Paper |
Title |
Page |
MOPJE035 |
An Extended SPS Longitudinal Impedance Model |
360 |
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- J.V. Campelo, T. Argyropoulos, T. Bohl, F. Caspers, J.F. Esteban Müller, J.B. Ghini, A. Lasheen, D. Quartullo, B. Salvant, E.N. Shaposhnikova, C. Zannini
CERN, Geneva, Switzerland
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Longitudinal multi-bunch instability in the CERN SPS with a very low intensity threshold is a serious limitation for the future doubling of bunch intensity required by Hi-Lumi LHC project. A complete and accurate impedance model is essential to understand the nature of this instability and to plan possible cures. This contribution describes in detail the current longitudinal impedance model of the SPS. Recently, the model was updated with new findings and includes now the impedance of accelerating cavities, kicker and septum magnets, beam position monitors, vacuum Flanges, shielded and unshielded pumping ports, electrostatic septa and resistive wall. Electromagnetic simulations and bench measurements were used to build the model. The contribution from each element is described and compared to the total machine impedance. Together with relevant beam measurements and simulations, the analysis of the different sources of impedance is used to identify the source of the longitudinal instability limiting the SPS performance so that the responsible elements can be acted upon.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE035
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THPF091 |
Detailed Studies of Beam Induced Scrubbing in the CERN-SPS |
3908 |
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- G. Iadarola, H. Bartosik, T. Bohl, B. Goddard, G. Kotzian, K.S.B. Li, L. Mether, G. Rumolo, M. Schenk, E.N. Shaposhnikova, M. Taborelli
CERN, Geneva, Switzerland
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In the framework of the LHC Injectors Upgrade (LIU) program, it is foreseen to take all the necessary measures to avoid electron cloud effects in the CERN-SPS. This can be achieved by either relying on beam induced scrubbing or by coating the vacuum chambers with intrinsically low Secondary Electron Yield (SEY) material over a large fraction of the ring. To clearly establish the potential of beam induced scrubbing, and to eventually decide between the two above options, an extensive scrubbing campaign is taking place at the SPS. Ten days in 2014 and two full weeks in 2015 are devoted to machine scrubbing and scrubbing qualification studies. This paper summarizes the main findings in terms of scrubbing efficiency and reach so far, addressing also the option of using a special doublet beam and its implication for LHC.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2015-THPF091
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THPF093 |
Status of the LHC Injectors Upgrade (LIU) Project at CERN |
3915 |
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- M. Meddahi, J. Coupard, H. Damerau, A. Funken, S.S. Gilardoni, B. Goddard, K. Hanke, L. Kobzeva, A.M. Lombardi, D. Manglunki, S. Mataguez, B. Mikulec, G. Rumolo, E.N. Shaposhnikova, M. Vretenar
CERN, Geneva, Switzerland
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CERN is currently carrying out an ambitious improvement programme of the full LHC Injectors chain in order to enable the delivery of beams with the challenging HL-LHC parameters. The LHC Injectors Upgrade project coordinates this massive upgrade program, and covers a new linac (Linac4 project) as well as upgrades to the Proton Synchrotron Booster, the Proton Synchrotron and Super Proton Synchrotron. The heavy ion injector chain is also included, adding the Linac3 and Low Energy Ion Ring to the list of accelerators concerned. The performance objectives and roadmap of the main upgrades will be presented, including the work status and outlook. The machine studies and milestones during LHC Run 2 will be discussed and a preliminary Long Shutdown 2 installation planning given. Finally, for the LHC Run 3, the beam performance across the full injector chain after all the upgrades will be estimated and the required commissioning stages outlined.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2015-THPF093
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