MC1: Circular and Linear Colliders
Paper Title Page
MOYPLM3 Progress with the High Luminosity LHC Project at CERN 17

• L. Rossi, O.S. Brüning
CERN, Geneva, Switzerland

The High Luminosity LHC (HL-LHC) project aims at upgrading the LHC by increasing the peak luminosity by a factor five, to allow to collect 3000 fb-1 for ATLAS and CMS experiments, each, which is ten times more than what is foreseen in the LHC. The upgrade is based on multiple factors. One factor is doubling the beam current, also thanks to the injector upgrade (LIU) project, and another one is operation in levelling mode. The most critical upgrade is the deploying of a stronger inner quadrupole triplet in the low-beta insertions with more than twice-larger aperture w.r.t. present LHC triplet, thanks to the use of Nb3Sn superconductor, a world first for accelerators, with almost 12 T peak field in the coils. The novel concept of ATS optics allows to utilise the increased aperture efficiently by generating β* values 3 to 4 times below the nominal values of the LHC. We will make use of compact crab cavities for hadrons (also a novelty in accelerators) to allow almost head-on collisions despite the larger crossing angle. We are developing new collimator insertions in the dispersion suppressor region to handle the losses in the cold part of the machine (the beam halo stores 30 MJ) thanks to the use of a few 11 T dipoles based on Nb3Sn technology. We also aim at reducing drastically the impedance contribution of collimators by utilizing new materials and coating techniques. Many other technologies are developed for HL-LHC like new SC links of 100 kA: HL-LHC is critical as a technology turning point for HEP colliders as it is for Physics reach. The technologies developed for HL-LHC, namely (but not only) the high field superconducting magnets, are critical for the post-LHC hadron collider, like a High Energy LHC or the 100 km Future Circular Collider
Slides MOYPLM3 [21.679 MB]
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOYPLM3
About • paper received ※ 19 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019
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MOZPLS2 Ion Collider Precision Measurements With Different Species 28

• G.J. Marr, E.N. Beebe, I. Blackler, W. Christie, K.A. Drees, P.S. Dyer, A.V. Fedotov, W. Fischer, C.J. Gardner, H. Huang, T. Kanesue, N.A. Kling, V. Litvinenko, C. Liu, Y. Luo, D. Maffei, B. Martin, A. Marusic, K. Mernick, M.G. Minty, C. Naylor, M. Okamura, I. Pinayev, G. Robert-Demolaize, T. Roser, P. Sampson, V. Schoefer, T.C. Shrey, D. Steski, P. Thieberger, J.E. Tuozzolo, K. Zeno, I.Y. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC, under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Precedent to electron cooling commissioning and collisions of Gold at various energies at RHIC in 2018, the STAR experiment desired an exploration of the chiral magnetic effect in the quark gluon plasma (QGP) with an isobar run, utilizing Ruthenium and Zirconium. Colliding Zr-96 with Zr-96 and Ru-96 with Ru-96 create the same QGP but in a different magnetic field due to the different charges of the Zr (Z=40) and Ru (Z=44) ions. Since the charge difference is only 10%, the experimental program requires exacting store conditions for both ions. These systematic error concerns presented new challenges for the Collider, including frequent reconfiguration of the Collider for the different ion species, and maintaining level amounts of instantaneous and integrated luminosity between two species. Moreover, making beams of Zr-96 and Ru-96 is challenging since the natural abundances of these isotopes are low. Creating viable enriched source material for Zr-96 required assistance processing from RIKEN, while Ru-96 was provided by a new enrichment facility under commissioning at Oak Ridge National Laboratory.

