Author: Stapley, N.
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WEOCAV03 RF Dipole Crab Cavity Testing for HL-LHC 687
  • N. Valverde Alonso, R. Calaga, S.J. Calvo, O. Capatina, O. Capatina, A. Castilla, M. Chiodini, C. Duval, L.M.A. Ferreira, M. Gourragne, P.J. Kohler, T. Mikkola, J.A. Mitchell, E. Montesinos, C. Pasquino, G. Pechaud, N. Stapley, M. Therasse, K. Turaj, J.D. Walker
    CERN, Meyrin, Switzerland
  • A. Castilla
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • A. Castilla
    Lancaster University, Lancaster, United Kingdom
  RF Crab Cavities are an essential element of the High Luminosity LHC (HL-LHC) upgrade at CERN. Two RF dipole crab cavity used for the compensation of the horizontal crossing angle were recently manufactured and integrated into Titanium Helium tank and RF ancillaries necessary for the beam operation. The two cavities will be integrated into a cryomodule in collaboration with UK-STFC and tested with proton beams in the SPS in 2023. This paper will highlight the RF measurements during the important manufacturing steps, surface preparation and cavity performance at 2K.  
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About • Received ※ 18 June 2021 — Revised ※ 07 September 2021 — Accepted ※ 16 September 2021 — Issue date ※ 22 November 2021
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Ferro-Electric Fast Reactive Tuners for SRF  
  • N.C. Shipman, M.R. Coly, F. Gerigk, A. Macpherson, N. Stapley, D. Valuch, W. Venturini Delsolaro
    CERN, Geneva, Switzerland
  • I. Ben-Zvi
    BNL, Upton, New York, USA
  • C.-J. Jing, A. Kanareykin
    Euclid TechLabs, Solon, Ohio, USA
  A Ferro-Electric Fast Reactive Tuner (FE-FRT) is a new type of tuner, utilising a novel ferro-electric material, which can change the frequency of an RF cavity on the sub-microsecond timescale and has the potential to reduce a cavity’s RF power requirements by an order of magnitude in some cases. During operation, power is continuously coupled out of the cavity, through the tuner, and reflected back into the cavity. By applying a high voltage across a ferro-electric within the tuner, the reactive load seen by the cavity is altered which causes a frequency shift in the cavity. The extremely fast response times of FE-FRTs make them especially suited to the correction of frequency variations caused by microphonics. New closed loop tuning measurements at CERN with a prototype FE-FRT and superconducting RF cavity have recently demonstrated excellent suppression of the cavity’s microphonics. The experimental set-up and the recent test results will be presented and the capabilities of this approach contrasted with more common systems, such as piezoelectric based tuners.  
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