X-Ray Diffraction Methods

X-Ray Powder Diffractometer (XRD)

The determination of angles and intensities produced by diffraction of X-Ray radiation by mineral lattices provides information, which is characteristic for their crystalline structures. X-Ray powder diffraction is used by for identification, quantitative phase analysis and structure refinement of phases in synthesized powders. Most diffraction data is processed by the Rietveld method using the GSAS software package.
The lab includes two STOE Stadi P diffractometer equipped with a curved Germanium (111) primary monochromator yielding a convergent primary beam of Kα1 radiation and a high resolution MYTHEN-detector. The typical sample size we use is around 1 mg.

Laue X-ray diffraction crystal orientation system

The precise characterization of the non-isotropic physical properties of crystalline geomaterials requires a precise knowledge of the orientation of samples used to perform experimental studies. The orientation of individual crystals can be obtained by Laue X-ray diffraction, a well-established technique that allows a precise determination of the orientation matrix of the crystal under investigation. The X-ray diffraction lab hosts a vertical Laue backscattering X-ray diffraction orientation system (by Photonic Science) that allows to determine the orientation of crystals down to sizes of the order of 200 microns. Our system uses a white beam with an energy range between 5 and 50 keV. The beam is focused to 200 microns beam spot, a CCD detector with wide active area (155 x 105 mm²) and high resolution (2500 x 1650 pixels). The sample positioning system is a completely automated XYZ stage. The system has also a dedicated analysis software to refine crystal orientation. The system allows to refine orientations with a resolution better than 0.1 degrees and accuracy of 0.1 degrees (tested on standard materials).