Apparatus for X-ray diffraction microscopy and tomography of cryo specimens

An apparatus for diffraction microscopy of biological and materials science specimens is described. In this system, a coherent soft X-ray beam is selected with a pinhole, and the illuminated specimen is followed by an adjustable beamstop and CCD camera to record diffraction data from non-crystalline specimens. In addition, a Fresnel zone plate can be inserted to allow for direct imaging. The system makes use of a cryogenic specimen holder with cryotransfer capabilities to allow frozen hydrated specimens to be loaded. The specimen can be tilted over a range of ±80∘ for three-dimensional imaging; this is done by computer-controlled motors, enabling automated alignment of the specimen through a tilt series. The system is now in use for experiments in soft X-ray diffraction microscopy.