Applications and Specifics of SAXS

This chapter is devoted to the powerful method of small-angle x-ray scattering (SAXS) and also discusses wide-angle x-ray scattering (WAXS) in the context of simultaneous SAXS/WAXS measurements. It begins with the description of the production of x-rays in laboratory instruments and at synchrotrons. Next, the chapter then describes the scattering processes for x-rays, including Thomson scattering, Compton scattering, and polarization-dependent scattering, with a particular focus on the elastic coherent scattering cross-section relevant to small-angle scattering. Atomic scattering factors for x-rays are then described. The important subject of solution SAXS from biomacromolecules, so-called BioSAXS, is outlined in some detail, in the context of individual proteins. The chapter is concerned with solution SAXS from multidomain and flexible macromolecules. It provides a brief resume of SAXS (and WAXS) studies on soft matter and a nonexhaustive set of examples. The chapter also describes the main features of SAXS/WAXS studies on crystalline polymers.