X-Ray Diffractometer (XRD)

This instrument is used to characterize materials in terms of internal dimensions that are roughly the size of a chemical bond (Ångstrom scale) by means of X-Ray diffraction.

Typical samples are powders* and thin films on substrates such as silicon wafers.  This is NOT a tool for solving crystallographic structures.

*Here a powder means a sample that is not a single crystal, but is made up of crys-tallites (microscopic crystals) oriented randomly in all possible directions.

Manufacturer: Bruker DB-Discover

  • Powder X-ray Diffraction (XRD)
  • Variable Temperature XRD (-100 C to +350 C)
  • High-Resolution XRD (HR-XRD)
  • Pole Figures
  • Reciprocal Space Mapping (RSM)
  • X-Ray Reflection (XRR)
  • Out-of-plane Grazing Incidence (OOP-GID)

The instrument has a Theta/2-Theta configuration, meaning that for standard powder XRD measurements the X-Ray source remains stationary while the detector is rotated though the full scattering angle (2-Theta) and the sample is rotated though half of the scattering angle (Theta). The main Theta/2Theta goniometer is sits horizontally, meaning that rotation is like a photograph record.  Samples sit vertically.

The instrument uses a “Parallel Beam” geometry in which the X-ray beam is fo-cused to a line by means of a Göbel mirror.  Bragg-Brentano geometry is not availa-ble. The detector is a single-pixel Thalium-doped sodium-iodide [NaI(Tl)] scintilla-tion detector. There is an in-line attenuator that can dynamically limit the intensity of the X-ray beam during a scan to protect the detector and prevent it from satu-rating.

The sample is held in a “Eulerian Cradle” that sits atop the Theta drive. The cradle has additional motorized drives for Phi, Chi, X, Y, and Y. The Z-drive moves the sample along an axis at 90-degrees to the X-ray beam, and is used to align the face of the same with the center of the x-ray beam. The Phi and Chi drives rotate the sample and are used for Pole Figures.  The instrument has an additional drive that can make small rotations of the X-ray source centered on the sample. This drive is used for In-plane Grazing Incidence (IP-GID) measurements.

Additional hardware:

  • Vacuum chuck (5 inch diameter) to hold wafer samples.
  • Heated and cooled sample stage (Anton-Parr DCS-350)
  • Incident-beam monochromator: 4-bounce germanium assymetric
  • Diffracted-beam monochromator: Bruker “Pathfinder.” This optic can switch be-tween a 3-bounce germanium monochromator and slit collimation under computer control.  
  • Bruker “Parallel Beam Attachment” – a diffracted-beam optic consisting of a sin-gle large Soller slit with plates oriented vertically, i.e., parallel to the collimating slit.
Equipment Rates & Fees
 RPI UsersExternal NonprofitExternal IndustryExternal Industry Partners
Night-Flat Rate*$350$576$1152$1037
 RPI UsersExternal NonprofitExternal IndustryExternal Industry Partners
Personnel Time$70$115$230$207

Valid through July 31, 2024. Rates are hourly unless specified otherwise and are subject to change without further notice.

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