Review: Pair distribution functions from neutron total scattering for the study of local structure in disordered materials

With the development of pulsed spallation sources of neutrons in recent years has come the possibility to generate intense beams of higher energy than possible at reactor sources. This has enabled neutron total scattering methods to develop significantly for studies across a wide range of application areas. In this article we will review the background theory for analysis of total scattering in terms of the pair distribution function, we will review modern facilities and instrumentation, we will describe a range of analysis methods, and finally we will present a number of examples of recent work that illustrate many of the ideas discussed here.