TY - CONF AU - Furuseth, S.V. AU - Buffat, X. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Change of Beam Distribution Due to Decoherence in the Presence of Transverse Feedback J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The effect of Landau damping is often calculated based on a Gaussian beam distribution in all degrees of freedom. The stability of the beam is however strongly dependent on the details of the distribution. The present study focuses on the change of bunch distributions caused by the decoherence of the excitation driven by an external source of noise, in the presence of both amplitude detuning and a transverse feedback. Both multiparticle tracking simulations and theoretical models show a similar change of the distribution. The possible loss of Landau damping driven by this change is discussed. PB - JACoW Publishing CP - Geneva, Switzerland SP - 281 EP - 284 KW - feedback KW - simulation KW - octupole KW - damping KW - emittance DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW078 UR - http://jacow.org/ipac2019/papers/mopgw078.pdf ER - TY - CONF AU - Zimmermann, F. AU - Abelleira, J.L. AU - Abramov, A. AU - Amorim, D. AU - Antipov, S.A. AU - Apyan, A. AU - Arsenyev, S. AU - Barranco García, J. AU - Benedikt, M. AU - Bruce, R. AU - Burkart, F. AU - Cai, Y. AU - Crouch, M.P. AU - Cruz Alaniz, E. AU - Fartoukh, S.D. AU - Giovannozzi, M. AU - Goddard, B. AU - Guillermo Cantón, G. AU - Hofer, M. AU - Keintzel, J. AU - Kersevan, R. AU - Mertens, V. AU - Mether, L. AU - Molson, J. AU - Muttoni, Y. AU - Nosochkov, Y.M. AU - Ohmi, K. AU - Oide, K. AU - Osborne, J.A. AU - Parma, V. AU - Pieloni, T. AU - Pikhartova, H. AU - Raginel, V. AU - Redaelli, S. AU - Risselada, T. AU - Rivkin, L. AU - Ruehl, I. AU - Salvant, B. AU - Schoerling, D. AU - Seryi, A. AU - Shaposhnikova, E.N. AU - Tambasco, C. AU - Tavian, L.J. AU - Todesco, E. AU - Tommasini, D. AU - Tomás, R. AU - Valchkova-Georgieva, F. AU - Venturi, V. AU - Wollmann, D. AU - Zhou, D. AU - van Riesen-Haupt, L. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Updated High-Energy LHC Design J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - 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. PB - JACoW Publishing CP - Geneva, Switzerland SP - 524 EP - 527 KW - injection KW - emittance KW - proton KW - impedance KW - damping DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPMP037 UR - http://jacow.org/ipac2019/papers/mopmp037.pdf ER - TY - CONF AU - van Riesen-Haupt, L. AU - Abelleira, J.L. AU - Barranco García, J. AU - Cruz Alaniz, E. AU - Hofer, M. AU - Keintzel, J. AU - Pieloni, T. AU - Tambasco, C. AU - Tomás, R. AU - Zimmermann, F. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Developments in the Experimental Interaction Regions of the High Energy LHC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - 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. PB - JACoW Publishing CP - Geneva, Switzerland SP - 532 EP - 535 KW - dipole KW - luminosity KW - dynamic-aperture KW - beam-beam-effects KW - shielding DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPMP039 UR - http://jacow.org/ipac2019/papers/mopmp039.pdf ER - TY - CONF AU - Salvant, B. AU - Amorim, D. AU - Antipov, S.A. AU - Arsenyev, S. AU - Beck, M.S. AU - Biancacci, N. AU - Brüning, O.S. AU - Campelo, J.V. AU - Carideo, E. AU - Caspers, F. AU - Dalascu, T. AU - Farricker, A. AU - Grudiev, A. AU - Kaltenbacher, T. AU - Koukovini-Platia, E. AU - Kramer, P. AU - Lasheen, A. AU - Migliorati, M. AU - Mounet, N. AU - Métral, E. AU - Nagaoka, R. AU - Nasr Esfahani, N. AU - Persichelli, S. AU - Popovic, B.K. AU - Rijoff, T.L. AU - Rumolo, G. AU - Shaposhnikova, E.N. AU - Smaluk, V.V. AU - Spataro, B. AU - Vaccaro, V.G. AU - Vollinger, C. AU - Wang, N. AU - White, S.M. AU - Zannini, C. AU - Zotter, B. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Building the Impedance Model of a Real Machine J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A reliable impedance model of a particle accelerator can be built by combining the beam coupling impedances of all the components. This is a necessary step to be able to evaluate the machine performance limitations, identify the main contributors in case an impedance reduction is required, and study the interaction with other mechanisms such as optics nonlinearities, transverse damper, noise, space charge, electron cloud, beam-beam (in a collider). The main phases to create a realistic impedance model, and verify it experimentally, will be reviewed, highlighting the main challenges. Some examples will be presented revealing the levels of precision of machine impedance models that have been achieved. