• A. Seryi, J. A. Amann, R. Arnold, F. Asiri, K. L.F. Bane, P. Bellomo, E. Doyle, A. F. Fasso, L. Keller, J. Kim, K. Ko, Z. Li, T. W. Markiewicz, T. V.M. Maruyama, K. C. Moffeit, S. Molloy, Y. Nosochkov, N. Phinney, T. O. Raubenheimer, S. Seletskiy, S. Smith, C. M. Spencer, P. Tenenbaum, D. R. Walz, G. R. White, M. Woodley, M. Woods, L. Xiao
  SLAC, Menlo Park, California
• I. V. Agapov, G. A. Blair, S. T. Boogert, J. Carter
  Royal Holloway, University of London, Surrey
• M. Alabau, P. Bambade, J. Brossard, O. Dadoun
  LAL, Orsay
• M. Anerella, A. K. Jain, A. Marone, B. Parker
  BNL, Upton, Long Island, New York
• D. A.-K. Angal-Kalinin, C. D. Beard, J.-L. Fernandez-Hernando, P. Goudket, F. Jackson, J. K. Jones, A. Kalinin, P. A. McIntosh
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• R. Appleby
  UMAN, Manchester
• J. L. Baldy, D. Schulte
  CERN, Geneva
• L. Bellantoni, A. I. Drozhdin, V. S. Kashikhin, V. Kuchler, T. Lackowski, N. V. Mokhov, N. Nakao, T. Peterson, M. C. Ross, S. I. Striganov, J. C. Tompkins, M. Wendt, X. Yang
  Fermilab, Batavia, Illinois
• K. Buesser
  DESY, Hamburg
• P. Burrows, G. B. Christian, C. I. Clarke, A. F. Hartin
  OXFORDphysics, Oxford, Oxon
• G. Burt, A. C. Dexter
  Cockcroft Institute, Warrington, Cheshire
• J. Carwardine, C. W. Saunders
  ANL, Argonne, Illinois
• B. Constance, H. Dabiri Khah, C. Perry, C. Swinson
  JAI, Oxford
• O. Delferriere, O. Napoly, J. Payet, D. Uriot
  CEA, Gif-sur-Yvette
• C. J. Densham, R. J.S. Greenhalgh
  STFC/RAL, Chilton, Didcot, Oxon
• A. Enomoto, S. Kuroda, T. Okugi, T. Sanami, Y. Suetsugu, T. Tauchi
  KEK, Ibaraki
• A. Ferrari
  UU/ISV, Uppsala
• J. Gronberg
  LLNL, Livermore, California
• Y. Iwashita
  Kyoto ICR, Uji, Kyoto
• W. Lohmann
  DESY Zeuthen, Zeuthen
• L. Ma
  STFC/DL, Daresbury, Warrington, Cheshire
• T. M. Mattison
  UBC, Vancouver, B. C.
• T. S. Sanuki
  University of Tokyo, Tokyo
• V. I. Telnov
  BINP SB RAS, Novosibirsk
• E. T. Torrence
  University of Oregon, Eugene, Oregon
• D. Warner
  Colorado University at Boulder, Boulder, Colorado
• N. K. Watson
  Birmingham University, Birmingham
• H. Y. Yamamoto
  Tohoku University, Sendai

• L. Xiao, K. Ko, Z. Li, C.-K. Ng, G. L. Schussman, A. Seryi, R. Uplenchwar
  SLAC, Menlo Park, California
• L. Bellantoni
  Fermilab, Batavia, Illinois
• G. Burt
  Cockcroft Institute, Lancaster University, Lancaster
• P. Goudket, P. A. McIntosh
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire

The FNAL 9-cell 3.9GHz deflecting cavity designed for the CKM experiment was chosen as the baseline design for the ILC BDS crab cavity. Effective damping is required for the lower-order TM01 modes (LOM), the same-order TM11 modes (SOM) as well as the HOM modes to minimize the beam loading and beam centroid steering due to wakefields. Simulation results of the original CKM design using the eigensolver Omega3P showed that both the notch filters of the HOM/LOM couplers are very sensitive to the notch gap, and the damping of the unwanted modes is suboptimal for the ILC. To meet the ILC requirements, the couplers were redesigned to improve the damping and tuning sensitivity. With the new design, the damping of the LOM/SOM/HOM modes is significantly improved, the sensitivity of the notch filter for the HOM coupler is reduced by one order of magnitude and appears mechanically feasible, and the LOM coupler is simplified by aligning it on the same plane as the SOM coupler and by eliminating the notch filter. In this paper, we will present the coupler optimization and tolerance studies for the crab cavity.

• K. L.F. Bane, A. Seryi
  SLAC, Menlo Park, California

The main linac of the International Linear Collider (ILC) accelerates short, high peak current bunches into the Beam Deliver System (BDS) on the way to the interaction point. In the BDS wakefields are excited by the resistance of the beam pipe walls and by beam pipe transitions that will tend to degrade the emittance of the beam bunches. In this report we calculate the effect on emittance of incoming jitter or drift, and of misalignments of the beam pipes with respect to the beam axis, both analytically and through multi-particle tracking. Finally, we discuss ways of ameliorating the wake effects in the BDS.

• B. Parker, M. Anerella, J. Escallier, P. He, A. K. Jain, A. Marone
  BNL, Upton, Long Island, New York
• Y. Nosochkov, A. Seryi
  SLAC, Menlo Park, California

A wide variety of superconducting magnets are needed in the ILC Beam Delivery System (BDS) to maximize luminosity and minimize experimental backgrounds. Compact final focus quadrupoles and multifunction correction coils are used with 14 mr total crossing angle to focus incoming beams to few nanometer spot sizes while focusing outgoing disrupted beams into a separate extraction beam line. Large aperture anti-solenoids correct deleterious nonlinear effects that arise due to the overlap of focusing fields with the main detector solenoid. Far from the interaction point (IP) sets of strong small aperture octupoles help minimize backgrounds at the IP due to beam halo particles while weak large aperture dipoles integrated with the experimental detector reduce backgrounds due to beamstrahlung pairs generated at the IP. The physics requirements and magnetic design solutions for these magnets are reviewed in this paper.

• L. Wang, Z. Li, A. Seryi
  SLAC, Menlo Park, California

The effects of the round edge beam hole on the frequency and wake field are studied using variational method, which allows for rounded iris disk hole without any approximation in shape treatment. The frequency and wake field of accelerating mode and dipole mode are studied for different edge radius cases, including the flat edge shape that is often used to approximately represent the actual structure geometry. The edge hole shape has weak effect on the frequency, but much effect on the wake field. Our study shows that the amounts of wake fields are not precise enough with the assumption of the flat edge beam hole instead of round edge.