doi:10.18429/JACoW-IPAC2016-THPMY007engSalemme, RobertoBaglin, VincentBregliozzi, GiuseppeChiggiato, PaoloVacuum Performance of Amorphous Carbon Coating at Cryogenic Temperature with Presence of Proton BeamsAccelerators and Storage RingsCERN-ACC-2016-157Amorphous carbon (a-C) coating is the baseline electron multipacting mitigation strategy proposed for the Inner Triplets (IT) in the High Luminosity upgrade of the Large Hadron Collider (HL-LHC). As of 2014, the COLD bore EXperiment (COLDEX) is qualifying the performance of a-C coating at cryogenic temperature in a LHC type cryogenic vacuum system. In this paper, the experimental results following a cryogenic vacuum characterization of a-C coating in the 5 to 150 K temperature range are reviewed. We discuss the dynamic pressure rise, gas composition, dissipated heat load and electron activity observed within an accumulated beam time of 9 Ah. The results of dedicated experiments including pre-adsorption of different gas species (H2, CO) on the a-C coating are discussed. Based of phenomenological modeling, up-to-date secondary emission input parameters for a-C coatings are retrieved for electron cloud build-up simulations. Finally, first implications for the HL-LHC ITs design are drawn.2016http://cds.cern.ch/record/220746610.18429/JACoW-IPAC2016-THPMY007http://cds.cern.ch/record/2207466oai:inspirehep.net:1470587 doi:10.18429/JACoW-IPAC2016-THPMW031engDay, HugoBarnes, MichaelDucimetière, LaurentVega Cid, LorenaWeterings, WimCurrent and Future Beam Thermal Behaviour of the LHC Injection Kicker MagnetAccelerators and Storage RingsCERN-ACC-2016-163During Run 1 of the LHC the injection kicker magnets caused occasional operational delays due to beam induced heating with high bunch intensity and short bunch lengths. Significant upgrades were carried out to the injection kicker magnets during long shutdown 1, including a new design of beam screen to reduce the beam induced heating. Nevertheless these kicker magnets may limit the performance of HL-LHC unless additional, mitigating, measures are taken. Hence extensive simulations have been carried out to predict the distribution of the beam induced power deposition within the magnet and detailed thermal analyses carried out to predict the temperature profiles. To benchmark the simulations the predicted temperatures are compared with observables in the LHC. This paper reports on observations of the thermal behaviour of the magnet during run 2 of the LHC, with 25ns beam. In addition the measurement data is used to extrapolate temperature rise for the beam parameters expected for high-luminosity LHC.2016http://cds.cern.ch/record/220746010.18429/JACoW-IPAC2016-THPMW031http://cds.cern.ch/record/2207460oai:inspirehep.net:1470573 doi:10.18429/JACoW-IPAC2016-THPMW030engBarnes, MichaelAdraktas, AntoniosBeck, MarioBregliozzi, GiuseppeDay, HugoDucimetière, LaurentFerreira Somoza, JoseGoddard, BrennanKramer, ThomasPasquino, ChiaraRumolo, GiovanniSalvant, BenoitSermeus, LucUythoven, JanVega Cid, LorenaVelotti, FrancescoWeterings, WimZannini, CarloStudies of Impedance-related Improvements of the SPS Injection Kicker SystemAccelerators and Storage RingsCERN-ACC-2016-164The injection kicker system for the SPS consists of sixteen magnets housed in a total of four vacuum tanks. The kicker magnets in one tank have recently limited operation of the SPS with high-intensity beam: this is due to both beam induced heating in the ferrite yoke of the kicker magnets and abnormally high pressure in the vacuum tank. Furthermore, operation with the higher intensity beams needed in the future for HL-LHC is expected to exacerbate these problems. Hence studies of the longitudinal beam coupling impedance of the kicker magnets have been carried out to investigate effective methods to shield the ferrite yoke from the circulating beam. The shielding must not compromise the field quality or high voltage behaviour of the kicker magnets and should not significantly reduce the beam aperture: results of these studies, together with measurements, are presented. In addition results of tests to identify the causes of abnormal outgassing are presented.2016http://cds.cern.ch/record/220745910.18429/JACoW-IPAC2016-THPMW030http://cds.cern.ch/record/2207459oai:inspirehep.net:1470572 doi:10.18429/JACoW-IPAC2016-THPMR040engCoello de Portugal, Jaime MariaCarlier, FelixGarcia-Tabares, AnaLangner, AndyMaclean, EwenMalina, LukasPersson, TobiasSkowroński, PiotrTomás, RogelioLocal Optics Corrections in the HL-LHC IRAccelerators and Storage RingsCERN-ACC-2016-176For the high luminosity upgrade of the LHC optics correction in the interaction regions is expected to be challenged by the very low β^{*} and the sizable expected quadrupolar errors in the triplet. This paper addresses the performance and limitations of the segment-by-segment technique to correct quadrupolar and skew quadrupolar errors in the HL-LHC IR via computer simulations. Required improvements to this technique and possible combinations with other correction approaches are also presented including experimental tests in the current LHC IR.2016http://cds.cern.ch/record/220744710.18429/JACoW-IPAC2016-THPMR040http://cds.cern.ch/record/2207447oai:inspirehep.net:1470529 doi:10.18429/JACoW-IPAC2016-THPMR038engMaclean, EwenCarlier, FelixGiovannozzi, MassimoLangner, AndyMönig, SaskiaPersson, TobiasSkowroński, PiotrTomás, RogelioNon-Linear Errors in the Experimental Insertions of the LHCAccelerators and Storage RingsCERN-ACC-2016-178Correction of nonlinear magnetic errors in low-β insertions can be of critical significance for the operation of a collider. This is expected to be of particular relevance to LHC Run II and the HL-LHC upgrade, as well as to future colliders such as the FCC. Current correction strategies for these accelerators have assumed it will be possible to calculate optimized local corrections through the insertions using a magnetic model of the errors. To test this assumption the nonlinear errors in the LHC experimental insertions have been examined via feed-down and amplitude detuning. It will be shown that while in some cases the magnetic measurements provide a sufficient description of the errors, in others large discrepancies exist which will require beam-based correction techniques.2016http://cds.cern.ch/record/220744510.18429/JACoW-IPAC2016-THPMR038http://cds.cern.ch/record/2207445oai:inspirehep.net:1470527 doi:10.18429/JACoW-IPAC2016-WEPOR018engSosin, MateuszDijoud, ThibaultMainaud Durand, HeleneRude, VivienPosition Monitoring System for HL-LHC Crab CavitiesAccelerators and Storage RingsCERN-ACC-2016-197The high luminosity upgrade for the LHC at CERN (HL-LHC project) will extend the discovery potential of the LHC by a factor 10. It relies on key innovative technologies like superconducting cavities for beam rotation, named 'crab cavities'. Two crab cavities will be hosted in a superconducting cryostat working at a cold (<3 K). The position of each cavity will be monitored during the cool-down and the operation in order to comply with the tight alignment tolerances: the misalignment of a cavity axis w.r.t. the other will have to be lower than 0.5 mm and each cavity roll w.r.t. the cryostat axis will have to be lower than 1 mrad. Moreover, the monitoring system will have to be radiation hard (up to 10 MGy) and maintenance free. We propose a solution based on the Frequency Scanning Interferometry to provide the position monitoring of the crab cavities. This paper describes the design and study of such a solution, including the engineering approach, the issues encountered and the lessons learnt.2016http://cds.cern.ch/record/220742610.18429/JACoW-IPAC2016-WEPOR018http://cds.cern.ch/record/2207426oai:inspirehep.net:1470302 doi:10.18429/JACoW-IPAC2016-WEPMW030engMirarchi, DanieleAppleby, RobertBertarelli, AlessandroBruce, RoderikCerutti, FrancescoGarcia Morales, HectorHermes, PascalKwee-Hinzmann, ReginaLechner, AntonMereghetti, AlessioQuaranta, ElenaRedaelli, StefanoCleaning Performance of the Collimation System of the High Luminosity Large Hadron ColliderAccelerators and Storage RingsCERN-ACC-2016-216Different upgrades of the LHC will be carried out in the framework of the High Luminosity project (HL-LHC), where the total stored energy in the machine will increase up to about 700 MJ. This unprecedented stored energy poses serious challenges for the collimation system, which was designed to handle safely up to about 360 MJ. In this paper the baseline collimation layout for HL-LHC is described, with main focus on upgrades related to the cleaning of halo and physics debris, and its expected performance is discussed. The