Keyword: ECR
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WEOA02 Optical Investigation to Minimize the Electron Bunch Arrival-time Jitter Between Femtosecond Laser Pulses and Electron Bunches for Laser-Driven Plasma Wakefield Accelerators laser, plasma, electron, polarization 332
 
  • S. Mattiello, A. Penirschke
    THM, Friedberg, Germany
  • H. Schlarb
    DESY, Hamburg, Germany
 
  Funding: The work of S. Mattiello is supported by the German Federal Ministry of Education and Research (BMBF) within the Project ' MAKE-PWA.
In a laser driven plasma based particle accelerators a stable synchronization of the electron bunch and of the plasma wakefield in the range of less than 2 fs is necessary in order to optimize the acceleration. For this purpose we are developing a new shot to shot feedback system with a time resolution of less than 1 fs. As a first step, stable THz pulses are generated by optical rectification of a fraction of the plasma generating high energy laser pulses in a nonlinear lithium niobate crystal. It is planed that the generated THz pulses will energy modulate the electron bunches shot to shot before the plasma to achieve the time resolution of 1 fs. In this contribution we systematically investigate the influence of the optical properties as well as the theoretical description of the THz generation on the conversion efficiency of the generation of short THz pulses in undepleted approximation. We compare different approximations for the modeling of the generation dynamics and of the dielectric function in order to investigate the importance of a detailed description of the optical properties. First results by considering intensity decreasing of the laser pump will be presented.
*The feedback system will be tested at the Accelerator R&D facility SINBAD (Short Innovative Bunches and Accelerators at DESY).
 
slides icon Slides WEOA02 [1.605 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEOA02  
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WEOC03 A Simple Model to Describe Smoke Ring Shaped Beam Profile Measurements With Scintillating Screens at the European XFEL FEL, electron, diagnostics, scattering 366
 
  • G. Kube, S. Liu, A.I. Novokshonov, M. Scholz
    DESY, Hamburg, Germany
 
  Standard beam profile measurements of high-brightness electron beams based on OTR may be hampered by coherence effects. Therefore it was decided for the European XFEL to measure transverse beam profiles based on scintillating screen monitors using LYSO:Ce. While it is possible to resolve beam sizes down to a few micrometers with this scintillator, the experience during the XFEL commissioning showed that the measured emittance values were significantly larger than the expected ones. In addition, beam profiles measured at bunch charges of a few hundred pC showed a 'smoke ring' structure. While coherent OTR emission and beam dynamical influence can be excluded, it is assumed that the profile distortions are caused by effects from the scintillator material. Following the experience in high energy physics, a simple model was developed which takes into account quenching effects of excitonic carriers inside a scintillator in a heuristic way. Based on this model, the observed beam profiles can be understood qualitatively. Together with the model description, first comparisons with experiments will be presented, and new scintillators suitable for beam profile diagnostics will be discussed.  
slides icon Slides WEOC03 [2.411 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEOC03  
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WEPC19 Selection of Wires for the New Generation of Fast Wire Scanners at CERN acceleration, proton, synchrotron, brightness 523
 
  • A. Mariet, R. Veness
    CERN, Geneva, Switzerland
 
  A new generation of fast wire scanners is being produced as part of the LHC Injector Upgrade (LIU) project at CERN. The LIU beam parameters imply that these wire scanners will need to operate with significantly brighter beams. This requires wires scanner systems with micron level accuracy and wires with a considerably increased tolerance to beam damage. This paper presents the method of selection of such wires in terms of material choice and geometry. It also reports on studies with novel materials with a potential to further extend the reach of wire scanners for high brightness beams.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPC19  
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