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Neutrons Coordinator: Nancy Ross, VT

Neutrons Coordinator: Nancy Ross, VT. 2004 COMPRES Annual Meeting. Goals of COMPRES Neutrons:. Identify and broaden the EAR neutron scattering community in the U.S. Stimulate and promote the use of neutron scattering in the Earth Sciences. Support educational activities

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Neutrons Coordinator: Nancy Ross, VT

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  1. Neutrons Coordinator: Nancy Ross, VT 2004 COMPRES Annual Meeting

  2. Goals of COMPRES Neutrons: • Identify and broaden the EAR neutron scattering community in the U.S. • Stimulate and promote the use of neutron scattering in the Earth Sciences. • Support educational activities • Identify needs of the community, including future requirements for instrumentation and sources

  3. COMPRES: Budget for Neutrons • Year 1: $70,000 • Year 2: $70,000 • Year 3: $70,000 • Virginia Tech • Webpage(www.crystal.vt.edu/compres)

  4. Convenors: N L Ross, Virginia Polytechnic Institute and State University; J Parise, Stony Brook Special Session: Applications of Neutron Scattering in Earth Sciences • Invited lectures: S. Redfern, R. Wenk, H-K Mao, B. Winkler, M. Welch • + Poster Session • Wendy Mao (Univ. Chicago): Hydrogen Storage in Clathrate Hydrate.

  5. NeutronsIn solid stateChemistry and the EarthSciencesToday and tomorrow (March 12–16, 2003)Co-chairs: A. Wilkinson (Georgia Tech), N. Ross (Virginia Tech) • Christopher Holl, Univ. Colorado • Wendy Mao, Univ. Chicago • Philip Neuhoff, Univ. Florida • Kim Tait, Univ. of Arizona • Charles Martin, SUNY Stony Brook • Meghan Kamp, Ohio State Univ. • Yang Ding, Geophysical Laboartory • Darren Locke, Arizona State Univ.

  6. COMPRES Neutrons: • Ross Angel (Virginia Tech): High-pressure phase transition in lead phosphate(ISIS) • Peter Chupas (Stony Brook): The local structure of “amorphous” FeS (LANSCE) • Aaron Celestian (Stony Brook): Origin of ionic conductivity in complex structures (LANSCE) • Julien Breger (Stony Brook): (LANSCE) • Steve Jacobsen (Geophysical Lab) Hydrogen in wadsleyite (ISIS) • Chris Holl (Univ. Colorado) Hydrogen in ringwoodite (ISIS)

  7. High-pressure Neutron Powder Diffraction at ISIS • Ferroelastic phase transition • Paris-Edinburgh cell • New gasket design that extends hydrostatic pressure range to 9 GPa (Marshall and Francis, 2002: J Appl. Cryst. 35, 122-125) • 2 samples to 6 GPa, 48 hours Ross Angel 2004

  8. Ferroelastic phase transition in lead phosphate Neutron powder diffraction showed: • High pressure phase has same symmetry as high temperature (R-3m) • High pressure phase has disordered atoms above the phase transition • This static disorder is suppressed at higher pressures • Model system for perovskites, garnets, feldspars and titanites. Ross Angel 2004

  9. 0.5-1.0 mm sized grains quench 3 mm Size of high P-T mantle minerals and neutron fluxes are merging . . . A collaboration between COMPRES participants: Steve Jacobsen (Geophysical Laboratory) Daniel Frost (Bayerisches Geoinstitut) Joseph Smyth (University of Colorado) e.g. hydrous wadsleyite: (containing ~1 wt% H2O) 5000-ton large-volume press in Bayreuth

  10. Measurements on hydrous wadsleyite and ringwoodite are being carried out on the SXD instrument at ISIS S. Jacobsen 2004 11-bank scintillating ZnS detector array

  11. mounting the wadsleyite crystal onto theSXD sample holder at ISIS Neutron diffraction from single-crystal wadsleyite! S. Jacobsen 2004

  12. Location of hydrogen atoms . . . H H Location of hydrogen even in un-deuterated samples is possible (from, Two proton positions in the very strong hydrogen bond of serandite, NaMn2[Si3O8(OH)] Jacobsen et al. (2000) Am Min, 85, 745-752). Measured at LANSCE

  13. COMPRES Neutrons Postdoc • High-pressure neutron experiments (LANSCE, IPNS, ISIS) • Test/design high P/T cells • Communicate results to community (conferences, website, workshop) • Help community with experiments

  14. A High Pressure Diffractometer for the Spallation Neutron Source • John B. Parise, Geosciences/Chemistry & Center for High Pressure Research, State University of New York, Stony Brook • Russell J. Hemley, H.-K Mao, Geophysical Laboratory & Center for High-Pressure Research, Carnegie Institution, Washington, D.C. • Chris Tulk, Instrument Scientist, Experimental Facilities Division, Spallation Neutron Source, Oak Ridge National Lab Fast track – on line in 2007

  15. Financial Assistance • To carry out neutron scattering experiments and/or to participate in workshops and conferences on neutron scattering • See www.crystal.vt.edu for details

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