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Beard, C. D.

Paper Title Page
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.

 
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.  
slides icon Slides  
FRPMS074 Measurements of the Transverse Collimator Wakefields due to Varying Collimator Characteristics 4207
 
  • S. Molloy, S. Seletskiy, M. Woods
    SLAC, Menlo Park, California
  • C. D. Beard, J.-L. Fernandez-Hernando
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • A. Bungau
    UMAN, Manchester
  • J. D.A. Smith
    Cockcroft Institute, Warrington, Cheshire
  • A. Sopczak
    Lancaster University, Lancaster
  • N. K. Watson
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  
  Funding: EUROtev Contract #011899RIDS US DOE Contract DEAC02-76SF00515

We report on measurements of the transverse wakefields induced by collimators of differing characteristics. An apparatus allowing the insertion of different collimator jaws into the path of a beam was installed in End Station A (ESA) in SLAC. Eight comparable collimator geometries were designed, including one that would allow easy comparison with previous results, and were installed in this apparatus. Measurements of the beam kick due to the collimator wakefields were made with a beam energy of 28.5 GeV, and beam dimensions of ~100 microns vertically and a range of 0.5 to 1.5 mm longitudinally. The trajectory of the beam upstream and downstream of the collimator test apparatus was determined from the outputs of ten BPMs (four upstream and six downstream), thus allowing a measurement of the angular kick imparted to the beam by the collimator under test. The transverse wakefield was inferred from the measured kick. The different aperture designs, data collection and analysis, and initial comparison to theoretical and analytic predictions are presented here.

* "An Apparatus for the Direct Measurement of Collimator Transverse Wakefields", P. Tenenbaum, PAC '99** "Direct Measurement of the Resistive Wakefield in Tapered Collimators", P Tenenbaum, PAC '04