Slides MOZPLS2 [4.758 MB]
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOZPLS2
About • paper received ※ 11 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019
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MOPMP001 Optic Corrections for FCC-hh 417

• D. Boutin
CEA-DRF-IRFU, France
• A. Chancé, B. Dalena
CEA-IRFU, Gif-sur-Yvette, France
• B.J. Holzer, D. Schulte
CERN, Geneva, Switzerland

The FCC-hh (Future Hadron-Hadron Circular Collider) is one of the options considered for the next generation accelerator in high-energy physics as recommended by the European Strategy Group. The evaluation of the various magnets mechanical error and field error tolerances in the arc sections of FCC-hh, as well as an estimation of the required correctors strengths, are important aspects of the collider design. In this study the mechanical tolerances, dipole and quadrupole field error tolerances for the arc sections of FCC-hh are evaluated. The consolidated correction schemes of the linear coupling (with skew quadrupoles) and of the beam tunes (with normal quadrupoles) are presented. The integration of the different ring insertions (interaction region, collimation, injection, etc) is also discussed.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP001
About • paper received ※ 14 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019
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MOPMP004 Consolidated Lattice of the Collider FCC-hh 428

• A. Chancé, D. Boutin, B. Dalena
CEA-IRFU, Gif-sur-Yvette, France
• W. Bartmann, M. Hofer, R. Martin, D. Schulte
CERN, Meyrin, Switzerland

Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 654305.
The FCC-hh (Future Hadron-Hadron Circular Collider) is one of the options considered for the next generation accelerator in high-energy physics as recommended by the European Strategy Group. The latest changes brought to the lattice of the FCC-hh collider are commented: impact of the new intra-beam distance, efforts to increase the beam stay clear in the dispersion suppressors, tuning procedures, and updates on the insertions.

DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP004
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019
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MOPMP015 Longitudinal Particle Dynamics in NICA Collider 455

• E. Syresin, A.V. Eliseev, A.V. Smirnov
JINR, Dubna, Moscow Region, Russia
• N. Mityanina, V.M. Petrov, E. Rotov, A.G. Tribendis
BINP SB RAS, Novosibirsk, Russia

A specific feature of the NICA acceleration complex is high luminosity of colliding beams. Three types of RF stations will be used in the NICA Collider to reach the necessary beam parameters. The first one is for accumulation of particles in the longitudinal phase space with the moving burrier buckets under action of stochastic and/or electron cooling systems. The second and third RF stations are for formation of the final bunch size in the colliding regime. This report presents numerical simulations of longitudinal beam dynamics which taken into account the longitudinal space charge effect during the accumulation and bunching procedures. Influence of space effects leads to some decrease in the accumulation efficiency and requires special manipulation with the 2nd and 3rd RF stations during the adiabatic capture and bunching procedures.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP015
About • paper received ※ 29 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019
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MOPMP019 High Luminosity LHC Optics and Layout HLLHCV1.4 468

• R. De Maria, R. Bruce, D. Gamba, M. Giovannozzi, F. Plassard
CERN, Geneva, Switzerland

The goal of the High Luminosity Project is the upgrade of the LHC to deliver an integrated luminosity of at least 250 \rm fb-1 per year in each of the two high-luminosity, general-purpose detectors ATLAS and CMS. This article presents the latest layout design and the corresponding optics features, which comprise optimisation of the orbit corrector and crab cavity systems, and new estimates of the performance reach thanks to the new concept of fully remote alignment. In addition, the new optics version incorporates improvements required by beam instrumentation, dump system, and collimation system, as well as low-beta solutions for the LHCb experiment.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP019
About • paper received ※ 17 April 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019
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MOPMP020 Smooth and Beta-Beating-Free Optics Transitions for HL-LHC 472

• R. De Maria, M. Solfaroli
CERN, Geneva, Switzerland

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.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP020
About • paper received ※ 18 April 2019       paper accepted ※ 17 May 2019       issue date ※ 21 June 2019
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MOPMP022 K-Modulation in Future High Energy Colliders 476

