Keyword: luminosity
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MOBD1 Preliminary Design of the High-Luminosity LHC Beam Screen with Shielding vacuum, shielding, cryogenics, impedance 60
 
  • C. Garion, V. Baglin, R. Kersevan
    CERN, Geneva, Switzerland
  
  A new beam screen is needed in the High-Luminosity LHC (HL-LHC) final focusing magnets. Such an essential vacuum component, while operating in the range 40-60 K, has to ensure the vacuum performance and to prevent the beam-induced heating from reaching the cold bore which is at 1.9 K. In addition, they have to shield the cold mass from physics debris coming from the nearby beam collision points. To such purpose, energy absorbers made of tungsten alloy are installed onto the beam screen in the vacuum system. In this contribution, the proposed mechanical design is shown; it covers different thermomechanical aspects such as the behaviour during a magnet quench and the heat transfer from the tungsten absorbers to the cooling tubes. Assembly and manufacturing tolerances are also considered to evaluate the impact on the aperture. Results obtained with a short prototype assembly test are discussed.  
slides icon Slides MOBD1 [3.089 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOBD1  
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MOBD2 Design and Prototyping of HL-LHC Double Quarter Wave Crab Cavities for SPS Test cavity, proton, simulation, HOM 64
 
  • S. Verdú-Andrés, S.A. Belomestnykh, I. Ben-Zvi, J. Skaritka, Q. Wu, B. P. Xiao
    BNL, Upton, Long Island, New York, USA
  • L. Alberty, K. Artoos, R. Calaga, O. Capatina, T. Capelli, F. Carra, N. Kuder, R. Leuxe, C. Zanoni
    CERN, Geneva, Switzerland
  • S.A. Belomestnykh, I. Ben-Zvi
    Stony Brook University, Stony Brook, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  • A. Ratti
    LBNL, Berkeley, California, USA
  
  Funding: Work supported by US DOE via US LARP program, through BSA LLC contract No.DE-AC02-98CH10886 and by EU FP7 HiLumi LHC grant No.284404. Used NERSC resources by US DOE contract No.DE-AC02-05CH11231.
The LHC high luminosity project envisages the use of the crabbing technique for increasing and levelling the LHC luminosity. Double-Quarter Wave (DQW) resonators are compact cavities especially designed to meet the technical and performance requirements for LHC beam crabbing. A couple of DQW crab cavities are under preparation and will be tested with beam in the Super Proton Synchrotron (SPS) of CERN by 2017. This paper describes the design and prototyping of DQW crab cavities for the SPS test. 		 
slides icon Slides MOBD2 [6.909 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOBD2  
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MOPWA049 Simulation of Crab Waist Collisions in DAΦNE with KLOE-2 Interaction Region simulation, electron, betatron, detector 229
 
  • M. Zobov, A. Drago, A. Gallo, C. Milardi
    INFN/LNF, Frascati (Roma), Italy
  • D.N. Shatilov
    BINP SB RAS, Novosibirsk, Russia
  • A. Valishev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Research supported by DOE via the US-LARP program and by EU FP7 HiLumi LHC - Grant Agreement 284404.
After the successful completion of the SIDDHARTA experiment run with crab waist collisions, the electron-positron collider DAΦNE has started routine operations for the KLOE-2 detector. The new interaction region also exploits the crab waist collision scheme, but features certain complications including the experimental detector solenoid, compensating anti-solenoids, and tilted quadrupole magnets. We have performed simulations of the beam-beam collisions in the collider taking into account the real DAΦNE nonlinear lattice. In particular, we have evaluated the effect of crab waist sextupoles and beam-beam interactions on the DAΦNE dynamical aperture and energy acceptance, and estimated the luminosity that can be potentially achieved with and without crab waist sextupoles in the present working conditions. A numerical analysis has been performed in order to propose possible steps for further luminosity increase in DAΦNE such as a better working point choice, crab sextupole strength optimization, correction of the phase advance between the sextupoles and the interaction region. The proposed change of the e- ring working point was implemented and resulted in a significant performance increase. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA049  
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MOPWA050 Beam Dynamics Studies to Develop a High-energy Luminosity Model for the LHC simulation, beam-beam-effects, collider, emittance 233
 
  • G. Campogiani
    Rome University La Sapienza, Roma, Italy
  • Y. Papaphilippou
    CERN, Geneva, Switzerland
  
  Funding: support provided by the EPS-AG through the EPS-AG student grant program
Luminosity, the key figure of merit of a collider as the LHC, depends on the brightness of the colliding beams. This makes the intensity dependent beam-beam effect the dominant performance limiting factor at collision. The parasitic interactions due to the electromagnetic mutual influence of the beams in the interaction region of a collider induce a diffusive behaviour in the tails of the beam. The evolution of charge density distribution is studied to model the beam tails evolution in order to characterize beam lifetime and luminosity. To achieve this, tools are developed for tracking distributions of arbitrary number of single particles interacting with the opposing strong-beam, to analyse the halo formation processes due to the combined effect of beam-beam and machine non-linearities. This paper presents preliminary results of the simulations, both for the LHC Run I and nominal LHC parameters. The former will be used to benchmark simulations while the latter aims at supporting luminosity estimate for the Run II. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA050  
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MOPWA062 Optimization of the Momentum Bandwidth for Final Focus System in CEPC sextupole, factory, collider, simulation 269
 
  • S. Bai, T.J. Bian, J. Gao, H. Geng, D. Wang, Y. Wang, M. Xiao
    IHEP, Beijing, People's Republic of China
  • F. Su
    Institute of High Energy Physics (IHEP), People's Republic of China
  
  With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 1034 cm-2s-1) is becoming more popular in the accelerator world. To achieve such high luminosity, a final focus system in non-local chromaticity correction scheme with very low β functions at the interaction point is designed. The narrow momentum bandwidth is a crucial problem of this kind of design. It is shown that by introducing additional sextupoles the momentum acceptance of the CEPC final focus system can be increased by about a factor of four.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA062  
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MOPJE072 Simulations and Measurements of Longitudinal Coupled-bunch Instabilities in the CERN PS feedback, cavity, synchrotron, impedance 479
 
