Author: Zhou, D.
Paper Title Page
MOPMF064 High-Energy LHC Design 269
 
  • F. Zimmermann, D. Amorim, S. A. Antipov, S. Arsenyev, M. Benedikt, R. Bruce, M.P. Crouch, S.D. Fartoukh, M. Giovannozzi, B. Goddard, M. Hofer, R. Kersevan, V. Mertens, Y. Muttoni, J.A. Osborne, V. Parma, V. Raginel, S. Redaelli, T. Risselada, I. Ruehl, B. Salvant, D. Schoerling, E.N. Shaposhnikova, L.J. Tavian, E. Todesco, R. Tomás, D. Tommasini, F. Valchkova-Georgieva, V. Venturi, D. Wollmann
    CERN, Geneva, Switzerland
  • J.L. Abelleira, E. Cruz Alaniz, P. Martinez Mirave, A. Seryi, L. van Riesen-Haupt
    JAI, Oxford, United Kingdom
  • A. Apyan
    ANSL, Yerevan, Armenia
  • J. Barranco García, L. Mether, T. Pieloni, L. Rivkin, C. Tambasco
    EPFL, Lausanne, Switzerland
  • F. Burkart
    DESY, Hamburg, Germany
  • Y. Cai, Y.M. Nosochkov
    SLAC, Menlo Park, California, USA
  • G. Guillermo Cantón
    CINVESTAV, Mérida, Mexico
  • K. Ohmi, K. Oide, D. Zhou
    KEK, Ibaraki, Japan
  
  In the frame of the FCC study we are designing a 27 TeV hadron collider in the LHC tunnel, called the High Energy LHC (HE-LHC).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF064  
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MOPMF067 Optimized Arc Optics for the HE-LHC 277
 
  • Y.M. Nosochkov, Y. Cai
    SLAC, Menlo Park, California, USA
  • M.P. Crouch, M. Giovannozzi, M. Hofer, J. Keintzel, T. Risselada, E. Todesco, R. Tomás, F. Zimmermann
    CERN, Geneva, Switzerland
  • D. Zhou
    KEK, Ibaraki, Japan
  • L. van Riesen-Haupt
    JAI, Oxford, United Kingdom
  
  Funding: Work supported by the European Commission under Capacities 7th Framework Programme project EuCARD-2, grant agreement 312453, and the HORIZON 2020 project EuroCirCol, grant agreement 654305.
The High Energy LHC (HE-LHC) proton-proton collider is a proposed replacement of the LHC in the existing 27-km tunnel, with the goal of reaching the centre-of-mass beam energy of 27 TeV. The required higher dipole field can be realized by using 16-T dipoles being developed for the FCC-hh design. A major concern is the dynamic aperture at injection energy due to degraded field quality of the new dipole based on Nb3Sn superconductor, the potentially large energy swing between injection and collision, and the slightly reduced magnet aperture. Another issue is the field in quadrupoles and sextupoles at top energy, for which it may be cost-effective, wherever possible, to stay with Nb-Ti technology. In this study, we explore design options differed by arc lattice, for three choices of injection energy, with the goal of attaining acceptable magnet field and maximum injection dynamic aperture with dipole non-linear field errors. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF067  
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MOPMK001 Optics for RF Acceleration Section for the High Energy Large Hadron Collider 345
 
  • L. van Riesen-Haupt, J.L. Abelleira
    University of Oxford, Oxford, United Kingdom
  • J.L. Abelleira, E. Cruz Alaniz, P. Martinez Mirave, A. Seryi
    JAI, Oxford, United Kingdom
  • M. Hofer, F. Zimmermann
    CERN, Geneva, Switzerland
  • D. Zhou
    KEK, Ibaraki, Japan
  
  Funding: Work supported by the Horizon 2020 project EuroCirCol, grant 654305 and by the Science and Technology Facilities Council
As part of the FCC study, the design of the High Energy LHC (HE-LHC) is addressed. A proposed layout for the interaction region for the containing the radio frequency (RF) cavities and various beam instrumentation will be discussed. The higher energy requires more RF cavities, which strongly restricts the space available for optics and instrumentation. Another challenge arises because the beam rigidity increases whilst the LHC geometry has to be conserved. To this end, next generation dipoles have to be used in order to achieve sufficient beam to beam separation. A design that provides enough beam stay clear (BSC) in all the magnets will be presented. The design introduces an additional quadrupole on either side of the RF region to be used for phase advance adjustments that can increase the dynamic aperture. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMK001  
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MOPMK002 Integrated Full HE-LHC Optics and Its Performance 348
 