• M. Hofer, F.S. Carlier, R. Tomás
CERN, Geneva, Switzerland

K-Modulation of the quadrupoles closest to the interaction point (IP) has been an indispensable tool to accurately measure the beta-function in the interaction point (β*) in the Large Hadron Collider (LHC) at CERN. K-Modulation may become even more important to control the lower β* and reach the design luminosities in the High-Luminosity LHC (HL-LHC) and the Future Circular Collider (FCC). K-Modulation results also provide important input for the luminosity calibration and help in the identification and correction of errors in the machines. This paper presents a method for determining β* using K-Modulation adapted to the characteristic layout of both colliders. Using the latest models for the HL-LHC and the FCC-hh, estimated uncertainties on the measurements are presented. The results are compared to the accuracy of an alternative modulation scheme using a different powering scheme.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP022
About • paper received ※ 06 May 2019       paper accepted ※ 18 May 2019       issue date ※ 21 June 2019
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MOPMP023 Dynamic Aperture at Injection Energy for the HE-LHC 480
SUSPFO101   use link to see paper's listing under its alternate paper code

• M. Hofer, M. Giovannozzi, J. Keintzel, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
• L. van Riesen-Haupt
JAI, Oxford, United Kingdom

As part of the Future Circular Collider study, the High Energy LHC (HE-LHC) is a proposed hadron collider situated in the already existing LHC tunnel. It aims at achieving a center of mass energy of 27 TeV, almost doubling the design c.o.m. energy of the LHC. This increase in energy relies on the use of 16 T Nb3Sn dipoles to be developed for the FCC-hh. The field quality of these dipoles is expected to have a big impact on the Dynamic Aperture (DA) at injection energy and subsequently tracking studies are conducted to evaluate the impact of magnetic field errors on the beam dynamics. In the following the results of these studies for the different injection energies considered for the HE-LHC are presented and a possible strategy for increasing the DA are discussed.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP023
About • paper received ※ 06 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019
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MOPMP024 Prospects for Future Asymmetric Collisions in the LHC 484

• M.A. Jebramcik, J.M. Jowett
CERN, Geneva, Switzerland

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.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP024
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   use link to see paper's listing under its alternate paper code

• M.A. Jebramcik, J.M. Jowett
CERN, Geneva, Switzerland

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.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP025
About • paper received ※ 18 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019
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MOPMP026 HE-LHC Optics Design Options 492
SUSPFO103   use link to see paper's listing under its alternate paper code

• J. Keintzel, M.P. Crouch, M. Hofer, T. Risselada, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
• M. Hofer, J. Keintzel
TU Vienna, Wien, Austria
• L. van Riesen-Haupt
University of Oxford, Oxford, United Kingdom
• L. van Riesen-Haupt
JAI, Oxford, United Kingdom

The High Energy Large Hadron Collider (HE-LHC), a possible successor of the High Luminosity Large Hadron Collider (HL-LHC) aims at reaching a centre-of-mass energy of about 27 TeV using basically the same 16 T dipoles as for the hadron-hadron Future Circular Collider FCC-hh. Designing the HE-LHC results in a trade off between energy reach, beam stay clear as well as geometry offset with respect to the LHC. In order to best meet the requirements, various arc cell and dispersion suppressor options have been generated and analysed, before concluding on two baseline options, which are presented in this paper. Merits of each design are highlighted and possible solutions for beam stay clear minima are presented.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP026
About • paper received ※ 02 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019
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MOPMP027 Second Order Dispersion Measurements in LHC 496

• J. Keintzel, M. Hofer
TU Vienna, Wien, Austria
• J. M. Coello De Portugal - Martinez Vazquez, J. Dilly, E. Fol, A. Garcia-Tabares, M. Hofer, J. Keintzel, E.H. Maclean, L. Malina, T. H. B. Persson, R. Tomás, A. Wegscheider
CERN, Geneva, Switzerland

