Author: Balling, A.
Paper Title Page
MOPPR008 The Beam Loss Monitoring System at ELSA 786
  • D. Proft, A. Balling, F. Frommberger, W. Hillert
    ELSA, Bonn, Germany
  A new diagnostic tool to monitor beam loss in the storage ring at the Electron Stretcher Facility ELSA has been set up. It enables the investigation of causes for electron loss in real time, providing an essential tool needed to achieve the planned beam current upgrade from 30 mA to 200 mA. The monitoring system consists of 32 pin-diode based radiation detectors spread around the storage ring. Therefore, individual electron loss can be localized after each quadrupole. The readout system was designed to allow an integration of single loss events within 70 μs in order to be able to correlate these events to machine state changes. The used monitoring hardware and readout system will be detailed. Furthermore first measurements of the beam loss during injection, the fast energy ramp during acceleration and the extraction phase will be presented.  
MOPPR009 Dynamic Closed Orbit Correction During the Fast Energy Ramp of ELSA 789
  • J.-P. Thiry, A. Balling, A. Dieckmann, F. Frommberger, W. Hillert
    ELSA, Bonn, Germany
  ELSA is a fast ramping stretcher ring supplying polarized electrons to hadron physics experiments. To preserve the degreee of polarization, it is necessary to continuously correct the vertical orbit when accelerating the beam from 1.2 GeV to 2.4 GeV. Acceleration is performed within 300 ms, thus with a ramping speed of 4 GeV/s. During the acceleration, beam positions are measured at a rate of 1 kHz using 32 beam position monitors, which are mounted close to the quadrupole magnets. The demanding task is to achieve a vertical rms deviation not exceeding 50 μm all along the fast energy ramp. Therefore, dynamic orbit corrections are applied by means of offline feed-forward techniques, driving 32 vertical steerer magnets which can change currents in less than 10 ms. In our contribution, we show the used concepts and the implementation of the precise closed orbit correction system at ELSA.  
THPPD050 Fast Ramping Arbitrary Waveform Power Supplies for Correction Coils in a Circular Electron Accelerator 3623
  • A. Dieckmann, A. Balling, O. Boldt, F. Frommberger, W. Hillert, W. Lindenberg
    ELSA, Bonn, Germany
  New fast ramping power supplies working in pulsed bridge technology upgrade the existing Corrector System at ELSA. Current changes of ±0.8 A/msec are achieved. The newly developed CAN-Bus Interface allows linear interpolation of up to 250 support points with minimal time steps of 1msec. The first stage uses 24 power supplies to improve the position of the beam orbit in the horizontal plane using dipole correction coils. It will be extended to include the vertical plane with new corrector coils in the near future. This poster describes the operating principles of the power supply and the interface.