Multilayer monochromators for neutron scattering

In an earlier paper Schoenborn et al. reported the fabrication of thin-film monochromators for neutrons. They showed that a multilayer consisting of alternating films of two materials acts as a good monochromator with large and adjustable periodicity and wide bandwidth. The technique of making these multilayers has been modified with a resultant improvement in their reflectivity and diffraction properties. A detailed study of the multilayers has shown that they can be used as monochromators with unique properties. The reflectivities of such monochromators are comparable with those of pyrolytic graphite crystals, and they have low high-order contamination. The multilayers may also be used as efficient polarizers and filters of neutrons. Both kinematical and dynamical approaches have been developed in order to understand the diffraction properties of these multilayers. The influence of some aperiodicity on the diffraction data has also been introduced within the framework of kinematical theory