Author: Mertens, V.
Paper Title Page
MOPFI050 Non-local Fast Extraction from the CERN SPS at 100 and 440 GeV 392
 
  • F.M. Velotti, A. Alekou, W. Bartmann, E. Carlier, K. Cornelis, I. Efthymiopoulos, B. Goddard, L.K. Jensen, V. Kain, M. Kowalska, V. Mertens, R. Steerenberg
    CERN, Geneva, Switzerland
 
  The Long Straight Section 2 (LSS2) of the CERN SPS is connected with the North Area (NA), to which the beam to date has always been extracted using a resonant extraction technique. For new proposed short- and long-baseline neutrino experiments, a fast single turn extraction to this experimental area is required. As there are no kickers in LSS2, and the integration of any new kickers with the existing electrostatic septum would be problematic, a solution has been developed to fast extract the beam using non-local extraction with other SPS kickers. Two different kicker systems have been used, the injection kicker in LSS1 and the stronger extraction kicker in LSS6 to extract 100 and 440 GeV beam, respectively. For both solutions a large emittance beam was extracted after 5 or 9 full betatron periods. The concept and simulation details are presented with the analysis of the aperture and beam loss considerations and experimental results collected during a series of beam tests.  
 
MOPFI052 A New Lead Ion Injection System for the CERN SPS with 50 ns Rise Time 398
 
  • B. Goddard, O. Aberle, J. Borburgh, E. Carlier, K. Cornelis, L. Ducimetière, L.K. Jensen, T. Kramer, D. Manglunki, A. Mereghetti, V. Mertens, D. Nisbet, B. Salvant, L. Sermeus
    CERN, Geneva, Switzerland
 
  The LHC High Luminosity upgrade project includes a performance upgrade for heavy ions. One of the present performance limitations is the rise time of the SPS injection kicker system, which imposes a spacing of at least 220 ns between injected bunch trains at the operational rigidity. A reduction of this rise time to 50 ns for lead ions is requested as part of the suite of measures needed to increase the present design performance by a factor three. A new injection system based on a fast pulsed septum and a fast kicker has been proposed to fulfil this rise time requirement, and to meet all the constraints associated with the existing high intensity proton injection in the same region. This paper describes the concept and the required equipment parameters, and explores the implications of such a system for SPS operation.  
 
MOPFI060 Beam Transfer to LHC with the Low Gamma-transition SPS Optics 419
 
  • G. Vanbavinckhove, W. Bartmann, H. Bartosik, C. Bracco, L.N. Drøsdal, B. Goddard, V. Kain, M. Meddahi, V. Mertens, Y. Papaphilippou, J.A. Uythoven, J. Wenninger
    CERN, Geneva, Switzerland
  • E. Gianfelice-Wendt
    Fermilab, Batavia, USA
 
  A new low gamma-transition optics with a lower integer tune, was introduced in the SPS to improve beam stability at high intensity. For transferring the beam to the LHC, the extraction bumps, extraction kickers and transfer lines needed to be adapted to the new optics. In particular, the transfer lines were re-matched and re-commissioned with the new optics. The first operational results are discussed for the SPS extraction, the transfer lines and the LHC injection. A detailed comparison is presented between the old and the new optics of the trajectories, dispersion, losses and other performance aspects.  
 
MOPWA030 Upgrade of the LHC Injection Kicker Magnets 729
 
  • M.J. Barnes, P. Adraktas, V. Baglin, G. Bregliozzi, S. Calatroni, F. Caspers, H.A. Day, L. Ducimetière, M. Garlaschè, V. Gomes Namora, J.M. Jimenez, N. Magnin, V. Mertens, E. Métral, B. Salvant, M. Taborelli, J.A. Uythoven, W.J.M. Weterings
    CERN, Geneva, Switzerland
 
  The two LHC injection kicker systems, comprising 4 magnets per ring, produce a kick of 1.3 T.m with a rise-time of less than 900 ns and a flattop ripple of less than ±0.5%. A beam screen is placed in the aperture of each magnet, to provide a path for the image current of the high intensity LHC beam and screen the ferrite yoke against wake fields. The screen consists of a ceramic tube with conductors in the inner wall. The initially implemented beam screen ensured a low rate of electrical breakdowns while providing an adequate beam coupling impedance. Operation with increasingly higher intensity beams, stable for many hours at a time, now results in substantial heating of the ferrite yoke, sometimes requiring cool down over several hours before the LHC can be refilled. During the long shutdown in 2013/2014 all 8 kicker magnets will be upgraded with an improved beam screen and an increased emissivity of the vacuum tank. In addition equipment adjacent to the injection kickers and various vacuum components will also be modified to help reduce the vacuum pressure in the kickers during high-intensity operation. This paper discusses the upgrades as well as their preparation and planning.  
 
