CXI Scientific Capabilities

Scientific Applications
  • Coherent X-ray imaging on single sub-micron particles
  • Serial Femtosecond Crystallography
  • High Fluence X-ray interactions with matter
  • Time-resolved imaging and scattering with hard X-rays
  • Matter in Extreme Conditions
  • Atomic, Molecular and Optical Science
  • Gas Phase Chemistry
Techniques and Scattering Geometry
  • Forward scattering on fixed-mounted samples, free-standing injected particles and in liquid jets
  • Back-scattering
  • Ion Time-of-flight
  • Small Angle X-ray Scattering
  • Wide Angle X-ray Scattering
  • X-ray Emission Spectroscopy

Source Parameters

Photon Energy 5-25 keV
Source Size 60 x 60 µm2 (H x V) FWHM @ 8.3 keV
78 x 78 µm2 (H x V) FWHM @ 2 keV
Source Divergence 2 x 2 µrad2 (H x V) FWHM @ 8.3 keV
~7 x 7 µrad2 (H x V) FWHM @ 2 keV
Repetition Rate 120 , 60, 30, 10 Hz, Single shot mode
Pulse Duration 10-300 fs (high charge mode)
<10 fs (low charge mode)
Pulse Energy 1-3 mJ  (high charge mode)
~ 0.2 mJ  (low charge mode)
Photons per Pulse ~1 x 1012 (high charge mode @ 8.3 keV)
~1 x 1011 (low charge mode @ 8.3 keV)

* Energies below 5 keV are in principle usable but the beam size at the end station is large leading to poor focusing performance and reduced flux. Also, the detector efficiency drops rapidly below 5 keV.

Photon Beam Properties

Focusing Capability KB1 mirrors (1.3 µm focus)
KB01 mirrors (~100 nm focus)
Beryllium Lenses in Hutch 5 (~1 µm focus)
Beam Size at Sample (8 keV)

(Calculated for perfect optics)

1.3 x 1.3 µm2 FWHM with 1 micron KB pair (KB1)
90 x 150 nm2 FWHM (V x H) with 100 nm KB pair (KB01)
~1 x 1 µm2 FWHM with Hutch 5 Be Lenses
750 x 750 µm2 FWHM unfocused beam
Beam Divergence

(Calculated for perfect optics)

0.12 x 0.12 mrad2 FWHM with 1 micron KB pair (KB1)
2 x 1 mrad2 FWHM (V x H) with 100 nm KB pair (KB01)
170x 170 µrad2 FWHM with XRT Be Lenses
~0.3 x 0.3 mrad2 FWHM with Hutch 5 Be Lenses
2 x 2 µrad2 FWHM unfocused beam
Energy Range 5-11 keV (kB Mirror Optics)
11-25  keV (Be Lens Optics)
Energy Resolution ΔE/E ~0.2% (bandwidth of the LCLS beam)
No monochromator currently

Sample Environment and Detector

Sample Environment
  • High vacuum: 10-7 Torr
  • Fixed sample on grids at room temperature
  • Possible to operate at atmospheric pressure with limitations on use of some CXI equipment.
Particle Injector
  • Free-standing nanoparticles delivered to the beam using an aerodynamic lens particle injector
  • User-provided injectors can be incorporated into the system
  • Liquid jet to delivered samples in hydrated conditions
  • Jungfrau 4M
    • 2-Dimensional pixel array detector, 75 x 75 µm2 pixel size
    • Single photon sensitivity, 104 dynamic range at 12 keV
    • Primary detector for forward scattering
  • Cornell-SLAC Pixel Array Detector (CSPAD)

    • 1516 x 1516 pixels
    • 2-Dimensional pixel array detector, 110 x 110 µm2 pixel size
    • Single photon sensitivity, 103 dynamic range at 8.3 keV
    • 1516 x 1516 pixels
    • 120 Hz operation
    • Dedicated to parasitic Serial Sample Chamber – used in tandem with Jungfrau for SAXS/WAXS
  • ePix10k – small area detector for flexible placement

    • 100 x 100 µm2 pixel size
    • Single photon sensitivity, 104 dynamic range at 8 keV
    • Dedicated to parasitic Serial Sample Chamber – used in tandem with Jungfrau for SAXS/WAXS


  • CSPAD 140K (380 x 380 pixels) small version of CSPAD available for miscellaneous use

Short Pulse UV Laser

In order to improve the overall time resolution of ultrafast X-ray scattering measurements performed at the CXI instrument, the UV capabilities of the CXI laser are being upgraded to produce shorter pulses. This is being done in 2 stages: first the 3rd and 4th harmonics (267 nm and 200 nm, respectively) of the Ti:sapphire laser are being improved by increasing the spectral bandwidth and minimizing the dispersion of the travelling pulses. In a second phase of upgrade, an OPA and a variety of sum frequency generation schemes will be used to generate tunable pulses in the 185-265 nm range.

Phase 1: Improving the time resolution of the 3rd and 4th harmonics

  Current Pulse Width
Expected Performance
267 nm (3ω) ~80 fs ~35 fs
200 nm (4ω) ~120 fs ~50 fs

Phase 2: Generating tunable deep UV pulses

  Current Capability Target Capability
245-260 nm Available Run 21 ~35 fs
220-245 nm Possible for Run 21* ~40 fs
280-330 nm Possible for Run 21* ~35 fs

*Ongoing R&D, please contact mliang@slac.stanford.edu for feasibility. All expected performance values are based off a best effort basis.