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Bahrdt, J.

Paper Title Page
TUPMN012 STARS - A Two-Stage High-Gain Harmonic Generation FEL Demonstrator 938
 
  • T. Kamps, M. Abo-Bakr, W. Anders, J. Bahrdt, P. Budz, K. B. Buerkmann-Gehrlein, O. Dressler, H. A. Duerr, V. Duerr, W. Eberhardt, S. Eisebitt, J. Feikes, R. Follath, A. Gaupp, R. Goergen, K. Goldammer, S. C. Hessler, K. Holldack, E. Jaeschke, S. Klauke, J. Knobloch, O. Kugeler, B. C. Kuske, P. Kuske, A. Meseck, R. Mitzner, R. Mueller, M. Neeb, A. Neumann, K. Ott, D. Pfluckhahn, T. Quast, M. Scheer, Th. Schroeter, M. Schuster, F. Senf, G. Wuestefeld
    BESSY GmbH, Berlin
  • D. Kramer
    GSI, Darmstadt
  • F. Marhauser
    JLAB, Newport News, Virginia
 
  Funding: Bundesministerium fur Bildung und Forschung and the Land Berlin

BESSY is proposing a demonstration facility, called STARS, for a two-stage high-gain harmonic generation free electron laser (HGHG FEL). STARS is planned for lasing in the wavelength range 40 to 70 nm, requiring a beam energy of 325 MeV. The facility consists of a normal conducting gun, three superconducting TESLA-type acceleration modules modified for CW operation, a single stage bunch compressor and finally a two-stage HGHG cascaded FEL. This paper describes the faciliy layout and the rationale behind the operation parameters.

 
TUPMN013 Dynamic Multipole Shimming of the APPLE Undulator UE112 941
 
  • J. Bahrdt, W. Frentrup, A. Gaupp, M. Scheer, G. Wuestefeld
    BESSY GmbH, Berlin
 
  The dynamic off axis field integrals of the BESSY UE112 are of the order of 3 Tmm. They reduce the dynamic aperture significantly which is not tolerable for top-up operation. The dynamic multipoles have successfully been shimmed for the elliptical mode using distributed Fe-shims. In the inclined mode the multipoles are minimized actively with rotatable permanent magnets which are adjusted dependent on gap and phase position. The dynamic properties of the unshimmed and the shimmed device have been simulated using an analytic model for the field description and a generating function algorithm for tracking.