Author: Frommberger, F.
Paper Title Page
MOP169 Optical Beam Diagnostics at ELSA 408
 
  • S. Zander, F. Frommberger, P. Haenisch, W. Hillert, S. Patzelt
    ELSA, Bonn, Germany
 
  Funding: Funded by the DFG within the SFB / TR 16.
The Electron Stretcher Facility ELSA consists of several accelerator stages, the last one being a storage ring providing a beam of polarized electrons of up to 3.5 GeV. At ELSA various diagnostic devices based on synchrotron radiation are installed or planned. A new beamline at the storage ring designed for high resolution diagnostics in the transversal plane will be presented. The measurement setup is sensitive at the UV range of the synchrotron light spectrum. Upgrade measures aiming to extend the diagnostic possibilities to the longitudinal direction will be detailed. In the external beamlines beam currents below 1 nA are delivered to photo production experiments. Beam profiles are detected using dedicated synchrotron light monitors optimized for low intensities. The characteristics of the monitors will be described. In addition, beam parameters derived from the measured profiles at different resonance extraction setups will be shown.
 
 
WEP003 A New Correction Scheme to Compensate Depolarizing Integer Resonances at ELSA 1507
 
  • O. Boldt, A. Dieckmann, F. Frommberger, W. Hillert
    ELSA, Bonn, Germany
 
  Funding: BMBF
Since more than four decades, the University of Bonn supports research at the in-house electron accelerator ELSA. Presently, the polarized electrons gained from an inverted source are accumulated in a stretcher ring and accelerated within a fraction of a second up to 3.2 GeV. During the fast ramping various depolarizing resonances are crossed. By taking several expedient measures (closed orbit correction, tune jumping, etc.) a high polarization degree of up to 65% is reached. One important part of these measures is the harmonic correction of integer resonances. Those resonances are compensated by applying additional horizontal fields, distributed sinusoidally along an one-turn orbit length. In case of an appropriate setting of amplitude and phase, all resonance driving effects should be neutralized completely. First studies have shown that vertical displacements and resulting horizontal fields in the quadrupole magnets, caused by the resonance correction, have to be taken into account as well. With regard to a new correction scheme, the first experimental results confirmed by simulative and theoretical studies will be presented.