CXI Specifications
Scientific Capabilities
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 & 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
*Ongoing R&D, please contact mliang@slac.stanford.edu for feasibility. All expected performance values are based off a best effort basis.
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) |
Sample Environment & 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 | |
Detectors | Jungfrau 4M
|
Cornell-SLAC Pixel Array Detector (CSPAD)
| |
ePix10k – small area detector for flexible placement
| |
CSPAD 140K
|
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 22 | ~35 fs |
220-245 nm | Possible for Run 22* | ~40 fs |
280-330 nm | Possible for Run 22* | ~35 fs |
CXI TECHNICAL SPECIFICATIONS
CXI CONTACTS
Meng Liang
CXI Instrument Lead
(650) 926-2827
mliang@slac.stanford.edu
Matt Hayes
Area Manager
(650) 926-3060
hayes@slac.stanford.edu
Joe Robinson
Lead Laser Scientist
(650) 926-5190
jsrob@slac.stanford.edu
Michael Minitti
Senior Scientist
(650) 926-7427
minitti@slac.stanford.edu
Andy Aquila
Staff Scientist
(650) 926-2682
aquila@slac.stanford.edu
Xinxin Cheng
Staff Scientist
(650) 926-3156
xcheng@slac.stanford.edu
Sandra Mous
Staff Scientist
(650) 926-6225
smous@slac.stanford.edu
Kirk Larsen
Associate Laser Scientist
(650) 926-3728
larsenk@slac.stanford.edu
Philip Hart
Detectors Engineer
(650) 926-2813
philiph@slac.stanford.edu
Stella Lisova
Sample Delivery Engineer
(650) 926-3272
stellal@slac.stanford.edu
Divya Thanasekaran
Controls Engineer
(650) 926-8917
divya@slac.stanford.edu
Serge Guillet
Staff Engineer
(650) 926-4771
sguillet@slac.stanford.edu
CXI Control Room
(650) 926-6295
(650) 926-6296
(650) 926-6297
(650) 926-6298
CXI Hutch
(650) 926-6291
CXI LOCATION
Beamline Specifications
Diagnostics Stand in the X-ray Tunnel
Devices
- Pulse Picker
- Attenuators (10 filters)
- X-ray Focusing Lenses
Purpose
- Rapidly shutter the X-ray beam
- Control the incident beam intensity
- Pre-focus the X-ray beam or produce a ~10 micron focus at CXI
Diagnostics Stand 1
Devices
- Reference Laser
- Slits 1
- Profile-Intensity Monitor
- Differential Pump
Purpose
- Produce a visible reference line for alignment
- Slit the beam down and reduce unwanted halo, Define the beam entering the KB mirrors
- Measure the incidnet beam profile entering the CXI hutch
- Separate the vacuum of the KB mirrors from the upstream beamline
0.1 micron KB Mirrors
Devices
- 100 nm KB mirrors
Purpose
- Focus the X-ray beam to a ~100 nm spot
1 micron KB Mirrors
Devices
- Slits 2
- 1 micron KB mirrors
- Slits 3
Purpose
- Slit the beam down and clean the beam before entering the KB mirrors
- Focus the X-ray beam to a ~1 micron spot
- Slit the beam down and clean the beam entering the KB01 mirrors or the beam exiting the KB1 mirrors
0.1 micron Sample Chamber
Devices
- 100 nm interaction region
Purpose
- Location of the ~100 nm focus
Detector Stage (A location)
Devices
- Full size CSPAD
- X-ray Focusing Lenses
- Attenuator or beam stop
Purpose
- Forward scattering measurements with the nanofocus chamber
- Refocusing or collimating the 100 nm focus for reuse downstream
- Attenuate the beam passing through the CSPAD hole or block it entirely
Diagnostics Stand 2
Devices
- CSPAD 140K or X-ray Focusing Lenses
- Slits 4
- Intensity-Position Monitor
- Profile-Intensity Monitor
- Differential Pump
Purpose
- Measure the low angle forward scattering from the 100 interaction region
OR
- Change the divergence of the 1 micron KB beam and control the spot size in SC1
- Slit the beam down after the refociusing lenses or clean the beam before after the 1 micron KB mirrors
- Non-destructive relative measurement of the pulse intensity
- Measure the beam profile on the way to the 1 micron focus, after the 100 nm focus or after the refocusing lenses
- Isolate the 1 micron sample chamber environment from the upstream part of the beamline
Detector Stage (B location)
Devices
- Full size CSPAD
OR
- Time Tool
- Pulse Selector
- Attenuators (6 filters)
- Slits 5
- Differential Pump
Purpose
- Back scattering measurements with the 1 micron focus
OR
- Cross-correlate the arrival time of the X-rays and pump lasers
- Rapidly shutter the X-ray beam or control the repetition rate for SC1
- Control the incident beam intensity
- Slit the beam down after the refocusing lenses or clean the beam before after the 1 micron KB mirrors
- Isolate the 1 micron sample chamber environment from the upstream part of the beamline
1 micro Sample Chamber
Devices
- 1 micro Sample Chamber
Purpose
- Location of the ~1 micron focus and of the refocused 100 nm beam
Detector Stage (C location)
Devices
- Full size CSPAD (Front detector for SC1)
- Attenuator or beam stop
- Pulse Selector for refocused 1 micron beam
- X-ray focusing lenses for refocusing or collimating the 1 micron focus
Purpose
- Forward scattering measurements with the micron focus chamber (High angle detector)
- Attenuate the beam passing through the CSPAD hole or block it entirely
- Rapidly shutter the X-ray beam or control the repetition rate for SSC
- Refocusing or collimating the 1 micron focus for reuse downstream
Serial Sample Chamber
Devices
- Interaction for refocused 1 micron beam
Purpose
- Location of the refocused 1 micron beam
Detector Stage (D location)
Devices
- Full size CSPAD (Back detector for SC1)
OR
- Full size CSPAD (Detector for SSC)
- Attenuator or beam stop
Purpose
- Forward scattering measurements with the micron focus chamber (Low angle detector)
OR
- Forward scattering measurements with the refocused beam in SSC
- Attenuate the beam passing through the CSPAD hole or block it entirely
Diagnostics Stand 3
Devices
- Single Shot Spectrometer
Purpose
- Measure the single shot X-ray spectrum
Diagnostics Stand 4
Devices
- Intensity-Position Monitor
- Profile-Intensity Monitor
Purpose
- Non-destructive relative measurement of the pulse intensity
- Measure the beam profile at the end of the CXI hutch, after all focusing optics and all interactions with samples or diagnostics
