Author: Kelly, S.
Paper Title Page
TUPFI023 Optics Design and Lattice Optimisation for the HL-LHC 1385
 
  • B.J. Holzer, R. De Maria, S.D. Fartoukh
    CERN, Geneva, Switzerland
  • R. Appleby, S. Kelly, M.B. Thomas, L.N.S. Thompson
    UMAN, Manchester, United Kingdom
  • A.V. Bogomyagkov
    BINP SB RAS, Novosibirsk, Russia
  • A. Chancé
    CEA, Gif-sur-Yvette, France
  • B. Dalena
    CEA/IRFU, Gif-sur-Yvette, France
  • A. Faus-Golfe, J. Resta
    IFIC, Valencia, Spain
  • K.M. Hock, M. Korostelev, L.N.S. Thompson, A. Wolski
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C. Milardi
    INFN/LNF, Frascati (Roma), Italy
  • J. Payet
    CEA/DSM/IRFU, France
  • A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: The HiLumi LHC Design Study is included in the High Luminosity LHC project and is partly funded by the European Commission within the Framework Programme 7 Cap. Spec. Progr, Grant Agreement 284404.
The luminosity upgrade project of the LHC collider at CERN is based on a strong focusing scheme to reach smallest beam sizes at the collision points. Depending on the available magnet technology (Nb3Sn or NbTi) a number of beam optics has been developed to define the specifications for the new super conducting quadrupoles. In the context of the optics matching new issues have been addressed and new concepts have been used: Quadrupole strength flexibility and chromatic corrections have been studied, as well as the influence of quadrupole fringe fields. The lattice has been optimised including the needs of the foreseen crab cavities and the transition between injection and low β optics had to guarantee smooth gradient changes over a wide range of β* values. Tolerances on misalignments and power converter ripple have been re-evaluated. Finally the combination of the quadrupole strengths in the high luminosity matching sections with those in the neighboring sectors is explained, a key concept of the ATS to reach smallest β* values. This paper presents the results obtained within the HiLumi collaboration Task 2.2 and summarises the main parameters of the project. 		 
 
WEPEA059 Study of the Impact of Fringe Fields of the Large Aperture Triplets on the Linear Optics of the HL-LHC 2642
 
  • B.J. Holzer, R. De Maria, S. Russenschuck
    CERN, Geneva, Switzerland
  • R. Appleby, S. Kelly, M.B. Thomas, L.N.S. Thompson
    UMAN, Manchester, United Kingdom
  • L.N.S. Thompson
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404
High-luminosity hadron colliders such as the High Luminosity LHC (HL-LHC) project place demanding requirements on existing and new magnet technology. The very low β* achieved by the Achromatic Telescopic Squeeze (ATS) optics scheme* for the HL-LHC in particular, requires large apertures in the high gradient Nb3Sn final focusing inner triplet triplet. Such magnets have extended fringe fields which perturb the linear and non-linear optics. This paper presents results of studies into the liner optics of the LHC using a range of fringe field models, including measurements of fringe fields from prototype magnets, and presents calculations of the beta-beating in the machine. Furthermore a similar study is presented on the nominal LHC optics, which uses final focus quadrupoles of higher gradient but significantly smaller aperture.
* S. Fartoukh, ‘’An Achromatic Telescopic Squeezing (ATS) Scheme for
LHC Upgrade’’, in proceedings of IPAC11, p. 2088.