In a dedicated SAXS instrument the distance from sample to the detector is longer to increase angular resolution.
Most diffractometers can be used to perform both WAXS and limited SAXS in a single run (small- and wide-angle scattering, SWAXS) by adding a beamstop/knife edge.
As with other diffraction methods, the sample is scanned in a wide-angle X-ray goniometer, and the scattering intensity is plotted as a function of the 2θ angle.
A crystalline solid consists of regularly spaced atoms (electrons) that can be described by imaginary planes.
The intensity of the d-space pattern is directly proportional to the number of electrons (atoms) in the imaginary planes.