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Effect of the Various Impedances on Longitudinal Beam Stability in the CERN SPS

The High Luminosity (HL)-LHC project at CERN aims at a luminosity increase by a factor ten and one of the necessary ingredients is doubling the bunch intensity to 2.4x10¹¹ ppb for beams with 25 ns bunch spacing. Many improvements are already foreseen in the frame of the LHC Injector Upgrade (LIU) pr...

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Autores principales: Lasheen, Alexandre, Argyropoulos, Theodoros, Repond, Joël, Shaposhnikova, Elena
Lenguaje:eng
Publicado: 2016
Materias:
Acceso en línea:https://dx.doi.org/10.18429/JACoW-IPAC2016-TUPOR008
http://cds.cern.ch/record/2207387
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author Lasheen, Alexandre
Argyropoulos, Theodoros
Repond, Joël
Shaposhnikova, Elena
author_facet Lasheen, Alexandre
Argyropoulos, Theodoros
Repond, Joël
Shaposhnikova, Elena
author_sort Lasheen, Alexandre
collection CERN
description The High Luminosity (HL)-LHC project at CERN aims at a luminosity increase by a factor ten and one of the necessary ingredients is doubling the bunch intensity to 2.4x10¹¹ ppb for beams with 25 ns bunch spacing. Many improvements are already foreseen in the frame of the LHC Injector Upgrade (LIU) project, but probably this intensity would still not be reachable in the SPS due to longitudinal instabilities. Recently a lot of effort went into finding the impedance sources of the instabilities. Particle simulations based on the latest SPS impedance model are now able to reproduce the measured instability thresholds and were used to determine the most critical impedance sources by removing them one by one from the model. It was found that impedance of vacuum flanges and of the already damped 630 MHz HOM of the main RF system gave for 72 bunches the comparable intensity thresholds. Possible intensity gains are defined for realistic impedance modifications and for various beam configurations (number of bunches, longitudinal emittances) and RF programs (single and double RF). The results of this study are used as a guideline for planning of a new campaign of the SPS impedance reduction.
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institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2016
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spelling oai-inspirehep.net-14699892022-08-10T12:48:00Zdoi:10.18429/JACoW-IPAC2016-TUPOR008http://cds.cern.ch/record/2207387engLasheen, AlexandreArgyropoulos, TheodorosRepond, JoëlShaposhnikova, ElenaEffect of the Various Impedances on Longitudinal Beam Stability in the CERN SPSAccelerators and Storage RingsThe High Luminosity (HL)-LHC project at CERN aims at a luminosity increase by a factor ten and one of the necessary ingredients is doubling the bunch intensity to 2.4x10¹¹ ppb for beams with 25 ns bunch spacing. Many improvements are already foreseen in the frame of the LHC Injector Upgrade (LIU) project, but probably this intensity would still not be reachable in the SPS due to longitudinal instabilities. Recently a lot of effort went into finding the impedance sources of the instabilities. Particle simulations based on the latest SPS impedance model are now able to reproduce the measured instability thresholds and were used to determine the most critical impedance sources by removing them one by one from the model. It was found that impedance of vacuum flanges and of the already damped 630 MHz HOM of the main RF system gave for 72 bunches the comparable intensity thresholds. Possible intensity gains are defined for realistic impedance modifications and for various beam configurations (number of bunches, longitudinal emittances) and RF programs (single and double RF). The results of this study are used as a guideline for planning of a new campaign of the SPS impedance reduction.CERN-ACC-2016-238oai:inspirehep.net:14699892016
spellingShingle Accelerators and Storage Rings
Lasheen, Alexandre
Argyropoulos, Theodoros
Repond, Joël
Shaposhnikova, Elena
Effect of the Various Impedances on Longitudinal Beam Stability in the CERN SPS
title Effect of the Various Impedances on Longitudinal Beam Stability in the CERN SPS
title_full Effect of the Various Impedances on Longitudinal Beam Stability in the CERN SPS
title_fullStr Effect of the Various Impedances on Longitudinal Beam Stability in the CERN SPS
title_full_unstemmed Effect of the Various Impedances on Longitudinal Beam Stability in the CERN SPS
title_short Effect of the Various Impedances on Longitudinal Beam Stability in the CERN SPS
title_sort effect of the various impedances on longitudinal beam stability in the cern sps
topic Accelerators and Storage Rings
url https://dx.doi.org/10.18429/JACoW-IPAC2016-TUPOR008
http://cds.cern.ch/record/2207387
work_keys_str_mv AT lasheenalexandre effectofthevariousimpedancesonlongitudinalbeamstabilityinthecernsps
AT argyropoulostheodoros effectofthevariousimpedancesonlongitudinalbeamstabilityinthecernsps
AT repondjoel effectofthevariousimpedancesonlongitudinalbeamstabilityinthecernsps
AT shaposhnikovaelena effectofthevariousimpedancesonlongitudinalbeamstabilityinthecernsps