Paper |
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MOPOST037 |
Characterisation of Bunch-by-Bunch Tune Shift Effects in the CERN SPS |
148 |
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- I. Mases Solé, H. Bartosik, V. Kain, K. Paraschou, M. Schenk, C. Zannini
CERN, Meyrin, Switzerland
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After the implementation of major upgrades as part of the LHC Injector Upgrade Project (LIU), the Super Proton Synchrotron (SPS) delivers high intensity bunch trains with 25 ns bunch spacing to the Large Hadron Collider (LHC) at CERN. These beams are exposed to several collective effects in the SPS, such as beam coupling impedance, space charge and electron cloud, leading to relatively large bunch-by-bunch coherent and incoherent tune shifts. Tune correction to the nominal values at injection is crucial to ensure beam stability and good beam transmission. During the beam commissioning of the SPS, measurements of the bunch-by-bunch coherent tune shifts have been conducted under different beam conditions, together with appropriate corrections of the average tunes at each injection. In this paper, we describe the methodology that has been developed to acquire bunch-by-bunch position data and to perform online computations of the coherent tune spectra of each bunch using refined Fourier transform analysis. The experimental data are compared to multiparticle tracking simulations using the SPS impedance model, in view of developing an accurate model for tune correction in the SPS.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST037
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About • |
Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022 |
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MOPOST056 |
Interplay between Space Charge and Intra-beam Scattering for the CERN Ion Injectors |
214 |
SUSPMF073 |
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- M. Zampetakis, F. Antoniou, F. Asvesta, H. Bartosik, Y. Papaphilippou
CERN, Meyrin, Switzerland
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The CERN ion injectors, SPS and LEIR, operate in a strong space charge and intra-beam scattering regime, which can lead to degradation of their beam performance. To optimize machine performance requires thus to study the interplay of these two effects in combined space charge and intrabeam scattering tracking simulations. In this respect, the kinetic theory approach of intra-beam scattering has been implemented in pyORBIT and benchmarked against analytical models. First results of combined space charge and intra-beam scattering simulations for SPS and LEIR are presented in this contribution. The simulation results are compared with observations from beam measurements.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST056
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About • |
Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 07 July 2022 |
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MOPOST057 |
Characterization of the Vertical Beam Tails in the CERN PS Booster |
218 |
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- T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, G.P. Di Giovanni, E. Renner
CERN, Meyrin, Switzerland
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The CERN Proton Synchrotron Booster (PSB) went through major upgrades in the framework of the LHC Injectors Upgrade Project (LIU) aiming to double the brightness of the LHC beams. Operation restarted in early 2021, demonstrating the expected performance improvement. The high-brightness beams, nevertheless, appear to have overpopulated tails in the vertical beam profiles, both at injection and at extraction energies. In an attempt to understand the origin and evolution of the observed tails, systematic profile measurements were performed for different machine and beam configurations using Wire Scanners (WS). The results are presented in this report and compared to simulations. The effect of the Coulomb scattering of the wire to the beam distribution is also addressed.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST057
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About • |
Received ※ 03 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022 |
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MOPOST058 |
Studies on the Vertical Half-Integer Resonance in the CERN PS Booster |
222 |
SUSPMF074 |
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- T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik
CERN, Meyrin, Switzerland
- G. Franchetti
GSI, Darmstadt, Germany
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Following the upgrades of the LHC Injectors Upgrade Project (LIU), the Proton Synchrotron Booster (PSB) at CERN successfully delivers beams with double brightness. An important contributing factor for this was the dynamic correction of the beta-beating induced by the injection chicane, which allowed stable operation closer to the half-integer resonance. Ideally, injection above the half-integer resonance could further improve the beam brightness. In this context, a series of studies were initiated in order to characterize the effects of space charge when crossing the half-integer resonance. In this contribution, the first results of these investigations are reported.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST058
