Author: Li, H.
Paper Title Page
MOPVA089 The Cryomodule Test Stands for the European Spallation Source 1064
 
  • E. Asensi Conejero, W. Hees
    ESS, Lund, Sweden
  • K. Fransson, K.J. Gajewski, L. Hermansson, M. Jobs, H. Li, T. Lofnes, R.J.M.Y. Ruber, R. Santiago Kern, R. Wedberg
    Uppsala University, Uppsala, Sweden
 
  The European Spallation Source (ESS) is currently under construction in Lund, in southern Sweden. The superconducting section of the linear accelerator consists of three parts; 26 double-spoke cavities at 352.21 MHz gathered in 13 cryomodules, 36 medium beta elliptical cavities at 704.42 MHz gathered in 9 cryomodules and 84 high beta elliptical cavities also at 704.42 MHz gathered in 21 cryomodules. These cryomodules allow the acceleration of the beam from 90 MeV to 2.0 GeV. The cryomodules have to be tested in dedicated test facilities before installation in the ESS tunnel, the Test Stand 2 (TS2) in Lund and the FREIA Test Stand at Uppsala University, Sweden, which are dedicated to the tests of the medium and high beta elliptical cryomodules and the spoke cavity cryomodules, respectively, for the ESS linear accelerator. All cryomodules will go through their Site Acceptance Tests (SAT) on these dedicated test stands which will each consist of an RP bunker, a test stand cryoplant and RF power sources. Both test stands will allow the SAT of cryomodules with full cryogenic load at the final operating temperature and with full RF load on all cavities in parallel.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA089  
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MOPVA094 ESS Spoke Cavity Conditioning at FREIA 1074
 
  • H. Li, K.J. Gajewski, L. Hermansson, M. Jobs, R.J.M.Y. Ruber, R. Santiago Kern
    Uppsala University, Uppsala, Sweden
 
  The first ESS double spoke cavity installed with RF power coupler was tested in the HNOSS cryostat at the FREIA Laboratory. Power coupler and cavity conditioning have been optimized in order to reach high efficiency and high availability by reducing the time and effort of the overall conditioning process. Meanwhile, an optimal procedure for ESS conditioning is studied. This paper presents the study result and experience of the RF conditioning procedure for the first ESS double spoke cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA094  
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THPIK090 352 MHz Tetrode RF Stations for Superconducting Spoke Cavities 4296
 
  • M. Jobs, K.J. Gajewski, V.A. Goryashko, H. Li, R.J.M.Y. Ruber, R. Wedberg
    Uppsala University, Uppsala, Sweden
 
  Two 352 MHz tetrode based RF stations for pulsed operation have been developed at the FREIA Laboratory, Uppsala University to validate the design and performance as RF source for the Spoke cavities in the first superconductive stage of the European Spallation Source(ESS) linear accelerator. The stations use dual TH595 tetrodes rated at 210 kW peak-power to provide a total power of 400 kW with a maximum pulse duration of 3.5 ms at 14 Hz repetition rate. Each tetrode is fed by a 10 kW solid state amplifier and the station is monitored by an internal control system with complete remote access. Extensive measurements have been performed on the RF performance, the power supplies as well as on the interlock systems. To conform to the specifications, special attention must be given for the response time of the tetrode power-supplies to acquire good quality RF output pulses. For the interlock system any shut-down condition due to tube malfunctioning or other sources must switch off the station in a controlled manner with minimal damage to any internal circuitry or to the tube itself whilst at the same time provide a fast discharge and cut-off of all relevant power supplies.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK090  
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