Powder X-ray Diffraction (PXRD) Analysis

Powder X-ray Diffraction (PXRD) Analysis

Instrumentation

The Department currently houses a Philips X’Pert MPD powder X-ray diffractometer in Cramer Hall. The instrument is capable of relatively quick, non-destructive analysis of crystalline samples.

PXRD Applications

Powder X-ray Diffraction (PXRD) is an analytical technique used to determine the following characteristics of crystalline materials:

  • phase identity
  • crystal structure
  • approximate percentage phase composition
  • lattice parameters

The samples must be homogeneous to provide proper resolution, which typically necessitates the conversion of a small amount of sample into a fine powder; at least 5g of sample are recommended for submission to PXRD analysis. The samples are exposed to X-ray radiation over a wide range of incident angles; the crystalline sample diffracts this radiation, and a detector receives the diffracted radiation and registers either constructive or destructive interferences between signals. Each distinct crystal system has a unique collection of diffractions; these patterns (diffractograms) serve as a mineral’s fingerprint and can be used to properly identify individual crystal phases within a sample, as well as the approximate contribution from each phase (percent composition).

Prospective Users

Please contact Alexandra Franco (afranc2@pdx.edu) with the Geology Department for more information or to schedule an appointment to run an analysis. All samples submitted must be crystalline solids capable of being powdered, and all users are required to complete any necessary X-ray radiation safety training prior to analysis.