Author: Kube, G.
Paper Title Page
WEPF03 Scintillating Screen Monitors for Transverse Electron Beam Profile Diagnostics at the European XFEL 807
  • Ch. Wiebers, M. Holz, G. Kube, D. Nölle, G. Priebe, H.-C. Schröder
    DESY, Hamburg, Germany
  Transverse beam profile diagnostics in modern electron linear accelerators like FELs or injector LINACs are mainly based on optical transition radiation (OTR) as standard technique which is observed in backward direction when a charged particle beam crosses the boundary between two media with different dielectric properties. The experience from modern LINAC based 4th generation light sources shows that OTR diagnostics might fail because of coherence effects in the OTR emission process. As a consequence, for the European XFEL which is currently under construction in Hamburg, transverse beam profile measurements are based on scintillating screen monitors. The LYSO:Ce screens are oriented such that coherent OTR generated at the screen boundaries will be geometrically suppressed. An additional advantage is that the imaging optics operate in Scheimpflug condition thus adjusting the plane of sharp focus with respect to the CCD chip and significantly increasing the apparent depth of field. This report gives an overview of the measuring principle and the monitor setup together with results of laboratory test measurements and a first prototype test at FLASH (DESY, Hamburg).  
WEPF05 An Electron Beam Detector for the FLASH II Beam Dump 814
  • F. Perlick, J.D. Good, N. Leuschner, M. Sachwitz
    DESY Zeuthen, Zeuthen, Germany
  • G. Kube, M. Schmitz, K. Wittenburg, T. Wohlenberg
    DESY, Hamburg, Germany
  For the electron absorber at FLASH II a detector is developed to control the position, dimensions and profile of the electron beam. Scintillation light, emitted from a luminescent screen in front of the dump window, is reflected by a mirror, located in 2 m distance from the screen, and passes through a vacuum window. Two different optical systems will be installed redundantly for beam image transfer: a conventional lens-mirror-system and a system using a radiation-hard optical fibre bundle. A CCD camera, located in one and a half meter distance from the beam line, is used for the optical analysis. An experimental setup, where the terms of installation of the components correspond to the FLASH accelerator, has been built up in a lab to coordinate the interaction of the screen with the components of the optical system. It was shown that the resolution of the lens-mirror-system is about one line pair per millimeter. An experiment is set up to test the impact of radiation on the optical qualities of the fibre optic bundle by installing it onto a “radioactive hot spot” at the bunch compressor in the FLASH accelerator.  
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