  • L. Ventura, H. Damerau, M. Migliorati, G. Sterbini
    CERN, Geneva, Switzerland
  • M. Migliorati, L. Ventura
    INFN-Roma1, Rome, Italy
  • M. Migliorati
    University of Rome La Sapienza, Rome, Italy
  • L. Ventura
    University of Rome "La Sapienza", Rome, Italy
  
  Among various and challenging objectives of the LHC Injectors Upgrade project (LIU), one aim is to double the beam intensity of the CERN Proton Synchrotron (PS) in order to achieve the integrated luminosity target of the High-Luminosity LHC project (HL-LHC). A known limitation to reach the required high intensity is caused by the longitudinal coupled-bunch oscillations developing above the transition energy. The unwanted oscillations induce large bunch-to-bunch intensity variations not compatible with the specifications of the future LHC-type beams. A wide-band longitudinal damper has been installed in the PS to suppress these instabilities and is going to be commissioned. A measurement campaign of coupled-bunch oscillations has been launched to substantiate the extrapolations and predictions for the future High Luminosity LHC beam with the final aim to determine the maximum intensity that could be provided to the LHC. In parallel a Simulink© model of the PS is going to be implemented to predict the machine behavior in the parameter space of LIU and to be used during the beam commissioning and optimization of the feedback system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE072  
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MOPJE082 Analytical Approach to the Beam-Beam Interaction with the Hourglass Effect coupling, detector, collider, framework 510
 
  • M.P. Crouch, R.B. Appleby
    UMAN, Manchester, United Kingdom
  • B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: STFC HL-LHC
The HL-LHC upgrade will allow higher luminosities to be reached in the LHC. To achieve higher luminosities the β-function at the IP is decreased, which in turn will result in the hourglass effect becoming more prominent as the transverse bunch sizes become comparable to the length of the bunch. This effect reduces the luminosity since not all particles in the bunch will collide at the minimum IP. The standard derivation of the electric and magnetic fields of the beam-beam interaction is that undertaken by Bassetti and Erskine. The derivation by Bassetti Erskine does not include a coupling between bunch planes. When the transverse bunch sizes are comparable to the length of the bunch the magnitude of the transverse kick will be dependent on the longitudinal position. Currently only numerical methods are available to evaluate this effect. Here a theoretical framework is outlined that provides an analytical approach to derive the electric field for the beam-beam interaction with a coupling between the transverse and longitudinal planes. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE082  
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MOPMA022 Numerical Analysis of Parasitic Crossing Compensation with Wires in DAΦNE positron, beam-beam-effects, collider, experiment 589
 
  • A. Valishev
    Fermilab, Batavia, Illinois, USA
  • C. Milardi, M. Zobov
    INFN/LNF, Frascati (Roma), Italy
  • D.N. Shatilov
    BINP SB RAS, Novosibirsk, Russia
  
  Funding: This work was partially supported by the US LARP. The HiLumi LHC Design Study is partially funded by the European Commission Grant Agreement 284404.
Current bearing wire compensators were successfully used in the 2005-2006 running of the DAΦNE collider to mitigate the detrimental effects of parasitic beam-beam interactions. A marked improvement of the positron beam lifetime was observed in machine operation with the KLOE detector. In view of the possible application of wire beam-beam compensators for the High Luminosity LHC upgrade, we revisit the DAΦNE experiments. We use an improved model of the accelerator with the goal to validate the modern simulation tools and provide valuable input for the LHC upgrade project. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA022  
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MOPMN003 Dynamic Aperture Studies for the LHC High Luminosity Lattice lattice, injection, optics, quadrupole 705
 
  • M. Giovannozzi, R. De Maria, E. McIntosh
    CERN, Geneva, Switzerland
  • Y. Cai, Y. Nosochkov, M.-H. Wang
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by the US LHC Accelerator Research Program and the DOE Contract DE-AC02-76SF00515. Research supported by FP7 HiLumi LHC, Grant Agreement 284404, http://hilumilhc.web.cern.ch.
Since quite some time, dynamic aperture studies have been undertaken with the aim of specifying the required field quality of the new magnets that will be installed in the LHC ring in the framework of the high-luminosity upgrade. In this paper the latest results concerning the specification work will be presented, taking into account both injection and collision energies and the field quality contribution from all the magnets in the newly designed interaction regions. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMN003  
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MOPHA004 Oide Limit Mitigation Studies radiation, quadrupole, octupole, focusing 781
 
  • O.R. Blanco-García, P. Bambade
    LAL, Orsay, France
  • R. Tomás
    CERN, Geneva, Switzerland
  
  Particle radiation when traversing a focusing quadrupole limits the minimum achievable beam size, known as the Oide limit. This effect may be compensated by a pair of multipoles which reduce the impact of the energy loss in the vertical beam size. Simulations in PLACET using the CLIC 3 TeV QD0 and L⃰ show a reduction of (4.3 ± 0.2)% in the vertical beam size.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPHA004  
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MOPHA054 Interaction Point Orbit Feedback System at SuperKEKB feedback, quadrupole, simulation, vacuum 921
 
  • Y. Funakoshi, H. Fukuma, T. Kawamoto, M. Masuzawa, T. Oki, S. Uehara, H. Yamaoka
    KEK, Ibaraki, Japan
  • S.D. Anderson, S.M. Gierman, M. Kosovsky, J.T. Seeman, C.M. Spencer, M.K. Sullivan, O. Turgut, U. Wienands
    SLAC, Menlo Park, California, USA
  • P. Bambade, D. El Khechen, D. Jehanno, V. Kubytskyi, C. Rimbault
    LAL, Orsay, France
  
  In order to maintain an optimum beam collision condition in a double ring collider such as SuperKEKB it is essential to have an orbit feedback system at the interaction point (IP). We have designed such a system based on experiences at KEKB and PEP-II. For the vertical offset and crossing angle, we will rely on the system based on the beam orbit measurement similar to that used at KEKB. For the horizontal offset, however, we will utilize the dithering system which was successfully used at PEP-II, because the horizontal beam-beam kick is very weak with the "nano-beam scheme". Some hardware devices have been already fabricated and others are in preparation. The present status of the development is reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPHA054  
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MOPTY053 Electromagnetic Design and Optimization of Directivity of Stripline Beam Position Monitors for the High Luminosity Large Hadron Collider simulation, impedance, hadron, collider 1051
 
  • D. Draskovic, C.B. Boccard, O.R. Jones, T. Lefèvre, M. Wendt
    CERN, Geneva, Switzerland
  