The quadratic dependence of the orbit on the relative momentum offset, also known as second order dispersion, is analysed for the first time for the LHC. In this paper, the measurement and analysis procedure are described. Results and implications on future optics are discussed.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP027
About • paper received ※ 02 May 2019       paper accepted ※ 17 May 2019       issue date ※ 21 June 2019
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MOPMP029 Analysis on Bunch-by-Bunch Beam Losses at 6.5 TeV in the Large Hadron Collider 500
SUSPFO105   use link to see paper's listing under its alternate paper code

• K. Paraschou, G. Iadarola, N. Karastathis, S. Kostoglou, Y. Papaphilippou, L. Sabato
CERN, Geneva, Switzerland
• S. Kostoglou
National Technical University of Athens, Zografou, Greece
• K. Paraschou
AUTH, Thessaloniki, Greece

In 2018, a large fraction of the physics data taking at the Large Hadron Collider has been performed with a beam energy of 6.5 TeV, the nominal bunch spacing of 25 ns and beta functions at the high luminosity interaction points of 30 cm. In order to maximize the integrated luminosity, the crossing angles are gradually reduced as the beam intensity reduces due to luminosity burn-off. In these conditions the beam lifetime is visibly affected by collective effects and in particular by beam-beam interaction and electron cloud effects. By analyzing the beam losses at a bunch-by-bunch level, it is possible to disentangle the contributions from different effects and to assess the impact on the losses of changes applied to the machine configuration.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP029
About • paper received ※ 10 May 2019       paper accepted ※ 20 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

• 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. Coello, 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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MOPMP037 Updated High-Energy LHC Design 524

• F. Zimmermann, D. Amorim, S. A. Antipov, S. Arsenyev, M. Benedikt, R. Bruce, M.P. Crouch, S.D. Fartoukh, M. Giovannozzi, B. Goddard, M. Hofer, J. Keintzel, R. Kersevan, V. Mertens, J. Molson, Y. Muttoni, J.A. Osborne, V. Parma, V. Raginel, S. Redaelli, T. Risselada, I. Ruehl, B. Salvant, D. Schoerling, E.N. Shaposhnikova, L.J. Tavian, E. Todesco, R. Tomás, D. Tommasini, F. Valchkova-Georgieva, V. Venturi, D. Wollmann
CERN, Geneva, Switzerland
• J.L. Abelleira, A. Abramov, E. Cruz Alaniz, H. Pikhartova, A. Seryi, L. van Riesen-Haupt
JAI, Oxford, United Kingdom
• A. Apyan
ANSL, Yerevan, Armenia
• J. Barranco García, L. Mether, T. Pieloni, L. Rivkin, C. Tambasco
EPFL, Lausanne, Switzerland
• F. Burkart
DESY, Hamburg, Germany
• Y. Cai, Y.M. Nosochkov
SLAC, Menlo Park, California, USA
• G. Guillermo Cantón
CINVESTAV, Mérida, Mexico
• K. Ohmi, K. Oide, D. Zhou
KEK, Ibaraki, Japan

Funding: This work was supported in part by the European Commission under the HORIZON 2020 project ARIES no.730871, and by the Swiss Accelerator Research and Technology collaboration CHART.
We present updated design parameters for a future High-Energy LHC. A more realistic turnaround time has led to a revision of the target peak luminosity, as well as a choice of a larger IP beta function, and longer physics fills. Pushed parameters of the Nb3Sn superconducting cable together with a modified layout of the 16 T dipole magnets resulted in revised field errors, updated dynamic-aperture simulations, and an associated re-evaluation of injector options. Collimators in the dispersion suppressors help achieve satisfactory cleaning performance. Longitudinal beam parameters ensure beam stability throughout the cycle. Intrabeam scattering rates and Touschek lifetime appear benign.

DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP037
About • paper received ※ 10 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019
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MOPMP039 Developments in the Experimental Interaction Regions of the High Energy LHC 532

• L. van Riesen-Haupt, J.L. Abelleira
University of Oxford, Oxford, United Kingdom
• J.L. Abelleira, E. Cruz Alaniz
JAI, Oxford, United Kingdom
• J. Barranco García, T. Pieloni, C. Tambasco
EPFL, Lausanne, Switzerland
• M. Hofer, J. Keintzel, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland

Funding: Work supported by the Swiss institute for Accelerator Research and Technology , CHART.
The High Energy LHC (HE-LHC) aims to collide 13.5 TeV protons in two high luminosity experiments and two low luminosity experiments. In the following, the recent updates in the two high luminosity experimental interaction regions (EIR) of the HE-LHC will be illustrated. These EIR aim to focus the beams to a β* of 0.45 m at the interaction point (IP) to achieve a lifetime integrated luminosity of 10 ab-1. On top of the triplet optics designed to achieve this, it will present energy deposition driven separation dipole designs, optics solutions for the matching section and dispersion suppressors as well as studies involving the integration into the lattice options. In particular it will outline geometric considerations, spurious dispersion suppression as well as results from dynamic aperture studies.

DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP039
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019
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MOPMP040 US Contributions to the High Luminosity LHC Upgrade - Focusing Quadrupoles and Crab Cavities 536

• G. Apollinari, G. Ambrosio, R.H. Carcagno, SF. Feher, L. Ristori
Fermilab, Batavia, Illinois, USA

In the early 2000’s, the US High Energy Physics community contributing to the Large Hadron Collider (LHC) launched the LHC Accelerator R&D Program) (LARP), a long-vision focused R&D program, intended to bring the Nb3Sn and other technologies to a maturity level that would allow applications in HEP machines. Around 2015, the technologies developed by LARP were mature enough to allow the spin-off of a major upgrade project to the LHC complex, the High Luminosity LHC (HL-LHC). This paper will focus on the US contribution to HL-LHC, namely the large-aperture low-beta focusing Nb3Sn quadrupoles and the Radio Frequency Dipole (RFD) Crab Cavities, located in close proximity to the ATLAS and CMS experiments. This contribution, called the HL-LHC Accelerator Upgrade Project (HL-LHC AUP), focuses on production of these quadrupoles and cavities by sharing the work among a consortium of US Laboratories (FNAL, LBNL, BNL and SLAC) and Universities and in close connection with the CERN-led HL-LHC Collaboration. The collaboration achieved commonality of specifications and uniformity of performance. Final development of design, construction and first results from the prototypes are described to indi-cate the status of these critical components for HL-LHC.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP040
About • paper received ※ 30 April 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019
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MOPMP044 Improving the Luminosity for Beam Energy Scan II at RHIC 540

• C. Liu, M. Blaskiewicz, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, H. Huang, D. Kayran, Y. Luo, G.J. Marr, A. Marusic, K. Mernick, M.G. Minty, C. Montag, I. Pinayev, S. Polizzo, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, T.C. Shrey, S. Tepikian, P. Thieberger, A. Zaltsman, K. Zeno, I.Y. Zhang, W. Zhang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The QCD (Quantum Chromodynamics) phase diagram has many uncharted territories, particularly the nature of the transformation from Quark-Gluon plasma (QGP) to the state of Hadronic gas. The Beam Energy Scan I (BES-I) at the Relativistic Heavy Ion Collider (RHIC) was completed but measurements had large statistical errors. To improve the statistical error and expand the search for first-order phase transition and location of the critical point, Beam Energy Scan II will commence in 2019 with a goal of improving the luminosity by a factor of 3-4. The beam lifetime at low energies was and will be limited by some physical effects of which the most significant are intrabeam scattering, space charge, beam-beam, persistent current effects. This article will review these potential limiting factors and introduce the countermeasures which will be in place to improve BES-II luminosity.

DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP044
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019
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MOPMP045 RHIC Heavy Ion Operation With Near-Integer Working Point 544

• C. Liu, G.J. Marr, A. Marusic, M.G. Minty, V. Schoefer
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The interplay of space charge and beam-beam effects limits the beam lifetime at low energies at the Relativistic Heavy Ion Collider (RHIC). To improve the beam lifetime, a near-integer working point (0.096/0.094) was tested at fixed energy and during acceleration. In the demonstration experiments, we observed the benefit of the near-integer working point on beam lifetime, however, did not achieve the desired level of orbit correction. This article will present the experimental results of operation with a near-integer working point, and analyze the causes of the orbit control problem.

DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP045
About • paper received ※ 14 May 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019
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MOPMP046 Mitigation of Persistent Current Effects in the RHIC Superconducting Magnets 548

• C. Liu, D. Bruno, A. Marusic, M.G. Minty, P. Thieberger
BNL, Upton, Long Island, New York, USA
• X. Wang
LBNL, Berkeley, California, USA

Funding: This work was supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Persistent currents in superconducting magnet introduce errors in the magnetic fields especially at low operating currents. In addition, their decay cause magnetic field variations therefore drifts of beam orbits, tunes and chromaticities. To reduce field errors and suppress magnetic field variations, new magnetic cycles were proposed for low energy beam operation at RHIC. In the new magnetic cycles, the magnet current oscillates around the operating current with diminishing amplitude a few times before it settles. The new magnetic cycle has been demonstrated experimentally to reduce field errors and the amplitude of magnetic field variations significantly and is essential for the ongoing RHIC Beam Energy Scan II (BES-II) program. This article will present beam-based experimental studies of the persistent current effects with the new magnetic cycle, and discuss its application in RHIC and accelerators based on superconducting magnet in general.

DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP046
About • paper received ※ 30 April 2019       paper accepted ※ 21 May 2019       issue date ※ 21 June 2019
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MOPMP048 LHC Doubler: CIC Dipole Technology May Make It Feasible and Affordable 552

• P.M. McIntyre
Texas A&M University, College Station, USA
• J. Breitschopf, J.N. Kellams, A. Sattarov
ATC, College Station, Texas, USA
• D.C.V. Chavez
Universidad de Guanajuato, División de Ciencias e Ingenierías, León, Mexico

There is new physics-driven interest in the concept of an LHC doubler with collision energy of 30 TeV and high luminosity. The cost-driver challenge for its feasibility is the ring of 16 T dual dipoles. Recent developments in cable-in-conduit (CIC) technology offer significant benefit for this purpose. The CIC windings provide robust stress management at the cable level and facilitate forming of the flared ends without degradation. The CIC windings provide a basis for hybrid windings, in which the innermost layers that operate in high field utilize Bi-2212, the center layers utilize Nb3Sn, and the outer layers utilize NbTi. Cryogen flows through the interior of all cables, so that heat transfer can be optimized throughout the windings. The design of the 18 T dipole and the 23 kA CIC conductor will be presented. Particular challenges for integration in an LHC doubler will be discussed.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP048
About • paper received ※ 18 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019
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MOPMP049 6 T Cable-in-conduit Dipole to Double the Ion Energy for JLEIC 556

• P.M. McIntyre, J. Breitschopf, J. Gerity
Texas A&M University, College Station, USA
• J. Breitschopf, D.C.V. Chavez, J.N. Kellams, A. Sattarov
ATC, College Station, Texas, USA

The proposed electron-ion collider JLEIC would make high-luminosity collisions of polarized ions and polarized electrons with electron energy up to 12 GeV and ion energy up to 40 GeV/u. Both the luminosity and the collision energy could be increased by doubling the dipole field in the ion ring from 3 T to 6 T, and the enhanced performance would access the full range of parameters for the physics objectives of the project. The Texas A&M group has developed the large-aperture 3 T dipoles for the baseline project, based upon a novel superconducting cable-in-conduit. (CIC). A closely similar 6 T design is being developed, utilizing a 2-layer CIC. Details of the magnet design and development of the 2-layer CIC will be presented.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP049
About • paper received ※ 19 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019
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MOPMP050 Performance of CeC PoP Accelerator 559

