Figure 1
The X-ray beam transport system from the undulator exit (at the right) to the experiment hutch of the FXE instrument (on the left) spans over 900 m. It includes three mirrors: two offset mirrors reject higher-energy synchrotron radiation (M1 and M2), and one deflection mirror (M3) guides the beam into the FXE beam path (the straight beam path with retracted M3 guides the beam to the neighboring Single Particles, clusters, and Biomolecules & Serial Femtosecond Crystallography (SPB/SFX) instrument (Mancuso et al., 2019). Compound refractive lenses (CRLs) collimate the beam to a beam size of 1–2 mm (depending on the X-ray energy). Beam imagers and a gas-based intensity position monitor (XGM) allow monitoring of the beam profile and location. Further components include the synchrotron radiation aperture (SRA), solid attenuator and, behind the offset mirror M2, an absorber to reject transmission of high-energy synchrotron radiation. |