  This paper presents the preliminary electromagnetic design of a stripline Beam Position Monitor (BPM) for the High Luminosity program of the Large Hadron Collider (HL-LHC) at CERN. The design is fitted into a new octagonal shielded Beam Screen for the low-beta triplets and is optimized for high directivity. It also includes internal Tungsten absorbers, required to reduce the energy deposition in the superconducting magnets. The achieved broadband directivity in wakefield solver simulations presents significant improvement over the directivity of the current stripline BPMs installed in the LHC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY053  
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TUYB2 Accelerator Physics in ERL Based Polarized Electron Ion Collider electron, ion, linac, radiation 1296
 
  • Y. Hao
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities. 		 
slides icon Slides TUYB2 [14.101 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUYB2  
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TUYB3 Progress on the Design of the Polarized Medium-energy Electron Ion Collider at JLab ion, electron, collider, polarization 1302
 
  • F. Lin, S.A. Bogacz, P.D. Brindza, A. Camsonne, E. Daly, Y.S. Derbenev, D. Douglas, R. Ent, D. Gaskell, R.L. Geng, J.M. Grames, J. Guo, L. Harwood, A. Hutton, K. Jordan, A.J. Kimber, G.A. Krafft, R. Li, T.J. Michalski, V.S. Morozov, P. Nadel-Turonski, F.C. Pilat, M. Poelker, R.A. Rimmer, Y. Roblin, T. Satogata, M. Spata, R. Suleiman, A.V. Sy, C. Tennant, H. Wang, S. Wang, H. Zhang, Y. Zhang, Z.W. Zhao
    JLab, Newport News, Virginia, USA
  • S. Abeyratne, B. Erdelyi
    Northern Illinois University, DeKalb, Illinois, USA
  • D.P. Barber
    DESY, Hamburg, Germany
  • Y. Cai, Y. Nosochkov, M.K. Sullivan, M.-H. Wang, U. Wienands
    SLAC, Menlo Park, California, USA
  • A. Castilla, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • Y. Filatov
    JINR, Dubna, Russia
  • J. Gerity, T.L. Mann, P.M. McIntyre, N. Pogue, A. Sattarov
    Texas A&M University, College Station, Texas, USA
  • C. Hyde, K. Park
    Old Dominion University, Norfolk, Virginia, USA
  • A.M. Kondratenko, M.A. Kondratenko
    Science and Technique Laboratory Zaryad, Novosibirsk, Russia
  • P.N. Ostroumov
    ANL, Argonne, Illinois, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357.
The Medium-energy Electron Ion Collider (MEIC) at JLab is designed to provide high luminosity and high polarization needed to reach new frontiers in the exploration of nuclear structure. The luminosity, exceeding 1033 cm-2s−1 in a broad range of the center-of-mass (CM) energy and maximum luminosity above 1034 cm-2s−1, is achieved by high-rate collisions of short small-emittance low-charge bunches made possible by high-energy electron cooling of the ion beam and synchrotron radiation damping of the electron beam. The polarization of light ion species (p, d, 3He) can be easily preserved and manipulated due to the unique figure-8 shape of the collider rings. A fully consistent set of parameters have been developed considering the balance of machine performance, required technical development and cost. This paper reports recent progress on the MEIC accelerator design including electron and ion complexes, integrated interaction region design, figure-8-ring-based electron and ion polarization schemes, RF/SRF systems and ERL-based high-energy electron cooling. Luminosity performance is also presented for the MEIC baseline design. 		 
slides icon Slides TUYB3 [6.245 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUYB3  
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TUBD2 Final Cooling For a High-luminosity High-energy Lepton Collider emittance, collider, solenoid, linac 1384
 
  • D.V. Neuffer
    Fermilab, Batavia, Illinois, USA
  • T.L. Hart, D.J. Summers
    UMiss, University, Mississippi, USA
  • H. K. Sayed
    BNL, Upton, Long Island, New York, USA
  
  Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy.
The final cooling system for a high-energy high-luminosity muon collider requires reduction of the transverse emittance by an order of magnitude to ~0.00003 m (rms, N), while allowing longitudinal emittance increase to ~0.1m. In the present baseline approach, this is obtained by transverse cooling of low-energy muons within a sequence of high field solenoids with low-frequency rf systems. Recent studies of such systems are presented. Since the final cooling steps are actually emittance exchange a variant form of that final system can be obtained by a round to flat transform in x-y, with transverse slicing of the enlarged flat transverse dimension followed by longitudinal recombination of the sliced bunchlets. Development of final exchange following lowest-emittance cooling is discussed. 		 
slides icon Slides TUBD2 [1.976 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUBD2  
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TUPTY007 Study of Beam-beam Effects in FCC-he electron, proton, simulation, emittance 2010
 
  • K. Ohmi
    KEK, Ibaraki, Japan
  • F. Zimmermann
    CERN, Geneva, Switzerland
  
  Beam-beam effects of the ring-ring scheme of FCC-he and LHeC are being studied using weak-strong simulations. The beam-beam tune shift of the electron beam is one order larger than that of proton beam. The study of the electron motion under the beam-beam interaction is the main subject. Luminosity and equilibrium beam size and beam lifetime are analysed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY007  
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TUPTY010 The Luminosity Reduction with Hourglass Effect and Crossing Angle in an e-p Collider collider, electron, proton, acceleration 2016
 
  • Y.M. Peng
    IHEP, Beijing, People's Republic of China
  • Y. Zhang
    JLab, Newport News, Virginia, USA
  
  This paper derived the luminosity reduction caused by crossing angle and hourglass effect in an asymmetric collision. Here, we gave the general expressions of the geometrical reduction factor of luminosity for the asymmetric case caused by crossing angle and hourglass effect, for tri-Gaussian bunches colliding. We also gave it simple expression in some special cases to recover the earlier results, such as the formulas for only hour-glass effect exist and only crossing angle exist. The expressions used in e-p collider are also analysed in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY010  
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TUPTY011 A Preliminary Design of the CEPC Interaction Region interaction-region, dynamic-aperture, detector, quadrupole 2019
 
  • Y. Wang, S. Bai, T.J. Bian, X. Cui, J. Gao, H. Geng, D. Wang, Y.S. Zhu
    IHEP, Beijing, People's Republic of China
  
