Author: Seebach, M.
Paper Title Page
WEPF24 Charge Monitors at the Relativistic Electron Gun for Atomic Exploration – REGAE 868
  • H. Delsim-Hashemi, K. Flöttmann, M. Seebach
    DESY, Hamburg, Germany
  • S. Bayesteh
    Uni HH, Hamburg, Germany
  A new linac is commissioned at DESY mainly as the electron source for femtosecond electron diffraction facility REGAE (Relativistic Electron Gun for Atomic Exploration). REGAE comprises a photo-cathode gun followed by normal conducting 1.5 cell rf-cavity to provide sub pC charge electron-bunches of 2-5 MeV with a coherence length of 30nm. In order to produce and maintain such electron bunches, sophisticated single-shot diagnostics are desired e.g. emittance, energy, energy-spread and bunch-length measurement. There are three methods at REGAE for charge measurement. The most routine method is based on Faraday-cups that are distributed along machine and can provide charge reading down to ~50 fC. The second method, which is non-destructive, is a cavity based antenna that measures beam induced fields. A third method is based on beam-profile measurement diagnostics. By proper calibration of integral intensity that arrives at detector one can measure charges down to fC level. The last method has the potential to reach the limit of few electrons charge when state-of-the-art intensifiers are used in profile monitors.  
WEPF25 Resonator for Charge Measurement at REGAE 872
  • D. Lipka, J. Lund-Nielsen, M. Seebach
    DESY, Hamburg, Germany
  A resonator has been developed for the diagnostics of dark current and charge measurements at the European XFEL, FLASH and PITZ. The first induced monopole mode TM01 at 1.3 GHz from charged bunches is used to detect the dark current and charge with high resolution at these accelerators. At REGAE this resonator with electronics is installed to detect the bunch charge because charges below pC are used and this device can resolve it non-destructively. The same electronics as for the dark current and charge measurement is used and the resolution is measured to be 2.3 fC for 200 fC.  
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