main upgrade items include the presence of new collimators in the dispersion suppressor of the betatron cleaning insertion installed between two 11 T dipoles, and two additional collimators for an improved local protection of triplet magnets. Thus, optimized settings for the entire and upgraded collimation chain were conceived and are shown here together with the resulting cleaning performance. Moreover, the cleaning performance taking into account crab cavities it is also discussed.2016http://cds.cern.ch/record/220740910.18429/JACoW-IPAC2016-WEPMW030http://cds.cern.ch/record/2207409oai:inspirehep.net:1470240 doi:10.18429/JACoW-IPAC2016-WEPMR038engVerdú-Andrés, SilviaArtoos, KurtBen-Zvi, IlanCalaga, RamaCapatina, OfeliaLeuxe, RaphaelSkaritka, JohnWu, QiongXiao, BinpingZanoni, CarloFrequency Tuning for a DQW Crab CavityAccelerators and Storage RingsCERN-ACC-2016-225The nominal operating frequency for the HL-LHC crab cavities is 400.79 MHz within a bandwidth of ±60kHz. Attaining the required cavity tune implies a good understanding of all the processes that influence the cavity frequency from the moment when the cavity parts are being fabricated until the cavity is installed and under operation. Different tuning options will be available for the DQW crab cavity of LHC. This paper details the different steps in the cavity fabrication and preparation that may introduce a shift in the cavity frequency and introduces the different tuning methods foreseen to bring the cavity frequency to meet the specifications.2016http://cds.cern.ch/record/220740010.18429/JACoW-IPAC2016-WEPMR038http://cds.cern.ch/record/2207400oai:inspirehep.net:1470198 doi:10.18429/JACoW-IPAC2016-TUPMW035engMedina Medrano, LuisTomás, RogelioPerformance and Operational Aspects of HL-LHC ScenariosAccelerators and Storage RingsCERN-ACC-2016-240Several alternatives to the present HL-LHC baseline configuration have been proposed, aiming either to improve the potential performance, reduce its risks, or to provide options for addressing possible limitations or changes in its parameters. In this paper we review and compare the performance of the HL-LHC baseline and the main alternatives with the latest parameters set. The results are obtained using refined simulations of the evolution of the luminosity with β^{*}-levelling, for which new criteria have been introduced, such as improved calculation of the intrabeam scattering and the addition of penalty steps to take into account the necessary time to move between consecutive optics during the process. The features of the set of optics are discussed for the nominal baseline.2016http://cds.cern.ch/record/220738510.18429/JACoW-IPAC2016-TUPMW035http://cds.cern.ch/record/2207385oai:inspirehep.net:1469944 doi:10.18429/JACoW-IPAC2016-TUPMW034engCalaga, RamaTomás, RogelioA 200 MHz SC-RF System for the HL-LHCAccelerators and Storage RingsCERN-ACC-2016-241A quarter wave β=1 superconducting cavity at 200 MHz is proposed for the LHC as an alternative to the present 400 MHz RF system. The primary motivation of such a system would be to accelerate higher intensity and longer bunches with improved capture efficiency. Advantages related to minimizing electron cloud effects, intra-beam scattering, heating and the possibility of luminosity levelling with bunch length are described. Some considerations related to cavity optimization, beam loading and technological challenges are addressed.2016http://cds.cern.ch/record/220738410.18429/JACoW-IPAC2016-TUPMW034http://cds.cern.ch/record/2207384oai:inspirehep.net:1469943 doi:10.18429/JACoW-IPAC2016-TUPMW025engSantamaría García, AndreaBruce, RoderikBurkhardt, HelmutCerutti, FrancescoKwee-Hinzmann, ReginaLechner, AntonSjobak, KyrreTsinganis, AndreaMachine Protection from Fast Crab Cavity Failures in the High Luminosity LHCAccelerators and Storage RingsCERN-ACC-2016-248The time constant of a crab cavity (CC) failure can be faster than the reaction time of the active protection system. In such a scenario, the beams cannot be immediately extracted, making the the protection of the machine rely on the passive protection devices. At the same time, the energy stored in the High Luminosity (HL) LHC beams will be doubled with respect to the LHC to more than 700 MJ, which increases the risk of damaging the machine and the experiments in a failure scenario. In this study we estimate the impact that different CC failures have on the collimation system. We also give a first quantitative estimate of the effect of these failures on the elements near the experiments based on FLUKA simulations, using an updated HL-LHC baseline.2016http://cds.cern.ch/record/220737710.18429/JACoW-IPAC2016-TUPMW025http://cds.cern.ch/record/2207377oai:inspirehep.net:1469936 doi:10.18429/JACoW-IPAC2016-TUPMW016engRomano, AnnalisaIadarola, GiovanniLi, KevinRumolo, GiovanniEffect of the LHC Beam Screen Baffle on the Electron Cloud BuildupAccelerators and Storage RingsCERN-ACC-2016-256Electron Cloud (EC) has been identified as one of the major intensity-limiting factors in the CERN Large Hadron Collider (LHC). Due to the EC, an additional heat load is deposited on the perforated LHC beam screen, for which only a small cooling capacity is available. In order to preserve the superconducting state of the magnets, pumping slots shields were added on the outer side of the beam screens. In the framework of the design of the beam screens of the new HL-LHC triplets, the impact of these shields on the multipacting process was studied with macroparticle simulations. For this purpose multiple new features had to be introduced in the PyECLOUD code. This contribution will describe the implemented simulation model and summarize the outcome of this study.2016http://cds.cern.ch/record/220736910.18429/JACoW-IPAC2016-TUPMW016http://cds.cern.ch/record/2207369oai:inspirehep.net:1469928 doi:10.18429/JACoW-IPAC2016-TUPMW013engGorzawski, ArkadiuszMirarchi, DanieleSalvachua, BelenWenninger, JorgExperimental Demonstration of β* Leveling at the LHCAccelerators and Storage RingsCERN-ACC-2016-259The HL-LHC project foresees to boost the LHC peak luminosity beyond the capabilities of the LHC experimental detectors. Leveling the luminosity down to a constant value that is sustainable for the experiments is therefore the operational baseline of HL-LHC. Various luminosity leveling techniques are available at the LHC. Leveling by adjusting β^{*}, the betatron function at the interaction point, to maintain a constant luminosity is favorable because the beams remain head-on which provides optimal stability from the point of view of collective effects. Smooth leveling by β^{*} requires however excellent control of the beam orbits and beam losses in the interaction regions since the beam offsets should not vary by more than around one r.m.s. beam size during the process. This leveling scheme has been successfully tested and experimentally demonstrated during the LHC machine development program in 2015. This paper presents results on luminosity leveling over a β^{*} range from 10 m to 0.8 m and provides an outlook on future developments and use of this technique at the LHC.2016http://cds.cern.ch/record/220736610.18429/JACoW-IPAC2016-TUPMW013http://cds.cern.ch/record/2207366oai:inspirehep.net:1469925 doi:10.18429/JACoW-IPAC2016-TUPMW007engCrouch, MatthewAppleby, RobertBanfi, DaniloBarranco, JavierBruce, RoderikBuffat, XavierMuratori, BrunoPojer, MirkoSalvachua, BelenTambasco, ClaudiaTrad, GeorgesImpact of Long Range Beam-Beam Effects on Intensity and Luminosity Lifetimes from the 2015 LHC RunAccelerators and Storage RingsCERN-ACC-2016-263Luminosity is one of the key parameters that determines the performance of colliding beams in the Large Hadron Collider (LHC). Luminosity can therefore be used to quantify the impact of beam-beam interactions on the beam lifetimes and emittances. The High Luminosity Large Hadron Collider (HL-LHC) project aims to reach higher luminosities, approximately a factor of 7 larger than the nominal LHC at peak luminosity without crab cavities. Higher luminosities are achieved by increasing the bunch populations and reducing the transverse beam sizes. This results in stronger beam-beam effects. Here the LHC luminosity and beam intensity decay rates are analysed as a function of reducing beam separation with the aim of characterising the impact of beam-beam effects on the luminosity and beam lifetime. The analysis and results are discussed with possible application to the HL-LHC upgrade.2016http://cds.cern.ch/record/220736210.18429/JACoW-IPAC2016-TUPMW007http://cds.cern.ch/record/2207362oai:inspirehep.net:1469921 