Author: Wenninger, J.
Paper Title Page
MOPMP031 Operation and Performance of the Cern Large Hadron Collider During Proton Run 2 504
 
  • R. Steerenberg, M. Albert, R. Alemany-Fernández, T. Argyropoulos, E. Bravin, G.E. Crockford, J.-C. Dumont, K. Fuchsberger, R. Giachino, M. Giovannozzi, G.H. Hemelsoet, W. Höfle, D. Jacquet, M. Lamont, E. Métral, D. Nisbet, G. Papotti, M. Pojer, L. Ponce, S. Redaelli, B. Salvachua, M. Schaumann, M. Solfaroli, R. Suykerbuyk, G. Trad, J.A. Uythoven, S. Uznanski, D.J. Walsh, J. Wenninger, M. Zerlauth
    CERN, Geneva, Switzerland
 
  Run 2 of the CERN Large Hadron Collider (LHC) was successfully completed on 10th December 2018, achieving largely all goals set in terms of luminosity production. Following the first two-year long shutdown and the re-commissioning in 2015 at 6.5 TeV, the beam performance was increased to reach a peak luminosity of more than twice the design value and a colliding beam time ratio of 50%. This was accomplished thanks to the increased beam brightness from the injector chain, the high machine availability and the performance enhancements made in the LHC for which some methods and tools, foreseen for the High Luminosity LHC (HL-LHC) were tested and deployed operationally. This contribution provides an overview of the operational aspects, main limitations and achievements for the proton Run 2.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP031  
About • paper received ※ 13 May 2019       paper accepted ※ 17 May 2019       issue date ※ 21 June 2019  
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MOPMP033 LHC Run 2 Optics Commissioning Experience in View of HL-LHC 508
 
  • R. Tomás, F.S. Carlier, J.M. Coello de Portugal, J. Dilly, S.D. Fartoukh, E. Fol, D. Gamba, A. Garcia-Tabares, M. Giovannozzi, M. Hofer, E.H. Maclean, L. Malina, T.H.B. Persson, P.K. Skowroński, M. Solfaroli, M.L. Spitznagel, A. Wegscheider, J. Wenninger, D.W. Wolf
    CERN, Geneva, Switzerland
 
  LHC Run 2 has achieved a beta lower than a factor 2 below design. This has significantly challenged optics measurement and correction techniques in the linear and non-linear regimes, leading to the development of new approaches. Furthermore, experimenting with a large variety of optics has allowed facing the difficulties of future optics and gaining understanding of the machine imperfections. A summary of these aspects is given in view of their implications for the HL-LHC Project.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP033  
About • paper received ※ 07 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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MOPMP036 Machine Protection Experience from Beam Tests with Crab Cavity Prototypes in the CERN SPS 520
 
  • B. Lindstrom, H. Bartosik, T. Bohl, A.C. Butterworth, R. Calaga, L.R. Carver, V. Kain, T.E. Levens, G. Papotti, R. Secondo, J.A. Uythoven, M. Valette, G. Vandoni, J. Wenninger, D. Wollmann, M. Zerlauth
    CERN, Meyrin, Switzerland
 
  Funding: Work supported by the High Luminosity LHC project.
Crab cavities (CCs) constitute a key component of the High Luminosity LHC (HL-LHC) project. In case of a failure, they can induce significant transverse beam offsets within tens of microseconds, necessitating a fast removal of the circulating beam to avoid damage to accelerator components due to losses from the displaced beam halo. In preparation for the final design to be employed in the LHC, a series of tests were conducted on prototype crab cavities installed in the Super Proton Synchrotron (SPS) at CERN. This paper summarizes the machine protection requirements and observations during the first tests of crab cavities with proton beams in the SPS. In addition, the machine protection implications for future SPS tests and for the use of such equipment in the HL-LHC are discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP036  
About • paper received ※ 01 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019  
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MOPRB055 First Partially Stripped Ions in the LHC (208Pb81+) 689
 
  • M. Schaumann, R. Alemany-Fernández, H. Bartosik, T. Bohl, R. Bruce, G.H. Hemelsoet, S. Hirlaender, J.M. Jowett, V. Kain, M.W. Krasny, J. Molson, G. Papotti, M. Solfaroli Camillocci, H. Timko, J. Wenninger
    CERN, Geneva, Switzerland
 
  The Gamma Factory initiative proposes to use partially stripped ion (PSI) beams as drivers of a new type of high intensity photon source. As part of the ongoing Physics Beyond Collider studies, initial beam tests with PSI beams have been executed at CERN. On 25 July 2018 lead ions with one remaining electron (208Pb81+) were injected and accelerated in the LHC for the first time. After establishing the injection and circulation of a few 208Pb81+ bunches, beam lifetimes of about 50 hours could be established at 6.5 TeV proton equivalent energy. This paper describes the setup of the beam tests and observations made.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB055  
About • paper received ※ 29 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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WEYYPLM2 The 2018 Heavy-Ion Run of the LHC 2258
 
  • J.M. Jowett, C. Bahamonde Castro, W. Bartmann, C. Bracco, R. Bruce, J.M. Coello de Portugal, J. Dilly, S.D. Fartoukh, E. Fol, N. Fuster-Martínez, A. Garcia-Tabares, M. Hofer, E.B. Holzer, M.A. Jebramcik, J. Keintzel, A. Lechner, E.H. Maclean, L. Malina, T. Medvedeva, A. Mereghetti, T.H.B. Persson, B.Aa. Petersen, S. Redaelli, B. Salvachua, M. Schaumann, C. Schwick, M. Solfaroli, M.L. Spitznagel, H. Timko, R. Tomás, A. Wegscheider, J. Wenninger, D. Wollmann
    CERN, Meyrin, Switzerland
  • D. Mirarchi
    The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
 