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2249 EP - 2254 KW - impedance KW - simulation KW - wakefield KW - coupling KW - cavity DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEYPLS1 UR - http://jacow.org/ipac2019/papers/weypls1.pdf ER - TY - CONF AU - Würkner, B. AU - Alexopoulos, A. AU - Barschel, C. AU - Bay, A. AU - Blanc, F. AU - Bravin, E. AU - Bregliozzi, G. AU - Chritin, N. AU - Dehning, B. AU - Ferro-Luzzi, M. AU - Gianì, S. AU - Giovannozzi, M. AU - Girard, O. AU - Greim, R. AU - Haefeli, G.J. AU - Hopchev, P. AU - Jacobsson, R. AU - Jensen, L.K. AU - Jones, O.R. AU - Kain, V. AU - Kieffer, R. AU - Kirn, T. AU - Kuonen, A. AU - Matev, R. AU - Nakada, T. AU - Rihl, M.N. AU - Salustino Guimaraes, V. AU - Schael, S. AU - Schneider, O. AU - Tobin, M. AU - Veness, R. AU - Vlachos, S. AU - Wlochal, M. AU - Xu, Z. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Measuring Beamsize with the LHC Beam Gas Vertex Detector J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - 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. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2680 EP - 2683 KW - emittance KW - detector KW - proton KW - injection KW - luminosity DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW084 UR - http://jacow.org/ipac2019/papers/wepgw084.pdf ER - TY - CONF AU - De Maria, R. AU - Andersson, J. AU - Dalena, B. AU - Field, L. AU - Giovannozzi, M. AU - Hermes, P.D. AU - Hoimyr, N. AU - Iadarola, G. AU - Kostoglou, S. AU - Maclean, E.H. AU - McIntosh, E. AU - Mereghetti, A. AU - Molson, J. AU - Olsen, V.K.B. AU - Pellegrini, D. AU - Persson, T. AU - Pugnat, T. AU - Schwinzerl, M. AU - Sjobak, K.N. AU - Zacharov, I. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - SixTrack Version 5: Status and New Developments J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - 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. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3200 EP - 3203 KW - simulation KW - electron KW - scattering KW - collimation KW - HOM DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPTS043 UR - http://jacow.org/ipac2019/papers/wepts043.pdf ER - TY - CONF AU - Furuseth, S.V. AU - Amorim, D. AU - Antipov, S.A. AU - Buffat, X. AU - Mounet, N. AU - Métral, E. AU - Pieloni, T. AU - Salvant, B. AU - Tambasco, C. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Instability Latency in the LHC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The Large Hadron Collider (LHC) has experienced multiple instabilities that occur between minutes and hours after the last modification of the machine settings. The existence of instabilities with high latency has been reproduced also in simulations. Dedicated experiments, injecting a controlled noise into the beam, have now been performed to discover the dependence of this latency on key parameters. The results seem compatible with a mechanism linked to a steady and slow modification of the transverse beam distribution leading to a loss of Landau damping. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3204 EP - 3207 KW - octupole KW - experiment KW - feedback KW - damping KW - simulation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPTS044 UR - http://jacow.org/ipac2019/papers/wepts044.pdf ER - TY - CONF AU - Furuseth, S.V. AU - Buffat, X. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - High-Performance Scheduling of Multi-Beam Multi-Bunch Simulations J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Coherent multi-bunch interactions through beam-beam forces or wake fields can cause severe impacts on the beams in circular colliders, if not well understood and countered for. COMBI is a parallel multiparticle tracking code developed to study such interactions. Its implementation greatly limits its efficiency when considering realistic configurations featuring effects with different computational requirements, such as the multi-bunch interaction through wake fields, beam-beam interactions, transverse feedback and lattice non-linearities. A new parallel scheduling method, pipelining the effects for each bunch, has greatly sped up the code. The new version of the code, COMBIp, is presented here. