X-Ray Diffraction

The Bruker AXS X-Ray Diffractometer

Dr. Hinthorne Explains How the X-Ray Diffractometer Works

"The X-Ray Diffractometer works by generating x-rays in this x-ray tube on the left side and collimating them into a parallel beam to impinge on the sample in the center of the chamber.  We have a camera with a laser attachment for vertical adjustment and horizontal positioning of our sample in the center of the x-ray beam.  The diffracted x-rays, that is, the ones that are reflected at particular angles off the crystalline substance we use for a sample, are detected by the moving arm and detector on the right-hand side of the unit and displayed on the computer screen as what's called an x-ray diffraction pattern.  Data processing on the diffraction pattern will extract the peaks from the background and compare them to a database of peaks for identification of the sample material."   -Dr. Hinthorne      

Student Researcher Thomas Mion Loads an Unknown Sample

The computer screen on the left depicts the diffraction pattern from the sample that was loaded by Thomas.  The height of the peak represents the relative intensity of the diffracted x-rays.  The position of the peak on the horizontal scale represents the angle of the x-ray diffracting from the sample material.  The combination of these intensities and angles are what make up a diffraction pattern, unique to a given material.

The diffraction pattern is processed through EVA, a data evaluation program.  As shown on the right-hand computer screen, the program searches through a database of all known minerals and inorganic compounds to find the matching diffraction pattern and thus identify the sample material.  X-ray diffraction may also be used to characterize the atomic-scale structure of an already identified crystalline substance.