Author: Neff, B.
Paper Title Page
MOPPR011 A New Diagnostic Beamline at ELSA 795
  • S. Zander, F. Frommberger, P. Hänisch, W. Hillert, B. Neff
    ELSA, Bonn, Germany
  Funding: Funded by the DFG within the SFB / TR 16.
At the Electron Stretcher Facility (ELSA), a new synchrotron light diagnostic Beamline has been installed in order to perform high resolution, transversal and longitudinal beam profile measurements by analyzing the emitted synchrotron light. For this purpose, the main deflecting AL mirror selects a wide range of wavelengths from 200–800 nm out of the whole synchrotron spectrum. The setup of the beamline and its relevant components will be presented.
TUPPD052 A New Load Lock System for the Source of Polarized Electrons at ELSA 1521
  • D. Heiliger, W. Hillert, B. Neff
    ELSA, Bonn, Germany
  Funding: supported by DFG (SFB/TR16)
Since 2000, an inverted source of polarized electrons at the electron stretcher accelerator ELSA routinely provides a pulsed beam with a current of 100 mA and a polarization degree of about 80%. One micro-second long pulses with 100 nC charge are produced by irradiating a GaAs strained-layer superlattice photocathode (8 mm in diameter) with laser light. Future accelerator operation requires a significantly higher beam intensity, which can be achieved by using photocathodes with sufficiently high quantum efficiency. Therefore, and in order to enhance the reliability and up time of the source, a new extreme high-vacuum (XHV) load lock system was installed and commissioned at the beginning of this year. It consists of three chambers: The activation chamber for heat cleaning of the photocathodes and activation with cesium and oxygen. The storage chamber in which up to five different types of photocathodes with various diameters of the emitting surface can be stored under XHV conditions. The loading chamber in which an atomic hydrogen source is used to remove any remaining surface oxidation. Additionally, tests of the photocathodes’ properties can be performed during operation.