X-ray scattering – the basics

Manfred Roessle

Scattering on macromolecules is a standard technique for non or less ordered systems, such as particles in solution, gels, lipid layers and fibers. The basic physical principle of the scattering process is common in all these materials, however the information content of the recorded scattering data is different. In small angle X-ray scattering (SAXS) scattering intensities a very small angle of a few degrees are recorded and a resolution of ~1 nm can be achieved. In biological solution SAXS determines the structure of macromolecules (e.g. proteins) in terms of average particle size and shape. Information about the overall protein envelope, the folding state and the protein volume can be analyzed already directly from the initial scattering data. SAXS stations at synchrotrons are the most powerful devices for scattering experiments, although X-ray tube based devices are advancing and comparable results to synchrotron data are obtained.

In this lecture the scattering process of X-rays on atoms is discussed. The focus will be on the special case of particles in solution, but biological systems such as lipids are presented as well. The technical aspects of X-ray production and X-ray optics will be introduced, explaining the devices and parts of a SAXS station. SAXS on X-ray tube-based lab sources are presented as an option. The basics of standard X-ray data recording are discussed.

Date/time: Wednesday, 17 October 2012, 9:30