X-ray Diffraction is an analytical technique that utilizes an inherent property of the x-ray beam - the wavelength - and the laws of physics that determine how that beam interacts with matter to characterize materials. Classically, the technique has been applied primarily to well-ordered crystalline materials to determine crystal structures, identify phase composition, measure stress, preferred orientation and crystallinity, but the field also encompasses the characterization of non- or semi-crystalline materials via small angle x-ray scattering (SAXS). Scattering experiments at very small angles can study electron density structures in materials on size scales greater than the electron density contrast due to atomic ordering observed in diffraction from crystalline materials and can provide information on size, shape, and distribution of electron density contrasted domains in polymers, dilute suspensions, gels, emulsions and more. Diffuse scattering to wide angles can study atomic structure in non-crystalline materials.
MCL maintains multiple X-Ray Diffractometers.
Sample requirements vary widely with instrument and the analysis required. Please contact a technical staff member to discuss your needs.
All users of analytical x-ray systems at Penn State are required to complete x-ray safety training through Environmental Health and Safety (EHS) prior to receiving instrument training. For more information on these requirements, see the EHS web site. Equipment training is provided at the hourly rate for equipment and analyst. Group training is available and can reduce cost per student significantly. Contact a technical staff member for more information.
|PANalytical XPert Pro MPD||Cu||theta-theta||para-focusing/parallel beam||line||Reflection||PIXcel 1D||powder/bulk/thin film|
|PANalytical Empryean||Cu, Mo||theta-theta||para-focusing||line||Reflection||PIXcel 3D||powder/bulk|
|PANalytical X'Pert3 MRD||Cu||4-circle||high resolution/para-focusing/focusing lens||line/point||Reflection||(1) PIXcel 3D and (1) Mini-prop Xe||bulk/thin film|
|Rigaku DMAX-Rapid II||Cu, Mo||omega/phi rotation||microfocus collimation||point - microfocus||Reflection or Transmission||Curved image plate||powder/bulk/thin film/single crystal|
|XENOCS Xeuss 2.0* SAXS/WAXS||Cu||none||collimation||scatterless slits - point||Transmission and GIXRD||Dectris Pilatus 200K||polymers, nanoparticles, nanocomposites, etc.|
|Multiwire Laue||white||3-axis||collimation||point||Back-reflection||Multiwire area||single crystal|
*coming Jan/Feb 2017
SAXS uses Cu Ka X-ray scattering at very small angles to probe structure in zones of electron density contrast with sizes in the range of 1nm to 100nm. Such structures can include particulate systems, multi-phase systems, pore structures, emulsions, biological and cellular structures and others. Information about size, shape, dispersity, periodicity, interphase boundary area and solution properties can be obtained. Specimens may be solids, films, powders, liquids, gels, crystalline or amorphous. Applications in polymers and biological samples are abundant and well known.
Solids and films must be thin enough to be X-ray transparent and thick enough to present adequate sample volume in transmission. Estimates of nominal thickness are 1-2 mm for polymers and biological samples, 0.3 - 0.8 mm for ceramics, 0.05 - 0.2 mm for metals and alloys, 1 mm for water solutions and 1.5-2 mm for organic solvent solutions. The area required is as small as 1 mm2. The beam cross section is approximately 0.8 mm diameter.