ChiChang Kao - PowerPoint PPT Presentation

Title: ChiChang Kao


1
Recent Developments in Synchrotron Facilities
Chi-Chang Kao National Synchrotron Light
Source Brookhaven National Laboratory
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Outline

• Advances in sources, optics
• and detectors
• COMPRES and facilities
• Inelastic x-ray scattering study of materials
  under high pressure

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Advances in Storage Rings Brightness
1 TPa?
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Advances in Storage Rings Flux
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X-ray Free Electron Lasers
Expected 2008
Richard Lee
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Advances in Optics

• Micro-focusing
• High energy focusing
• High energy resolution
• optics

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Advances in Detectors

• Multi-Element Solid
• State Detectors
• Pixel-Array Detectors
• High Energy Detectors

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Integrated Experimental Design
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COMPRES and Facilities

• Represent the interests of the community
• Ex 1 Scientific agenda and needs
• Ex 2 Coordination of activities
• Leverage facility resources
• Ex 1 X17 hutch upgrade
• Ex 2 High energy focusing optics
• Collaborate on education and outreach
• Ex Synchrotron technique and data analysis
  training courses

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Some interesting things to find out after EOS

• Phase diagram and structure refinement
• Strain mapping
• Electron structure and lattice dynamics
• Local structure information in disordered and
  liquid phases
• Statistical physics and origin of
  structural/magnetic/metal- insulator phase
  transitions
• Systematic study of electron correlation effects
• Control the coupling between lattice and
  electronic
• degrees of freedom in strongly correlated
  electron
• systems
• ..

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Kinematics of Inelastic X-ray Scattering
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Double Differential Scattering Cross Section
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Inelastic X-ray Spectrum
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Dynamic Structure Factor of Diamond and LiF
PRL, 84 (2000) 3907
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Dynamic Structure Factors of Metals
Aluminum
Eguiluz et al, J. of Physics and Chemistry of
Solids 61 (2000) 383390
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Spatial and Temporal Scales of Scattering
Techniques

• IXS covers a unique frequency
• -momentum space, complementary
• to optical, electron scattering, and
• neutron scattering techniques.

• No restriction on energy and
• momentum transfer.

• Single scattering simplifies
• comparison with theory

• Offers great flexibility in sample
• size and sample environment.

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Current Status of Inelastic X-ray Scattering

• Lattice dynamics 1-2 meV
• -liquids
• -Amorphous solids
• -Biological systems
• -Extreme conditions

• Charge dynamics 0.1-1 eV
• -Liquids
• -Metals to insulators
• -Strongly correlated electrons
• -Extreme conditions

Third generation high energy synchrotrons 1013
to 1014 in Si(111) bandwidth
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Pressure vs Temperature
PV work per atom
Atomic unit of pressure
Thermal energy 103 Ry
vs
Ashcroft
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SPring-8/ SRRC IXS Spectrometer
Analyzer
In Collaboration with Advanced Design Consulting,
Inc., NY, USA
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IXS Beamlines at Third Generation Synchrotrons
-ESRF ID16/ ID 28
-APS Sector 3 HP-CAT IXS-CAT
-Several CATs at APS are part time used for IXS
-SPring-8 BL35XU BL11XU BL12XU
Nuclear Resonance and Compton scattering
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Magnetic Collapse in Transition Metal Oxides
R.E.Cohen, I.I. Mazin, D.G. Isaak, Science 275
(1997)
http//www.windows.ucar.edu
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High Resolution X-ray Emission
High Spin
Low Spin
2
3d
Fe
3p
3s
Emitted x-rays
Incident x-rays
2p
2s
1s
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High-spin to Low-spin Transition in FeS
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High-spin to Low-spin Transition in FeS
Phys. Rev. Lett. 82, 3284 (1999)
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Magnetic Collapse in Transition Metal Oxides
Ferropericlase (Mg0.83Fe0.17)O 60-70 GPa Badro,
Science 2003
Silicate perovskite Jie Li private communication
http//www.windows.ucar.edu
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H.-K. Mao and R.J. Hemly, CIW J.-P. Rueff,
CNRS Y. Cai and P. Chow, NSRRC/SPring-8