Justus, M.

Paper	Title	Page
TUPPH060	Three Years of CW-Operation at FELBE - Experiences and Applications	382
	W. Seidel, E. Cizmar, O. Drachenko, M. Helm, M. Justus, U. Lehnert, P. Michel, M. Ozerov, H. Schneider, R. Schurig, D. Stehr, M. Wagner, S. Winnerl, D. Wohlfarth, S. Zvyagin FZD, Dresden L. Eng, S. C. Kehr Dresden University of Technology, Institute of Applied Photophysics, Dresden
	This paper reviews the basic properties of the infrared free-electron laser FELBE at the Forschungszentrum Dresden-Rossendorf. A few highlight experiments using the cw-operation are discussed. Driven by a superconducting linear accelerator, FELBE continuously generates infrared pulses with a repetition rate of 13 MHz. In addition, operation in a macropulse modus (pulse duration >100 μs, repetition rate ≤ 25 Hz) is possible. At present FELBE delivers microJ pulses with typical duration of about 0.9-30 ps in the wavelength range 4-230 micrometer. Furthermore we give an outlook on the experiments will use the beam of FELBE in the High Magnetic Field Laboratory Dresden (HLD). The HLD will provide pulsed magnetic fields up to 60 T. It operates as a user facility since 2007.
THAAU02	Initial Commissioning Experience with the Superconducting RF Photoinjector at ELBE	467
	J. Teichert, A. Arnold, H. Buettig, D. Janssen, M. Justus, U. Lehnert, P. Michel, P. Murcek, A. Schamlott, Ch. Schneider, R. Schurig, F. Staufenbiel, R. Xiang FZD, Dresden T. Kamps, J. Rudolph, M. Schenk BESSY GmbH, Berlin G. Klemz, I. Will MBI, Berlin
	A radio frequency photo injector with a superconducting acceleration cavity (SRF gun) for installation at the Radiation Source ELBE was developed within a collaboration of BESSY, DESY, FZD, and MBI. The aim of the project is to improve the electron beam quality and to extend the parameter range of the ELBE accelerator. Especially the bunch charge will be increased up to 1 nC and the transverse emittance will be reduced to 1 - 3 mm mrad. At present, the thermionic injector at ELBE delivers bunches of 77 pC at about 8 mm mrad. Furthermore, the SRF gun together with its diagnostic beam line is an excellent test bench for extended studies and improvements of this new and promising injector type. The gun cryostat, the electron diagnostic beamline, and the driver laser with optical beamline were installed in summer and fall 2007. In November the first beam was produced. It will be reported on the experience gained at the first phase of commissioning. Results of rf and beam parameter measurements with Cu and Cs2Te photo cathodes will be presented.
	Slides
FRAAU03	Investigation and Improvement of Beam Stability at the ELBE FELs	543
	P. Michel, M. Justus, U. Lehnert, P. Michel, D. Proehl, R. Schurig, W. Seidel, J. Teichert FZD, Dresden
	At the radiation source ELBE in the Forschungszentrum Dresden-Rossendorf two free electron lasers (4-20 μm and 20-230 μm) are in routine user operation for a wide range of IR experiments for some years. The lasers are driven by a superconducting RF Linac which permits the generation of a cw-beam with high average beam power. For many experiments the frequency and power stability of the laser beam is of outstanding importance. Therefore studies on fluctuations and drifts in different time scales (from μs to hours) were accomplished and possible causes for these instabilities were investigated. To improve the long and short term stability we developed and implemented active feed back controls for electron energy and thus laser wavelength and out-coupled IR-beam power at ELBE.