Diffraction Program

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Overview

Synchrotron x-ray sources have revolutionized x-ray methods for structural characterization of materials of all types. The APS will enable measurements on samples of Earth-relevant materials, an extremely important capability for studies of minute run-products from high pressure devices, such as diamond anvil cells. Additional new opportunities will include the study of specimens containing a large proportion of defects, the use of anomalous scattering techniques on powder samples with Rietveld methods, structural characterization of mineral surfaces, and measurement of rapid structural changes via time-dependent scattering methods.

Principal Techniques

l Powder diffraction
l Micro-crystal diffraction
l Differential anomalous scattering
l Diffraction anomalous fine structure
l Surface scattering
l Standing waves

Experiments

l Identification of minerals in complex earth materials
l Structural determination on microcrystals
l Real time studies of sorption/desorption processes
l Diffraction from mineral interfaces
l Chemical speciation of atoms in specific lattice sites
l Microcrystal structures under extreme conditions (P,T)
l Structures of melts and glasses

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GSECARS beamline scientist Peter Eng explains (his baby) the recently installed 13 ID-C general purpose 2+2+Kappa diffractometer to APS Director David Moncton. Newport engineers installed and tested the diffractometer in May, 1998. The device is currently undergoing commissioning and testing.

Design Team

	John Parise, Chairman Department of Earth and Space Sciences, SUNY-Stony Brook, Stony Brook, NY, 11794-2100; phone : 516-631-8196, john.parise@sunysb.edu Parise Group Home Page : http://sbmp32.ess.sunysb.edu
	Larry Finger Geophysical Laboratory, 5251 Broad Branch Rd., NW , Carnegie Institution of Washington, Washington, DC; 20015-1305, phone : 202-686-2410 x2464, fax : 202-686-2419, finger@gl.ciw.edu
	Joseph Pluth University of Chicago, 5734 South Ellis, Chicago, IL 60637; phone : 773-702-8109, fax : 773-702-9505, pluth@cars.uchicago.edu
	Charles Prewitt Geophysical Laboratory, 5251 Broad Branch Rd., NW , Carnegie Institution of Washington, Washington, DC, 20015-1305; phone : 202-686-2410 x2450, fax : 202-686-2419, prewitt@gl.ciw.edu
	Joseph Stuck i Agronomy Department, 1102 South Goodwin Ave., University of Illinois, Urbana, IL, 61801; phone : 217-333-9636, fax : 217-333-9817, jstucki@ux1.cso.uiuc.edu
	Peter Eng (r) University of Chicago, Building 434A, Argonne National Laboratory, 9700 South Cass Ave., Argonne, IL 60439; phone : 630-252-0424, fax : 630-252-0443, eng@cars.uchicago.edu
	Joseph Smith University of Chicago, 5734 South Ellis, Chicago, IL 60637; phone : 773-702-8110, fax : 773-702-9505, smith@cars.uchicago.edu