  CEPC (Circular Electron and Positron Collider) is a circular Higgs Factory with optimized energy 240 GeV. In order to achieve luminosity as high as 2×1034/cm2/s, CEPC calls for a small vertical beta function at IP (betay∗=1.2 mm) which was provided by the final focus of the interaction region. In this paper, a preliminary design of the CEPC interaction region was presented. The optimization of dynamic aperture with interaction region insertion and the machine detector interface was discussed as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY011  
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TUPTY018 Interaction region for crab waist scheme of the Future Electron-Positron Collider (CERN) sextupole, quadrupole, collider, lattice 2034
 
  • A.V. Bogomyagkov, E.B. Levichev
    BINP SB RAS, Novosibirsk, Russia
  
  Funding: Work is supported by the Ministry of Education and Science of the Russian Federation
Design study of the accelerator that would fit 80-100~km tunnel called Future Circular Colliders (FCC) includes high-luminosity e+e- collider (FCC-ee) with center-of-mass energy from 90 to 350~GeV to study Higgs boson properties and perform precise measurements at the electroweak scale. Crab waist interaction region provides collisions with luminosity higher than 2×1036~cm-2sec-1 at beam energy of 45~GeV. The small values of the beta functions at the interaction point and distant final focus lenses are the reasons for high nonlinear chromaticity limiting energy acceptance of the whole ring. The paper describes interaction region for crab waist collision scheme in the FCC-ee, principles of tuning the chromaticity correction section in order to provide large energy acceptance. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY018  
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TUPTY020 Building a Luminosity Model for the LHC and HL-LHC emittance, brightness, injection, proton 2042
 
  • F. Antoniou, G. Arduini, Y. Papaphilippou, G. Papotti
    CERN, Geneva, Switzerland
  
  One key objective of the High Luminosity LHC Upgrade is to determine a set of beam parameters and the hardware configuration that will enable the LHC to reach a peak luminosity of 5×1034 cm-2 s-1 and ultimately 7.5x1034 cm-2 s-1 with levelling, allowing an integrated luminosity of 250-300 fb-1 per year. In order to determine the integrated performance it is important to develop a realistic model of the luminosity evolution during a physics fill. In this paper, the different mechanisms affecting luminosity lifetime in the LHC are discussed and a luminosity model is presented. The model is benchmarked with data from LHC Run I.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY020  
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TUPTY028 Collimator Layouts for HL-LHC in the Experimental Insertions ion, collimation, proton, heavy-ion 2064
 
  • R. Bruce, F. Cerutti, L.S. Esposito, J.M. Jowett, A. Lechner, E. Quaranta, S. Redaelli, M. Schaumann, E. Skordis, G.E. Steele
    CERN, Geneva, Switzerland
  • H. Garcia Morales, R. Kwee-Hinzmann
    JAI, Egham, Surrey, United Kingdom
  
  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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TUPTY036 Crossing Scheme and Orbit Correction in IR1/5 for HL-LHC optics, alignment, injection, quadrupole 2086
 
  • M. Fitterer, R. De Maria, S.D. Fartoukh, M. Giovannozzi
    CERN, Geneva, Switzerland
  
  Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
In this paper we review the orbit correction strategy and crossing scheme adjustment for the HL-LHC orbit correctors in IR1/5 in view of the new optics and layout version HLLHCV1.1. The main objectives are to optimize the crossing scheme, in particular to reduce the strength of the orbit correctors at D2, and to validate the strength specifications of the several orbit corrector magnets involved, including a budget reserved for the correction of the orbit distortions from various sources. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY036  
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TUPTY037 HLLHCV1.1 Optics Version for the HL-LHC Upgrade optics, cavity, hardware, quadrupole 2090
 
  • R. De Maria, S.D. Fartoukh, M. Fitterer
    CERN, Geneva, Switzerland
  
  Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
The optics and layout of the HL-LHC are evolving as the new hardware is being studied and integrated, any additional requirements from the experiments detailed, and other constraints of different nature clarified. Here we present the changes of version 1.1 of the optics and layout with respect to the previous version 1.0, which include the current hardware choices and an outlook on the main resulting optics limitations and the possible future evolutions of the layout. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY037  
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TUPTY038 BPM Tolerances for HL-LHC Orbit Correction in the Inner Triplet Area optics, impedance, simulation, emittance 2094
 
  • M. Fitterer, R. De Maria
    CERN, Geneva, Switzerland
  
  Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
For the HL-LHC beam spot sizes as small as 7 mum are considered for the high luminosity insertions IR1 and IR5. In addition, the luminosity has to be levelled over several hours by changing β* resulting in constant changes of the optics and thus orbit changes. The small beam size and the continuous optics changes in general make the alignment of the beams at the IP challenging. In order to avoid continuous luminosity scans for the alignment of the beams at the IP, the orbit correction has to rely on the readings of the BPMs in the IT region. In this paper we review the requirements on resolution and accuracy of the BPMs and compare different options for the placement of the BPMs in the IT region. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY038  
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TUPTY048 Changes to the Transfer Line Collimation System for the High-Luminosity LHC Beams optics, collimation, injection, brightness 2124
 
  • V. Kain, O. Aberle, C. Bracco, M.A. Fraser, F. Galleazzi, A. Kosmicki, F.L. Maciariello, M. Meddahi, F.-X. Nuiry, G.E. Steele, F.M. Velotti
    CERN, Geneva, Switzerland
  • E. Gianfelice-Wendt
    Fermilab, Batavia, Illinois, USA
  
  The current LHC transfer line collimation system will not be able to provide enough protection for the high brightness beams in the high-luminosity LHC era. The new collimation system will have to attenuate more and be more robust than its predecessor. The active jaw length of the new transfer line collimators will therefore be 2.1 m instead of currently 1.2 m. The transfer line optics will have to be adjusted for the new collimator locations and larger beta functions at the collimators for absorber robustness reasons. In this paper the new design of the transfer line collimation system will be presented with its implications on transfer line optics and powering, maintainability, protection of transfer line magnets in case of beam loss on a collimator and protection of the LHC aperture  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY048  
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TUPTY053 Roadmap towards High Accelerator Availability for the CERN HL-LHC Era radiation, operation, beam-losses, target 2143
 
