Single shot spatial and temporal coherence properties of the SLAC Linac Coherent Light Source in the hard x-ray regime

Phys Rev Lett. 2012 Jan 13;108(2):024801. doi: 10.1103/PhysRevLett.108.024801. Epub 2012 Jan 11.

Abstract

We measured the transverse and longitudinal coherence properties of the Linac Coherent Light Source (LCLS) at SLAC in the hard x-ray regime at 9 keV photon energy on a single shot basis. Speckle patterns recorded in the forward direction from colloidal nanoparticles yielded the transverse coherence properties of the focused LCLS beam. Speckle patterns from a gold nanopowder recorded with atomic resolution allowed us to measure the shot-to-shot variations of the spectral properties of the x-ray beam. The focused beam is in the transverse direction fully coherent with a mode number close to 1. The average number of longitudinal modes behind the Si(111) monochromator is about 14.5 and the average coherence time τ(c)=(2.0±1.0) fc. The data suggest a mean x-ray pulse duration of (29±14) fs behind the monochromator for (100±14) fc electron pulses.

MeSH terms

  • Electrons
  • Gold / chemistry*
  • Light*
  • Metal Nanoparticles / chemistry*
  • Models, Theoretical*
  • Nanostructures / chemistry*
  • Particle Accelerators
  • Photons*
  • Scattering, Radiation
  • X-Rays

Substances

  • Gold