The combination of exceptionally high flux of monochromatic photons, far exceeding that at current facilities, delivered in the form transform-limited femtosecond X-ray pulses, will make the NEH 2.2 beamline at LCLS-II one with transformational capabilities. It will enable new ways to capture rare chemical events, characterize fluctuating heterogeneous complexes, and reveal quantum phenomena in matter, using chemical, site and orbital-specific resonant techniques that are possible only with X-ray lasers. This facility will provide access to the soft X-ray regime (250 eV to 1.6 keV) to provide fully coherent X-rays in a uniformly spaced series of pulses with programmable repetition rate and rapidly tunable photon energies.

The beamline monochromator will be placed in the Front End Enclosure (FEE).  NEH 2.2 beamline will have two separate instruments with fixed interaction points – qRIXS and chemRIXS.  In the hutch the qRIXS endstation will be situated upstream, while the chemRIXS endstation will be located downstream. A common set of bendable Kirkpatrick-Baez focusing optics will be used.  Individual laser tables optimized for conditioning and delivery of beams with particular parameters will be employed for each endstation.  Provisions for a third, roll-up station will be considered.

Beamline Specifications

Parameter Requirement Comment
Photon Energy Range [eV] 250-1600
  • Oxygen K-edge 3rd harmonic rejection of >10-5
  • Experiments on rare earth M-edges
Beamline Transmission [%]

1 - 2


  • In monochromatic mode at beamline resolving power of 2,000.
Bandwidth Control
[Resolving Power]

  • Mono Requirements RP in the 2,000-3,000 range is needed for experiments needing very high temporal resolution.

Specifications Experimental Spot Size Range

  1. Horizontal [μm]
  2. Vertical [μm]
  • Spot size adjustable to each end station interaction location
Beam Position Stability
[% of FWHM]
Pulse Stretching <2  x Transform Limit
  • This requirement should be achievable for all RP modes of operation and at all photon energies in the range specified

Visible to THz

Visible to NIR

  • For correlated materials studies
  • For chemistry applications