doi:10.18429/JACoW-IPAC2016-TUPMW002engAntoniou, FanouriaArduini, GianluigiHostettler, MichaelLamont, MikePapadopoulou, StefaniaPapaphilippou, YannisPapotti, GiuliaPojer, MirkoSalvachua, BelenWyszynski, MichalLHC Luminosity Modeling for RUNIIAccelerators and Storage RingsCERN-ACC-2016-268After a long shut-down (LS1), LHC restarted its operation on April 2015 at a record energy of 6.5TeV, achieving soon a good luminosity performance. In this paper, a luminosity model based on the three main components of the LHC luminosity degradation (intrabeam scattering, synchrotron radiation and luminosity burn-off), is compared with data from runII. Based on the observations, other sources of luminosity degradation are discussed and the model is refined. Finally, based on the experience from runI and runII, the model is used for integrated luminosity projections for the HL-LHC beam parameters.2016http://cds.cern.ch/record/220735710.18429/JACoW-IPAC2016-TUPMW002http://cds.cern.ch/record/2207357oai:inspirehep.net:1469916 doi:10.18429/JACoW-IPAC2016-TUPMR048engGoddard, BrennanCarlier, EtienneDucimetière, LaurentKotzian, GerdUythoven, JanVelotti, FrancescoSPS Injection and Beam Quality for LHC Heavy Ions With 150 ns Kicker Rise TimeAccelerators and Storage RingsCERN-ACC-2016-273As part of the LHC Injectors Upgrade project for LHC heavy ions, the SPS injection kicker system rise time needs reduction below its present 225 ns. One technically challenging option under consideration is the addition of fast Pulse Forming Lines in parallel to the existing Pulse Forming Networks for the 12 kicker magnets MKP-S, targeting a system field rise time of 100 ns. An alternative option is to optimise the system to approach the existing individual magnet field rise time (2-98%) of 150 ns. This would still significantly increase the number of colliding bunches in LHC while minimising the cost and effort of the system upgrade. The observed characteristics of the present system are described, compared to the expected system rise time, together with results of simulations and measurements with 175 and 150 ns injection batch spacing. The expected beam quality at injection into LHC is quantified, with the emittance growth and simulated tail population taking into account expected jitter and synchronisation errors, damper performance and SPS non-linear optics behavior. The outlook for deployment is discussed, with the implications for LHC operation and HL-LHC performance.2016http://cds.cern.ch/record/220735210.18429/JACoW-IPAC2016-TUPMR048http://cds.cern.ch/record/2207352oai:inspirehep.net:1469903 doi:10.18429/JACoW-IPAC2016-MOPOY058engShaposhnikova, ElenaArgyropoulos, TheodorosBohl, ThomasCruikshank, PaulGoddard, BrennanKaltenbacher, ThomasLasheen, AlexandrePerez Espinos, JaimeRepond, JoëlSalvant, BenoitVollinger, ChristineRemoving Known SPS Intensity Limitations for High Luminosity LHC GoalsAccelerators and Storage RingsCERN-ACC-2016-289In preparation of the SPS as an LHC injector its impedance was significantly reduced in 1999 - 2000. A new SPS impedance reduction campaign is planned now for the High Luminosity (HL)-LHC project, which requires bunch intensities twice as high as the nominal one. One of the known intensity limitations is a longitudinal multi-bunch instability with a threshold 3 times below this operational intensity. The instability is presently cured using the 4th harmonic RF system and controlled emittance blow-up, but reaching the HL-LHC parameters cannot be assured without improving the machine impedance. Recently the impedance sources responsible for this instability were identified and implementation of their shielding and damping is foreseen during the next long shutdown (2019 - 2020) in synergy with two other important upgrades: amorphous carbon coating of (part of) the vacuum chamber against the e-cloud effect and rearrangement of the 200 MHz RF system. In this paper the strategy of impedance reduction is presented together with beam intensity achievable after its realisation. The potential effect of other proposals on remaining limitations is also considered.2016http://cds.cern.ch/record/220733610.18429/JACoW-IPAC2016-MOPOY058http://cds.cern.ch/record/2207336oai:inspirehep.net:1469789 doi:10.18429/JACoW-IPAC2016-MOPOY006engAlbright, SimonQuartullo, DaniloShaposhnikova, ElenaPreparations for Upgrading the RF Systems of the PS BoosterAccelerators and Storage RingsCERN-ACC-2016-292The accelerators of the LHC injector chain need to be upgraded to provide the HL-LHC beams. The PS Booster, the first synchrotron in the LHC injection chain, uses three different RF systems (first, second and up to tenth harmonic) in each of its four rings. As part of the LHC Injector Upgrade the current ferrite RF systems will be replaced with broadband Finemet cavities, increasing the flexibility of the RF system. A Finemet test cavity has been installed in Ring 4 to investigate its effect on machine performance, especially beam stability, during extensive experimental studies. Due to large space charge impedance Landau damping is lost through most of the cycle in single harmonic operation, but is recovered when using the second harmonic and controlled longitudinal emittance blow-up. This paper compares beam parameters during acceleration with and without the Finemet test cavity. Comparisons were made using beam measurements and simulations with the BLonD code based on a full PS Booster impedance model. This work, together with simulations of future operation, have provided input for the decision to adopt a fully Finemet RF system.2016http://cds.cern.ch/record/220733310.18429/JACoW-IPAC2016-MOPOY006http://cds.cern.ch/record/2207333oai:inspirehep.net:1469749 doi:10.18429/JACoW-IPAC2016-MOPOR011engBiancacci, NicoloCarver, LeePapotti, GiuliaPersson, TobiasSalvant, BenoitTomás, RogelioImpedance Localization Measurements using AC Dipoles in the LHCAccelerators and Storage RingsCERN-ACC-2016-302The knowledge of the LHC impedance is of primary importance to predict the machine performance and allow for the HL-LHC upgrade. The developed impedance model can be benchmarked with beam measurements in order to assess its validity and limit. This is routinely done, for example, moving the LHC collimator jaws and measuring the induced tune shift. In order to localize possible unknown impedance sources, the variation of phase advance with intensity between beam position monitors can be measured. In this work we will present the impedance localization measurements performed at injection in the LHC using AC dipoles as exciter as well as the underlying theory.2016http://cds.cern.ch/record/220732310.18429/JACoW-IPAC2016-MOPOR011http://cds.cern.ch/record/2207323oai:inspirehep.net:1469681 doi:10.18429/JACoW-IPAC2016-MOPOR009engBiancacci, NicoloLi, KevinMétral, EliasSalvant, BenoitThe HL-LHC Impedance Model and Aspects of Beam StabilityAccelerators and Storage RingsCERN-ACC-2016-309The LHC upgrade to the HLLHC foresees new challenging operational scenarios from the beam dynamics point of view. In order to ensure good machine operation and performance, the machine impedance, among other possible sources of instabilities like beam-beam and electron cloud, needs to be carefully quantified profiting also from the current LHC operation. In this work we present the HLLHC impedance model mainly focusing on the contribution of low-impedance collimators and crab cavities: the first reduces the broad-band impedance baseline thanks to the higher jaw material conductivity, the second increases the machine luminosity at the price of increasing the coupled bunch stabilizing octupole current threshold. Other elements like the injection protection absorber (TDI) will be also discussed.2016http://cds.cern.ch/record/220732110.18429/JACoW-IPAC2016-MOPOR009http://cds.cern.ch/record/2207321oai:inspirehep.net:1469679 doi:10.18429/JACoW-IPAC2016-WEOCA03engGuillermo Cantón, GerardoSagan, DavidZimmermann, FrankSimulating Proton Synchrotron Radiation in the Arcs of the LHC, HL-LHC, and FCC-hhAccelerators and Storage Rings5: Extreme Beams (XBEAM)5.2: Extreme colliders (XCOL)CERN-ACC-2016-0079At high proton-beam energies, beam-induced synchrotron radiation is an important source of heating, of beam-related vacuum pressure increase, and of primary photoelectrons, which can give rise to an electron cloud. We use the Synrad3D code developed at Cornell to simulate the photon distributions in the arcs of the LHC, HL-LHC, and FCC-hh. Specifically, for the LHC we study the effect of the “sawtooth” chamber, for the HL-LHC the consequences of the ATS optics with large beta beating in the arcs, and for the FCC-hh the effect of a novel