A general approach in multilayer optical system design for SAXS

An approach to using multilayer optics for SAXS is discussed. The approach consists of employing a two-dimensional multilayer focusing optic to monochromatize and intensify the x-ray beam, and a pinhole system to further shape the beam. Depending on the sample scattering power, different pinhole systems can be used. With a two-pinhole system, high flux can be achieved but with nonblocked parasitic scattering from the pinholes and scattering from multilayer reflectors. With a three-pinhole system, parasitic scattering and scattering from multilayer are completely shielded beyond certain angular range for weak scattering samples. Using ray-tracing method, the performances of the proposed systems are compared to the most commonly used graphite-pinhole system and found to provide a factor 10 more flux for similar resolution and background requirements.