Author: Jones, T.J.
Paper Title Page
MOPVA096 The Crab Cavities Cryomodule for SPS Test 1081
 
  • C. Zanoni, A. Amorim Carvalho, K. Artoos, S. Atieh, K. Brodzinski, R. Calaga, O. Capatina, T. Capelli, F. Carra, L. Dassa, T. Dijoud, K. Eiler, G. Favre, P. Freijedo Menendez, M. Garlaschè, L. Giordanino, S.A.E. Langeslag, R. Leuxe, H. Mainaud Durand, P. Minginette, M. Narduzzi, V. Rude, M. Sosin, J.S. Swieszek
    CERN, Geneva, Switzerland
  • T.J. Jones, N. Templeton
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
 
  RF Crab Cavities are an essential part of the HL-LHC upgrade. Two concepts of such systems are being developed: the Double Quarter Wave (DQW) and the RF Dipole (RFD). A cryomodule with two DQW cavities is in advanced fabrication stage at CERN for their tests with protons in the SPS during the 2018 run. The cavities must be operated at 2 K, without excessive heat loads, in a low magnetic environment and in compliance with CERN safety guidelines on pressure and vacuum systems. A large set of components, such as a thermal shield, a two layers magnetic shield, RF lines, helium tank and tuner is required for the successful and safe operation of the cavities. The assembly of all these components with the cavities and their couplers forms the cryomodule. An overview of the design and fabrication strategy of this cryomodule is presented. The main components are described along with the present status of cavity fabrication and processing and cryomodule assembly. The lesson learned from the prototypes, the helium tank above all, and first manufactured systems is also included.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA096  
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THPIK106 Low Power RF Characterisation of the 400 Hz Photoinjector for CLARA 4342
 
  • L.S. Cowie, P. Goudket, B.L. Militsyn
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G. Burt
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • T.J. Jones
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
 
  The CLARA High Repetition Rate Photoinjector comprises an S-band dual feed cavity and will operate at a repetition rate of up to 400 Hz and is capable of reaching an electric field strength on the cathode of 120 MV/m. The cavity was brazed after tuning and arrived at Daresbury Laboratory in February 2016. Extensive low power RF testing has been performed including measurements of the quality factors and coupling, pass-band mode frequencies, on axis field and RF repeatability of replacement of cathode plug. The dual feed coupler has been tuned and a Magic Tee type splitter installed. The photoinjector is now installed on the VELA beam line for commissioning and characterisation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK106  
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THPIK107 Design and Characterisation of the Focusing Solenoidal System for the CLARA High Repetition Rate Electron Source 4346
 
  • D.J. Scott, A.R. Bainbridge, K.B. Marinov, B.L. Militsyn, B.J.A. Shepherd
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • R.J. Cash, T.J. Jones
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • C.S. Edmonds
    The University of Liverpool, Liverpool, United Kingdom
 
  One of the critical components of electron injectors based on RF photoelectron sources is the focusing system. The system typically consists of a Main Focusing Solenoid and a Bucking Coil. Combination of these two solenoids should provide proper focusing of the beam at the exit of the RF cavity and zero longitudinal magnetic field in the photocathode plane to minimise the beam emittance. Imperfection of the solenoid design, manufacturing and alignment frequently leads to asymmetry of the focusing field which has to be compensated with additional coils. In order to eliminate mechanical and magnetic misalignment the CLARA photoinjector solenoids are mounted on one integrated bench and before installation into the beamline have been aligned in the magnet laboratory with simultaneous measurement of the magnetic field. In order to define multipole field components, dedicated measurements of the transverse magnetic field have been done. The amplitudes of the multipoles have been obtained from analysis of the transverse field map. We present here the results of field characterisation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK107  
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