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MOPMP020 |
Smooth and Beta-Beating-Free Optics Transitions for HL-LHC |
472 |
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- R. De Maria, M. Solfaroli
CERN, Geneva, Switzerland
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In the CERN LHC, optics transitions are mainly required to control the beam size at the four experimental interaction points. The current method, based on linearly-interpolated optics functions over a small set of matched optics and parabolic time-domain segments, introduces non-zero beta-beating and it is not optimal in time. This contribution presents an alternative approach, based on continuously-matched optics solutions distributed in time domain by using a realistic model of the superconducting circuits, which optimises the overall process duration. This method requires a change in the paradigm used in the control system and it is proposed for the future High Luminosity LHC (HL-LHC) runs.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP020
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About • |
paper received ※ 18 April 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019 |
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MOPMP031 |
Operation and Performance of the Cern Large Hadron Collider During Proton Run 2 |
504 |
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- 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
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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.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP031
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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 |
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- 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
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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.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP033
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About • |
paper received ※ 07 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 |
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- 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
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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.
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Slides WEYYPLM2 [10.884 MB]
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2019-WEYYPLM2
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About • |
paper received ※ 08 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 |
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WEYYPLM3 |
First Results of the Compensation of the Beam-Beam Effect with DC Wires in the LHC |
2262 |
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- G. Sterbini, D. Amorim, H. Bartosik, A. Bertarelli, R. Bruce, X. Buffat, F. Carra, L.R. Carver, G. Cattenoz, E. Effinger, S.D. Fartoukh, N. Fuster-Martínez, M. Gąsior, M. Gonzalez-Berges, A.A. Gorzawski, G.H. Hemelsoet, M. Hostettler, G. Iadarola, O.R. Jones, N. Karastathis, S. Kostoglou, I. Lamas Garcia, T.E. Levens, L.E. Medina Medrano, D. Mirarchi, J. Olexa, S. Papadopoulou, Y. Papaphilippou, D. Pellegrini, M. Pojer, L. Ponce, A. Poyet, S. Redaelli, A. Rossi, B. Salvachua, H. Schmickler, F. Schmidt, K. Skoufaris, M. Solfaroli, R. Tomás, G. Trad, D. Valuch, C. Xu, C. Zamantzas, P. Zisopoulos
CERN, Geneva, Switzerland
- D. Amorim
Grenoble-INP Phelma, Grenoble, France
- M. Fitterer, A. Valishev
Fermilab, Batavia, Illinois, USA
- D. Kaltchev
TRIUMF, Vancouver, Canada
- S. Kostoglou
National Technical University of Athens, Zografou, Greece
- A.E. Levichev
BINP SB RAS, Novosibirsk, Russia
- A. Poyet
Université Grenoble Alpes, Grenoble, France
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The compensation of the long-range beam-beam interactions using DC wires is presently under study as an option for enhancing the machine performance in the frame of the High-Luminosity LHC project (HL-LHC). The original idea dates back more than 15 years. After the installation of four wire prototypes in the LHC in 2018, a successful experimental campaign was performed during the last months. The experimental setup and the main results are reported in this paper.
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Slides WEYYPLM3 [6.371 MB]
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2019-WEYYPLM3
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About • |
paper received ※ 06 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 |
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