X-ray Requirements

LJE Instrument

LJE Instrument

The LJE Instrument will be optimized for studying systems with C, N, O and transition metal elements using resonant scattering and spectroscopy. Suppression of the third harmonic contribution above the oxygen edge is required and will be achieved by using a separate coating stripe on the mirrors. Spectroscopic studies of rare earth elements will also be relevant so the beamline reach shall extend to 1600 eV.

  • Focusing: Adjustable
    • 2 μm–1 mm in horizontal
    • 2 μm–1 mm in vertical
  • Energy Range:
    • Carbon K-edge through Rare Earth M-edges
      • Harmonic Rejection: 250 eV–1350 eV (to reject 3rd harmonic at oxygen and 2nd harmonic from transition metals)
    • Higher Energy: Up to 1600 eV for rare earth M-edge (via striped mirror coating)
    • Spectral Resolution: 1000-5000 resolving power
    • Beamline Transmission: ~2-60%
    • Repetition Rate: up to 929 kHz

RIXS Instrument

RIXS Instrument

The RIXS Instrument will be optimized for operation in the range 0.25–1.6 keV. This is dictated by the need to cover:

  • the L2,3 edges of the 3d transition metals, where resonant enhancements are particularly strong
  • M2,3 edges of the 4d transition metals
  • K edges of C, N, and O, necessary for studying biological systems
  • the M4,5 edges of the lanthanides
  • Scattering Angle:
    • In order to maximize the flexibility of the experimental geometry, the range of scattering angle is specified to be 2θ = (40–160) degrees.
  • Spectrometer Resolution: The spectrometer will house two blazed spherical varied-line spacing gratings ruled at different groove density:

    • Very high resolution grating: Target resolving power is 50,000 at 1 keV, matching the resolving power of the beamline monochromator.

    • Medium resolution grating: Target resolving power ~10,000 at 1 keV, optimized for higher throughput when studying out-of-equilibrium systems.

  • Polarization Analysis: Polarization analysis of RIXS adds extremely valuable information about the nature of the probed excitations, especially in magnetic systems. We plan to use multilayer mirrors for the analysis of the scattered X-rays, while control over the polarization state of the incident beam will be provided by the DELTA undulator.

  • X-ray Focusing Capabilities: The re-focusing bendable Kirkpatrick-Baez optics are designed to provide a minimum of ~ 2 × 2 µm (vertical × horizontal) focus and the position of the focal spot can be changed independently in the horizontal and vertical directions, effectively changing the spot size on the sample.

Optical Laser

The laser will be temporally synchronized to the X-rays with <10 fs RMS jitter

  • Controllable on sample fluence at the rate of at least 100 kHz

  • <20 fs tunable optical pulses needed for the LJE

  • Fourier-transform limited IR, MIR and THz pulses for the RIXS endstation

  • Provisions for <10 fs optical pulses on samplee

  • Pulse repetition rates from 120 Hz and 1 KHz to 929 kHz depending on the fluence and wavelength requirements

  • Remotely controllable position on the sample

  • Remotely controllable polarization on the sample