  • M. Hofer
    TU Vienna, Wien, Austria
  • M.P. Crouch, J. Keintzel, T. Risselada, R. Tomás, F. Zimmermann
    CERN, Geneva, Switzerland
  • Y.M. Nosochkov
    SLAC, Menlo Park, California, USA
  • D. Zhou
    KEK, Ibaraki, Japan
  • L. van Riesen-Haupt
    JAI, Oxford, United Kingdom
  
  One possible future hadron collider design investigated in the framework of the Future Circular Collider (FCC) study is the High-Energy LHC (HE-LHC). Using the 16 T dipoles developed for the FCC-hh the center of mass energy of the LHC is set to increase to 27 TeV. To achieve this set energy goal, a new optics design is required, taking into account the constraint from the LHC tunnel geometry. In this paper, two different lattices for the HE-LHC are presented. Initial considerations take into account the physical aperture at the proposed injection energy as well as the energy reach of these lattices. The dynamic aperture at the injection energies is determined using latest evaluations of the field quality of the main dipoles.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMK002  
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MOPMK006 Experimental Interaction Region Optics for the High Energy LHC 360
SUSPF002   use link to see paper's listing under its alternate paper code  
 
  • L. van Riesen-Haupt, J.L. Abelleira
    University of Oxford, Oxford, United Kingdom
  • J.L. Abelleira, E. Cruz Alaniz, A. Seryi
    JAI, Oxford, United Kingdom
  • M.P. Crouch, F. Zimmermann
    CERN, Geneva, Switzerland
  • D. Zhou
    KEK, Ibaraki, Japan
  
  Funding: Work supported by the Horizon 2020 project EuroCirCol, grant 654305 and by the Science and Technology Facilities Council
The High Energy LHC (HE-LHC) is one option for a next generation hadron collider explored in the FCC-hh program. The core concept of the HE-LHC is to install FCC-hh technology magnets in the LHC tunnel. The higher beam rigidity and the increased radiation debris, however, impose severe challenges on the design of the triplet for the low beta insertions. In order to achieve 25 cm β* optics and survive a lifetime integrated luminosity of 10 ab-1 a new longer triplet was designed that provides sufficient shielding and enough beam stay clear. This triplet has been designed using complimentary radiation studies to optimise the shielding that will also be presented. The optics for the rest of the interaction region had to be adjusted in order to host this more rigid beam and longer triplet whilst leaving enough room for crab cavities. Moreover, the effects non-linear errors in this triplet have on the dynamic aperture will be outlined. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMK006  
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THPAF089 Mode Coupling Theory in Collisions With a Large Crossing Angle 3197
 
  • N. Kuroo
    UTTAC, Tsukuba, Ibaraki, Japan
  • K. Hirosawa, K. Ohmi, D. Zhou
    KEK, Ibaraki, Japan
  • K. Oide, F. Zimmermann
    CERN, Geneva, Switzerland
  
  We discuss a novel coherent beam-beam instability in collisions with a large crossing angle. The instability appears in the correlated head-tail motion of the two colliding beams. Cross wake force is introduced to represent the head-tail correlation between colliding beams. The cross wake force is localized at the collision point. Mode coupling theory based on the cross wake force is developed. Collision scheme with a large crossing angle is being very popular in design of electron positron collider. In SuperKEKB project, a collision with a large crossing angle is performed to boost the luminosity ~ 1036 cm-2s−1. Future circular collider, FCC is also designed with a large crossing angle. Strong-strong simulations have shown a strong coherent head-tail instability, which can limit the performance of proposed future colliders. The mode coupling theory using the cross wake force explains the instability. The instability may affect all colliders designs based on the crab waist scheme.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF089  
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THPAK099 The Influence of Higher Order Multipoles of IR Magnets on Luminosity for SuperKEKB 3463
SUSPF061   use link to see paper's listing under its alternate paper code  
 
  • K. Hirosawa, T. Okada
    Sokendai, Ibaraki, Japan
  • N. Kuroo
    UTTAC, Tsukuba, Ibaraki, Japan
  • K. Ohmi, N. Ohuchi, D. Zhou
    KEK, Ibaraki, Japan
  
  SuperKEKB is an electron-positron circular collider upgraded from KEKB. To reach higher luminosity, values of beta are extremely small at Interaction Point. Although magnets in interaction region have a very strong focusing effect, they make a large disturbance to beams. Higher order multipoles and their skew components of magnetic fields of IR magnets are located at a very high beta section with pi/2 phase difference from IP. These multipoles can give critical effect to beam dynamics at interaction point and reduce luminosity on SuperKEKB design. In this study, we calculated beam dynamics for effect of skew components for multipole magnet, and estimated the influence on luminosity by them.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK099  
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