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Winter, A.

  
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TUBAU05 Technical Aspects of the Integration of the Optical Replica Synthesizer for the Diagnostics of Ultra-short Bunches into FLASH at DESY 296
 
  • P. van der Meulen, N. X. Javahiraly, M. Larsson
    FYSIKUM, AlbaNova, Stockholm University, Stockholm
  • E. Saldin, H. Schlarb, E. Schneidmiller, A. Winter, M. V. Yurkov
    DESY, Hamburg
  • V. G. Ziemann
    UU/ISV, Uppsala
  
  Recently, Saldin et al.* introduced a novel scheme to characterise ultra-short electron bunches in a FEL. The method is based on producing an 'optical copy' of the electron bunch, which can then be easily analysed using well-known non-linear optical techniques. To this end, a near-IR laser beam is overlapped with the electron beam in the first undulator of an optical klystron. In the following dispersive section the laser-induced energy modulation is transformed into a density modulation . The modulated electron bunch then produces a strong optical pulse in the second undulator. Analysis of this near-IR pulse (the optical copy) then provides information about the length, the slice emittance and the slice energy spread of the original electron bunch. We discuss the implementation of such a measurement set-up at the VUV-FEL at DESY and investigate the influence of various parameters on the performance of the device. Topics we address include the electron beam optics of the undulators, quadrupoles and the dispersive chicane, as well as the requirements for the seed laser pulses. The detection and analysis of the near-IR pulse and an extension to the XUV-FEL are also covered.

* E. Saldin, et al. "A simple method for the determination of the structure of ultrashort relativistic electron bunches," Nucl. Inst. and Methods A 539 (2005) 499.

 
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TUPPH056 Comparative Study of Digital and Analog Synchronization Techniques for Lasers in Accelerators 459
 
  • A. Winter
    DESY, Hamburg
  • W. J. Jalmuzna
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw
  
  Laser systems play an important role in present and future light sources. These lasers need to be synchronized very precisely to the accelerator RF. One aproach is using an analog controller, which offers low-noise performance and has been demonstrated to achieve sub-50 fs stability. A digital controller based on a high-performance FPGA on the other hand offers great flexibility, for instancethe possibility to implement notch filters to evade the limitations of piezo resonances. This paper presents results obtained with both approaches.