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An Office of Science User Facility

Coherent X-ray Imaging  (CXI)

This site is OBSOLETE as of 30 Oct. 2017
Please go to the new CXI site
 

 

Specifications

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
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 Emmission Spectroscopy

Source Parameters

Photon Energy 5-10 keV for the 1st harmonic*
Up to 25  keV for 2nd and 3rd harmonic
Source Size 60 x 60 µm2 (HxV) FWHM @ 8.3 keV
78 x 78 µm2 (HxV) FWHM @ 2 keV
Source Divergence 2 x 2 µrad2 (HxV) FWHM @ 8.3 keV
~7 x 7 µrad2 (HxV) FWHM @ 2 keV
Repetition Rate 120 , 60, 30, 10 Hz, Single shot mode
Pulse Duration 40-300 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 (~100nm focus)
Beryllium Lenses in XRT (10 µm 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)
10 x 10 µm2 FWHM with XRT Be Lenses
~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
Beam Size at Sample (4 keV) 4 x 4 µm2 FWHM with 1st KB pair (KB1)
300 x 450 nm2 FWHM (V x H) with 2nd KB pair (KB01)
Unusable with XRT Be Lenses
Unusable with Hutch 5 Be Lenses
3000 x 3000 µm2 FWHM unfocused beam
Energy Range 2-10 keV (1st harmonic)
10-25  keV (2nd and 3rd harmonic)
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. Also, large increase in air scatter might prevent operation of the detector in the forward direction.
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
Detectors 2-Dimensional pixel array detector, 110 x 110 µm2 pixel size
Single photon sensitivity, 103 dynamic range at 8.3 keV
Cornell-SLAC Pixel Array Detector (CSPAD) 1516 x 1516 pixels
120 Hz operation
Two full CSPAD detectors available for wide angle and small angle measurements
CSPAD 140K (380 x 380 pixels) small version of CSPAD available for miscellaneous use

 

SLAC SLAC National Accelerator Laboratory, Menlo Park, CA
Operated by Stanford University for the U.S. Dept. of Energy