Steffen, B.

Paper	Title	Page
MOPKF020	Proposal for a Sub-100 fs Electron Bunch Arrival-time Monitor for the VUV-FEL at DESY	345
	H. Schlarb, S. Düsterer, J. Feldhaus, J. Hauschildt, R. Ischebeck, K. Ludwig, B. Schmidt, P. Schmüser, S. Simrock, B. Steffen, F. Van den Berghe, A. Winter DESY, Hamburg P.H. Bucksbaum, A. Cavalieri, D. Fritz, S. Lee, D. Reis Michigan University, Ann Arbor, Michigan
	For pump-probe experiments at the VUV-Free Electron Laser at DESY, an external optical laser system will be installed, capable of delivering ultra-short pulses of high intensity. The laser pulses with a center wavelength of 800 nm are synchronized with the VUV-FEL beam which covers the wavelength range between 6 nm and 80 nm. The expected pulse durations are typically 100 fs FWHM or below. For high-resolution pump-probe experiments a precise knowledge of the time difference between both pulses is mandatory. In this paper we describe the layout and the design of a high-precision electron bunch arrival time monitor based on an electro-optic technique. We present the numerical results of simulations that include: the laser propagation in a specifically designed demanding optical system, the laser transport through a 150 m long optical fibre, the electro-optically induced effect in different types of crystals and for different electron bunch shapes as well as the effects of wake fields on the co-propagating electric-fields and their impact on the observable signals.
THOALH01	Bunch Length Measurements at the SLS Linac using Electro-optical Techniques	253
	A. Winter, M. Tonutti RWTH, Aachen S. Casalbuoni, P. Schmüser, S. Simrock, B. Steffen DESY, Hamburg T. Korhonen, T. Schilcher, V. Schlott, H. Sigg, D. Suetterlin PSI, Villigen
	The temporal profile of the electron bunches in the SLS Linac will be determined by means of electro-optical techniques. A mode locked Ti:Sa Laser with 15 fs pulse width is used for coincidence measurements between the laser pulse and the coherent transition radiation (CTR) generated by short electron bunches. Synchronization accuracy of 100 fs rms between the 3 GHz Linac RF and the 81 MHz repetition rate of the laser was achieved, which is important for the optimum time resolution of the applied electro-optical sampling technique. Likewise, a mode locked Nd:YAG laser with 400 ps long pulses will be used for electro-optical autocorrelation measurements between the CTR and the laser pulses. This alternative technique promises single shot capability and requires much relaxed synchronization stability between laser and electron beam.
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