  • A. Apollonio, M. Brugger, L. Rossi, R. Schmidt, B. Todd, D. Wollmann, M. Zerlauth
    CERN, Geneva, Switzerland
  
  High Luminosity-LHC is the future upgrade of the LHC that aims at delivering an integrated luminosity of 3000 fb-1 over about 10 years of operation, starting from 2025. Significant modifications [1] will be implemented to accelerator systems, including new superconducting magnets, crab cavities, superconducting links, new collimators and absorbers based on advanced materials and design and additional cryo-plants. Due to the limit imposed by the number of simultaneous events at the experiments (pile-up) on peak luminosity, the latter will be levelled to 5*1034 cm-2s−1. The target integrated luminosity can only be achieved with a significant increase of the total available time for beam collisions compared to the 2012 LHC run, despite a beam current that is planned to double the nominal 0.58 A. Therefore one of the key figures of merit to take into account for system upgrades and new designs is their impact on the accelerator availability. In this paper the main factors affecting LHC availability will be discussed and predictions on the impact of future system upgrades on integrated luminosity presented. Requirements in terms of the maximum allowed number of dumps for the main contributing systems to LHC unavailability will be derived.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY053  
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TUPTY057 Scenarios for Circular Gamma-Gamma Higgs Factories collider, laser, electron, factory 2156
 
  • F. Zimmermann, Y. Papaphilippou
    CERN, Geneva, Switzerland
  • R. Aleksan
    CEA/DSM/IRFU, France
  • A. Apyan
    NU, Evanston, Illinois, USA
  
  Funding: The research leading to these results has received partial funding from the European Commission under the FP7 Research Infrastructures project EuCARD-2, grant agreement no.312453.
The Higgs boson can be produced directly in gamma-gamma collisions generated by laser Compton back scattering off 80-90 GeV electron or positron beams. We discuss options for realizing a gamma-gamma Higgs factory using a high-energy circular e+e− collider, such as FCC-ee or CEPC, and/or its top-up injector ring, and compare the parameters and advantages of such a facility, including the expected performance, with those for a Higgs factory based on a recirculating linac, such as SAPPHiRE. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY057  
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TUPTY058 Mitigating Performance Limitations of Single Beam-pipe Circular e+e− Colliders collider, electron, synchrotron, operation 2160
 
  • M. Koratzinos
    DPNC, Genève, Switzerland
  • F. Zimmermann
    CERN, Geneva, Switzerland
  
  Renewed interest in circular e+e− colliders has spurred designs of single beam-pipe machines, like the CEPC in China, and double beam pipe ones, such as the FCC-ee effort at CERN. Single beam-pipe designs profit from lower costs but are limited by the number of bunches that can be accommodated in the machine. We analyse these performance limitations and propose a solution that can accommodate O(1000) bunches while keeping more than 90% of the ring with a single beam pipe.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY058  
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TUPTY061 Combined Operation and Staging Scenarios for the FCC-ee Lepton Collider emittance, collider, optics, operation 2169
 
  • M. Benedikt, B.J. Holzer, E. Jensen, R. Tomás, J. Wenninger, F. Zimmermann
    CERN, Geneva, Switzerland
  • A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov
    BINP SB RAS, Novosibirsk, Russia
  • K. Ohmi, K. Oide
    KEK, Ibaraki, Japan
  • U. Wienands
    SLAC, Menlo Park, California, USA
  
  FCC-ee is a proposed high-energy electron positron circular collider that would initially occupy the 100-km FCC tunnel that will eventually house the 100 TeV FCC-hh hadron collider. The parameter range for the e+/e− collider is large, operating at a cm energy from 90 GeV (Z-pole) to 350 GeV (t-tbar production) with the maximum beam current ranging from 1.5 A to 6 mA for each beam, corresponding to a synchrotron radiation power of 50 MW and a radiative energy loss varying from ~30 MeV/turn to ~7500 MeV/turn. This presents challenges for the rf system due to the varying rf voltage requirements and beam loading conditions. In this paper we present a possible gradual evolution of the FCC-ee complex by step-wise expansion, and possibly reconfiguration, of the superconducting RF system. The performance attainable at each step is discussed, along with the possible advantages and drawbacks.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY061  
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TUPTY062 FCC-hh Hadron Collider - Parameter Scenarios and Staging Options operation, damping, proton, radiation 2173
 
  • M. Benedikt, B. Goddard, D. Schulte, F. Zimmermann
    CERN, Geneva, Switzerland
  • M.J. Syphers
    NSCL, East Lansing, Michigan, USA
  • M.J. Syphers
    Fermilab, Batavia, Illinois, USA
  
  FCC-hh is a proposed future energy-frontier hadron collider, based on dipole magnets with a field around 16 T installed in a new tunnel with a circumference of about 100 km, which would provide proton collisions at a centre-of-mass energy of 100 TeV, as well as heavy-ion collisions at the equivalent energy. The FCC-hh should deliver a high integrated proton-proton luminosity at the level of several 100 fb-1 per year, or more. The challenges for operating FCC-hh with high beam current and at high luminosity include the heat load from synchrotron radiation in a cold environment, the radiation from collision debris around the interaction region, and machine protection. In this paper, starting from the FCC-hh design baseline parameters we explore different approaches for increasing the integrated luminosity, and discuss the impact of key individual parameters, such as the turnaround time. We also present some injector considerations and options for early hadron-collider operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY062  
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TUPTY067 Beam Induced Background Simulation Studies at IR1 with New High Luminosity LHC Layout optics, background, simulation, collimation 2184
 
  • R. Kwee-Hinzmann, S.M. Gibson
    JAI, Egham, Surrey, United Kingdom
  • R. Bruce, F. Cerutti, L.S. Esposito, A. Lechner
    CERN, Geneva, Switzerland
  • S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  
  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. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY067  
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TUPTY070 Strong-Strong Simulations of Beta star Levelling for Flat and Round Beams emittance, simulation, resonance, detector 2192
 
