Steffen, B.

Paper	Title	Page
MOPPH055	Low Thermal Emittance Measurements at the PSI-XFEL Low Emittance Gun Test Facility	110
	Y. Kim, Å. Andersson, M. Dach, R. Ganter, C. Gough, C. P. Hauri, R. Ischebeck, F. Le Pimpec, M. Paraliev, M. Pedrozzi, T. Schietinger, B. Steffen, A. F. Wrulich PSI, Villigen
	To check performance of a planned low emittance gun (LEG) for the PSI XFEL project, a 500 kV pulsed diode based gun test facility was constructed at PSI in 2007. The gun was specially designed to have an adjustable gap between the cathode and the anode, and to allow extensive high gradient tests. Since the electron temperature at the cathode determines the minimum achievable slice emittance, we concentrated our efforts to measure the thermal emittance of a diamond turned copper cathode and stainless steel ones. To minimize emittance growth due to space charge effects, a single bunch with a charge of about 0.6 pC was used to characterize the beam. Since the experimental setup does not include an RF cavity, there was no dilution effects due to the non-linearity of the RF field. After optimizing the pulser to get a stable operation at 40 MV/m with the copper cathode, we could get about 0.2 mm.mrad range thermal emittance for a laser spotsize at the cathode of about 0.330 mm (RMS). In this paper, we report on our realistic thermal emittance measurements with copper and stainless steel cathodes at the LEG facility, which are much smaller than measured results by other laboratories.
	Slides
TUPPH076	Electro-optic Techniques for Longitudinal Electron Bunch Diagnostics	413
	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 B. Schmidt, P. Schmüser, B. Steffen DESY, Hamburg
	Electro-optic (EO) techniques are becoming increasingly important in ultrafast electron bunch longitudinal diagnostics and have been successfully implemented at various accelerator laboratories. The longitudinal bunch shape is directly obtained from a single-shot, non-intrusive, measurement of the temporal electric field profile of the bunch. Furthermore, the same EO techniques are used to measure the temporal profile of terahertz / far-infrared optical pulses generated by a CTR screen, at a bending magnet (CSR) or by an FEL. This contribution summarizes the results obtained at FELIX and FLASH.