beam-screen design, with a long slit surrounded by a “folded” antechamber.2016http://cds.cern.ch/record/215968610.18429/JACoW-IPAC2016-WEOCA03http://cds.cern.ch/record/2159686oai:cds.cern.ch:2159686 doi:10.18429/JACoW-IPAC2016-WEPMW036engValloni, A.Rafique, H.Mereghetti, A.Molson, J. G.Appleby, R.Bruce, R.Quaranta, E.Redaelli, S.MERLIN Cleaning Studies with Advanced Collimator Materials for HL-LHCAccelerators and Storage Rings11: Collimator Materials for fast High Density Energy Deposition (COMA-HDED)11.2: Material testing for fast energy density deposition and high irradiation dosesCERN-ACC-2016-0064The challenges of the High-Luminosity upgrade of the Large Hadron Collider require improving the beam collimation system. An intense R&D program has started at CERN to explore novel materials for new collimator jaws to improve robustness and reduce impedance. Particle tracking simulations of collimation efficiency are performed using the code MERLIN which has been extended to include new materials based on composites. After presenting two different implementations of composite materials tested in MERLIN, we present simulation studies with the aim of studying the effect of the advanced collimators on the LHC beam cleaning.2016http://cds.cern.ch/record/215697010.18429/JACoW-IPAC2016-WEPMW036http://cds.cern.ch/record/2156970oai:cds.cern.ch:2156970 doi:10.18429/JACoW-IPAC2016-WEPMW031engQuaranta, E.Bertarelli, A.Biancacci, N.Bruce, R.Carra, F.Métral, E.Redaelli, S.Rossi, A.Salvant, B.Towards Optimum Material Choices for HL-LHC Collimator UpgradeAccelerators and Storage Rings11: Collimator Materials for fast High Density Energy Deposition (COMA-HDED)11.3: Material mechanical modellingCERN-ACC-2016-0062The first years of operation at the LHC showed that collimator material-related concerns might limit the performance. In addition, the HL-LHC upgrade will bring the accelerator beyond the nominal performance through more intense and brighter proton beams. A new generation of collimators based on advanced materials is needed to match present and new requirements. After several years of R&D on collimator materials, studying the behaviour of novel composites with properties that address different limitations of the present collimation system, solutions have been found to fulfil various upgrade challenges. This paper describes the proposed staged approach to deploy new materials in the upgraded HL-LHC collimation system. Beam tests at the CERN HiRadMat facility were also performed to benchmark simulation methods and constitutive material models.2016http://cds.cern.ch/record/215696810.18429/JACoW-IPAC2016-WEPMW031http://cds.cern.ch/record/2156968oai:cds.cern.ch:2156968 doi:10.1088/1742-6596/874/1/012001doi:10.18429/JACoW-IPAC2017-MOPAB005engCarra, FBertarelli, ABerthomé, EFichera, CFurness, TGuinchard, MMettler, L KPortelli, MRedaelli, SSacristan de Frutos, OThe “Multimat” experiment at CERN HiRadMat facility: advanced testing of novel materials and instrumentation for HL-LHC collimatorsAccelerators and Storage RingsARIES-2007-002CERN-ACC-2017-333The increase of the stored beam energy in future particle accelerators, such as the HL-LHC and the FCC, calls for a radical upgrade in the design, materials and instrumentation of Beam Intercepting Devices (BID), such as collimators Following successful tests in 2015 that validated new composite materials and a novel jaw design conceived for the HL-LHC collimators, a new HiRadMat experiment, named “HRMT36-MultiMat”, is scheduled for autumn 2017. Its objective is to determine the behaviour under high intensity proton beams of a broad range of materials relevant for collimators and beam intercepting devices, thin-film coatings and advanced equipment. The test bench features 16 separate target stations, each hosting various specimens, allowing the exploration of complex phenomena such as dynamic strength, internal damping, nonlinearities due to anisotropic inelasticity and inhomogeneity, effects of energy deposition and radiation on coatings. This paper details the main technical solutions and engineering calculations for the design of the test bench and of the specimens, the candidate target materials and the instrumentation system.2017http://cds.cern.ch/record/227595810.1088/1742-6596/874/1/01200110.18429/JACoW-IPAC2017-MOPAB005http://cds.cern.ch/record/2275958oai:inspirehep.net:1611144 doi:10.1088/1742-6596/874/1/012005doi:10.18429/JACoW-IPAC2017-TUPVA008engCarra, FApeland, JCalaga, RCapatina, OCapelli, TVerdú-Andrés, SZanoni, CAssessment of thermal loads in the CERN SPS crab cavities cryomodule$^1$Accelerators and Storage RingsCERN-ACC-2017-331As a part of the HL-LHC upgrade, a cryomodule is designed to host two crab cavities for a first test with protons in the SPS machine. The evaluation of the cryomodule heat loads is essential to dimension the cryogenic infrastructure of the system. The current design features two cryogenic circuits. The first circuit adopts superfluid helium at 2 K to maintain the cavities in the superconducting state. The second circuit, based on helium gas at a temperature between 50 K and 70 K, is connected to the thermal screen, also serving as heat intercept for all the interfaces between the cold mass and the external environment. An overview of the heat loads to both circuits, and the combined numerical and analytical estimations, is presented. The heat load of each element is detailed for the static and dynamic scenarios, with considerations on the design choices for the thermal optimization of the most critical components.2017http://cds.cern.ch/record/227596110.1088/1742-6596/874/1/01200510.18429/JACoW-IPAC2017-TUPVA008http://cds.cern.ch/record/2275961oai:inspirehep.net:1611147 doi:10.1088/1742-6596/874/1/012007doi:10.18429/JACoW-IPAC2017-TUPVA010engPellegrini, DFartoukh, SKarastathis, NPapaphilippou, YMultiparametric response of the HL-LHC Dynamic Aperture in presence of beam-beam effectsAccelerators and Storage RingsCERN-ACC-2017-323We performed extended simulations of HL-LHC dynamic aperture in the presence of beam-beam effects in the weak-strong approximation, evaluating the contributions of parameters such as: bunch intensity, crossing angle, chromaticity, current in the Landau octupoles and multipole errors. From the beam dynamics point of view, the main difference between the LHC (until 2017) and the HL-LHC is the deployment of the achromatic telescopic squeezing (ATS) optics, allowing not only for a smaller β* reach, but also modifying the phase advances between the lattice correctors (sextupoles, octupoles) and the main IPs, and increasing the peak β functions in the arcs. These correctors become therefore more efficient for the chromatic correction, but also a mitigation of the beam-beam long range interactions using the Landau octupoles is enabled, resulting in a possible reduction of the normalised crossing angle. The limits have been investigated in a tracking simulation campaign aimed at exploring the operational space for the HL-LHC and two possible options for luminosity levelling.2017http://cds.cern.ch/record/227604710.1088/1742-6596/874/1/01200710.18429/JACoW-IPAC2017-TUPVA010http://cds.cern.ch/record/2276047oai:inspirehep.net:1611149 doi:10.1088/1742-6596/874/1/012092doi:10.18429/JACoW-IPAC2017-MOPVA096engZanoni, CAmorim Carvalho, AArtoos, KAtieh, SBrodzinski, KCalaga, RCapatina, OCapelli, TCarra, FDassa, LDijoud, TEiler, KFavre, GFreijedo Menendez, PGarlaschè, MGiordanino, LJones, TLangeslag, S A ELeuxe, RMainaud-Durand, HMinginette, PNarduzzi, MRude, VSosin, MSwieszek, J STempleton, NThe crab cavities cryomodule for SPS testAccelerators and Storage RingsCERN-ACC-2017-313RF Crab Cavities are an essential part of the HL-LHC upgrade. Two concepts of such systems are being developed: the Double Quarter Wave (DQW) and the RF Dipole (RFD). A cryomodule with two DQW cavities is in advanced fabrication stage for the tests with protons in the SPS. The cavities must be operated at 2 K, without excessive heat loads, in a low magnetic environment and in compliance with CERN safety guidelines on pressure and vacuum systems. A large set of components, such as a thermal shield, a two layers magnetic shield, RF lines, helium tank and tuner are required for the successful and safe operation of the cavities. The sum of all these components with the cavities and their couplers forms the cryomodule. An overview of the design and fabrication strategy of this cryomodule is presented. The main components are described along with the present status of cavity fabrication and processing and cryomodule assembly. The lesson learned from the prototypes and first