• W. Singer, S. Aderhold, A. Brinkmann, R. Brinkmann, J.A. Dammann, J. Iversen, G. Kreps, L. Lilje, A. Matheisen, W.-D. Möller, D. Reschke, J. Schaffran, A. Schmidt, J.K. Sekutowicz, X. Singer, H. Weise
  DESY, Hamburg
• P.M. Michelato
  INFN/LASA, Segrate (MI)

The preparation phase for the European XFEL cavity production includes a number of actions. Material issues: qualification of high purity niobium vendors, verifying of large grain material as a possible option, construction of the scanning device for the niobium sheets. Mechanical fabrication issues: accommodation of the TESLA cavity design to the XFEL demands, device construction for RF measurement of components, integration of the helium tank and it's welding to the cavity into the fabrication sequence, documentation and data transfer, application of a new high resolution camera for inspection of the inside surface. Treatment and RF measurement: establishing the XFEL recipe, in particular the final surface treatment (final 40 μm EP or short 10 μm Flash BCP), and the cavity preparation strategy (vertical acceptance test with or without helium tank welded, with or without assembly of HOM antennas), construction of the cavity tuning machine. About 50 prototype cavities are produced at the industry, treated (partially in industry and partially at DESY) and RF-tested at DESY. The XFEL requirements are fulfilled with a yield of approx. 90%.

Slides

• N. Ohuchi, H. Hayano, N. Higashi, E. Kako, Y. Kondou, H. Nakai, S. Noguchi, T. Saeki, M. Satoh, M. Sawabe, T. Shidara, T. Shishido, A. Terashima, K. Tsuchiya, K. Watanabe, A. Yamamoto, Y. Yamamoto, K. Yokoya
  KEK, Ibaraki
• T.T. Arkan, S. Barbanotti, H. Carter, M.S. Champion, R.D. Kephart, J.S. Kerby, D.V. Mitchell, Y. Orlov, T.J. Peterson, M.C. Ross
  Fermilab, Batavia
• A. Bosotti, C. Pagani, R. Paparella, P. Pierini
  INFN/LASA, Segrate (MI)
• D. Kostin, L. Lilje, A. Matheisen, W.-D. Möller, H. Weise
  DESY, Hamburg

In an attempt at demonstrating an average field gradient of 31.5 MV/m as per the design accelerating gradient for ILC, a program called S1-Global is in progress as an international research collaboration among KEK, INFN, FNAL, DESY and SLAC. The S1-Global cryomodule will contain eight superconducting cavities from FNAL, DESY and KEK. The cryomodule will be constructed by joining two half-size cryomodules, each 6 m in length. The module containing four cavities from FNAL and DESY has been constructed by INFN. The module for four KEK cavities is being modified at present. The assembly of the cryomodules is scheduled from January 2010, and the operation of the system is scheduled from June 2010 at the KEK-STF. In this paper, the construction of the S1-Global cryomodule will be presented.