  • M.P. Crouch, R.B. Appleby
    UMAN, Manchester, United Kingdom
  • B.D. Muratori
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: STFC HL-LHC
The HL-LHC project aims to reach larger peak luminosities, however this can lead to a high pile up in the detectors. To control the pile up, luminosity levelling has been suggested. One proposed method is β*-luminosity levelling, in which beams collide at a larger than nominal β*. The β* is then reduced in steps as the beam intensity decays. This allows the luminosity to be kept constant over part of a physics fill. The use of round or flat optics will change the beam-beam effect of the head on collisions as well as the long range interactions. Here simulations of β* levelling are presented for the case of flat and round beam optics and the difference in terms of the beam-beam effect is highlighted. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY070  
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TUPTY073 An Alternative High Luminosity LHC with Flat Optics and Long-Range Beam-Beam Compensation optics, beam-beam-effects, simulation, electron 2199
 
  • S.D. Fartoukh
    CERN, Geneva, Switzerland
  • D.N. Shatilov
    BINP SB RAS, Novosibirsk, Russia
  • A. Valishev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Research supported by DOE via the US-LARP program and by EU FP7 HiLumi LHC - Grant Agreement 284404
In the baseline scenario of the High-Luminosity LHC (HL-LHC), the geometric loss of luminosity in the two high luminosity experiments due to collisions with a large crossing angle is recovered by tilting the bunches in the interaction region with the use of crab cavities. A possible backup scenario would rely on a reduced crossing angle together with flat optics (with different horizontal and vertical β* values) for the preservation of luminosity performance. However, the reduction of crossing angle coupled with the flat optics significantly enhances the strength of long-range beam-beam interactions. This paper discusses the possibility to mitigate the long-range beam-beam effects by current bearing wire compensators (or e-lens). We develop a new HL-LHC parameter list and analyse it in terms of integrated luminosity performance as compared to the baseline. Further, we evaluate the operational scenarios using numerical simulations of single-particle dynamics with beam-beam effects. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY073  
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TUPTY076 Beam-Beam Simulation of Crab Cavity White Noise for LHC Upgrade cavity, simulation, emittance, beam-beam-effects 2206
 
  • J. Qiang
    LBNL, Berkeley, California, USA
  • J. Barranco García
    EPFL, Lausanne, Switzerland
  • K. Ohmi
    KEK, Ibaraki, Japan
  • T. Pieloni
    CERN, Geneva, Switzerland
  
  High luminosity LHC upgrade will improve the luminosity of the current LHC operation by an order of magnitude. Crab cavity as a critical component for compensating luminosity loss from large crossing angle collision and also providing luminosity leveling for the LHC upgrade is being actively pursued. In this paper, we will report on the study of potential effects of the crab cavity noise on the beam luminosity lifetime based on strong-strong beam-beam simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY076  
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TUPWI033 Matching into the Helical Bunch Coalescing Channel for a High Luminosity Muon Collider emittance, acceleration, simulation, collider 2315
 
  • A.V. Sy, Y.S. Derbenev, V.S. Morozov
    JLab, Newport News, Virginia, USA
  • C.M. Ankenbrandt, R.P. Johnson
    Muons, Inc, Illinois, USA
  • D.V. Neuffer, K. Yonehara, C.Y. Yoshikawa
    Fermilab, Batavia, Illinois, USA
  
  Funding: This work was supported in part by U.S. DOE STTR Grant DE-SC0007634. This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
For high luminosity in a muon collider, muon bunches that have been cooled in the six-dimensional helical cooling channel (HCC) must be merged into a single bunch and further cooled in preparation for acceleration and transport to the collider ring. The helical bunch coalescing channel has been previously simulated [*, **] and provides the most natural match from helical upstream and downstream subsystems. This work focuses on the matching from the exit of the multiple bunch HCC into the start of the helical bunch coalescing channel. The simulated helical matching section simultaneously matches the helical spatial period λ in addition to providing the necessary acceleration for efficient bunch coalescing. Previous studies assumed that the acceleration of muon bunches from p=209.15 MeV/c to 286.816 MeV/c and matching of λ from 0.5 m to 1.0 m could be accomplished with zero particle losses and zero emittance growth in the individual bunches. This study demonstrates nonzero values for both particle loss and emittance growth, and provides considerations for reducing these adverse effects to best preserve high luminosity.
*C. Yoshikawa, et al., “Bunch Coalescing in a Helical Channel,” MAP-doc-4302-v2.
**C. Yoshikawa, et al., “Bunch Coalescing in a Helical Channel,” IPAC12 TUPPD013, New Orleans, Louisiana, USA. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI033  
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TUPWI038 A High Energy e-p/A Collider Based on CepC-SppC proton, electron, collider, ion 2329
 
  • Y. Zhang
    JLab, Newport News, Virginia, USA
  • Y.M. Peng
    IHEP, Beijing, People's Republic of China
  
  Construction of CepC and SppC, the proposed future energy frontier circular e+e− and pp colliders in China, provides an opportunity to realize e-p or e-A collisions in a CM energy range up to 4.1 TeV. This paper presents a preliminary conceptual design of this e-p/A collider. The design parameters and anticipated luminosities will be given. We also discuss staging approaches to realize this collider with a low cost and at an earlier time.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI038  
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TUPWI048 Experimental Demonstration of an Interaction Region Beam Waist Position Knob for Luminosity Leveling optics, controls, detector, experiment 2357
 
  • Y. Hao, Y. Luo, A. Marusic, G. Robert-Demolaize, X. Shen
    BNL, Upton, Long Island, New York, USA
  • M. Bai
    FZJ, Jülich, Germany
  • Z. Duan
    IHEP, Beijing, People's Republic of China
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this paper, we report on the experimental implementation of the model-dependent control of the interaction region beam waist position (s* knob) at the Relativistic Heavy Ion Collider (RHIC). The s* adjustment provides an alternative way of controlling the luminosity and is the only known method to control the luminosity and to reduce the pinch effect of the future eRHIC. We first demonstrate the effectiveness of the s* knob in luminosity controlling and its application in the future electron ion collider, eRHIC, followed by details of the experimental demonstration of such knob in RHIC. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI048  
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WEYB3 Interplay of Beam-Beam, Lattice Nonlinearity, and Space Charge Effects in the SuperKEKB Collider lattice, space-charge, quadrupole, resonance 2413
 
  • D. Zhou, H. Koiso, A. Morita, K. Ohmi, Y. Ohnishi, K. Oide, H. Sugimoto
    KEK, Ibaraki, Japan
  • Y. Zhang
    IHEP, Beijing, People's Republic of China
  