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About • |
Received ※ 03 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022 |
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MOPOTK028 |
Zero Dispersion Optics to Improve Horizontal Emittance Measurements at the CERN Proton Synchrotron |
503 |
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- W. Van Goethem, F. Antoniou, F. Asvesta, H. Bartosik, A. Huschauer
CERN, Meyrin, Switzerland
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In modern particle accelerators, the horizontal dispersion function is forced to zero at locations with instrumentation measuring the transverse beam distribution, in order to remove the dispersive contribution to the horizontal beam size. The design of the CERN Proton Synchrotron did not foresee such a zero-dispersion insertion, making it challenging to get a good precision on the beam size measurements. In this contribution, we present a new optics configuration, which allows to reach zero horizontal dispersion at the locations of different beam size measurement locations. This can be achieved by powering a set of trim quadrupoles, the so-called Low Energy Quadrupoles (LEQ). We investigate how the resulting optics perturbation affects beam parameters.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK028
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About • |
Received ※ 07 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 08 July 2022 |
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MOPOTK029 |
Improved Low-Energy Optics Control for Transverse Emittance Preservation at the CERN Proton Synchrotron |
507 |
SUSPMF055 |
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- W. Van Goethem, F. Antoniou, F. Asvesta, H. Bartosik, A. Huschauer
CERN, Meyrin, Switzerland
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Preservation of the transverse emittances across the CERN accelerator chain is an important requirement for beams produced for the Large Hadron Collider (LHC). In the CERN Proton Synchrotron (PS), high brightness LHC-type beams are stored on a long flat bottom for up to 1.2 seconds. During this storage time, direct space charge effects may lead to resonance crossing and subsequent growth of the transverse emittances. Previous studies showed an important emittance increase when the PS working point is moved near integer tune values. Subsequent simulation studies confirmed that this observation is caused by an interplay of space charge effects and the optics beatings induced by the Low Energy Quadrupoles (LEQ). A new optics configuration using these quadrupoles to reduce the optics beating and the emittance growth was developed and experimentally validated. The results of simulation and experimental studies are presented in this contribution.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK029
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About • |
Received ※ 07 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 10 July 2022 |
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WEIYGD1 |
Achievements and Performance Prospects of the Upgraded LHC Injectors |
1610 |
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- V. Kain, S.C.P. Albright, R. Alemany-Fernández, M.E. Angoletta, F. Antoniou, T. Argyropoulos, F. Asvesta, B. Balhan, M.J. Barnes, D. Barrientos, H. Bartosik, P. Baudrenghien, G. Bellodi, N. Biancacci, A. Boccardi, J.C.C.M. Borburgh, C. Bracco, E. Carlier, D.G. Cotte, J. Coupard, H. Damerau, G.P. Di Giovanni, A. Findlay, M.A. Fraser, A. Funken, B. Goddard, G. Hagmann, K. Hanke, A. Huschauer, M. Jaussi, I. Karpov, T. Koevener, D. Küchler, J.-B. Lallement, A. Lasheen, T.E. Levens, K.S.B. Li, A.M. Lombardi, N. Madysa, E. Mahner, M. Meddahi, L. Mether, B. Mikulec, J.C. Molendijk, E. Montesinos, D. Nisbet, F.-X. Nuiry, G. Papotti, K. Paraschou, F. Pedrosa, T. Prebibaj, S. Prodon, D. Quartullo, E. Renner, F. Roncarolo, G. Rumolo, B. Salvant, M. Schenk, R. Scrivens, E.N. Shaposhnikova, P.K. Skowroński, A. Spierer, F. Tecker, D. Valuch, F.M. Velotti, R. Wegner, C. Zannini
CERN, Meyrin, Switzerland
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To provide HL-LHC performance, the CERN LHC injector chain underwent a major upgrade during an almost 2-year-long shutdown. In the first half of 2021 the injectors were gradually re-started with the aim to reach at least pre-shutdown parameters for LHC as well as for fixed target beams. The strategy of the commissioning across the complex, a summary of the many challenges and finally the achievements will be presented. Several lessons were learned and have been integrated to define the strategy for the performance ramp-up over the coming years. Remaining limitations and prospects for LHC beam parameters at the exit of the LHC injector chain in the years to come will be discussed. Finally, the emerging need for improved operability of the CERN complex will be addressed, with a description of the first efforts to meet the availability and flexibility requirements of the HL-LHC era while at the same time maximizing fixed target physics output.
