x-ray spectroscopy andrew preston andrew@preston.co.nz

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  • X-ray spectroscopyAndrew Prestonandrew@preston.co.nz

  • Outline of proceedingsSynchrotrons Beamlines Advantages/Applications How to get access

  • 1. Synchrotrons

  • What is a synchrotron?A big circlewhich accelerates charged particleswhich radiate lightwhich we use

  • Its a light source!

  • A very useful light sourceVery brightMillions of times brighter than x-ray tubesVery colourfulEnergies from infrared to hard x-rayHighly polarizedlinear or circularGreat time resolutionPulses of nanosecond durationKey point: new uses, improves other uses

  • UsesBiosciencesMedicineEnvironmental sciencesAgricultureMinerals explorationAdvanced materialsEngineeringForensics

  • Light sources around the world

  • NSLS (New York)

  • Maxlab (Sweden)

  • Australian synchrotron

  • Australian synchrotronBeamlinesProtein crystallograppyInfrared spectroscopySoft x-ray spectroscopyX-ray absorption spectroscopyPowder diffraction

  • Australian synchrotronBeamlines under constructionSmall and wide angle scatteringProtein micro-crystal and small moleculte XRDMicrospectroscopyImaging and theray

  • 2. BeamlinesGenerate light (synchrotron)Isolate particular colour (monochromator)Conduct experiment

  • 3. Advantages

  • Atom specificEmptyFilled

  • Very bright

  • X-ray absorptionXAS, XANES, NEXAFS, EXAFSProbe the unoccupied states around an atom

  • XASBand structure of ZnO from resonant x-ray emission spectroscopyPreston et al. Phys. Rev. B 78, 155114 (2008)

  • Photoelectron spectroscopyXPS, ARPESPhotoelectric effectMeasure kinetic energy of emitted electrons

    EmptyFilled

  • XPS/ARPESMeasure the total density of states around an atomSurface state effectsARPESresolve momentum of emitted electrons

  • ARPESOrigin of the metallic properties of boron-doped diamondYokoya et al. Nature 438, 647 (2005)

  • X-ray diffractionSimilar to conventional XRDHigh fluxBetter signal:noise rationHigh resolutionAngle/time

  • Highly oriented polythiophene thin-film transistors Kline et al. Nat. Mat. 5, 222 (2006)

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

  • New Zealand Synchrotron GroupYour university is a shareholderDesigned to encourage useTwo types of accessMerit (50%)Preferred (30%)Can you apply?YES!

  • ReferencesTour of the ALShttp://www.youtube.com/watch?v=iEHWQv7b-CwLight sourceshttp://www.lightsources.org/Australian synchrotronhttp://www.synchrotron.org.auNew Zealand Synchrotron Group Ltd.http://www.synchrotron.rsnz.org/X-ray data booklethttp://xdb.lbl.gov/