A review of X-ray intensity fluctuation spectroscopy

This article reviews the literature on X-ray intensity fluctuation spectroscopy (XIFS) or, as it is often called, X-ray photon correlation spectroscopy. It highlights measurements using different types of diffuse scattering. It is shown that XIFS is ideally suited to study the relationship between kinetics and structure and this gives insight into the type of measurements where XIFS can play an important role. Obvious examples are systems that have a microstructure, heterogeneous materials, polymers, non-Newtonian fluids, colloids and other systems where one expects kinetic to be different on different length scales. XIFS is in the process of becoming a routine tool in the growing toolbox of diffraction techniques. Synchrotrons around the world are designing beamlines dedicated to this technique