manufactured systems are also included.2017http://cds.cern.ch/record/227605710.1088/1742-6596/874/1/01209210.18429/JACoW-IPAC2017-MOPVA096http://cds.cern.ch/record/2276057oai:inspirehep.net:1611207 doi:10.1088/1742-6596/874/1/012102doi:10.18429/JACoW-IPAC2017-WEPVA117engZanoni, CarloGobbi, GiorgiaPerini, DiegoStancari, GiulioPreliminary Mechanical Design Study of the Hollow Electron Lens for HL-LHCAccelerators and Storage RingsFERMILAB-CONF-17-275-AD-APCCERN-ACC-2017-309A Hollow Electron Lens (HEL) has been proposed in order to improve performance of halo control and collimation in the Large Hadron Collider in view of its High Luminosity upgrade (HL-LHC). The concept is based on a hollow beam of electrons that travels around the protons for a few meters. The electron beam is produced by a cathode and then guided by a strong magnetic field. The first step of the design is the definition of the magnetic field that drives the electron trajectories. The estimation of such trajectories by means of a dedicated MATLAB tool is presented. The influence of the main geometrical and electrical parameters is analyzed and discussed. Then, the main mechanical design choices for the solenoids, cryostats gun and collector are described. The aim of this paper is to provide an overview of the feasibility study of the Electron Lens for LHC. The methods used in this study also serve as examples for future mechanical and integration designs of similar devices.2017http://cds.cern.ch/record/227606110.1088/1742-6596/874/1/01210210.18429/JACoW-IPAC2017-WEPVA117http://cds.cern.ch/record/2276061oai:inspirehep.net:1611213 doi:10.18429/JACoW-IPAC2017-TUPVA027Barranco Garcia, JavierPieloni, TatianaBuffat, XavierTambasco, ClaudiaStudy of beam-beam long range compensation with octupolesAccelerators and Storage RingsCERN-ACC-2017-0065Long range beam-beam effects are responsible for particle losses and define fundamental operational parameters of colliders (i.e. crossing angles, intensities, emittances, ${\beta}$${^∗}$). In this study we propose octuple magnets as a possible scheme to efficiently compensate long-range beam-beam interactions with a global correction scheme. The impact and improvements on the dynamic aperture of colliding beams together with estimates of the luminosity potentials are dis- cussed for the HL-LHC upgrade and extrapolations made for the FCC project.2017-05-19http://cds.cern.ch/record/228116910.18429/JACoW-IPAC2017-TUPVA027ACChttp://cds.cern.ch/record/2281169oai:cds.cern.ch:2281169On behalf of EuroCirCol WP3 doi:10.18429/JACoW-IPAC2017-THPAB041engFitterer, MStancari, GValishev, aDe Maria, RRedaelli, SSjobak, KWagner, J FImplementation of Hollow Electron Lenses in SixTrack and First Simulation Results for the HL-LHCAccelerators and Storage RingsFERMILAB-CONF-17-197-ADCERN-ACC-2017-307Electron lenses have found a wide range of applications for hadron colliders, where the main applications are machine protection and beam-beam compensation. This paper summarizes the status of the current electron lens implementation in SixTrack with the focus on hollow electron beams for beam collimation and shows some first simulation results of the High-Luminosity upgrade of the LHC (HL-LHC).2017http://cds.cern.ch/record/228713310.18429/JACoW-IPAC2017-THPAB041http://cds.cern.ch/record/2287133oai:inspirehep.net:1622679 doi:10.18429/JACoW-IPAC2017-WEOBA2engFitterer, MStancari, GValishev, ABruce, RPapotti, GRedaelli, SValentino, GValentino, GValuch, DXu, CHollow Electron Beam Collimation for HL-LHC - Effects on the Beam CoreAccelerators and Storage RingsFERMILAB-CONF-17-153-ADCERN-ACC-2017-306Collimation with hollow electron beams is currently one of the most promising concepts for active halo control in the High Luminosity Large Hadron Collider (HL-LHC). To ensure the successful operation of the hollow beam collimator the unwanted effects on the beam core, which might arise from the operation with a pulsed electron beam, must be minimized. This paper gives a summary of the effect of hollow electron lenses on the beam core in terms of sources, provides estimates for HL-LHC and discusses the possible mitigation methods.2017http://cds.cern.ch/record/228713410.18429/JACoW-IPAC2017-WEOBA2http://cds.cern.ch/record/2287134oai:inspirehep.net:1622968 doi:10.18429/JACoW-IPAC2017-MOPAB006engNuiry, Francois-XavierAberle, OliverBergeret, MaximeBertarelli, AlessandroBiancacci, NicoloBruce, RoderikCalviani, MarcoCarra, FedericoDallocchio, AlessandroGentini, LucaGilardoni, SimoneIllan Fiastre, RicardoLamas Garcia, InigoMasi, AlessandroPerillo-Marcone, AntonioPianese, StefanoRedaelli, StefanoRigutto, EmilienSalvant, BenoitDesign and Prototyping of New CERN Collimators in the Framework of the LHC Injector Upgrade (LIU) Project and the High-Luminosity (HL-LHC) ProjectAccelerators and Storage RingsCERN-ACC-2017-302In the framework of the Large Hadron Collider (LHC) Injectors Upgrade (LIU) and the High-Luminosity LHC (HL-LHC) Projects at CERN (European Organization for Nuclear Research, in Geneva, Switzerland), collimators in the Super Proton Synchrotron (SPS) to LHC transfer lines as well as ring collimators in the LHC will undergo important upgrades in the forthcoming years, mainly focused during the Long Shutdown 2 foreseen during 2019-2020. This contribution will detail the current design of the TCDIL collimators with a particular emphasis on the engineering developments performed on the collimator jaws, aiming at getting a stringent flatness while consid-ering also the integration of thermal shock resistant materials. The prototyping phase done at CERN will be also described. The activities ongoing to prepare the series production for other LHC collimator types (TCPPM, TCSPM, TCTPM, TCLD) will be presented, describing the role that each of these collimators play on the HL-LHC Project. A focus on the series production processes, the manufacturing and assembly technologies involved and the quality and performance assurance tests will be given.2017http://cds.cern.ch/record/228733710.18429/JACoW-IPAC2017-MOPAB006http://cds.cern.ch/record/2287337oai:inspirehep.net:1626188 doi:10.18429/JACoW-IPAC2017-MOPAB011engTsinganis, AndreaBruce, RoderikCerutti, FrancescoLechner, AntonImpact on the HL-LHC Triplet Region and Experiments From Asynchronous Beam Dumps on Tertiary CollimatorsAccelerators and Storage RingsCERN-ACC-2017-301Accidental beam impacts on the tertiary collimators (TCTs) can lead to significant energy deposition in the triplet region and to leakage of the induced particle shower towards the experimental cavern. In this work, carried out in the context of the planned High Luminosity Upgrade of the LHC, severe impacts from asynchronous beam dumps on the horizontal tertiary collimators in cells 4 and 6 of the CMS insertion were studied, with half or a full proton bunch impacting on a collimator jaw. The choice of jaw material is shown to be of great importance, with over a factor of 10 increase in peak energy density values in the triplet coils moving from tungsten (Inermet) to molybdenum graphite jaws. Nevertheless, although the quench limit is exceeded in at least one or more triplet magnets in all the evaluated scenarios, values remain well below the damage limit. Energy spectra of particles leaking into the experimental cavern have also been estimated and are presented here.2017http://cds.cern.ch/record/228733810.18429/JACoW-IPAC2017-MOPAB011http://cds.cern.ch/record/2287338oai:inspirehep.net:1626189 doi:10.18429/JACoW-IPAC2017-MOPAB012engSkordis, EleftheriosBruce, RoderikCerutti, FrancescoFerrari, AlfredoHermes, PascalLechner, AntonMereghetti, AlessioRedaelli, StefanoSalvachua, BelenVlachoudis, VasilisWelsch, CarstenStudy of the 2015 Top Energy LHC Collimation Quench Tests Through an Advanced Simulation ChainAccelerators and Storage RingsCERN-ACC-2017-300While the LHC has shown record-breaking perfor-mance during the 2016 run, our understanding of the behaviour of the machine must also reach new levels. The collimation system and especially the betatron cleaning insertion region (IR7), where most of the beam halo is intercepted to protect superconducting (SC) magnets from quenching, has so far met the expectations but could nonetheless pose a bottleneck for future operation at higher beam intensities for HL-LHC. A better under-standing of the collimation leakage to SC magnets is required in order to quantify potential limitations in terms of cleaning efficiency, ultimately optimising the collider capabilities. Particle tracking simulations com-bined with shower simulations represent a powerful tool for quantifying the power deposition in magnets next to