Author: Morvillo, M.
Paper Title Page
WEPOTK046 Improved Longitudinal Performance of the LHC Beam in the CERN PS 2165
 
  • H. Damerau, V.D. Desquiens, A. Huschauer, A. Jibar, A. Lasheen, B. Mikulec, M. Morvillo, C. Rossi, B.J. Woolley
    CERN, Meyrin, Switzerland
 
  At the end of the 2018 run the intensity target for the High-Luminosity LHC (HL-LHC) had just been reached at extraction from the Proton Synchrotron (PS). In the framework of the LHC Injectors Upgrade (LIU) project additional RF improvements have been implemented during the 2019/2020 long shutdown (LS2), mainly impacting the impedance of the 10 MHz, 40 MHz, and 80 MHz RF systems. With the upgraded injection energy of 2 GeV (kinetic), also the intermediate plateau energy for RF manipulations has been increased. Following a campaign of beam studies throughout the 2021 run, a bunch intensity of up to 2.9·1011 p/b in trains of 72 bunches is achieved with the required longitudinal beam quality, surpassing the LIU target of 2.6·1011 p/b. The threshold of longitudinal quadrupolar coupled-bunch instabilities is increased during acceleration, but they are again observed at the flat-top. While dipolar coupled-bunch oscillations are well damped by a dedicated feedback system, the quadrupolar modes are suppressed by operating a 40 MHz system as an active higher-harmonic Landau cavity. The main commissioning steps are outlined, together with the key contributions to the improved beam performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK046  
About • Received ※ 07 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022  
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