Biological Crystallography with Cu-K_α

Single crystals of macromolecules and proteins are usually very small and show only poor diffraction thus making the determination of such crystal structures a challenging task. In general, the interaction of electromagnetic radiation with matter increases with the wavelength (approximately by the power of three). The use of Cu-K_α radiation, therefore, results in a more efficient diffraction ? compared to e.g. Mo-K_α or Ag-K_α ? and leads to a reasonable atomic and spatial resolution of the diffraction pattern. This is indispensable in particular for crystal structures with long cell axes.

During the last ten years, the introduction of multilayer mirrors, such as the Montel 200 mirrors, has lead to a dramatic increase in the number of crystals structures solved with home laboratory equipment. The combination of a traditional rotating anode generator with a Montel 200 multilayer mirror has been the state-of-the-art X-ray source in many protein crystallography labs.

Helios mirrors	IµS for Cu-radiation