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free-electron-laser

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CT04 The Beam Inhibit System for TTF II diagnostics, instrumentation, linac, electron 62
 
  • D. Nölle, P. Göttlicher, R. Neumann, D. Pugachov, K. Wittenburg, M. Wendt, M. Werner, H. Schlarb, M. Staack
    DESY, Deutsches Elektronen-Synchrotron, Hamburg, Germany
  • M. Desmons, A. Hamdi, M. Jablonka, M. Loung
    CEA, Commissariat à l'Energie Atomique, Saclay, France
  The new generation of light sources based on SASE Free-Electron-Lasers driven by LINACs operate with electron beams with high beam currents and duty cycles. This is especially true for the superconducting machines like TTF II and the X-RAY FEL, under construction or planning at DESY. Elaborate fast protections systems are required not only to protect the machine from electron beams hitting and destroying the vacuum chamber, but also to prevent the machine from running at high loss levels, dangerous for components like the FEL undulator. This paper will give an overview over the different protection systems currently under construction for TTF II. The very fast systems, based on transmission measurements and distributed loss detection monitors, will be described in detail. This description will include the fast electronics to collect and to transmit the different interlock signals.  
 
PT09 Cavity-Type BPMs For The TESLA Test Facility Free Electron Laser diagnostics, instrumentation, radio-frequency, undulator, TTF 190
 
  • H. Waldmann, H.J. Schreiber
    DESY-Zeuthen, Deutsches Elektronen-Synchrotron, Zeuthen, Germany
  For measurements of the beam position at the undulator section of the TESLA Test Facility (TTF) at DESY cavity-type beam position monitors were developed, installed and brought into operation. Besides of some theoretical aspects results of in-beam measurements at the TTF are presented and pros and cons of this monitor concept are discussed.  
 
PT23 Transverse Emittance Measurements at the Photo Injector Test Facility at DESY Zeuthen (PITZ) diagnostics, emittance, linac, transverse-dynamics, PITZ 225
 
  • V. Miltchev, K. Abrahamyan, J. Bähr, I. Bohnet, M. Krasilnikov, D. Lipka, A. Oppelt, F. Stephan
    DESY-Zeuthen, Deutsches Elektronen-Synchrotron, Zeuthen, Germany
  • K. Flöttmann
    DESY, Deutsches Elektronen-Synchrotron, Hamburg, Germany
  • I. Tsakov
    NRNE, Institute for Nuclear Reseach and Nuclear Energy of the Bulgarian Academy of Science, Sofia, Bulgaria
  The main research goal of the Photo Injector Test Facility at DESY Zeuthen (PITZ) is the development of electron sources with minimized transverse emittance like they are required for the successful operation of Free Electron Lasers and future linear colliders. The process of electron beam optimization requires characterization of the transverse emittance at a wide range of operation parameters. The design and functionality of the emittance measurement system at PITZ is presented. The methods applied as well as the resolution limits of the system are discussed. The latest measurements of the transverse properties of the electron beam are presented.  
 
PT31 Optical Fibre Dosimeter for SASE FEL Undulators beam-losses, diagnostics, instrumentation, optics 248
 
  • M. Körfer
    DESY, Deutsches Elektronen-Synchrotron, Hamburg, Germany
  • H. Henschel, J. Kuhnhenn
    Fraunhofer-INT, Fraunhofer-INT, Euskirchen, Germany
  • F. Wulf
    HMI, Hahn-Meitner Institut, Berlin, Germany
  Single pass Free Electron Lasers (FELs) based on self-amplified spontaneous emission (SASE) are developed for high brightness and short wavelength applications. They use permanent magnet undulators which are radiation sensitive devices. During accelerator commissioning beam losses can appear anywhere along the undulator line. To avoid damage of the permanent magnets due to radiation, an optical fibre dosimeter system can be used. The increase of absorption caused by ionizing radiation is measured in radiation sensitive optical fibers. The dose system enables relatively fast particle loss tuning during accelerator operation and allows the monitoring of the accumulated dose. Dose measurements in narrow gaps which are inaccessible for any other (online) dosimeter type become possible. The electromagnetic insensitivity of optical fibre sensor is an advantage of applications in strong magnetic undulator fields. At each location the light absorption is measured by using an optical power-meter. The dynamic range is about 50 dB and covers the linear range of the dose calibration of the fibre. The resolution of the system is 140 mGy. The time between successive measurements is about 5 minutes. The system was installed and successfully tested at the TESLA Test Facility TTF1. The fibre sensors will be a standard diagnostic tool in the soft X-ray user facility TTF2.