Author: Barranco, J.
Paper Title Page
TUPMW007 Impact of Long Range Beam-Beam Effects on Intensity and Luminosity Lifetimes from the 2015 LHC Run 1422
  • M.P. Crouch, R.B. Appleby
    UMAN, Manchester, United Kingdom
  • D. Banfi, C. Tambasco
    EPFL, Lausanne, Switzerland
  • J. Barranco, R. Bruce, X. Buffat, T. Pieloni, M. Pojer, B. Salvachua, G. Trad
    CERN, Geneva, Switzerland
  • B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  Funding: Research supported by the High Luminosity LHC project
Luminosity is one of the key parameters that determines the performance of colliding beams in the Large Hadron Collider (LHC). Luminosity can therefore be used to quantify the impact of beam-beam interactions on the beam lifetimes and emittances. The High Luminosity Large Hadron Collider (HL-LHC) project aims to reach higher luminosities, approximately a factor of 7 larger than the nominal LHC at peak luminosity without crab cavities. Higher luminosities are achieved by increasing the bunch populations and reducing the transverse beam sizes. This results in stronger beam-beam effects. Here the LHC luminosity and beam intensity decay rates are analysed as a function of reducing beam separation with the aim of characterising the impact of beam-beam effects on the luminosity and beam lifetime. The analysis and results are discussed with possible application to the HL-LHC upgrade.
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW007  
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TUPMW011 Current Status of Instability Threshold Measurements in the LHC at 6.5 TeV 1434
  • L.R. Carver, J. Barranco, N. Biancacci, X. Buffat, W. Höfle, G. Kotzian, T. Lefèvre, T.E. Levens, E. Métral, T. Pieloni, B. Salvant, C. Tambasco
    CERN, Geneva, Switzerland
  • N. Wang
    IHEP, Beijing, People's Republic of China
  • M. Zobov
    INFN/LNF, Frascati (Roma), Italy
  Throughout 2015, many measurements of the minimum stabilizing octupole current required to prevent coherent transverse instabilities have been performed. These measurements allow the LHC impedance model at flat top to be verified and give good indicators of future performance and limitations. The results are summarized here, and compared to predictions from the simulation code DELPHI.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW011  
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TUPMW009 Simulation of Head-on Beam-Beam Limitations in Future High Energy Colliders 1430
  • X. Buffat, T. Pieloni, C. Tambasco
    CERN, Geneva, Switzerland
  • J. Barranco, A. Florio
    EPFL, Lausanne, Switzerland
  The Future Circular Hadron Collider (FCC-hh) project calls for studies in a new regime of beam-beam interactions. While the emittance damping due to synchrotron radiation is still slower than in past or existing lepton colliders, it is significantly larger than in other hadron colliders. The slow reduction of the emittance is profitable for higher luminosity in term of transverse beam size at the interaction points and also to mitigate long-range beam-beam effects, potentially allowing for a reduction of the crossing angle between the beams during the operation. In such conditions, the strength of head-on beam-beam interactions increases, potentially limiting the beam brightness. 4D weak-strong and strong-strong simulations are performed in order to assess these limitations.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW009  
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TUPOR017 Beam-beam Simulation of Crab Cavity with Frequence Dependent Noise for LHC Upgrade 1691
  • J. Qiang
    LBNL, Berkeley, California, USA
  • G. Arduini, Y. Papaphilippou, T. Pieloni
    CERN, Geneva, Switzerland
  • J. Barranco
    EPFL, Lausanne, Switzerland
  High luminosity LHC upgrade will improve the luminosity of the current LHC operation by an order of magnitude. Crab cavity as a critical component for compensating luminosity loss from large crossing angle collision and also providing luminosity leveling for the LHC upgrade is being actively pursued. In this paper, we will report on the study of potential effects of the frequence-dependent crab cavity noise on the beam luminosity lifetime using strong-strong beam-beam simulations.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR017  
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WEPOY030 First BTF Measurements at the Large Hadron Collider 3051
SUPSS061   use link to see paper's listing under its alternate paper code  
  • C. Tambasco, A. Boccardi, X. Buffat, K. Fuchsberger, M. Gąsior, R. Giachino, T. Lefèvre, T.E. Levens, T. Pieloni, M. Pojer, B. Salvachua, M. Solfaroli Camillocci
    CERN, Geneva, Switzerland
  • J. Barranco, C. Tambasco
    EPFL, Lausanne, Switzerland
  During the Run I in 2012, several instabilities have been observed at the Large Hadron Collider (LHC) during the Betatron squeeze. The predictions of instability thresholds are based on the computation of the beam Landau damping by calculating the Stability Diagrams (SD). These instabilities could be explained by a deterioration of the SD due to beam-beam resonance excitation which could change the particle distributions. Beam Transfer Functions (BTF) provide a measurement of the Stability Diagram. The BTFs are sensitive to the particle detuning with amplitude as well as to the particle distributions therefore they represent a powerful tool to understand experimentally the stability of beams during the LHC operational cycle. First BTF measurements at the LHC are presented for different machine configurations and settings and compared to predictions.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY030  
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