X-ray diffraction from materials under extreme pressures (Invited Paper)

Keith Brister*

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    Diamond anvil cells have been used to generate a wide range of pressures, from 0.1 GPa to over 400 GPa (for reference, the center of Earth is about 360 GPa). Samples are squeezed between two diamond anvils and studied using infrared, visible, and X-ray probes. In the past year a new synchrotron beam line has become available at CHESS for the general user for diamond anvil cell work using X-rays. This has opened up new areas of research as the experimenters need only to bring a sample in a diamond anvil cell and can leave with the X-ray data mostly analyzed. Current X-ray diffraction work at CHESS on materials subjected to static pressures up to 400 GPa are reviewed. Both energy dispersive and Laue diffraction techniques have been applied to phase transition, equation of state, and state of stress problems. Since most samples at very high pressures are powders, energy dispersive diffraction is most often used. An example of this is xenon which turns metallic at 150 GPa. Since the plasma frequency of xenon is in the infrared and because of the presence of an absorption band at 2 eV, xenon is a transparent blue metal at this pressure. The energy dispersive diffraction data provided the structural and equation of state information needed to understand the physics of the problem. An example of Laue diffraction using diamond anvil cell is the study of the state of stress of diamond anvils themselves. In an ongoing experiment at CHESS, the tips of highly stressed diamonds are analyzed by studying the energy distribution of various Laue spots using a solid-state detector.

    Original languageEnglish (US)
    Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
    PublisherPubl by Int Soc for Optical Engineering
    Pages2-10
    Number of pages9
    Volume1550
    ISBN (Print)0819406783
    StatePublished - Dec 1 1991
    EventX Rays in Materials Analysis II: Novel Applications and Recent Developments - San Diego, CA, USA
    Duration: Jul 25 1991Jul 26 1991

    Other

    OtherX Rays in Materials Analysis II: Novel Applications and Recent Developments
    CitySan Diego, CA, USA
    Period7/25/917/26/91

    ASJC Scopus subject areas

    • Electrical and Electronic Engineering
    • Condensed Matter Physics

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