A   B   C   D   E   F   G   H   I   K   L   M   O   P   Q   R   S   T   V   W    

closed-orbit

Paper Title Other Keywords Page
IT04 Fast Positional Global Feedback for Storage Rings feedback, dipole, power-supply, damping 7
 
  • E. Plouviez
    ESRF, The European Synchrotron Radiation Facility, Grenoble, France
  Stability of the closed orbit of a storage ring is limited by the stability of the components defining this orbit: magnets position and field values. Measurements of the variation of the stored beam orbit with respect to a nominal orbit and application of orbit correction derived from these measurements can reduce these distortions. The subject of this talk is the implementation of such correction at high frequencies (up to about 100 Hz) using global correction schemes. The basic theoretical aspects of the problem will be presented:
  • Global versus local scheme
  • Feedback loop dynamics.
The technical problems associated with the implementation of such systems will also be addressed:
  • BPM and correctors design
  • Feedback loop electronic design
 
 
PT01 Closed-orbit correction using the new beam position monitor electronic of Elsa Bonn quadrupole, electron, resonance, alignment 153
 
  • J. Dietrich, I. Mohos, J. Keil
    IKP, Forschungszentrum Jülich GmbH, Jülich, Germany
  RF and digital electronics, developed at the Forschungszentrum Jülich/IKP were integrated to form the new beam position monitor (BPM) system at the Electron Stretcher Accelerator (ELSA) of the University of Bonn. With this system the preservation of the polarization level during acceleration was currently improved by a good correction of the closed-orbit. All BPM offsets relative to the magnetic quadrupole centers were determined by the method of beam-based alignment. The optics functions measured by the BPM system are in good agreement with theoretical predictions.  
 
PT06 New digital BPM system for the Swiss light source feedback, storage-ring, booster, alignment 168
 
  • M. Dehler, A. Jaggi, P. Pollet, T. Schilcher, V. Schlott, R. Uršič, R. deMonte
    PSI, Paul Scherrer Institut, Villigen, Switzerland
  This paper presents a new digital beam position monitor (DBPM) system which is currently under development for the Swiss Light Source (SLS). It is designed to provide sub-micron position data in normal closed orbit, and feedback mode as well as turn by turn information for machine studies and real time tune measurements. The self calibrating four channel system consists of a RF front end, a digital receiver and a DSP module. The same electronics will be used in all sections of the SLS accelerator complex. The system can be reconfigured in real time to perform different kind of measurements like: pulsed for linac and transfer lines, first turn, turn-by-turn, closed orbit, feedback and even tune mode for booster and storage ring. These reconfigurations only involve downloading of new signal processing software and will be performed via EPICS control system. An independent system for monitoring mechanical drifts of the BPM stations will be installed as well. The measured data will be permanently updated in a database and taken into account, when processing the final electron beam positions.  
 
PT09 The closed-orbit measurement system for the CERN antiproton decelerator antiproton, pick-up, vacuum, shielding 177
 
  • M. LeGras, L. Søby, D.J. Williams
    CERN, Geneva, Switzerland
  The closed-orbit measurement system for the new Antiproton Decelerator (AD) employs 59 electrostatic pick-ups (PU). The intensity range from 2·1010 down to 107 particles poses challenging demands on the dynamic range and noise of the head amplifier. A low noiseamplifier has been developed, having an equivalent input noise of 0.6nV/√(Hz), allowing beam positions to be measured to ±0.5 mm with 5·106 particles. Two different gains take care of the large dynamic range. After amplification and multiplexing, the PU signals are fed to a network analyser, where each measurement point corresponds to one PU. The network analyser is phase locked to the RF of the AD, thus acting as a “tracking filter” instrument. An orbit measurement takes from 0.2 to 12 s depending on the IF-bandwidth of the network analyser, selected according to the beam intensity, and the precision required. At the end of the network analyser sweep the data are read via a GPIB interface and treated by a real-time task running in a VME based Power PC.