• I. Pinayev, Z. Altinbas, J.C. Brutus, A.J. Curcio, A. Di Lieto, T. Hayes, R.L. Hulsart, P. Inacker, Y.C. Jing, V. Litvinenko, J. Ma, G.J. Mahler, M. Mapes, K. Mernick, K. Mihara, T.A. Miller, M.G. Minty, G. Narayan, F. Severino, K. Shih, Z. Sorrell, J.E. Tuozzolo, E. Wang, G. Wang, A. Zaltsman
BNL, Upton, Long Island, New York, USA
• I. Petrushina
SUNY SB, Stony Brook, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Coherent electron cooling experiment is aimed for demonstration of the proof-of-principle demonstration of reduction energy spread of a single hadron bunch circulating in RHIC. The electron beam should have the required parameters and its orbit and energy should be matched to the hadron beam. In this paper we present the achieved electron beam parameters including emittance, energy spread, and other critical indicators. The operational issues as well as future plans are also discussed.

DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP050
About • paper received ※ 15 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019
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MOPMP051 56 MHz SRF System for SPHENIX Experiments at RHIC 562

• Q. Wu, M. Blaskiewicz, K. Mernick, S. Polizzo, F. Severino, K.S. Smith, T. Xin
BNL, Upton, Long Island, New York, USA

Funding: Work supported by by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The sPHENIX experiment is a proposal for a new detector at the Relativistic Heavy Ion Collider (RHIC), that plans to expand on discoveries made by RHIC’s existing STAR and PHENIX research groups. To minimize the luminosity outside the 20 cm vertex detector and keeping the radiation to other detector components as low as possible, a 56 MHz SRF system is added to the existing RHIC RF systems to compress the bunches with less beam loss. The existing 56 MHz SRF cavity was commissioned in previous RHIC runs, and contributed to the luminosity at a voltage of 300kV with thermal limitations from the Higher Order Mode coupler at high field, and at 1MV while using its fundamental damper for HOM damping. In this paper, we will analyze and compare the effect of different RF systems at various scenarios, and discuss possible solutions to the Higher Order Mode (HOM) damping scheme to bring the cavity to 2 MV.

DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP051
About • paper received ※ 15 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019
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MOPMP052 Numerical Simulations of the DC Wire Prototypes in LHC for Enhancing the HL-LHC Performances 566

• A. Poyet
Université Grenoble Alpes, Grenoble, France
• S.D. Fartoukh, N. Karastathis, Y. Papaphilippou, K. Skoufaris, G. Sterbini
CERN, Geneva, Switzerland

For the last 15 years, the compensation of the Beam-Beam Long-Range (BBLR) interaction in colliders using DC wires has been studied. In 2015, in the frame of the HL-LHC project, it has been shown that a compensation of all the Resonance Driving Terms (RDTs) generated by the BBLR interaction is possible using wires with constraints on their transverse and longitudinal positions. In 2017, an experimental campaign has been launched in the present LHC, with wires installed in sub-optimal positions due to integration constraints. The aim of this paper is therefore to apply the formalism developped for HL-LHC to the LHC case and to compare the experimental results to the numerical tracking studies of the compensation using wires.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP052
About • paper received ※ 06 May 2019       paper accepted ※ 20 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

• N. Fuster-Martínez, R. Bruce, J.M. Jowett, A. Mereghetti, D. Mirarchi, S. Redaelli
CERN, Meyrin, Switzerland

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.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB050
About • paper received ※ 07 May 2019       paper accepted ※ 19 May 2019       issue date ※ 21 June 2019
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MOPRB092 Symplectic and Exact Tracking of Low Energy 197Au78+ in the Relativistic Heavy Ion Collider 791

