| Paper | Title | Page |
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| TUPTY024 | Updated Simulation Studies of Damage Limit of LHC Tertiary Collimators | 2053 |
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| The tertiary collimators (TCTs) in the LHC, installed in front of the experiments, in standard operation intercept fractions of 103 halo particles. However, they risk to be hit by high-intensity primary beams in case of asynchronous beam dump. TCT damage thresholds were initially inferred from results of destructive tests on a TCT jaw, supported by numerical simulations, assuming simplified impact scenarios with one single bunch hitting the jaw with a given impact parameter. In this paper, more realistic failure conditions, including a train of bunches and taking into account the full collimation hierarchy, are used to derive updated damage limits. The results are used to update the margins in the collimation hierarchy and could thus potentially have an influence on the LHC performance. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY024 | |
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| TUPTY028 | Collimator Layouts for HL-LHC in the Experimental Insertions | 2064 |
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| This paper presents the layout of collimators for HL-LHC in the experimental insertions. On the incoming beam, we propose to install additional tertiary collimators to protect potential new aperture bottlenecks in cells 4 and 5, which in addition reduce the experimental background. For the outgoing beam, the layout of the present LHC with three physics debris absorbers gives sufficient protection for high-luminosity proton operation. However, collisional processes for heavy ions cause localized beam losses with the potential to quench magnets. To alleviate these losses, an installation of dispersion suppressor collimators is proposed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY028 | |
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| TUPTY045 | Interactions between Macroparticles and High-Energy Proton Beams | 2112 |
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| A known threat to the availability of the LHC is the interaction of macroparticles (dust particles) with the LHC proton beam. At the foreseen beam energy of 6.5 TeV during Run 2, quench margins in the superconducting magnets will be 2-3 times lower, and beam losses due such interactions may result in magnet quenches. The study introduce an improved numerical model of such interactions, as well as Monte-Carlo simulations that give the probability that such events will result in a beam-dump during Run 2. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY045 | |
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| TUPTY046 | Impact of Beam Losses in the LHC Collimation Regions | 2116 |
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| The upgrade of the LHC energy and brightness, from the 2015 restart at close to design energy until the HL-LHC era with considerable hardware development and layout renewal, poses tight challenges in terms of machine protection. The collimation insertions and especially the one dedicated to betatron cleaning (IR7), where most of the beam halo is intercepted to spare from losses the cold sectors of the ring, will be subject to a significant increase of radiation load, whose leakage to the nearby dispersion suppressors must be kept sustainable. The past LHC run, while displaying a remarkable performance of the collimation system, offered the opportunity for a demanding benchmarking of the complex simulation chain describing the beam losses and the macroscopic effects of the induced particle showers, this way strengthening the confidence in the reliability of its predictions. This paper discusses the adopted calculation strategy and its evolution options, showing the accuracy achieved with respect to Beam Loss Monitor measurements in controlled loss scenarios. Expectations at design energy, including lifetime considerations concerning critical elements, will also be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY046 | |
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| TUPTY049 | Protection of Superconducting Magnets in Case of Accidental Beam Losses during HL-LHC Injection | 2128 |
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Funding: Research supported by the High Luminosity LHC project. The LHC injection regions accommodate a system of beam-intercepting devices which protect superconducting magnets and other accelerator components in case of mis-steered injected beam or accidentally kicked stored beam, e.g. due to injection kicker or timing malfunctions. The brightness and intensity increase required by the High Luminosity (HL) upgrade of the LHC necessitates a redesign of some devices to improve their robustness and to reduce the leakage of secondary particle showers to downstream magnets. In this paper, we review possible failure scenarios and we quantify the energy deposition in superconducting coils by means of FLUKA shower calculations. Conceptual design studies for the new protection system are presented, with the main focus on the primary injection protection absorber (TDI) and the adjacent mask (TCDD). |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY049 | |
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| TUPTY050 | Considerations for the Beam Dump System of a 100 TeV Centre-of-mass FCC hh Collider | 2132 |
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| A 100 TeV centre-of-mass energy frontier proton collider in a new tunnel of 80–100 km circumference is a central part of CERN’s Future Circular Colliders (FCC) design study. One of the major challenges for such a machine will be the beam dump system, which for each ring will have to reliably abort proton beams with stored energies in the range of 8 Gigajoule, more than an order of magnitude higher than planned for HL-LHC. The transverse proton beam energy densities are even more extreme, a factor of 100 above that of the presently operating LHC. The requirements for the beam dump subsystems are outlined, and the present technological limitations are described. First concepts for the beam dump system are presented and the feasibility is discussed, highlighting in particular the areas in which major technological progress will be needed. The potential implications on the overall machine and other key subsystems are described, including constraints on filling patterns, interlocking, beam intercepting devices and insertion design. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY050 | |
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| TUPTY051 | Injection Protection Upgrade for the HL-LHC | 2136 |
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| The injector complex of the LHC is undergoing important changes in the light of the LIU project to provide brighter beams to the LHC. For this reason and as part of the High Luminosity LHC project the injection protection system of the LHC will be upgraded in the Long Shutdown 2 (2018 - 2019) to be able to protect downstream elements against injection failures with the high brightness, high intensity HL-LHC beams. The upgraded LHC injection protection system will consist of a segmented injection protection absorber TDIS, and auxiliary collimators and masks. The layout modifications are described, and the machine element protection and absorber jaw robustness studies are presented for the new systems. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY051 | |
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| TUPTY067 | Beam Induced Background Simulation Studies at IR1 with New High Luminosity LHC Layout | 2184 |
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Funding: Research supported by FP7 HiLumi LHC – Grant agreement 284404 In the High Luminosity LHC (HL-LHC), the collimation system will be upgraded in the high-luminosity experimental regions. Additional protection is planned for the Q4 and Q5 magnets that are located further upstream of the tertiary collimators that protect the inner triplet magnets. We evaluate the effect of this proposed collimation layout for the incoming beam 1 on machine-induced background in the experimental area of IR1 (ATLAS). The main scenario is the round optics with β∗ of 15 cm, but a flat scenario is also briefly discussed. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY067 | |
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