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Slides WEIYGD1 [5.905 MB]
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-WEIYGD1
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About • |
Received ※ 08 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 09 July 2022 |
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WEOZSP2 |
Suppression of Crab Cavity Noise Induced Emittance Growth by Transverse Beam Coupling Impedance |
1659 |
SUSPMF068 |
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- N. Triantafyllou, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
- F. Antoniou, H. Bartosik, P. Baudrenghien, X. Buffat, R. Calaga, Y. Papaphilippou
CERN, Meyrin, Switzerland
- T. Mastoridis
CalPoly, San Luis Obispo, California, USA
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Crab Cavities are a key component of the High Luminosity LHC (HL-LHC) upgrade, as they aim to minimize the luminosity reduction caused by the crossing angle. Two superconducting crab cavities were installed in the Super Proton Synchrotron (SPS) at CERN in 2018 to test their operation in a proton machine for the first time. An important point to consider is the increase in transverse emittance induced by noise in the Low-Level RF (LLRF) system. During the first experimental campaign in 2018, the measured emittance growth was found to be a factor of 4 lower than predicted by the available analytical models. In this report, the effects of transverse beam impedance in the presence of CC LLRF noise on transverse emittance growth are presented and the results of the second experimental campaign, which took place in the SPS in 2021, are discussed.
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Slides WEOZSP2 [2.694 MB]
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-WEOZSP2
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About • |
Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022 |
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WEPOPT055 |
Linac3, LEIR and PS Performance with Ions in 2021 and Prospects for 2022 |
1983 |
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- N. Biancacci, S.C.P. Albright, R. Alemany-Fernández, D. Alves, M.E. Angoletta, D. Barrientos, H. Bartosik, G. Bellodi, S.B. Bertolo, D. Bodart, M. Bozzolan, H. Damerau, F.D.L. Di Lorenzo, A. Frassier, D. Gamba, A. Huschauer, S. Jensen, V. Kain, T. Koevener, G. Kotzian, D. Küchler, A. Lasheen, G. Le Godec, T.E. Levens, N. Madysa, E. Mahner, O. Marqversen, C.M. Mastrostefano, P.D. Meruga, C. Mutin, M. O’Neil, G. Piccinini, R. Scrivens, P.S. Solvang, D. Valuch, F.M. Velotti, R. Wegner, C. Wetton, M. Zampetakis
CERN, Meyrin, Switzerland
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CERN accelerators underwent a period of long shutdown from the end of 2018 to 2020. During this time frame, significant hardware and software upgrades have been put in place to increase the performance of both proton and ion accelerator chains in the High Luminosity LHC era. In the context of the CERN lead ion chain, 2021 has been mainly devoted to restore the injectors’ performance and to successfully prove the slip-stacking technique in SPS. In this paper we summarise the key milestones of the ion beam commissioning and the achieved beam performance for the Linac 3 (including the source), LEIR and PS accelerators, together with an outlook on 2022 operation.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT055
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About • |
Received ※ 03 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022 |
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WEPOTK011 |
High Intensity Studies in the CERN Proton Synchrotron Booster |
2056 |
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- F. Asvesta, S.C.P. Albright, F. Antoniou, H. Bartosik, C. Bracco, G.P. Di Giovanni, G. Rumolo, P.K. Skowroński, C. Zannini
CERN, Meyrin, Switzerland
- E. Renner
TU Vienna, Wien, Austria
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After the successful implementation of the LHC Injectors Upgrade (LIU) project, studies were conducted in the CERN Proton Synchrotron Booster (PSB) in order to assess the intensity reach with the increased beam brightness. The studies focused on the high intensity beams delivered to the PSB users, both at 1.4 and 2 GeV. In addition, possible intensity limitations in view of the Physics Beyond Colliders (PBC) Study were investigated. To this end, various machine configurations were tested including different resonance compensation schemes and chromaticity settings in correlation with the longitudinal parameters. This paper summarizes the results obtained since the machine recommissioning.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK011
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About • |
Received ※ 05 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 19 June 2022 |
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WEPOTK058 |
Experimental Study of the Transverse Mode Coupling Instability with Space-Charge at the CERN SPS |
2193 |
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- X. Buffat, H. Bartosik
CERN, Meyrin, Switzerland
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Past studies on the Transverse Mode Coupling Instability (TMCI) suggested that it can be suppressed in the presence of space-charge forces. Recent developments in this field show that for higher strength, space-charge forces leads to other types of instabilities. We investigate the characteristics of these instabilities by means of stability threshold measurements at the CERN SPS for various intensities, longitudinal and transverse emittances. These observations are compared to numerical tracking simulations.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK058
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About • |
Received ※ 03 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 18 June 2022 |
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