• Y. Luo, W. Fischer, F. Méot, G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In the coming RHIC low energy scan, the electron cooling technique is to be used to cool the ions 197Au79+ with its energy range between 3.85~GeV/nucleon to 5.75~GeV/nucleon. To overlap the electron beam and the 197Au79+ beam at the cooling section, a recombination monitor is to be used to detect the maximum flux of 197Au78+ ions generated in the cooling section. In the previous studies, we tracked 197Au78+ ions through the RHIC lattice defined with 197Au79+ with an equivalent momentum deviation. In the article, we explode different symplectic ways to track 197Au78+ ions exactly. We calculate and compare the trajectories and loss map of 197Au78+ ions through the RHIC ring.

DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB092
About • paper received ※ 14 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. Coello, 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, Geneva, 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 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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WEYYPLM3 First Results of the Compensation of the Beam-Beam Effect with DC Wires in the LHC 2262

• 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
• S. Kostoglou
National Technical University of Athens, Zografou, Greece
• A.E. Levichev
BINP SB RAS, Novosibirsk, Russia
• A. Poyet
Université Grenoble Alpes, Grenoble, France

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.
Slides WEYYPLM3 [6.371 MB]
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEYYPLM3
About • paper received ※ 06 May 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019
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WEPTS046 Monitoring and Modelling of the LHC Emittance and Luminosity Evolution in 2018 3212

• S. Papadopoulou, F. Antoniou, I. Efthymiopoulos, M. Hostettler, G. Iadarola, N. Karastathis, S. Kostoglou, Y. Papaphilippou, G. Trad
CERN, Geneva, Switzerland

Operating at 6.5 TeV, the LHC surpassed the expectations and delivered an average of 66 fb−1 integrated luminosity to the two high luminosity experiments ATLAS and CMS by the end of 2018. In order to provide a continuous feedback to the machine coordination for further optimizing the performance, an automated tool for monitoring the main beam parameters and machine configurations, has been devised and extensively used. New features like the coupling between the two planes and effects of noise, were added to the numerical model used since 2016 to calculate the machine luminosity. Estimates, based both on simulations and on observed beam parameters, were reported fill-by-fill as well as in overall trends during the year. Highlights of the observations including the observed additional emittance blow up (on top of IBS, SR and elastic scattering) as well as additional losses (on top of the expected proton burn off) are presented for the 2018 data. Finally, cumulated integrated luminosity projections from the model for the entire 2018 data based on different degradation mechanisms are compared also with respect to the achieved luminosity.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS046
About • paper received ※ 17 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019
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THPRB113 Concept of Beam-Related Machine Protection for the Future Circular Collider 4085

• Y.C. Nie, R. Schmidt, J.A. Uythoven, C. Wiesner, D. Wollmann, M. Zerlauth
CERN, Meyrin, Switzerland

In the Future Circular Collider (FCC) study, a proton-proton circular collider (FCC-hh) is considered with a stored beam energy 20 times higher than that of the LHC. Any uncontrolled release of such energy could potentially result in severe damage to the accelerator components. Machine protection of the FCC-hh is hence very important and challenging. With a machine-protection strategy similar to the LHC, FCC would require up to three turns to dump the beam synchronously after a failure detection. Due to several possible ultrafast failures, which could lead to significant beam losses in a few turns, it is important to further reduce the reaction time of the machine protection system (MPS) for the FCC. Reducing the detection time of a failure by using faster beam monitors, e.g. diamond detectors, can reduce the time between a beam loss and the beam dump request. Communication delay of the interlock system to the beam dumping system can be reduced by using a more direct signal path. More than one beam-free abort gap will shorten the time required for the synchronization between the abort gap and the extraction kicker. Different failure scenarios are classified according to the speed of the failure onset and the subsequent increase of induced beam losses. The critical failure modes, their potential mitigations and impacts on the design of the MPS are presented.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB113
About • paper received ※ 14 May 2019       paper accepted ※ 23 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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