Schmidt, B.

Paper	Title	Page
WG506	Compact Ultra-High Precision Beam Phase Monitor System
	F. Loehl, K. E. Hacker, F. Ludwig, H. Schlarb, B. Schmidt DESY, Hamburg A. Winter Uni HH, Hamburg
	For the operation of free-electron lasers, in particular for experiments carried out in pump-probe configurations, a precise synchronization between the photo-injector laser, low-level RF-systems, probe lasers, and other components is mandantory. A measurement of the jitter in the arrival-time of the electron bunch with respect to the clock signal of a master oscillator is, therefore, of special importance. We present an ultra-precise arrival-time monitor system based on a broadband beam pick-up which permits measurements in the sub-100 fs regime. With the inductively shaped RF-pulse from the beam pick-up the amplitude of an ultra-short laser pulse is modulated using an electro-optical modulator with appropriate bandwidth. This modulation is detected by a photo detector and sampled by a fast ADC. As sampling laser the master laser oscillator of the machine is used directly. Therefore, no additional devices are required that may add timing jitter. We present the layout of the system and first experimental results.
	Slides
WG512	Longitudinal Diagnostics with THz Radiation	48
	H. Delsim-Hashemi, P. Schmüser Uni HH, Hamburg O. Grimm, B. Schmidt DESY, Hamburg
	According to the FEL theory, the longitudinal charge distribution in an electron bunch has an important effect on lasing process. For FLASH at DESY, structures in the order of 10 μm play a crucial role in SASE production. The investigation of the electron bunch longitudinal charge distribution and its bunch to bunch changes is one of the most important issues for optimizing the operation of the machine and improving its stability. Single shot spectroscopic in the 10–200 μm regime is beyond the capability of existing spectroscopic diagnostic tools. This paper introduces a new diagnostics method based on fast spectrally resolved detection of coherent infrared radiation from electron bunches. Measurement results at FLASH with this spectrometer in both scanning mode and single shot mode are presented and discussed.
	Slides
WG514	Electro-optical measurements of the longitudinal bunch shape at FLASH
	B. Steffen, E.-A. Knabbe, B. Schmidt DESY, Hamburg G. Berden FOM Rijnhuizen, Nieuwegein S. P. Jamison CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire P. J. Phillips UAD, Dundee P. Schmüser Uni HH, Hamburg
	Latest results on spectral decoding and temporal decoding EO measurements of the longitudinal bunch shape at FLASH will be presented, showing sub-200 fs EO signals.
	Slides