Author: Sinn, H.
Paper Title Page
MOP010 The Photon Beam Loss Monitors as a Part of Equipment Protection System at European XFEL 37
  • N. Gerasimova, H. Sinn
    XFEL. EU, Hamburg, Germany
  • S. Dziarzhytski, R. Treusch
    DESY, Hamburg, Germany
  For the X-ray beam transport systems, the problem of potential damage to the equipment by mis-steered photon beam emerged with advent of powerful X-ray FELs. In particular high repetition rate machines as European XFEL, where not only focused beam can produce ablation, but even unfocused beam can melt the beamline components while machine operates in multibunch mode, demand for implementation of equipment protection. Here we report on development of photon beam loss monitors at European XFEL facility. The photon beam loss monitors will react on the mis-steered photon beam and interface the machine protection system. The prototype comprises the vacuum chamber with fluorescence crystals positioned outside the photon beampath. The fast sub-hundred ns fluorescence induced by mis-steered beam can be detected by photomultiplier tube allowing for intra-train reaction of machine protection system. First tests have been carried out at FLASH and shown the feasibility of detection based on PMT-detected fluorescence. In addition to efficient YAG:Ce crystal, the robust low-Z material as CVD microcrystalline diamonds has shown a potential to be used as fluorescence crystals.  
The SASE3 Monochromator Beamline at the European XFEL  
  • N. Gerasimova, D. La Civita, L. Samoylova, H. Sinn, M. Vannoni
    XFEL. EU, Hamburg, Germany
  The photon beam transport at novel X-ray FEL machines is a challenging task. The unprecedented brilliance of European XFEL demands for optics operating close to damage limit; deterioration of spatial and temporal properties of coherent pulses should be minimized. To handle the XFEL beam, the beamlines have been designed being very long (hundreds of meters), along with very long optical elements (up to 1 m) and extremely high demands on the optical surface (50 nrad slope error, 2 nm PV residual height error). The mechanical design in terms of vibrational stability, deformations (of both mechanical and thermal origin) and movement resolution should be compliant to the optical one. Here we discuss on the optical and mechanical design of the SASE3 beamline at European XFEL. Operational in the soft X-ray regime, the SASE3 beamline comprises several reflective optical elements of specified above quality, including VLS plane grating monochromator. Expected to serve multipurpose user community, the monochromator would allow controlling temporal pulse properties and will be operational in both low and high resolution modes.