Paper |
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MOPMP024 |
Prospects for Future Asymmetric Collisions in the LHC |
484 |
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- M.A. Jebramcik, J.M. Jowett
CERN, Geneva, Switzerland
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The proton-lead runs of the LHC in 2012, 2013 and 2016 provided luminosity far beyond expectations in a diversity of operating conditions and led to important new results in high-density QCD. This has permitted the scope of the future physics programme to be expanded in a recent review. Besides further high-luminosity p-Pb collisions, lighter nuclei are also under consideration. A short proton-oxygen run, on the model of the 2012 p-Pb run, would be of interest for cosmic-ray physics. Other collision systems like proton-argon or collisions of protons with other noble gases are also discussed. We provide an overview of the operational strategies and potential performance of various asymmetric collision options. Potential performance limits from moving beam-beam encounters at injection and various beam-loss mechanisms are evaluated in the light of our understanding of the LHC to date.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP024
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About • |
paper received ※ 18 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019 |
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MOPMP025 |
Moving Long-range Beam-beam Encounters in Heavy-ion Colliders |
488 |
SUSPFO102 |
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- M.A. Jebramcik, J.M. Jowett
CERN, Geneva, Switzerland
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Asymmetric ion beam collisions like proton-lead in the LHC or gold-deuteron in RHIC have become major components of heavy-ion physics programmes. The injection and ramp of two different ion species with the same magnetic rigidity and consequently unequal revolution frequencies generate moving long-range beam-beam encounters in the interactions regions of the collider. These encounters led to fast beam losses and can cause emittance blow-up as observed in RHIC in the early 2000s and, more recently, in 2015. Yet such effects are absent at the LHC so the difference between the two colliders requires explanation. Tools and models have been developed to describe the beam dynamics of moving long-range beam-beam encounters and to predict the evolution of emittance and other beam parameters. Besides presenting results for RHIC and the LHC we give an outlook for the HL-LHC and potential operational restrictions.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP025
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About • |
paper received ※ 18 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 |
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MOPRB050 |
Performance of the Collimation System During the 2018 Lead Ion Run at the Large Hadron Collider |
677 |
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- N. Fuster-Martínez, R. Bruce, J.M. Jowett, A. Mereghetti, D. Mirarchi, S. Redaelli
CERN, Geneva, Switzerland
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As part of the Large Hadron Collider (LHC) heavy-ion research programme, the last month of the 2018 LHC run was dedicated to Pb ion physics. Several heavy-ion runs have been performed since the start-up of the LHC. These runs are challenging for collimation, despite lower intensities, because of the degraded cleaning observed compared to protons. This is due to the differences of the interaction mechanisms in the collimators. Ions experience fragmentation and electromagnetic dissociation that result in a substantial flux of off-rigidity particles that escape the collimation system. In this paper, the collimation system performance and the experience gained during the 2018 Pb ion run are presented. The measured performance is compared with the expectation from the Sixtrack-FLUKA coupling simulations and the agreement discussed.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB050
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About • |
paper received ※ 07 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019 |
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MOPRB052 |
Gamma Factory at CERN: Design of a Proof-of-Principle Experiment |
685 |
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- 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
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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.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB052
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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 |
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- 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
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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.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB055
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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 |
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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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