Casalbuoni, S.

Paper	Title	Page
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.
	Video of talk
	Transparencies
THPLT046	The Synchrotron Radiation Beamline at TTF2	2583
	O. Grimm, S. Casalbuoni, L. Fröhlich, O. Peters, J. Rossbach DESY, Hamburg
	The VUV-FEL at DESY, Hamburg, will require novel techniques to characterize the longitudinal charge distribution of the electron bunches that drive the free-electron laser. Conventional methods are inadequate at the short bunch lengths that will be obtained. One technique under study uses coherent far-infrared radiation to reconstruct the bunch shape through Fourier analysis of the spectrum. In a first step, a beam line to guide both far-infrared (50-1000 um) and optical synchrotron radiation from one of the bunch compressor magnets of the linear accelerator to a diagnostic station outside of the controlled area is currently under construction. It will also allow a comparison between streak camera and far-infrared measurements for features on length scales above some 100 um (the streak camera resolution). Later, infrared techniques extending to shorter wavelengths, i.e. to shorter bunch lengths, will also be used further downstream the accelerator, employing synchrotron, transition and undulator radiation. The beam line design, measurement principle and first measurements will be presented.