MOPWA031 Beam Induced Ferrite Heating of the LHC Injection Kickers and Proposals for Improved Cooling 732
 
  • M.J. Barnes, S. Calatroni, F. Caspers, L. Ducimetière, M. Garlaschè, V. Gomes Namora, V. Mertens, Z.K. Sobiech, M. Taborelli, J.A. Uythoven, W.J.M. Weterings
    CERN, Geneva, Switzerland
  • H.A. Day
    UMAN, Manchester, United Kingdom
 
  The two LHC injection kicker systems produce a kick of 1.3 T.m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. A beam screen is placed in the aperture of each magnet, which consists of a ceramic tube with conductors in the inner wall. The conductors provide a path for the beam image current and screen the ferrite yoke against wake fields. Recent LHC operation, with high intensity beam stable for many hours, resulted in significant heating of both the ferrite yoke and beam impedance reduction ferrites. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the ferrites can require several hours to cool enough to re-inject beam, thus limiting the availability of the LHC. Thermal measurement data has been analysed, a thermal model developed and emissivity measurements carried out. The effects of various measures to improve the ferrite cooling have been simulated, including an improved emissivity of the vacuum tank and active cooling on the outside of the tank.  
 
MOPWA032 Reduction of Surface Flashover of the Beam Screen of the LHC Injection Kickers 735
 
  • M.J. Barnes, P. Adraktas, S. Calatroni, F. Caspers, L. Ducimetière, V. Gomes Namora, V. Mertens, R. Noulibos, M. Taborelli, B. Teissandier, J.A. Uythoven, W.J.M. Weterings
    CERN, Geneva, Switzerland
 
  The LHC injection kicker magnets include beam screens to shield the ferrite yokes against wake fields resulting from the high intensity beam. The screening is provided by conductors lodged in the inner wall of a ceramic support tube. Operation with increasingly higher bunch intensity, and narrow bunches, now requires improved ferrite screening. This will be implemented by additional conductors; however the good high-voltage behaviour of the kicker magnets must not be compromised by the supplementary screening. Extensive studies and optimisations have been carried out, to better satisfy the often conflicting requirements for low beam coupling impedance, fast magnetic field rise-time, high vacuum and good high voltage behaviour. A new configuration is proposed which reduces significantly the electric field associated with the screen conductors and the secondary electron yield of the surface of the ceramic tube. Results of high voltage test results are also presented.  
 
TUPME032 Update on Beam Induced RF Heating in the LHC 1646
 
  • B. Salvant, O. Aberle, G. Arduini, R.W. Aßmann, V. Baglin, M.J. Barnes, W. Bartmann, P. Baudrenghien, O.E. Berrig, A. Bertarelli, C. Bracco, E. Bravin, G. Bregliozzi, R. Bruce, F. Carra, F. Caspers, G. Cattenoz, S.D. Claudet, H.A. Day, M. Deile, J.F. Esteban Müller, P. Fassnacht, M. Garlaschè, L. Gentini, B. Goddard, A. Grudiev, B. Henrist, S. Jakobsen, O.R. Jones, O. Kononenko, G. Lanza, L. Lari, T. Mastoridis, V. Mertens, N. Mounet, E. Métral, A.A. Nosych, J.L. Nougaret, S. Persichelli, A.M. Piguiet, S. Redaelli, F. Roncarolo, G. Rumolo, B. Salvachua, M. Sapinski, R. Schmidt, E.N. Shaposhnikova, L.J. Tavian, M.A. Timmins, J.A. Uythoven, A. Vidal, J. Wenninger, D. Wollmann, M. Zerlauth
    CERN, Geneva, Switzerland
  • H.A. Day
    UMAN, Manchester, United Kingdom
  • L. Lari
    IFIC, Valencia, Spain
 
  Since June 2011, the rapid increase of the luminosity performance of the LHC has come at the expense of increased temperature and pressure readings on specific near-beam LHC equipment. In some cases, this beam induced heating has caused delays whilie equipment cools down, beam dumps and even degradation of these devices. This contribution gathers the observations of beam induced heating attributable to beam coupling impedance, their current level of understanding and possible actions that are planned to be implemented during the long shutdown in 2013-2014.  
 
WEPEA053 Progress with the Upgrade of the SPS for the HL-LHC Era 2624
 
  • B. Goddard, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, F. Caspers, K. Cornelis, H. Damerau, L.N. Drøsdal, L. Ducimetière, J.F. Esteban Müller, R. Garoby, M. Gourber-Pace, W. Höfle, G. Iadarola, L.K. Jensen, V. Kain, R. Losito, M. Meddahi, A. Mereghetti, V. Mertens, Ö. Mete, E. Montesinos, Y. Papaphilippou, G. Rumolo, B. Salvant, E.N. Shaposhnikova, M. Taborelli, H. Timko, F.M. Velotti
    CERN, Geneva, Switzerland
  • E. Gianfelice-Wendt
    Fermilab, Batavia, USA
 
  The demanding beam performance requirements of the HL-LHC project translate into a set of requirements and upgrade paths for the LHC injector complex. In this paper the performance requirements for the SPS and the known limitations are reviewed in the light of the 2012 operational experience. The various SPS upgrades in progress and still under consideration are described, in addition to the machine studies and simulations performed in 2012. The expected machine performance reach is estimated on the basis of the present knowledge, and the remaining decisions that still need to be made concerning upgrade options are detailed.