Facility News: 100ps Picosecond Time Resolution In Sight at BioCARS

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- September 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.


There were three major activities in this project.

  1. 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)
  2. 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
  3. 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


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