Title :
Measurements of impedance distributions and instability thresholds in LEP
Author :
Brandt, D. ; Castro, P. ; Cornelis, K. ; Hofmann, A. ; Morpurgo, G. ; Sabbi, G.L. ; Wenninger, J. ; Zotter, B.
Author_Institution :
CERN, Geneva, Switzerland
Abstract :
The distribution of reactive and resistive components of the transverse impedance around the circumference of LEP has been obtained by exciting the beam and measuring the variations of phase advance and of closed orbit displacements with beam current. Tune shifts with current and instability thresholds were determined for two machine lattices with different beta functions and momentum compaction for various values of bunch length and synchrotron frequency. These measurements are particularly interesting for LEP2, which will require larger bunch currents to achieve the design luminosity
Keywords :
beam handling techniques; colliding beam accelerators; electric impedance measurement; electron accelerators; particle beam diagnostics; particle beam stability; storage rings; synchrotrons; LEP; LEP2; beam current; beta functions; bunch length; closed orbit displacements; design luminosity; impedance distributions measurements; instability thresholds; machine lattices; momentum compaction; phase advance variations; reactive component; resistive component; synchrotron frequency; transverse impedance; tune shifts; Compaction; Current measurement; Displacement measurement; Extraterrestrial measurements; Frequency; Impedance measurement; Lattices; Particle measurements; Phase measurement; Synchrotrons;
Conference_Titel :
Particle Accelerator Conference, 1995., Proceedings of the 1995
Conference_Location :
Dallas, TX
Print_ISBN :
0-7803-2934-1
DOI :
10.1109/PAC.1995.504722
