Author: Schaumann, M.
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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MOPRB052 Gamma Factory at CERN: Design of a Proof-of-Principle Experiment 685
 
  • Y. Dutheil, R. Alemany-Fernández, H. Bartosik, N. Biancacci, R. Bruce, P. Czodrowski, V. Fedosseev, B. Goddard, S. Hirlaender, J.M. Jowett, R. Kersevan, M. Kowalska, M. Lamont, D. Manglunki, J. Molson, A.V. Petrenko, M. Schaumann, F. Zimmermann
    CERN, Meyrin, Switzerland
  • S.E. Alden, A. Bosco, S.M. Gibson, L.J. Nevay
    JAI, Egham, Surrey, United Kingdom
  • A. Apyan
    ANSL, Yerevan, Armenia
  • E.G. Bessonov
    LPI, Moscow, Russia
  • A. Bosco, S.M. Gibson, L.J. Nevay
    Royal Holloway, University of London, Surrey, United Kingdom
  • F. Castelli
    Università degli Studi di Milano, Milano, Italy
  • F. Castelli, C. Curatolo, L. Serafini
    INFN-Milano, Milano, Italy
  • K. Kroeger
    FSU Jena, Jena, Germany
  • A. Martens
    LAL, Orsay, France
  • V. Petrillo
    Universita’ degli Studi di Milano, Milano, Italy
  • M. Sapinski, T. Stöhlker
    GSI, Darmstadt, Germany
  • G. Weber
    IOQ, Jena, Germany
  • Y.K. Wu
    FEL/Duke University, Durham, North Carolina, USA
 
  The Gamma Factory (GF) initiative proposes to create novel research tools at CERN by producing, accelerating and storing highly relativistic partially stripped ion beams in the LHC rings and by exciting their atomic degrees of freedom by lasers, to produce high-energy photon beams. Their intensity would be several orders of magnitude higher than those of the presently operating light sources in the particularly interesting gamma-ray energy domain reaching up to 400 MeV. In this energy domain, the high-intensity photon beams can be used to produce secondary beams of polarized electrons, polarized positrons, polarized muons, neutrinos, neutrons and radioactive ions. Over the years 2017-2018 we have demonstrated that these partially stripped ion beams can be successfully produced, accelerated and stored in the CERN accelerator complex, including the LHC. The next step of the project is to build a proof of principle experiment in the SPS to validate the principal GF concepts. This contribution will present the initial conceptual design of this experiment along with its main challenge - the demonstration of the fast cooling method of partially stripped ion beams.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB052  
About • paper received ※ 19 May 2019       paper accepted ※ 20 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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MOPRB058 Collimation of Partially Stripped Ion Beams in the LHC 700
 
  • A. Abramov, L.J. Nevay
    JAI, Egham, Surrey, United Kingdom
  • R. Bruce, N. Fuster-Martínez, A.A. Gorzawski, M.W. Krasny, J. Molson, S. Redaelli, M. Schaumann
    CERN, Meyrin, Switzerland
 
  In the scope of the Physics Beyond Colliders studies, the Gamma Factory initiative proposes the use of partially stripped ions as a driver of a new type, high intensity photon source in CERN’s Large Hadron Collider (LHC). In 2018, the LHC accelerated and stored partially stripped 208-Pb-81+ ions for the first time. The collimation system efficiency recorded during this test was found to be prohibitively low. The worst losses were localised in the dispersion suppressor (DS) of the betatron-cleaning insertion. Analytic arguments and simulations show that the large losses are driven by the stripping of the remaining electron from the Pb nucleus by the primary collimators. The rising dispersion in the DS pushes the resulting off-rigidity, fully-stripped ions into the aperture of the superconducting magnets. In this study the measured loss maps are compared against results from simulations. Different mitigation strategies are outlined, including a dispersion suppressor (DS) collimator, crystal collimation or an orbit bump.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB058  
About • paper received ※ 10 May 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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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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