. These diffractometers consist of monochromator, sample and eventually a post-specimen analyser. The theory is thus similar to that of two- or three-axis diffractometers. Special attention has to be given to the different diffraction mechanisms occurring at perfect crystals, synthetic multilayers or mosaic crystals. Resolution functions for all three types of monochromators are presented. Experiments performed at HASYLAB and other laboratories show good agreement with theory.