Title :
Simulation study of the horizontal head-tail instability observed at injection of the CERN Proton Synchrotron
Author :
Métral, E. ; Rumolo, G. ; Steerenberg, R. ; Salvant, B.
Author_Institution :
CERN, Geneva
Abstract :
For many years, a horizontal head-tail instability has been observed at the CERN Proton Synchrotron during the long 1.2 s injection flat-bottom. This slow instability has been damped using linear coupling only, i.e. with neither octupoles nor feedbacks. Using the nominal machine and beam parameters for LHC, the sixth head-tail mode number is usually observed. Several other modes were also observed in the past by tuning the chromaticity, and these observations were found to be in good agreement with Sacherer´s formula. The purpose of this paper is to present the results of assessing the effect of chromaticity and linear coupling on this slow head-tail instability using the HEADTAIL simulation code, and to compare these simulations with both measurements performed over the last few years, and theoretical calculations.
Keywords :
particle beam injection; particle beam stability; proton accelerators; synchrotrons; CERN PS; CERN Proton Synchrotron; HEADTAIL simulation code; LHC; Sacherer formula; beam parameters; chromaticity effect; head-tail mode number; horizontal head-tail instability; injection flat-bottom; linear coupling; nominal machine; Computational modeling; Current measurement; Feedback; Impedance; Large Hadron Collider; Optical coupling; Performance evaluation; Protons; Space charge; Synchrotrons;
Conference_Titel :
Particle Accelerator Conference, 2007. PAC. IEEE
Conference_Location :
Albuquerque, NM
Print_ISBN :
978-1-4244-0916-7
DOI :
10.1109/PAC.2007.4439983