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McIntosh, P. A.

Paper Title Page
TUPMN084 The Status of the Daresbury Energy Recovery Linac Prototype 1106
  • S. L. Smith, D. J. Holder, P. A. McIntosh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • N. Bliss
    STFC/DL, Daresbury, Warrington, Cheshire
  • A. R. Goulden, G. Priebe
    STFC/DL/SRD, Daresbury, Warrington, Cheshire
  As part of the UK's R&D programme to develop an advanced energy recovery linac-based light source (4GLS); a 35 MeV technology demonstrator called the Energy Recovery Linac Prototype (ERLP) has been constructed. It is based on a combination of a DC photocathode electron gun, a superconducting injector linac and main linac operating in energy recovery mode, driving an IR-FEL. The priorities for this machine are to gain experience of operating a photoinjector gun and superconducting linacs; to produce and maintain high-brightness electron beams; achieving energy recovery from an FEL-disrupted beam and studying important synchronisation issues. The current status of this project is presented, including construction and commissioning progress, including plans for the future exploitation of this scientific and technical R&D facility.  
WEPMN077 Impedance Measurements on a Test Bench Model of the ILC Crab Cavity 2206
  • P. Goudket, C. D. Beard, P. A. McIntosh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • G. Burt
    Cockcroft Institute, Lancaster University, Lancaster
  • N. Chanlek, R. M. Jones
    UMAN, Manchester
  • A. C. Dexter
    Cockcroft Institute, Warrington, Cheshire
  Funding: This work was supported by the EC under the FP6 'Research Infrastructure Action - Structuring the European Research Area' EUROTeV DS Project Contract no.011899, RIDS and PPARC.

In order to verify detailed impedance simulations, the modes in an aluminium model of the ILC crab cavity were investigated using a bead-pulling technique as well as a stretched-wire frequency domain measurement. The combination of these techniques allow for a comprehensive study of the modes of interest. For the wire measurement, a transverse alignment system was fabricated and rf components were carefully designed to minimize any potential impedance mismatches. The measurements are compared with direct simulations of the stretched-wire experiments using numerical electromagnetic field codes. High impedance modes of particular relevance to the ILC crab cavity are identified and characterized

WEPMN078 RF Cavity Development for FFAG Application on ERLP at Daresbury 2209
  • E. Wooldridge, C. D. Beard, B. D. Fell, P. A. McIntosh, B. Todd
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R. M. Jones, B. Spencer
    UMAN, Manchester
  Funding for a non-scaling, Fixed Field Alternating Gradient (FFAG) facility has been approved for installation on the Energy Recovery Linac Prototype (ERLP) at Daresbury. The RF system specification for this project requires the development of a high efficiency, 1.3 GHz, normal conducting accelerating structure, capable of delivering the required accelerating voltage, whilst adhering to stringent space limitations imposed by the extremely compact nature of the FFAG ring. We have optimised a cavity design, providing the necessary acceleration and minimising the RF power requirements to match with commercially available power sources.  
WEPMN079 Power Coupler for the ILC Crab Cavity 2212
  • G. Burt, R. G. Carter, A. C. Dexter, R. O. Jenkins
    Cockcroft Institute, Lancaster University, Lancaster
  • C. D. Beard, P. Goudket, P. A. McIntosh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • L. Bellantoni
    Fermilab, Batavia, Illinois
  Funding: This work was supported by the EC under the FP6 "Research Infrasctructure Action - Structuring the European Research Area" EUROTeV DS Project Contract no.011899 RIDS and PPARC.

The ILC crab cavity will require the design of an appropriate power coupler. The beamloading in dipole cavities is considerably more variable than accelerating cavities, hence simulations have been performed to establish the required external Q. Simulations of a suitable coupler were then performed and were verified using a normal conducting prototype with variable coupler tips.

WEPMN080 Development of Circuits and System Models for the Synchronization of the ILC Crab Cavities 2215
  • A. C. Dexter, G. Burt, R. G. Carter, R. O. Jenkins, M. I. Tahir
    Cockcroft Institute, Lancaster University, Lancaster
  • C. D. Beard, P. Goudket, A. Kalinin, L. Ma, P. A. McIntosh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Funding: The Commission of the European Communities under the 6th Framework Programme (Structuring the European Research Area) The UK particle physics and astromony research council.

The ILC reference design report (RDR) recommends a 14 mrad crossing angle for the positron and electron beams at the IP. A matched pair of crab cavity systems are required in the beam delivery system to align both bunches at the IP. The use of a multi-cell, 3.9GHz dipole mode superconducting cavity, derived from the Fermilab CKM cavity. Dipole-mode cavities phased for crab rotation are shifted by 90 degrees with respect to similar cavities phased for deflection. Uncorrelated phase errors of 0.086 degrees (equivalent to 61fs) for the two cavity systems, gives an average of 180nm for the relative deflection of the bunch centers. For a horizontal bunch size of 655nm, a deflection of 180nm reduces the ILC luminosity by 2%. The crab cavity systems are to be placed ~28m apart and their synchronization to within 61fs is on the limit of what is presently achievable. This paper describes the design and testing of circuits and control algorithms under development at the Cockcroft Institute in the UK for proof of principle experiments planned on the ERLP at Daresbury and on the ILCTA test beamline at FNAL. Simulation results for measurement and control systems are also given.

WEPMS050 HOM and LOM Coupler Optimizations for the ILC Crab Cavity 2457
  • 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
  Funding: Work supported by DOE contract DE-AC02-76SF00515

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.

WEOCAB01 Design of the Beam Delivery System for the International Linear Collider 1985
  • 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
  The beam delivery system for the linear collider focuses beams to nanometer sizes at the interaction point, collimates the beam halo to provide acceptable background in the detector and has a provision for state-of-the art beam instrumentation in order to reach the physics goals. The beam delivery system of the International Linear Collider has undergone several configuration changes recently. This paper describes the design details and status of the baseline configuration considered for the reference design.  
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