Author: Farricker, A.
Paper Title Page
MOPGW076 Verification by RF Measurements of New HOM Mitigation Scheme Developed for Future SPS 33-Cell Accelerating Structures 274
 
  • P. Kramer, A. Farricker, C. Vollinger
    CERN, Geneva, Switzerland
 
  Longitudinal higher-order modes (HOMs) at a frequency of around 630 MHz in the 200 MHz travelling wave RF structures currently limit the beam intensities in the CERN SPS to less than that required by the High Luminosity (HL-) LHC. In the framework of the LHC Injectors Upgrade (LIU) project, the performance of the already existing HOM damping scheme for these standing wave modes must be improved. This involves improving the existing HOM-couplers as well as the possible use of a new mitigation technique via the insertion of resonant posts in some cells of the multi-cell structures. The development of the new damping scheme has been performed using theoretical analysis of the cavity-coupler interaction in conjunction with full-wave electromagnetic (EM) field simulations. This contribution will show the verification of the improved HOM damping performance by measurements on a single section with 11 cells and on the future 33-cell structures. The parasitic impact of the damping scheme on the travelling wave fundamental passband (FPB) will also be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW076  
About • paper received ※ 11 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPGW077 Impedance Reduction in the CERN SPS Through Element Layout Optimisation 277
 
  • A. Farricker, C. Vollinger
    CERN, Geneva, Switzerland
 
  The CERN accelerator complex is currently in its long shutdown while the LHC Injector Upgrade is being carried out. The upgrade of the SPS includes but is not limited to: the relocation of the beam dumping system, upgrade of the RF system, replacement of the electrostatic septa and impedance reduction. These major upgrades present an opportunity to perform additional impedance reduction in areas not normally modified due to the large amount of work being performed across the accelerator complex. In this paper, we look at the impedance minimization in the sections near the large aperture quadrupoles of the extraction regions in the CERN SPS. By optimizing the locations of existing equipment and the introduction of a new, more impedance optimised type of bellows, significant reductions in the beam-coupling impedance can be achieved.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW077  
About • paper received ※ 08 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPTS082 Status of ESS Linac Upgrade Studies for ESSnuSB 1038
 
  • B. Gålnander, M. Eshraqi, C.A. Martins, R. Miyamoto
    ESS, Lund, Sweden
  • M. Collins
    Lund Technical University, Lund, Sweden
  • A. Farricker
    CERN, Geneva, Switzerland
 
  Funding: ESSnuSB has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 777419.
The European Spallation Source (ESS), currently under construction in Lund, Sweden, is the world’s most powerful neutron spallation source, with an average power of 5 MW at 2.0 GeV. In the ESS neutrino Super Beam Project (ESSnuSB) it is proposed to utilise this powerful accelerator as a proton driver for a neutrino beam that will be sent to a large underground Cherenkov detector in Garpenberg, mid-Sweden. In this paper we discuss the required modifications of the ESS linac to reach an additional 5 MW beam power for neutrino production in parallel to the spallation neutron production.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS082  
About • paper received ※ 17 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEYPLS1 Building the Impedance Model of a Real Machine 2249
 
  • B. Salvant, D. Amorim, S. A. Antipov, S. Arsenyev, M.S. Beck, N. Biancacci, O.S. Brüning, J.V. Campelo, E. Carideo, F. Caspers, A. Farricker, A. Grudiev, T. Kaltenbacher, E. Koukovini-Platia, P. Kramer, A. Lasheen, M. Migliorati, N. Mounet, E. Métral, N. Nasr Esfahani, S. Persichelli, B.K. Popovic, T.L. Rijoff, G. Rumolo, E.N. Shaposhnikova, V.G. Vaccaro, C. Vollinger, N. Wang, C. Zannini, B. Zotter
    CERN, Meyrin, Switzerland
  • D. Amorim
    Grenoble-INP Phelma, Grenoble, France
  • T. Dalascu
    EPFL, Lausanne, Switzerland
  • M. Migliorati
    Sapienza University of Rome, Rome, Italy
  • R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  • V.V. Smaluk
    BNL, Upton, Long Island, New York, USA
  • B. Spataro
    INFN/LNF, Frascati, Italy
  • N. Wang
    IHEP, Beijing, People’s Republic of China
  • S.M. White
    ESRF, Grenoble, France
 
  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.  
slides icon Slides WEYPLS1 [5.648 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEYPLS1  
About • paper received ※ 10 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)