Undulator radiation is the X-ray source of choice for modern macromolecular crystallography beamlines. Here, the basic properties of undulator sources are described and it is indicated why they make such good X-ray sources for macromolecular crystallography. Collection of excellent data from these beamlines is not always straightforward; therefore, a number of rules are postulated for undulator data collection and guidelines are offered which will help to ensure a satisfactory experiment.
Flot, D., Gordon, E. J., Hall, D. R., Leonard, G. A., McCarthy, A., McCarthy, J., … Shepard, W. (2006). The care and nurture of undulator data sets. In Acta Crystallographica Section D: Biological Crystallography (Vol. 62, pp. 65–71). https://doi.org/10.1107/S0907444905032646