100ps Picosecond Time Resolution In Sight At BioCARS

Sep 2, 2007

BioCARS is completing infrastructure changes that aim to expand our time resolution from 5ns to ~100 ps and to enable data collection within a single 100-ps X-ray pulse. These enhancements are a collaboration with Philip Anfinrud (NIH/NIDDK) and are partly supported by funding from NIH/NIDDK.

UPGRADES

There were three major activities in this project.

  • Upgrades to X-ray source and optics
    • Two collinear undulators
    • KB mirror pair and new optics enclosure: beam size 90 µm2 (h) x 35 µm2 (v)
  • Upgrade of the BioCARS fast X-ray chopper
    • isolates a single 100-ps X-ray pulse in the 24-bunch mode
    • enhances the beamtime availability for time-resolved research
  • Installation of a picosecond laser system.

The laser system is a Ti:Sapphire Spitfire Pro 5 from Spectra Physics (780nm, 2ps, 5mJ/pulse, 1kHz). It is equipped with a TOPAS optical parametric amplifier from Light Conversion. The output of TOPAS is tunable in a wide wavelength range:

  • 75µJ @ 290-400nm
  • >300µJ @ 475-600nm
  • >250µJ @ 600-800nm

TIMELINE

  • May 2006    —    Vertically-focusing mirror installed
  • May 2006    —    Monochromator installed
  • September 2006    —    Undulator installed (U27)
  • October 2006    —    Horizontally-focusing mirror installed
  • December 2006    —    X-ray chopper upgraded
  • January 2007    —    Undulator installed (U23)
  • January 2007    —    New ps laser system installed