X-Ray Microprobe, Spectroscopy & Microtomography

Overview – XAFS / XANES

X-ray absorption fine structure (XAFS) probes the local atomic and chemical environment of a selected atomic species. By analyzing the modulations in the absorption coefficient at energies just above the x-ray absorption edge threshold, XAFS measurements give quantitative information about coordination species, number and distance. The x-ray absorption near-edge spectra (XANES) are also sensitive to the valence state of the probe atom.

Principal Techniques

  • Near edge XANES
  • Extended x-ray absorption (EXAFS)
  • Grazing incidence XAFS
  • Quick – XAFS

XAFS Experiments

  • Speciation of metals in soils, sediments and organisms
  • Grazing incidence studies of cations and anions on surfaces (model systems and natural crystallites)
  • Time-resolved studies of reactions on surfaces and interfaces
  • High temperature studies (trace elements in melts)
  • Oxidation states of planetary materials

Overview – X-ray Microprobe

Microprobe Characteristics

  • Microfocused undulator radiation (KB Mirrors)
  • High-resolution fluorescence detection
  • Micro-XAFS

Microprobe Experiments

  • Compositions of buried components (fluid inclusions)
  • Trace element partitioning in natural and experimental samples
  • Compositional mapping (diffusion, zonation)
  • Sector zoning in minerals
  • Compositions of mocroparticles (soils, micrometeorites, aerosols)
  • Oxidation state mapping (microXAFS)

X-Ray Microprobe, Spectroscopy & Microtomography Contacts

 

Matt Newville

Beamline Scientist
University of Chicago Research Associate Professor
X-ray Absorption Fine Structure (XAFS)
Microprobe
(630) 252-0431
newville@cars.uchicago.edu

Tony Lanzirotti

Beamline Scientist
University of Chicago Research Associate Professor
Microprobe
(630) 252-0433
lanzirotti@uchicago.edu

Steve Sutton

Co-Director GSECARS
Beamline Scientist
University of Chicago Research Professor
Microprobe
(630) 252-0426
sutton@cars.uchicago.edu

Links for Additional Information

 

  • Beamline Manual
  • XAFS.org
    XAFS.org is a community site for x-ray absorption fine-structure (XAFS) and related spectroscopies.
  • EnviroSync
    EnviroSync is an organization of environmental science users of synchrotron radiation facilities.
  • IUCr Commission on XAFS
    This organization promotes the development and acceptance of XAFS standards, works ot increase the interaction among XAFS reseaqrchers and promotes the improvement of the XAFS experimental facilities at synchrotron sources.
  • Lunar and Planetary Institute
    The Lunar and Planetary Institute is a research institute that provides support services to NASA and the planetary science community