the cleaning insertion. In this study, we benchmark the simulation models against beam loss monitor measure-ments from magnet quench tests (QT) with 6.5 TeV pro-ton and 6.37Z TeV Pb ion beams. In addition, we investi-gate the effect of possible imperfections on the collima-tion leakage and the power deposition in magnets.2017http://cds.cern.ch/record/228733910.18429/JACoW-IPAC2017-MOPAB012http://cds.cern.ch/record/2287339oai:inspirehep.net:1626190 doi:10.18429/JACoW-IPAC2017-WEPVA097engBarnes, MichaelBeck, MarioDay, HugoDucimetière, LaurentGarcia-Tabares Valdivieso, ElisaGoddard, BrennanNeupert, HolgerRomano, AnnalisaVega Cid, LorenaWeterings, WimZannini, CarloUpgrading the SPS Fast Extraction Kicker Systems for HL-LHCAccelerators and Storage RingsCERN-ACC-2017-217The CERN SPS has two fast extraction systems, each consisting of travelling wave kicker magnets (MKEs). The beam induced heating in the ferrite yoke of these magnets was historically kept to an acceptable level by implementing water cooling of the kicker magnets: in addition serigraphy was applied on the surfaces of the ferrite yoke facing the beam. Nevertheless, high intensity beams needed in the future for HL-LHC will significantly increase the beam induced heating, potentially raising the MKE ferrite yoke temperature to its Curie point. Hence detailed studies of longitudinal beam coupling impedance were carried out to identify simple but effective methods of further reducing beam induced power deposition. Based on the results of these studies, and in the framework of the LHC Injectors Upgrade (LIU) project, an upgraded MKE kicker magnet was installed during the 2015-2016 shutdown. This paper reports and compares results of predictions, laboratory measurements, temperature measurements during SPS operation, and machine development studies. Measurements of both dynamic pressure rise in the upgraded magnet and Secondary Electron Yield, on samples, are also reported.2017http://cds.cern.ch/record/228946810.18429/JACoW-IPAC2017-WEPVA097http://cds.cern.ch/record/2289468oai:inspirehep.net:1626401 doi:10.18429/JACoW-IPAC2017-WEPVA116engYammine, SamerThiesen, HuguesHL-LHC Inner Triplet Powering and Control StrategyAccelerators and Storage RingsCERN-ACC-2017-215In order to achieve the target 3000 fb-1 integrated field for the HL-LHC (High Luminosity ' Large Hadron Collider) at ATLAS and CMS, new large aperture quadrupoles are required for the final focusing triplet magnets before the interaction points. These low-' magnets, based on the Nb$_{3}$Sn technology, deliver a peak field of 11.4 T. They consist of two outer quadrupoles, Q1 and Q3 and a central one divided into two identical magnets, Q2a and Q2b. To optimize the powering and the beam dynamics of these triplets, the quadrupoles will be powered in series by a single high-current two quadrants (2-Q) converter [18 kA, ±10 V]. Three 4-Q trim power converters are added over Q1 [±2 kA, ±10 V], Q2a [±0.12 kA, ±10 V] and Q3 [±2 kA, ±10 V] to account for possible transfer function difference between the quadrupoles. This paper presents the powering scheme of the four mentioned coupled circuits. A digital control strategy, using four standard LHC digital controllers, to decouple the four systems and to achieve a high precision control is proposed and discussed.2017http://cds.cern.ch/record/228947010.18429/JACoW-IPAC2017-WEPVA116http://cds.cern.ch/record/2289470oai:inspirehep.net:1626403 doi:10.18429/JACoW-IPAC2017-WEPIK066engWanzenberg, RainerMetral, EliasSalvant, BenoitZagorodnova, OlgaCalculation of Wakefields and Higher Order Modes for the Vacuum Chamber of the CMS, ATLAS, ALICE and LHCb Experiments for the HL-LHCAccelerators and Storage RingsCERN-ACC-2017-212The High Luminosity Large Hadron Collider (HL-LHC) project was started with the goal to extend the discovery potential of the Large Hadron Collider (LHC). The HL-LHC study implies also upgraded dimensions of the experimental beam pipes of the CMS, ATLAS, ALICE and LHCb experiments. The trapped monopole and dipole Higher Order Modes (HOMs) and the short range wakefields for the new design of the vacuum chambers were calculated with help of the computer codes MAFIA and ECHO2D. The results of the short range wakefields calculations and the HOMs calculations are presented in this report. The short range wakefields are presented in terms of longitudinal and transverse wake potentials and also in terms of loss and kick parameters. Selected results from the HOMs calculations , including the the frequency, the loss parameter, the R/Q and the Q value are presented.2017http://cds.cern.ch/record/228947310.18429/JACoW-IPAC2017-WEPIK066http://cds.cern.ch/record/2289473oai:inspirehep.net:1626422 doi:10.18429/JACoW-IPAC2017-TUPVA011engGuillermo Cantón, GerardoAdy, MartonAngelucci, MarcoCimino, RobertoKersevan, RobertoLa Francesca, ElianaSagan, DavidZimmermann, FrankComparing Behaviour of Simulated Proton Synchrotron Radiation in the Arcs of the LHC with MeasurementsAccelerators and Storage RingsCERN-ACC-2017-209In previous work it was shown that at high proton-beam energies, synchrotron radiation is an important source of beam-screen heating, of beam-related vacuum pressure increase, and of primary photoelectrons, which can contribute to electron cloud formation. We have used the Synrad3D code developed at Cornell to simulate the photon distributions in the arcs of the LHC, HL-LHC, and FCC-hh. Specifically, for the LHC we studied the effect of the sawtooth chamber. In this paper specific results of the Synrad3D simulations are compared with simulations in Synrad+, developed at CERN; and later on compared with experimental data for actual LHC vacuum-chamber samples.2017http://cds.cern.ch/record/228947610.18429/JACoW-IPAC2017-TUPVA011http://cds.cern.ch/record/2289476oai:inspirehep.net:1626426 doi:10.18429/JACoW-IPAC2017-TUPVA021engTsinganis, AndreaCerutti, FrancescoImpact of Collision Debris in the HL-LHC ATLAS and CMS InsertionsAccelerators and Storage RingsCERN-ACC-2017-205The High Luminosity upgrade of the LHC (HL-LHC) foresees the baseline operation of the accelerator at a 5 times higher peak luminosity (5.0x1034cm⁻²s^{−1}). The impact of collision debris on the magnets and other equipment in the triplet region and matching section of the ATLAS and CMS insertions has been evaluated by means of detailed FLUKA models implementing the latest optics and layout version. Qualitative and quantitative differences between the vertical and horizontal beam crossing schemes are highlighted. With measures in place to mitigate the effects of the interruption of the beam screen in the triplet interconnections and the Q4 aperture reduction, peak dose values in the superconducting coils remain below 30MGy in the triplet-D1 and below 12MGy in the matching section magnets for an integrated luminosity of 3000fb-1. Peak power density values are lower than 3mW/cm³ and 1mW/cm³ in the triplet and matching section respectively. Total heat loads in magnets, collimators, masks and absorbers were also estimated, along with dose and particle fluence maps relevant for Radiation to Electronics (R2E) aspects. The effect of a displacement of the interaction point is also addressed.2017http://cds.cern.ch/record/228948010.18429/JACoW-IPAC2017-TUPVA021http://cds.cern.ch/record/2289480oai:inspirehep.net:1626430 doi:10.18429/JACoW-IPAC2017-WEPVA114engSanchez Galan, FranciscoAdorisio, CristinaBergstrom, IdaBrethoux, DamienEvrard, SebastienGaddi, AndreaKrzkempek, LukaszLazzaroni, MichaelPerez Espinos, JaimeRaymond, MichelVincke, HeinzOptimising Machine-Experiment Interventions in HL-LHCAccelerators and Storage RingsCERN-ACC-2017-193The luminosity reach of the HL-LHC experiments implies new constraints for the protection of the inner triplets from the machine debris. In general activation levels will increase a factor of 15-30 from the 2015 values (LS1), affecting both radiation tolerance of equipment and maintenance scenarios. The design of new equipment takes into account these constraints and the entire layout of tunnel equipment near the interaction regions will al-low for simplified maintenance. In particular, new ab-sorbers will replace the existing protection of the ma-chine-experiment cavern boundaries, with an optimised layout of the region. This paper summarises the main constraints (both physical and operational) existing at the region, together with the solutions adopted to reduce worker's dose.2017http://cds.cern.ch/record/228963610.18429/JACoW-IPAC2017-WEPVA114http://cds.cern.ch/record/2289636oai:inspirehep.net:1626252 doi:10.18429/JACoW-IPAC2017-MOPVA102engApsimon, RobertAppleby, RobertBaudrenghien, PhilippeBurt, GraemeDexter, AmosSjobak, KyrreModeling