  The SuperKEKB B-factory adopts nanobeam scheme for the collision, which consists of large crossing angle and very small vertical beta function at the interaction point. Simulations have revealed that the luminosity of SuperKEKB will be very sensitive to perturbations from various sources. This paper discusses various beam dynamics issues involved in the SuperKEKB collider, including beam-beam, lattice nonlinearity, and space charge effects, as well as their interplay and planned mitigations.  
slides icon Slides WEYB3 [11.722 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEYB3  
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WEPJE025 Phase Space Density as a Measure of Cooling Performance for the International Muon Ionization Cooling Experiment emittance, simulation, experiment, scattering 2726
 
  • J.S. Berg
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The International Muon Ionization Cooling Experiment (MICE)* is an experiment to demonstrate ionization cooling of a muon beam in a beamline that shares characteristics with one that might be used for a muon collider or neutrino factory. I describe a way to quantify cooling performance by examining the phase space density of muons, and determining how much that density increases. This contrasts with the more common methods that rely on the covariance matrix and compute emittances from that. I discuss why a direct measure of phase space density might be preferable to a covariance matrix method. I apply this technique to an early proposal for the MICE final step beamline. I discuss how matching impacts the measured performance.
* http://mice.iit.edu/ I am not a MICE collaboration member, and nothing herein should be construed as representing the work or views of the collaboration. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE025  
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WEPMA045 Energy Deposition and DPA in the Superconducting Links for the HiLumi LHC project at the LHC Interaction Points neutron, photon, simulation, radiation 2865
 
  • F. Broggi, A. Bignami, C. Santini
    INFN/LASA, Segrate (MI), Italy
  • A. Ballarino, F. Cerutti, L.S. Esposito
    CERN, Geneva, Switzerland
  
  Funding: The work is part of HiLumi LHC Design Study, partly funded by the European Commission, GA 284404, and included in the High Luminosity LHC project.
In the framework of the upgrade of the LHC machine, the powering of the LHC magnets foresees the removal of the power converters and distribution feedboxes from the tunnel and its location at the surface[1]. The Magnesium Diboride (MgB2) connecting lines in the tunnel will be exposed to the debris from 7+7 TeV p-p interaction. The Superconducting (SC) Links will arrive from the surface to the tunnel near the separation dipole, at about 80 m from the Interaction Point at IP1 and IP5. The Connection Box (where the cables of the SC Links are connected to the NbTi bus bar) will be close to the beam pipe. The debris and its effect on the MgB2 SC links in the connection box (energy deposition and displacement per atom) are presented. The effect of thermal neutrons on the Boron consumption and the contribution of the lithium nucleus and the alpha particle on the DPA are evaluated. The results are normalized to an integrated luminosity of 3000 fb-1, value that represents the LHC High Luminosity lifetime. The dose delivered to the SC Links is found to be below the damage limit. Further studies are necessary to correlate the induced displacement per atom to the superconducting properties. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA045  
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WEPWI036 Design and Prototyping of a 400 MHz RF-dipole Crabbing Cavity for the LHC High-Luminosity Upgrade cavity, dipole, cryomodule, HOM 3568
 
  • S.U. De Silva, J.R. Delayen, H. Park
    ODU, Norfolk, Virginia, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  • T.H. Nicol
    Fermilab, Batavia, Illinois, USA
  
  LHC High Luminosity Upgrade is in need of two crabbing systems that deflects the beam in both horizontal and vertical planes. The 400 MHz rf-dipole crabbing cavity system is capable of crabbing the proton beam in both planes. At present we are focusing our efforts on a complete crabbing system in the horizontal plane. Prior to LHC installation the crabbing system will be installed for beam test at SPS. The crabbing system consists of two rf-dipole cavities in the cryomodule. This paper discusses the electromagnetic design and mechanical properties of the rf-dipole crabbing system for SPS beam test.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI036  
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WEPWI037 Imperfection and Tolerance Analysis of HOM Couplers for ODU/SLAC 400 MHz Crabbing Cavity HOM, cavity, impedance, dipole 3572
 
  • S.U. De Silva, J.R. Delayen, H. Park
    ODU, Norfolk, Virginia, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  • R.G. Olave
    Old Dominion University, Norfolk, Virginia, USA
  
  In preparation for the LHC High Luminosity upgrade, a 400 MHz crab cavity has been developed jointly at ODU/SLAC, including two higher order mode couplers designed to dampen the wakefields in order to comply with the impedance budget specified for the LHC system. During fabrication, assembly, and processing of the couplers, a number of imperfections may arise that could modify the higher order mode spectrum and the associated impedance for each mode. We present here a detailed study of the imperfections of the horizontal- and vertical- HOM couplers, and the associated allowed tolerances for manufacture, assembly and processing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI037  
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WEPWI039 Engineering Study of Crab Cavity HOM Couplers for LHC High Luminosity Upgrade HOM, niobium, cavity, damping 3578
 
  • H. Park, S.U. De Silva, J.R. Delayen, R.G. Olave
    ODU, Norfolk, Virginia, USA
  • T. Capelli
    CERN, Geneva, Switzerland
  • S.U. De Silva, J.R. Delayen, H. Park
    JLab, Newport News, Virginia, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  • T.H. Nicol
    Fermilab, Batavia, Illinois, USA
  • N. Templeton
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  
  The LHC is planning to employ crab cavities for the high luminosity upgrade. Old Dominion University and SLAC National Laboratory are developing the crab cavity completed with the HOM damping couplers. The HOM couplers are coaxial type and perform over broad band up to 2 GHz. The amount of extracted power requires active cooling using liquid helium. The electromagnetic study has provided expected power dissipation on the coupler. Correlations between the fabrication tolerance and its damping performance have been studied and the results are providing guidelines on how to manufacture the HOM couplers. This paper summarizes the engineering studies; mechanical strength as a part of pressure system, thermal stability, and fabrication method to ensure the required tolerance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI039  
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WEPWI059 Higher Order Mode Filter Design for Double Quarter Wave Crab Cavity for the LHC High Luminosity Upgrade HOM, cavity, impedance, coupling 3627
 
