Structure determination of small molecules and macromolecules

The XtaLAB R-AXIS series of single crystal diffractometers addresses a wide range of sample types, from small molecules to MOFs, to biological macromolecules. The key component that is common for this series of diffractometers is the use of an imaging plate (IP) detector. There are three standard detectors in the XtaLAB R-AXIS series. The R-AXIS IV++ is the most popular IP based diffractometer in the world for macromolecular crystallography and is based on two imaging plates. The R-AXIS RAPID is a very versatile diffractometer that employs a curved imaging plate and partial χ goniometer and is mainly used in small molecule crystallography, charge density studies, powder diffraction and micro-diffraction.

Why the IP detector?

IP technology has been used to measure diffraction data since the 1980’s. It continues to be popular because inexpensive apertures can be made very large relative to electronic detectors and the detectors can be curved so that the capture angle of diffraction is increased. In addition, IP detectors have no electronic dark current and the high dynamic range allows strong and weak reflections to be measured accurately simultaneously. Although IP and electronic detectors are both very reliable, IP detectors have the advantage that they are mechanical and thus field serviceable.

X-ray Sources

While the IP detector is the common element of the XtaLAB R-AXIS series, the selection of X-ray sources is quite diverse and allows one to select an X-ray source configuration based on the radiation type or types as well as the level of flux desired. The most common configuration for the XtaLAB R-AXIS series would be the R-AXIS IV++ with a MicroMax-007HF microfocus rotating anode. For research groups that require higher flux, the FR-X microfocus rotating anode generator provides the highest flux at the sample of any currently available rotating anode. The R-AXIS RAPID can be configured with a MicroMax-007 dual wavelength generator giving the researcher the ability to switch between wavelengths, such as Cu and Mo, without having to move the crystal. All XtaLAB R-AXIS systems can also be configured with either microfocus sealed tube X-ray sources or standard sealed tube X-ray sources.