| EPSRC Reference: |
GR/R25699/01 |
| Title: |
Studies of Dynamic Properties of Shock Compressed Crystals By In-Situ Picosecond X-Ray Diffraction |
| Principal Investigator: |
Wark, Professor J |
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| Department: |
Oxford Physics |
| Organisation: |
University of Oxford |
| Scheme: |
Standard Research (Pre-FEC) |
| Starts: |
01 October 2001 |
Ends: |
31 March 2005 |
Value (£): |
194,201
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| No relevance to Underpinning Sectors |
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Summary on Grant Application Form |
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Time-resolved X-ray diffraction measurements can give information on the lattice level on shock compressed crystals. As such, the technique provides the opportunity to significantly extend our understanding of many processes that occur in shock compressed matter. In recent experiments we have observed, using diffraction, two-wave structures in shock-compressed silicon that are indicative of a polymorphic phase transition. We propose to extend these studies to identify the new phase, supporting the experimental measurements with ab initio quantum calculations. In contrast to the work with silicon, recent molecular dynamics simulations have shown that shock-compressed fcc metals should deform to the hydrostatic state on picosecond timescales via the generation of large numbers of stacking faults. We have confirmed the existence of the hydrostatic state behind the shock front via picosecond X-ray diffraction, and now propose to directly measure for the first time the stacking fault density by simultaneously diffracting from the (200) and (400) planes: the stacking faults shift the diffraction from these planes in opposite angular directions. Such a measurement would constitute a significant experimental result, and confirm the presence of large stacking fault densities during the shock compression process, resolving a long-standing problem in shock-wave physics.
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Key Findings |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Potential use in non-academic contexts |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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Impacts |
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| Description |
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk |
| Summary |
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| Date Materialised |
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Sectors submitted by the Researcher |
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This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
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| Project URL: |
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| Further Information: |
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| Organisation Website: |
http://www.ox.ac.uk |