Determination of particle size and shape

The characterization of shape and size distribution of nanoparticle suspensions is a traditional area where SAXS excels. Although the primary results of a scattering experiments are indirect and difficult to interpret, they have a few advantages over more direct approaches such as electron microscopy:

statistical significance

when analyzing electron micrographs, results are typically obtained from a few hundreds or thousands of particle images. In a SAXS pattern every particle inside the illuminated sample volume (a few mm³s) gives a contribution, this is typically on the order of 10⁹ particles.

free from operator bias

all particles are counted in the illuminated sample volume. Additionally, the boundary of the particle (where the particle ends and where the solvent begins) is drawn “automatically” by the X-rays. Whereas in imaging techniques, the user or the algorithm needs to make a choice.