the Low Level RF Response on the Beam during Crab Cavity QuenchAccelerators and Storage RingsCERN-ACC-2017-186The High Luminosity Upgrade for the LHC (HL-LHC) relies on crab cavities to compensate for the luminosity reduction due to the crossing angle of the colliding bunches at the interaction points. In this paper we present the simulation studies of cavity quenches and the impact on the beam. The cavity voltage and phase during the quench is determined from a simulation in Matlab and used to determine the impact on the beam from tracking simulations in SixTrack. The results of this study are important for determining the required machine protection and interlock systems for HL-LHC.2017http://cds.cern.ch/record/228964310.18429/JACoW-IPAC2017-MOPVA102http://cds.cern.ch/record/2289643oai:inspirehep.net:1626275 doi:10.18429/JACoW-IPAC2017-WEPVA094engVlachodimitropoulos, VasileiosBarnes, MichaelDucimetière, LaurentVega Cid, LorenaWeterings, WimStudy of an Improved Beam Screen Design for the LHC Injection Kicker Magnet for HL-LHCAccelerators and Storage RingsCERN-ACC-2017-177During Run 1 of the LHC, one of the injection kicker magnets (MKIs) occasionally exhibited an excessively high ferrite temperature, caused by coupling of the high intensity beam to the real impedance of the magnet. Beam-screen upgrades have been very effective in reducing beam coupling impedance during Run 2. However, temperature measurements during LHC operation have shown that one end of the MKIs ferrite yoke is consistently hotter than the other: this effect is due to highly non-uniform beam induced power deposition along the kicker. Electromagnetic and thermal simulations show that part of the ferrite yoke will be above its Curie temperature when the LHC is operated with HL-LHC beam parameters, which could increase the turn-around time between fills of the LHC. An impedance mitigation study is presented in this paper with emphasis on the effect of the beam screen layout upon both total beam induced power deposition and its longitudinal distribution. Results of complex thermal simulations, to benchmark the effectiveness of the proposed schemes, are reported. To validate the proposed modification a test bench measurement was performed and preliminary results are discussed2017http://cds.cern.ch/record/228965210.18429/JACoW-IPAC2017-WEPVA094http://cds.cern.ch/record/2289652oai:inspirehep.net:1626286 doi:10.18429/JACoW-IPAC2017-WEPVA113engSacristan De Frutos, OscarBertarelli, AlessandroBianchi, LauraCarra, FedericoGuardia, JorgeGuinchard, MichaelRedaelli, StefanoThermo-Physical and Mechanical Characterisation of Novel Materials under Development for HL-LHC Beam Intercepting DevicesAccelerators and Storage RingsCERN-ACC-2017-170The collimation system for high energy particle accelerators as HL-LHC, must be designed to withstand the close interaction with intense and energetic particle beams, safely operating over an extended range of temperatures in extreme conditions (pressure, strain-rate, radiation), which are to become more demanding with the High Luminosity LHC. In order to withstand such conditions, the candidate materials must possess among other properties outstanding thermal shock resistance and high thermal and electrical conductivity, condition only met by advanced or novel materials. Therefore, an extensive R&D; program has been launched to develop novel materials capable of replacing or complementing materials used for present collimators. So far, Molybdenum Carbide - Graphite and Copper-Diamond composites have been identified as the most promising materials. Literature data are scarce or non-existing for these materials. For this reason the successive characterisation campaigns constitute a linchpin of the R&D; program. This paper reviews the experimental program followed for the thermo-physical and mechanical characterisation of the materials, and discusses the most relevant results.2017http://cds.cern.ch/record/228965910.18429/JACoW-IPAC2017-WEPVA113http://cds.cern.ch/record/2289659oai:inspirehep.net:1626293 doi:10.18429/JACoW-IPAC2017-WEPIK093engMaclean, EwenCarlier, FelixCoello de Portugal, Jaime MariaGarcia-Tabares, AnaGiovannozzi, MassimoMalina, LukasPersson, TobiasSkowroński, PiotrTomás, RogelioNew Methods for Measurement of Nonlinear Errors in LHC Experimental IRs and Their Application in the HL-LHCAccelerators and Storage RingsCERN-ACC-2017-166Studies of nonlinear errors in LHC experimental insertions (IRs) during Run 1 were based upon feed-down to tune and coupling from the crossing angle orbit bumps. Useful for validating the magnetic model, this method alone is of limited use to understand discrepancies between magnetic and beam-based measurement. Feed-down from high-order multipoles is also difficult to observe. During Run 2 several alternative methods were tested in the LHC. This paper summarizes the results of these tests, and comments on their potential application to the High-Luminosity LHC upgrade.2017http://cds.cern.ch/record/228966310.18429/JACoW-IPAC2017-WEPIK093http://cds.cern.ch/record/2289663oai:inspirehep.net:1626300 doi:10.18429/JACoW-IPAC2017-WEPIK033engWiesner, ChristophBartmann, WolfgangBracco, ChiaraCarlier, EtienneDucimetière, LaurentFrankl, MatthiasFraser, MatthewGoddard, BrennanKramer, ThomasLechner, AntonMagnin, NicolasMazzoni, StefanoMeddahi, MalikaSenaj, ViliamLHC Beam Dump Performance in View of the High Luminosity UpgradeAccelerators and Storage RingsCERN-ACC-2017-159The High Luminosity Large Hadron Collider (HL-LHC) project will increase the total beam intensity in the LHC by nearly a factor of two. Analysis and follow-up of recent operational issues as well as dedicated studies of the LHC Beam Dump System (LBDS) have been carried out to ensure the safe operation with HL-LHC parameters and to decide on possible hardware upgrades to meet the HL-LHC requirements. The fail-safe design must ensure the LBDS performance also for abnormal operation such as asynchronous beam dumps or failing dilution kickers. In this paper, we report on newly observed failure scenarios as the erratic firing of more than one dilution kicker, and discuss their consequences as well as possible mitigation measures in view of the high luminosity upgrade.2017http://cds.cern.ch/record/228967010.18429/JACoW-IPAC2017-WEPIK033http://cds.cern.ch/record/2289670oai:inspirehep.net:1626313 doi:10.18429/JACoW-IPAC2017-TUPVA115engRossi, AdrianaAberle, OliverAlbertone, JoelBarnyakov, AlexeyBertarelli, AlessandroBoccard, ChristianCarra, FedericoCattenoz, GregoryDelaup, YorickFartoukh, StephaneFitterer, MiriamGobbi, GiorgiaLendaro, JeromeLevichev, AlexeyNikiforov, DanilaPapaphilippou, YannisPatapenka, AndreiPerini, DiegoRedaelli, StefanoSchmickler, HermannStancari, GiulioValishev, AlexanderZanoni, CarloProgress with Long-Range Beam-Beam Compensation Studies for High Luminosity LHCAccelerators and Storage RingsCERN-ACC-2017-158Long-range beam-beam (LRBB) interactions can be a source of emittance growth and beam losses in the LHC during physics and will become even more relevant with the smaller '* and higher bunch intensities foreseen for the High Luminosity LHC upgrade (HL-LHC), in particular if operated without crab cavities. Both beam losses and emittance growth could be mitigated by compensat-ing the non-linear LRBB kick with a correctly placed current carrying wire. Such a compensation scheme is currently being studied in the LHC through a demonstration test using current-bearing wires embedded into col-limator jaws, installed either side of the high luminosity interaction regions. For HL-LHC two options are considered, a current-bearing wire as for the demonstrator, or electron lenses, as the ideal distance between the particle beam and compensating current may be too small to allow the use of solid materials. This paper reports on the ongoing activities for both options, covering the progress of the wire-in-jaw collimators, the foreseen LRBB experiments at the LHC, and first considerations for the design of the electron lenses to ultimately replace material wires for HL-LHC.2017http://cds.cern.ch/record/228967110.18429/JACoW-IPAC2017-TUPVA115http://cds.cern.ch/record/2289671oai:inspirehep.net:1626322 doi:10.18429/JACoW-IPAC2017-TUPVA022engValette, MatthieuApollonio, AndreaUythoven, JanWollmann, DanielRequirements for Crab Cavity System Availability in HL-LHCAccelerators and Storage RingsCERN-ACC-2017-153Crab Cavities will be installed in the High Luminosity LHC in order to increase the effective peak luminosity through a partial compensation of the geometric factor. This will