| Paper | Title | Page |
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| MOPMP019 | High Luminosity LHC Optics and Layout HLLHCV1.4 | 468 |
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| 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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| MOPMP023 | Dynamic Aperture at Injection Energy for the HE-LHC | 480 |
| SUSPFO101 | use link to see paper's listing under its alternate paper code | |
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| 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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| MOPMP031 | Operation and Performance of the Cern Large Hadron Collider During Proton Run 2 | 504 |
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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. | ||
| 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 |
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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. | ||
| 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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| MOPMP037 | Updated High-Energy LHC Design | 524 |
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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. |
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| 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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| MOPRB049 | Study of Beam-Gas Interactions at the LHC for the Physics Beyond Colliders Fixed-Target Study | 673 |
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| Among several working groups formed in the framework of Physics Beyond Colliders study, launched at CERN in September 2016, there is one investigating specific fixed-target experiment proposals. Of particular interest is the study of high-density unpolarized or polarized gas target to be installed in the LHCb detector, using storage cells to enhance the target density. This work studies the impact of the interactions of 7 TeV proton beams with such gas targets on the LHC machine in terms of particle losses. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB049 | |
| About • | paper received ※ 17 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019 | |
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| MOPTS102 | Linear and Non-Linear Optics Measurements in PS using Turn-by-Turn BPM Data | 1114 |
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| For the first time, the optics of the CERN Proton Synchrotron (PS) was measured using turn-by-turn BPM data of forced betatron oscillations excited with an AC dipole. We report results of phase advance and beta beating measurements. Linear coupling was globally minimized along the machine by measuring and correcting coupling resonance driving terms. Finally, non-linear properties of the ring were probed looking at third and fourth order resonance driving terms and amplitude detuning. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS102 | |
| About • | paper received ※ 07 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019 | |
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| MOPTS107 | Beam Manipulations With Barrier Buckets in the CERN PS | 1132 |
| SUSPFO120 | use link to see paper's listing under its alternate paper code | |
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| A barrier bucket scheme is being considered to reduce losses during the Multi-Turn Extraction from the CERN Proton Synchrotron to the Super Proton Synchrotron for the fixed-target physics programme. For effective loss reduction, the extraction kicker has to be triggered during the gap at the time of the longitudinal barrier. Initial beam studies at injection energy and with low intensity beams allowed to fully qualify an existing wide-band cavity to generate one or multiple beam synchronous pulses per turn. Bunch-length stretching and shortening have been exercised with barriers moving in azimuth with respect to the beam. The encouraging results obtained at injection energy guided the implementation of a de-bunching manipulation at higher energy to move all bunches into a single barrier bucket. Beam measurements at a momentum of 14GeV/c, varying intensity and the width of the barrier, demonstrate that a quasi-constant longitudinal line density and an almost fully depleted gap can be achieved at highest intensities. The contribution summarises the results of the beam studies at high energy together with some observations related to the Multi-Turn Extraction. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS107 | |
| About • | paper received ※ 18 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | |
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| WEPGW084 | Measuring Beamsize with the LHC Beam Gas Vertex Detector | 2680 |
| SUSPFO109 | use link to see paper's listing under its alternate paper code | |
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| The Beam Gas Vertex detector (BGV) is an innovative beam profile monitor being developed as part of the High Luminosity LHC (HL-LHC) project at CERN. The goal is to continually measure the transverse beam size by reconstructing beam-gas interaction vertices using high precision tracking detectors. To confirm the feasibility of such a device, a demonstrator based on eight modules of scintillating fiber detectors has been constructed, installed in the LHC and operated for the past 3 years. It will be shown that using the BGV the average transverse beam size can be obtained with a statistical accuracy of better than 5µm (for a gaussian beam with a σ of 200µm). This precision is obtained with an integration time of less than one minute. In addition, the BGV measures the size of individual bunches with a statistical accuracy of better than 5% within 5 minutes. The results obtained from all the data gathered over the past 3 years will be presented and compared to measurements from other beam profile monitors. Some ideas for improvements for the final HL-LHC instrument will also be discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW084 | |
| About • | paper received ※ 10 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019 | |
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| WEPTS043 | SixTrack Version 5: Status and New Developments | 3200 |
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| SixTrack Version 5 is a major SixTrack release that introduces new features, with improved integration of the existing ones, and extensive code restructuring. New features include dynamic-memory management, scattering-routine integration, a new initial-condition module, and reviewed post-processing methods. Existing features like on-line aperture checking and Fluka-coupling are now enabled by default. Extensive performance regression tests have been developed and deployed as part of the new-release generation. The new features of the tracking environment developed for the massive numerical simulations will be discussed as well. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS043 | |
| About • | paper received ※ 17 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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| THPGW057 | HL-LHC Full Remote Alignment Study | 3716 |
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Funding: Research supported by the HL-LHC project. This study explores the benefits of extending the monitoring and remote alignment concept, proposed in the HL-LHC baseline, to additional components of the matching sections of the HL-LHC. The objective was to evaluate the benefits in terms of equipment performance and new opportunities for system simplification. In collaboration with the HL-LHC Working Group on Alignment, critical input parameters such as ground motion, manufacturing, assembly, and alignment tolerances, have been quantified. Solutions for the selected, manually aligned compo-nents have been investigated with the particular focus on vacuum design, mechanical design and the new alignment concept compatible with reliability and maintainability requirements. In this context, collimators and masks are key elements to be included in the extended alignment system. Their supporting systems will integrate the concept of on-line monitoring sensors and an actuator based, remote alignment platform. The full remote alignment of components will provide a positive impact to the machine operation reducing the need of human intervention in the tunnel and providing enhanced flexibility to perform the required alignment adjustment as part of an operational tool for the HL-LHC. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW057 | |
| About • | paper received ※ 09 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019 | |
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