X-ray diffraction

Our X-ray diffraction lab now has three diffractometers (two pictured below), a Siemens D5000 (left) a Panalytical X-pert Pro (right), and a new D8 Advance which we are setting up currently, each instrument has its own associated Bruker or Panalytical software.

                    

The Siemens D5000 diffractometer is a theta/theta powder diffractometer.  This means that the both the X-ray source and the X-ray detector move. The D5000 is equipped with a 40 position automatic sample changer and is fitted with a cobalt X-ray tube.  It is sometimes advantageous to use cobalt radiation when examining samples rich in iron to avoid the strong fluorescence that arises from the more common copper radiation. The longer wavelength of cobalt radiation can also be useful if trying to measure or observe very low angle reflections that may arise from some clay minerals. 

The Panalytical Xpert Pro diffractometer has a variety of interchangeable stages and optics.  These include an Anton Par XRK 900 reaction chamber which is used for controlled humidity experiments and non-ambient diffraction at temperatures up to 900°C and a capillary stage that is used with an incident beam monochromator.  This instrument is fitted with a copper X-ray tube.

The detector on the D5000 is a scintillation detector, whereas the Xpert Pro uses an X-celerator position sensitive detector capable of very rapid data acquisition.

 

Once collected diffraction data may be processed and analysed using a variety of software, including Bruker's Diffrac Plus Eva, and Panalytical's X-pert Highscore.  In addition we have the latest versions of the International Centre for Diffraction (ICDD) databases, including the PDF-4 inorganic and PDF-4 organic databases that are used for identification of unknowns.

Bruker's Topas program and Sietronics Siroquant both of which can be used to make quantitative analyses of powder diffraction data are also available.