CXI Specifications

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
Source Size	78 x 78 µm² (H x V) FWHM @ 2 keV
Source Divergence	2 x 2 µrad² (H x V) FWHM @ 8.3 keV
Source Divergence	~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)
Pulse Duration	<10 fs (low charge mode)
Pulse Energy	1-3 mJ (high charge mode)
Pulse Energy	~ 0.2 mJ (low charge mode)
Photons per Pulse	~1 x 10¹² (high charge mode @ 8.3 keV)
Photons per Pulse	~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)
Energy Range	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
Detectors	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 3^rd and 4^th 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.