Experimental Methods

NEH 2.2, will host a wide range of experimental methods with flexible instrumentation. The high repetition rate of LCLS-II will provide outstanding signal-to-noise ratio. All of these methods will be compatible with ultrafast time resolved pump-probe studies.


  • X-ray Absorption Spectroscopy (XAS): In absorption, transmission and reflection geometries, the high repetition rate at LCLS-II will extend the spectral quality to enable studies with chemical and charge state sensitivity.

  • X-ray Emission Spectroscopy (XES): Probes the occupied electronic structure and is well suited for time resolved studies at high repetition rate. Scanning the incident photon energy over an atomic resonance enables resonant inelastic X-ray scattering (RIXS) which is a power tool for mapping electronic structure. Samples take the form of liquids and solids.


  • Resonant Inelastic X-ray Scattering (RIXS): RIXS in condensed matter systems will be used to extract the energy-momentum dispersion of elementary excitations of lattice, electronic, spin and orbital nature. It provides bulk, chemical and site specificity.

  • X-ray Absorption Spectroscopy (XAS): Precise determination of the photon energy and bandwidth that needs to be delivered by the beamline monochromator can be made only on the basis of an accurate XAS measurement from the sample under investigation.  This requirement calls for the use of single photon sensitive point detectors, such as avalanche photodiodes (APD) or microchannel plate detectors (MCP), that must also be shielded from stray optical light. XAS measurements will be made in total fluorescence yield mode.

  • Resonant Elastic X-ray Scattering (REXS): Bragg and/or superstructure reflections measurements are needed for accurate positioning of the sample in reciprocal space.

  • X-ray Photon Correlation Spectroscopy (XPCS): Intrinsic fluctuations in the ground state of correlated systems can be traced by monitoring the speckle correlation at different time scales.

Both LJE and RIXS

  • Optical Pump / X-ray Probe – And vise versa.

  • Soft X-ray Pump / X-ray Probe – Slotted foil, double or single bunch 2-pulse-2-color (2p2c) techniques