X-ray Diffraction
Featured Equipment
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The X-Ray Diffraction SEF contains a suite of 8 diffractometers for analysis of polycrystalline, single crystal, thin film, polymer, and nanostructured samples.
*For more information about the X-Ray facility, please click here*
Personnel
Dr. Scott A Speakman, Research Specialist
Office: 13-4009A
Phone: (617)253-6887
Fax: (617)258-6478
E-mail: speakman@mit.edu
Location:
Building 13, Rooms 4027, 4040, 4041 (4th floor)
Instruments available:
Rigaku Powder Diffractometers
Fast, precision XRPD is facilitated by a high-powered rotating anode generator that supplies a high flux of X-rays to two different horizontal-circle powder diffractometers: 185mm Bragg-Brentano diffractometer is optimized for high intensity for fast data collection; 250mm Bragg-Brentano diffractometer is optimized for high resolution at slightly slower data collection speeds. Sample size is generally 20mm x 10mm x 0.3mm, though we have a variety of sample holders and mounting procedures to accommodate varied sample geometries.
Bruker D8 Multipurpose Diffractometer
Permits simultaneous collection of diffraction data over a 2theta range as large as 30° and a chi (tilt) range as large as 30°. Combines a Eularian cradle, which permits many unique tilts and rotations of the sample, with a very fast two-dimensional area detector. This configuration makes this instrument ideal for texture and stress measurements, as well as traditional XRPD and limited SCD and GIXD. A selectable collimator, which conditions the X-ray beam to a spot with a size from 0.5mm to 0.05mm diameter, combined with a motorized xy stage stage permits microdiffraction for multiple select areas of a sample or mapping across a sample's surface.
Samples can include thin films on wafers or dense pieces up to 6" in diameter (maximum thickness of 3 mm), powders in top-loaded sample holders or in capillaries, dense pieces up to 60mm x 50mm x 15mm (and maybe even larger).
PANalytical Multipurpose Diffractometer
This diffractometer can be used to collect XRPD, GIXD, XRR, and residual stress data. Some texture analysis is also possible. Sample sizes may be as large as 60mm diameter by 3-12mm thick, though a more typical sample size is 10-20mm diameter. Data collection modes can be changed between high-speed high-resolution divergent beam diffraction and parallel beam diffraction.
Bruker Single Crystal Diffractometer
This diffractometer uses a two-dimensional CCD detector for fast, high precision transmission Laue diffraction through small single crystals. Designed primarily to determine the crystal structure of single crystals, this diffractometer can also be used for determining crystal orientation. A cryostat is available to cool samples down to 100 K in air, which permits more precise determination of atom positions in large organic crystals.
Back Reflection Laue Diffractometer
This system uses either Polaroid film or a two-dimensional multiwire detector to collect back-reflection Laue patterns to determine the orientation of large single crystals and thin film single crystal substrates.
Bede Triple Axis Diffractometer
This instrument uses a high precision Bede D3 goniometer combined with a powerful rotating anode generator and several beam-condition analyzer crystals for high precision GIXD analyses of thin films and semiconductors. Typically used to measure the perfection or imperfection of the crystal lattice in thin films (i.e. rocking curves), the misalignment between film and substrate in epitaxial films, and reciprocal space mapping. This diffractometer could also be used, theoretically, for high precision XRR.
Bruker Small Angle Diffractometer
Used for SAXS, this diffractometer combines a high-power rotating anode with a two-dimensional detector and a long X-ray beam path to measure X-rays that are only slightly scattered away from the incident beam. The two-dimensional detector allows entire Debye rings to be collected and observed in real time. The current beam path length of 60.4 cm allows the resolution of crystallographic and structural features on a length scale from 1.8nm to 40nm (1.8nm is near the maximum resolvable length scale for XRPD in our other systems). A heater is available to heat the sample up to 200°C.
Data Analysis Software:
A variety of commercial and public domain software is available for data analysis.
The most commonly used software includes:
ICDD PDF Database
A database of over 270,000 powder diffraction patterns that can be used for phase identification and for data mining. Accessible through Jade, DiffracPlus, and HighScore Plus.
MDI Jade
- phase identification
- peak location and profiling
- indexing and refinement of unit cell lattice parameters
- size-strain analysis of peak broadening
- whole pattern refinement
- crystal structure visualization
PANalytical X'Pert HighScore Plus
- phase identification
- peak location and profiling
- indexing and refinement of unit cell lattice parameters
- whole pattern and Rietveld refinement to determine
- crystal structure
- quantitative phase analysis
- size-strain analysis
- percent crystallinity
- crystal structure visualization
- Fourier maps
- data cluster analysis
PANalytical X'Pert Data Suite
- residual stress analysis
- XRR simulation and refinement
- pole figure and texture analysis
Bruker DiffracPlus/EVA
- phase identification
- peak location
Bruker TOPAS
- whole pattern and Rietveld refinement
Bruker Shelxtl
- single crystal diffraction crystal structure refinement
Bruker GADDS and SAXS
- analysis of 2D detector data for XPRD or SAXS
- residual stress
POPLA
- texture and pole figures
GSAS
- Rietveld refinement of powder and single crystal diffraction data
PowderCell
- crystal structure visualization
- XRPD data simulation
Orient Express
- determines crystal orientation for Laue patterns