allow extending the levelling time resulting in an increased production of integrated luminosity. Based on the availability of the LHC during 2016 operation, the expected yearly-integrated luminosity of the future HL-LHC was estimated using a Monte Carlo model. Crab cavity faults were added to the observed failure distribu-tions and their impact on integrated luminosity produc-tion as a function of fault time and fault frequency was studied. This allows identifying a breakeven point in luminosity production and defining minimum system availability requirements for the crab cavities to reach the design goal of 250 fb-1 of integrated luminosity per year.2017http://cds.cern.ch/record/228967610.18429/JACoW-IPAC2017-TUPVA022http://cds.cern.ch/record/2289676oai:inspirehep.net:1626327 doi:10.18429/JACoW-IPAC2017-TUPVA029engBuffat, XavierBarranco García, JavierPieloni, TatianaTambasco, ClaudiaValuch, DanielObservations of Emittance Growth in the Presence of External Noise in the LHCAccelerators and Storage RingsCERN-ACC-2017-152Dedicated experiments were perfomed in the LHC to study the impact of noise on colliding high brightness beams. The results are compared to theoretical models and multiparticle tracking simulations. The impacts on the LHC operation and the HL-LHC project are discussed.2017http://cds.cern.ch/record/228967710.18429/JACoW-IPAC2017-TUPVA029http://cds.cern.ch/record/2289677oai:inspirehep.net:1626328 doi:10.18429/JACoW-IPAC2017-TUPVA030engGonçalves Jorge, PatrikBarranco García, JavierBuffat, XavierCarlier, FelixCoello de Portugal, Jaime MariaFol, ElenaMedina Medrano, LuisPieloni, TatianaTomás, RogelioWegscheider, AndreasMeasurement of Beta-Beating Due to Strong Head-on Beam-Beam Interactions in the LHCAccelerators and Storage RingsCERN-ACC-2017-151The LHC operation relies on a good knowledge of the optics, usually corrected in absence of beam-beam interactions. In a near future, both the LHC and the HL-LHC will need to cope with large head-on beam-beam parameters, the impact on the optics needs to be understood and, if necessary, corrected. The results of a dedicated experiment performed at injection energy are discussed in this paper.2017http://cds.cern.ch/record/228967810.18429/JACoW-IPAC2017-TUPVA030http://cds.cern.ch/record/2289678oai:inspirehep.net:1626329 doi:10.18429/JACoW-IPAC2017-TUPVA006engApollonio, AndreaRey Orozko, OdeiSchmidt, RuedigerValette, MatthieuWollmann, DanielZerlauth, MarkusLessons Learnt from the 2016 LHC Run and Prospects for HL-LHC AvailabilityAccelerators and Storage RingsCERN-ACC-2017-145The LHC exhibited unprecedented availability during the 2016 proton run, producing about 40 fb-1 of integrated luminosity, surpassing the sum of production during the 4 previous years. This was achieved while running steadily with a peak luminosity above the design target of 1034 cm- 2s^{−1}. Individual system performance and an increased experience operating the LHC were fundamental for these achievements, following the consolidations and improvements deployed during the Long Shutdown 1 and the Year End Technical Stop in 2015. The implications of this excellent performance in the context of the High Luminosity LHC are discussed in this paper, with the goal of defining the possible integrated luminosity reach of HL-LHC when considering the different operating conditions and the newly developed systems and technologies.2017http://cds.cern.ch/record/228968410.18429/JACoW-IPAC2017-TUPVA006http://cds.cern.ch/record/2289684oai:inspirehep.net:1626341 doi:10.18429/JACoW-IPAC2017-TUPVA015engMartinella, CorinnaBrugger, MarkusDanzeca, SalvatoreGarcia Alia, RubenKadi, YacineStein, OliverXu, ChenRadiation Levels at the LHC: 2012, 2015 and 2016 Proton Physics Operations in View of HL-LHC requirementsAccelerators and Storage RingsCERN-ACC-2017-142The variety of beam losses produced in the Large Hadron Collider (LHC) creates a mixed and complex radiation field. During 2012, 2015 and 2016, Beam Loss Monitors and RadMons were used to monitor the inte-grated dose and the High Energy Hadrons fluence in order to anticipate the electronics degradation and inves-tigate the cause of failures. The annual radiation levels are compared; highlighting the mechanisms in the pro-duction of beam losses and the impact of the different squeeze and crossing angle. In addition, the increase of beam-gas interaction is discussed comparing operations at 25 ns and 50 ns bunch spacing. A strategy is presented to allow for a continuous respective evaluation during the upcoming LHC and future High Luminosity LHC (HL-LHC) operations.2017http://cds.cern.ch/record/228968710.18429/JACoW-IPAC2017-TUPVA015http://cds.cern.ch/record/2289687oai:inspirehep.net:1626344 doi:10.18429/JACoW-IPAC2017-TUPIK085engMainaud Durand, HeleneBartolome-Jimenez, SoniaDijoud, ThibaultDuquenne, MathieuHerty, AndreasRude, VivienSosin, MateuszHL-LHC Alignment Requirements and Associated SolutionsAccelerators and Storage RingsCERN-ACC-2017-138To increase by more than 10 times the luminosity reach w.r.t the first 10 years of the LHC lifetime, the HL-LHC project will replace nearly 1.2 km of the accelerator during the Long Shutdown 3 scheduled in 2024 [1][2][3]. This paper presents the HL-LHC alignment and internal metrology requirements of all the new components to be installed, from the magnet components to the beam instrumentation and vacuum devices. As for the LHC, a combination of Hydrostatic Levelling Sensors (HLS) and Wire Positioning Sensors (WPS) is proposed for the alignment of the main components, but on a longer distance (210 m instead of 50 m), generating technical challenges for the installation of the stretched wire and for the maintenance of the alignment systems. Innovative measurements methods and instrumentation are under study to perform the position monitoring inside a cryostat of cold masses and crab cavities, in a cold (2K) and radioactive (1 MGy/year) environment, as well as to carry remote measurements in the tunnel of the intermediary components. The proposed solutions concerning the determination of the position and the re-adjustment of the components are detailed in this paper.2017http://cds.cern.ch/record/228969110.18429/JACoW-IPAC2017-TUPIK085http://cds.cern.ch/record/2289691oai:inspirehep.net:1626352 doi:10.18429/JACoW-IPAC2017-TUPIK089engMedina Medrano, LuisArduini, GianluigiTomás, RogelioStudies on Luminous Region, Pile-up and Performance for HL-LHC ScenariosAccelerators and Storage RingsCERN-ACC-2017-135Studies on luminous region and pile-up density are of great interest for the experiments at the future High Luminosity LHC (HL-LHC) in order to optimize the detector performance. The evolution of these parameters at the two main interaction points of the HL-LHC along optimum physics fills is studied for the baseline and alternative operational scenarios with the latest set of parameters, including a refined description of the longitudinal bunch profile. Results are discussed in terms of a new figure-of-merit, the effective pile-up density.2017http://cds.cern.ch/record/228969410.18429/JACoW-IPAC2017-TUPIK089http://cds.cern.ch/record/2289694oai:inspirehep.net:1626355 doi:10.18429/JACoW-IPAC2017-MOPAB004engBahamonde Castro, CristinaCerutti, FrancescoFessia, PaoloLechner, AntonMereghetti, AlessioMirarchi, DanieleRedaelli, StefanoSkordis, EleftheriosImproved Protection of the Warm Magnets of the LHC Betatron Cleaning InsertionAccelerators and Storage RingsCERN-ACC-2017-120After the High Luminosity (HL) upgrade in 2024-2026, the LHC is anticipated to increase its integrated luminosity by a factor of 10 beyond its original design value of 300 fb-1. In preparation for this, several improvements to the equipment will already be implemented during the next Long Shutdown (LS2) starting in 2019. In the betatron cleaning insertion, the debris leaking out of several collimators will deposit energy in the downstream warm magnets, causing long-term radiation damage. A new layout has been proposed in which the most exposed magnet of each assembly is removed, reducing the assembly from 6 to 5 magnet units and gaining 2 spare magnets. New absorbers are therefore required to enhance the shielding of the remaining magnet string. In this paper, we present an evaluation of the dose to the warm magnets for post-LS2 operation, and we quantify the achievable reduction of the long-term radiation damage for different absorber configurations. A solution for an improved magnet protection that fulfills the HL-LHC requirements is proposed.2017http://cds.cern.ch/record/228970910.18429/JACoW-IPAC2017-MOPAB004http://cds.cern.ch/record/2289709oai:inspirehep.net:1626376