  The fourth one-month Pb-Pb collision run brought LHC Run 2 to an end in December 2018. Following the tendency to reduce dependence on the configuration of the preceding proton run, a completely new optics cycle with the strongest ever focussing at the ALICE and LHCb experiments was designed and rapidly implemented, demonstrating the maturity of the collider’s operating modes. Beam-loss monitor thresholds were carefully adjusted to provide optimal protection from the multiple loss mechanisms in heavy-ion operation. A switch from a basic bunch-spacing of 100 ns to 75 ns was made as the beam became available from the injector chain. A new record luminosity, 6 times the original design and close to the operating value proposed for HL-LHC, provided validation of the strategy for mitigating quenches due to bound-free pair production (BFPP) at the interaction points of the ATLAS and CMS experiments. Most of the beam parameters of the HL-LHC Pb-Pb upgrade were attained during this run and the integrated luminosity goals for the first 10 years of LHC operation were substantially exceeded.  
slides icon Slides WEYYPLM2 [10.884 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEYYPLM2  
About • paper received ※ 08 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPMP030 LHC Injection Losses and Trajectories During Run 1 and 2 and Outlook to Injection of HL-LHC Beams 2387
 
  • W. Bartmann, C. Bracco, B. Goddard, F.M. Velotti, J. Wenninger
    CERN, Meyrin, Switzerland
 
  The LHC turn-around time is impacted by the control of injection losses and trajectories. While shot-to-shot trajectory variations dominated the injection efficiency during LHC Run 1, several improvements of hardware and operational settings allowed for a high rate of successful injections during Run 2. Injection losses and trajectories are analysed and presented for the high intensity proton runs, as well as for different beam types used from the injectors. Based on this analysis, an outlook is shown for the HL-LHC era, where double the bunch intensity will have to be injected.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP030  
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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WEPGW116 LHC Optics Measurement and Correction Software Progress and Plans 2773
 
  • R. Tomás, F.S. Carlier, J.M. Coello de Portugal, J. Dilly, E. Fol, A. Garcia-Tabares, M. Hofer, E.H. Maclean, L. Malina, T.H.B. Persson, P.K. Skowroński, M.L. Spitznagel, A. Wegscheider, J. Wenninger
    CERN, Meyrin, Switzerland
  • J.F. Cardona, Y. Rodriguez
    UNAL, Bogota D.C, Colombia
  • F.S. Carlier
    NIKHEF, Amsterdam, The Netherlands
  • D. Esperante Pereira, J. Fuster, D. Gonzalez-Iglesias
    IFIC, Valencia, Spain
  • R. Hoekstra
    KVI, Groningen, The Netherlands
 
  LHC Optics Measurements and Corrections (OMC) require efficient on-line software applications to acquire and analyze data and to compute the necessary corrections. During Run 2 various measurement and correction techniques have been merged to yield unprecedented optics quality, increasing the required number of steps to finalize the optics commissioning and the size of the software project. In turn, this calls for a higher level of automation, where machine learning techniques are being implemented. During the Long Shutdown 2 a large refactoring of the codes will be in place to improve performance, maintainability and extensibility. A description of the current status of the software and future plans is given.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW116  
About • paper received ※ 07 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019  
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THPRB031 Operational Performance of the Machine Protection Systems of the Large Hadron Collider During Run 2 and Lessons Learnt for the LIU/HL-LHC Era 3875
 
  • M. Zerlauth, A. Antoine, W. Bartmann, C. Bracco, E. Carlier, Z. Charifoulline, R. Denz, B. Goddard, A. Lechner, N. Magnin, C. Martin, R. Mompo, S. Redaelli, I. Romera, B. Salvachua, R. Schmidt, J.A. Uythoven, A.P. Verweij, J. Wenninger, C. Wiesner, D. Wollmann, C. Zamantzas
    CERN, Geneva, Switzerland
 
  The Large Hadron Collider (LHC) has successfully completed its second operational run of four years length in December 2018. Operation will be stopped during two years for maintenance and upgrades. To allow for the successful completion of the diverse physics program at 6.5 TeV, the LHC has been routinely operating with stored beam energies close to 300 MJ per beam during high intensity proton runs as well as being frequently reconfigured to allow for special physic runs and important machine developments. No significant damage has incurred to the protected accelerator equipment throughout the run thanks to the excellent performance of the various machine protection systems, however a number of important observations and new failure scenarios have been identified, which were studied experimentally as well as through detailed simulations. In this contribution, we provide an overview of the performance of the machine protection systems throughout Run 2 as well as the important lessons learnt that will impact consolidation actions and the upgrade of the machine protection systems for the LIU/HL-LHC era.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB031  
About • paper received ※ 15 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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THPRB116 Effect of Ground Motion Introduced by HL-LHC CE Work on LHC Beam Operation 4092
 
  • M. Schaumann, D. Gamba, M. Guinchard, L. Scislo, J. Wenninger
    CERN, Geneva, Switzerland
 
  Funding: Research supported by the HL-LHC project
The official groundbreaking of the civil engineering (CE) work for the high luminosity upgrade of the LHC started on 15 June 2018 parallel to LHC beam operation. Compactor work and shaft excavation around the two low beta experiments, ATLAS and CMS, were expected to induce vibrations to the accelerator magnets and cause orbit disturbance, beam loss and potentially premature beam dumps. Ground motion sensors were installed on the surface and close to the triplets, where the CE works were expected to have the largest impact on the beams. This paper discusses the observations made on the LHC beams that could be correlated to CE work.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB116  
About • paper received ※ 13 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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