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X-ray spectroscopy

X-ray spectroscopy. Andrew Preston andrew@preston.co.nz. Outline of proceedings. Synchrotrons Beamlines Advantages/Applications How to get access. 1. Synchrotrons. What is a synchrotron?. A big circle… …which accelerates charged particles… …which radiate light… …which we use.

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X-ray spectroscopy

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  1. X-ray spectroscopy Andrew Preston andrew@preston.co.nz

  2. Outline of proceedings • Synchrotrons • Beamlines • Advantages/Applications • How to get access

  3. 1. Synchrotrons

  4. What is a synchrotron? • A big circle… • …which accelerates charged particles… • …which radiate light… • …which we use

  5. It’s a light source!

  6. A very useful light source • Very bright • Millions of times brighter than x-ray tubes • Very colourful • Energies from infrared to hard x-ray • Highly polarized • linear or circular • Great time resolution • Pulses of nanosecond duration • Key point: new uses, improves other uses

  7. Uses • Biosciences • Medicine • Environmental sciences • Agriculture • Minerals exploration • Advanced materials • Engineering • Forensics

  8. Light sources around the world

  9. NSLS (New York)

  10. Maxlab (Sweden)

  11. Australian synchrotron

  12. Australian synchrotron • Beamlines • Protein crystallograppy • Infrared spectroscopy • Soft x-ray spectroscopy • X-ray absorption spectroscopy • Powder diffraction

  13. Australian synchrotron • Beamlines under construction • Small and wide angle scattering • Protein micro-crystal and small moleculte XRD • Microspectroscopy • Imaging and theray

  14. Experiment Light source 2. Beamlines • Generate light (synchrotron) • Isolate particular colour (monochromator) • Conduct experiment

  15. 3. Advantages

  16. Ef Atom specific Empty Filled

  17. Very bright

  18. X-ray absorption • XAS, XANES, NEXAFS, EXAFS • Probe the unoccupied states around an atom

  19. XAS Band structure of ZnO from resonant x-ray emission spectroscopy Preston et al. Phys. Rev. B 78, 155114 (2008)

  20. Ef Photoelectron spectroscopy • XPS, ARPES • Photoelectric effect • Measure kinetic energy of emitted electrons Empty Filled

  21. XPS/ARPES • Measure the total density of states around an atom • Surface state effects • ARPES • resolve momentum of emitted electrons

  22. ARPES Origin of the metallic properties of boron-doped diamond Yokoya et al. Nature 438, 647 (2005)

  23. X-ray diffraction • Similar to conventional XRD • High flux • Better signal:noise ration • High resolution • Angle/time

  24. Highly oriented polythiophene thin-film transistorsKline et al. Nat. Mat. 5, 222 (2006)

  25. 4. How to get access • Apply! • Apply!! • Apply!!! • New Zealand Synchrotron Group Ltd. • http://www.synchrotron.rsnz.org/user/

  26. New Zealand Synchrotron Group • Your university is a shareholder • Designed to encourage use • Two types of access • Merit (50%) • Preferred (30%) • Can you apply? • YES!

  27. References • Tour of the ALS • http://www.youtube.com/watch?v=iEHWQv7b-Cw • Light sources • http://www.lightsources.org/ • Australian synchrotron • http://www.synchrotron.org.au • New Zealand Synchrotron Group Ltd. • http://www.synchrotron.rsnz.org/ • X-ray data booklet • http://xdb.lbl.gov/

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