The Coherent X-ray Imaging (CXI) instrument makes use of the unique brilliant hard X-ray pulses from LCLS to perform a wide variety of experiments utilizing various techniques. The primary capability of CXI is to make use of the high peak power of the focused X-ray beam using the “diffraction-before-destruction” method.
This technique prevents damage to a sample during the measurement by acquiring the data faster than the damage or destruction process with ultrashort pulses. This is particularly advantageous for systems that suffer from electronic and structural damage during long continuous exposures to X-rays.
While originally designed to image single sub-micron particles using Coherent Diffractive Imaging (CDI) techniques, the CXI instrument consists of a highly flexible instrumentation suite to make use of hard X-rays primarily in a vacuum sample environment. CXI has hosted experiments for many scientific fields, including structural biology, materials science, materials in extreme conditions, atomic molecular and optical physics, chemistry, soft condensed matter and high field X-ray science.
CXI is suitable for forward scattering experiments requiring or benefiting from a vacuum sample environment which provides extremely low background, particularly beneficial for weakly scattering systems. A variety of tools and devices have been developed that allow CXI to make use of other techniques such as X-ray Emission Spectroscopy, back-scattering, small and wide angle scattering, ion and electron time of flight spectroscopy.
A flexible pump laser system with wavelengths from UV to IR is available for time-resolved experiments in the femtosecond time scale. Samples can be introduced to the X-ray beam either fixed on targets, using a particle injector that can deliver free-standing particles or in a liquid jet.
Experiments at atmospheric pressure are possible under certain limited circumstances. High quality Kirkpatrick-Baez focusing optics are available to generate three foci (10, 1 and 0.1 micron) in the 5-11keV range. Photon energies greater than 11keV can be used by focusing with compound refractive lenses to a focal size of >2 microns.
For more information about CXI instrument, please read the following article:
- Liang et al., The Coherent X-ray Imaging instrument at the Linac Coherent Light Source. J. Synchrotron Rad. (2015), 22, 514-519
The CXI instrument is located in Hutch 5 of the Far Experimental Hall of LCLS. The hutch is 20 m long by 7 m wide and located 440 m away from the LCLS source.