• J. Rochford
  STFC/RAL/ASTeC, Chilton, Didcot, Oxon
• I.R. Bailey
  Lancaster University, Lancaster
• E. Baynham, T.W. Bradshaw, A.J. Brummitt, D.A. Burton, F.S. Carr, A.J. Lintern
  STFC/RAL, Chilton, Didcot, Oxon
• J.A. Clarke, O.B. Malyshev, D.J. Scott, B.J.A. Shepherd
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• Y. Ivanyushenkov
  ANL, Argonne
• G.A. Moortgat-Pick
  Durham University, Durham
• N.C. Ryder
  University of Bristol, Bristol

The ILC positron source relies upon a ~200 m long superconducting helical undulator in order to generate the huge flux of gamma photons required. The period is only 11.5 mm but the field strength is ~1 T. The UK is building and testing a full scale 4 m long ILC cryomodule at the moment. It will be completed in 2008 and the results used to demonstrate the feasibility of the full (200 m long) system.

Slides

• M. Korostelev, A. Wolski
  Cockcroft Institute, Warrington, Cheshire
• N.A. Collomb, J.M. Lucas
  STFC/DL, Daresbury, Warrington, Cheshire
• O.B. Malyshev
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire

Vacuum chamber transitions of the ILC damping rings associated with BPM insertions, vacuum ports, antechamber tapers etc, may make a significant contribution to the overall machine impedance. Since most transitions are not azimuthally symmetric, commercial 3D codes based on the finite element method have been used to compute their wake fields. The results for selected vacuum chamber components are presented in this paper, together with some estimates of the impact of the wake fields on the beam dynamics in the damping rings.