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                - V. R. Arsov, E.-A. Knabbe, B. Schmidt, P. Schmüser, B. Steffen
 
                       DESY, Hamburg 
                - G. Berden, A. F.G. van der Meer
 
                       FOM Rijnhuizen, Nieuwegein 
                - W. A. Gillespie, P. J. Phillips
 
                       University of  Dundee, Nethergate, Dundee, Scotland 
                - S. P. Jamison
 
                       STFC/DL/ASTeC, Daresbury, Warrington, Cheshire 
                - A. MacLeod
 
                       UAD, Dundee 
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            At the superconducting linac of FLASH at DESY, we have installed an electro-optic experiment for single shot, non-destructive measurements of the longitudinal electric charge distribution of individual electron bunches. The profile of the electric bunch field is electro-optically encoded onto a stretched Ti:Sa laser pulse. In the decoding step, the profile is retrieved from a cross-correlation of the encoded pulse with a 35 fs laser pulse, obtained from the same laser. At FLASH, sub-100 fs electron bunches have been measured during FEL operation with a resolution of better than 50 fs. The electro-optic encoding process in gallium phosphide as well as the decoding step in a frequency doubling BBO crystal were numerically simulated using bunch shapes simultaneously measured with a transverse-deflecting rf structure as input data. In this contribution, we present electro-optically measured profiles and compare them with the simulation.
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