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3208 EP - 3211 KW - simulation KW - wakefield KW - collider KW - site KW - hadron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPTS045 UR - http://jacow.org/ipac2019/papers/wepts045.pdf ER - TY - CONF AU - Barnes, M.J. AU - Bracco, C. AU - Bregliozzi, G. AU - Chmielinska, A. AU - Ducimetière, L. AU - Goddard, B. AU - Iadarola, G. AU - Kramer, T. AU - Vega Cid, L. AU - Vlachodimitropoulos, V. AU - Weterings, W.J.M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Operational Experience of a Prototype LHC Injection Kicker Magnet with a Low SEY Coating and Redistributed Power Deposition J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In the event that it is necessary to exchange an LHC injection kicker magnet (MKI), the newly installed kicker magnet would limit HL-LHC operation for a few hundred hours due to dynamic vacuum activity. A surface coating with a low secondary electron yield, applied to the inner surface of an alumina tube to reduce dynamic vacuum activity without increasing the probability of UFOs, and which is compatible with the high voltage environment, was included in a prototype MKI installed in the LHC during the 2017-18 Year End Technical Stop. In addition, this MKI included an upgrade to relocate a significant portion of beam induced power from the yoke to a ’damping element’: this element is not at pulsed high voltage. The effectiveness of the upgrades has been demonstrated during LHC operation, hence a future version will include water cooling of this ’damping element’. This paper reviews dynamic vacuum around the MKIs and summarizes operational experience of the upgraded MKI. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3974 EP - 3977 KW - kicker KW - injection KW - operation KW - vacuum KW - electron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB072 UR - http://jacow.org/ipac2019/papers/thprb072.pdf ER - TY - CONF AU - Vlachodimitropoulos, V. AU - Barnes, M.J. AU - Chmielinska, A. AU - Ducimetière, L. AU - Vega Cid, L. AU - Weterings, W.J.M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Studies Towards the New Beam Screen System of the LHC Injection Kicker Magnet for HL-LHC Operation J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Although no heating issues were observed in the Large Hadron Collider’s (LHC) injection kicker magnets (MKIs) during Run 2, simulations suggest that for operation with the high intensity beams of the High Luminosity LHC (HL-LHC) project, the magnet’s ferrite yokes will reach their Curie temperature, thus leading to long turnaround times before a new beam can be safely injected into the machine. To safely enter the HL-LHC era, a campaign to redesign the kicker’s beam screen was launched. An improved beam-screen has already been implemented in an upgraded MKI, that was installed in the LHC tunnel in the Year End Technical Stop (YETS) 17/18, and has been successfully tested during 2018 operation. However, the improved design alone is not expected to be enough for HL-LHC operation, and further modifications are required. In this work, the approach to the design from an electromagnetic point of view is presented and different considered options are reported, emphasising the final design of the new beam screen system that is currently being implemented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3982 EP - 3985 KW - kicker KW - injection KW - operation KW - vacuum KW - simulation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB074 UR - http://jacow.org/ipac2019/papers/thprb074.pdf ER - TY - CONF AU - Vlachodimitropoulos, V. AU - Barnes, M.J. AU - Chmielinska, A. AU - Ducimetière, L. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Transverse Impedance Measurements and Simulations of the LHC Injection Kicker Magnet J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Kicker magnets contribute significantly to the total impedance budget of many accelerators. Of particular interest, from a beam stability point of view, is the transverse beam coupling impedance (TBCI) that is used to determine intensity limitations of a machine. Until recently, no conclusive TBCI data for the Large Hadron Collider (LHC) injection kicker magnets (MKIs) was available. However, in view of the upgrade of the MKIs for the High-Luminosity LHC (HL-LHC) project, the TBCI of the existing design needed to be estimated to be used as reference for an upgraded version. To that end, electromagnetic simulations were carried out to determine the dipolar and quadrupolar components of the TBCI in the two transverse planes. To validate the simulations, test bench measurements were performed using standard RF measurement techniques. In the present work, the results from TBCI simulations and measurements are reported and compared. Detailed descriptions of the methods and techniques used as well as the realization of the experimental set-up are also given. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3986 EP - 3989 KW - impedance KW - simulation KW - kicker KW - injection KW - coupling DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB075 UR - http://jacow.org/ipac2019/papers/thprb075.pdf ER -