  • B. P. Xiao, S.A. Belomestnykh, I. Ben-Zvi, J. Skaritka, S. Verdú-Andrés, Q. Wu
    BNL, Upton, Long Island, New York, USA
  • S.A. Belomestnykh, I. Ben-Zvi
    Stony Brook University, Stony Brook, USA
  • G. Burt, B.D.S. Hall
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  • R. Calaga, O. Capatina
    CERN, Geneva, Switzerland
  • T.J. Jones
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: Work partly supported by US LARP, by US DOE under contract No. DE-AC02-05CH11231 and through BSA under contract No. DE-AC02-98CH10886. Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404.
A double quarter wave crab cavity (DQWCC) was designed for the Large Hadron Collider (LHC) luminosity upgrade. A compact Higher Order Mode (HOM) filter with wide stop band at the deflecting mode is developed for this cavity. Multi-physics finite element simulation results are presented. The integration of this design to the cavity cryomodule is described. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI059  
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WEPWI060 Cryogenic Test of Double Quarter Wave Crab Cavity for the LHC High Luminosity Upgrade cavity, cryogenics, radiation, higher-order-mode 3630
 
  • B. P. Xiao, S.A. Belomestnykh, I. Ben-Zvi, C. Cullen, L.R. Hammons, C. Marques, J. Skaritka, S. Verdú-Andrés, Q. Wu
    BNL, Upton, Long Island, New York, USA
  • L. Alberty, R. Calaga, O. Capatina
    CERN, Geneva, Switzerland
  • S.A. Belomestnykh, I. Ben-Zvi
    Stony Brook University, Stony Brook, USA
  • Z. Li
    SLAC, Menlo Park, California, USA
  
  Funding: Work partly supported by US LARP, by US DOE under contract No. DE-AC02-05CH11231 and through BSA under contract No. DE-AC02-98CH10886. Research supported by EU FP7 HiLumi LHC - Grant Agreement 284404.
A Proof-of-Principle (PoP) Double Quarter Wave Crab Cavity (DQWCC) was designed and fabricated for the Large Hadron Collider (LHC) luminosity upgrade. A vertical cryogenic test has been done at Brookhaven National Lab (BNL). The cavity achieved 4.5 MV deflecting voltage with a quality factor above 3×109. We report the test results of this design. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI060  
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THXB2 Crab Cavities: Past, Present, and Future of a Challenging Device cavity, collider, HOM, operation 3643
 
  • Q. Wu
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with LARP and the U.S. Department of Energy and EU FP7 HiLumi LHC - Grant Agreement 284404
In two-ring facilities operating with a crossing angle collision scheme, the luminosity can be limited due to incomplete overlap of the colliding bunches. Crab cavities are introduced to restore head-on collisions by providing destined opposite deflection to the head and tail of the bunch. Luminosity increase has been demonstrated at KEKB with global crab crossing, and the Large Hardron Collider (LHC) at CERN is currently designing local crab crossing for the Hi-Lumi upgrade. Future colliders may investigate both approaches. This paper reviews the challenges in the technology and implementation of crab cavities, discusses experience in past colliders, ongoing R&D and proposed implementations for future facilities such as HL-LHC, CLIC, ILC, and eRHIC/MEIC. 		 
slides icon Slides THXB2 [4.307 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THXB2  
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THPF095 Limits on Failure Scenarios for Crab Cavities in the HL-LHC simulation, optics, collimation, beam-losses 3923
 
  • A. Santamaría García, H. Burkhardt, A. Macpherson, K.N. Sjobak, D. Wollmann, B. Yee-Rendón
    CERN, Geneva, Switzerland
  • K. Hernandez-Chahin
    DCI-UG, León, Mexico
  • B. Yee-Rendón
    CINVESTAV, Mexico City, Mexico
  
  The High Luminosity (HL) LHC upgrade aims for a tenfold increase in integrated luminosity compared to the nominal LHC, and for operation at a levelled luminosity of 5 1034 cm-2.s-1, which is five times higher than the nominal LHC peak luminosity. Crab Cavities (CCs) are planned to compensate the geometric luminosity loss created by the increased crossing angle by rotating the bunch, allowing quasi head-on collisions at the Interaction Points (IP). The CCs work by creating transverse kicks, and their failure may have short time constants comparable to the reaction time of the Machine Protection System (MPS), producing significant coherent betatron oscillations and fast emittance growth. Simulations of CC failure modes have been carried out with the tracking code SIXTRACK, using the newly added functionality called DYNK, which allows to dynamically change the attributes of the CCs. We describe these simulations and discuss early, preliminary results.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF095  
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THPF134 Magnet Design and Synchrotron Damping Considerations for a 100 TeV Hadron Collider collider, dipole, synchrotron, radiation 4034
 
  • P.M. McIntyre, S. Assadi, J. Gerity, T.L. Mann, A. Sattarov
    Texas A&M University, College Station, Texas, USA
  • D. Chavez
    DCI-UG, León, Mexico
  • N. Pogue
    PSI, Villigen, Villigen, Switzerland
  • M. Tomsic
    Hypertech Research, Inc., Columbus, USA
  
  A conceptual design is presented for a 100 TeV hadron collider based upon a 4.5 T NbTi cable-in-conduit dipole technology. It incorporates a side radiation channel to extract synchrotron radiation from the beam channel so that it does not produce limitations from heating on a beam liner or gas load limits on collider performance. Synchrotron damping can be used to support ‘bottom-up’ stacking to sustain maximum luminosity in the collisions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF134  
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FRXC1 The Luminosity Upgrade at RHIC ion, heavy-ion, operation, lattice 4091
 
  • G. Robert-Demolaize
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Starting with the high energy heavy ion run for Fiscal Year 07 (Run7), the Relativistic Heavy Ion Collider (RHIC) underwent a series of upgrades in all three tiers of its activities: machine hardware, lattice design and operational efficiency. The following presents a review of these upgrades and how their combined contributions to heavy ion operations lead to average store luminosities that exceed the initial RHIC design by a factor of 25. 		 
slides icon Slides FRXC1 [4.570 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-FRXC1  
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FRXC2 The High Luminosity LHC Project operation, dipole, radiation, experiment 4096
 
  • O.S. Brüning
    CERN, Geneva, Switzerland
  
  This presentation reviews the status of the high luminosity LHC project, and highlights the main challenges from the technology and beam physics point of view. It will mention the outcome of the 2015 Cost and Schedule review for the HL-LHC project and summarizes the status of the high field quadrupole and crab cavity development.  
slides icon Slides FRXC2 [7.951 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-FRXC2  
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