The Synchrotron Radiation Research Section is located at the Argonne National Laboratory near Chicago, Illinois. The aim of the research within this Section is to utilize the unique properties of the X-ray radiation generated at synchrotron storage rings-in particular, at the Southeast Regional Collaborative Access Team (SERCAT) beamlines of the Advanced Photon Source (APS). The two most important characteristics of synchrotron radiation are the high intensity of the X-ray beam and the tunability of the wavelength; both of these properties are utilized in the research investigations within the Section. The SERCAT beamlines (based on the undulator and the bending magnet) are easily tunable within the wavelength range from beyond the bromine absorption edge to long wavelengths, and successful MAD experiments have been performed on such anomalous scatterers as bromine, selenium, mercury, platinum, zinc, holmium, and iron. Several atomic-resolution diffraction data sets extending to about 1 Å have been collected and used for precise model refinements.

In addition to conducting research investigations, the Section personnel provide technological and scientific support for NIH researchers collecting diffraction data at APS. The NIH Intramural Synchrotron Consortium of macromolecular crystallographers is a part of SERCAT and uses about 20% of the total available time at SERCAT beamlines. Collecting diffraction data at the synchrotron beamline involves a very high level of technology-but it is a scientific process, not a technicality. Therefore, a proper selection of all the necessary parameters can be done only if based on scientific considerations.