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Bradshaw, T.W.

Paper Title Page
MOPLS069 Development of a Superconducting Helical Undulator for the ILC Positron Source 706
 
  • Y. Ivanyushenkov, E. Baynham, T.W. Bradshaw, A.J. Brummitt, F.S. Carr, J. Rochford
    CCLRC/RAL, Chilton, Didcot, Oxon
  • I.R. Bailey, D.P. Barber, J.A. Clarke, J.B. Dainton, O.B. Malyshev, D.J. Scott, B.J.A. Shepherd
    Cockcroft Institute, Warrington, Cheshire
  • P. Cooke, L.I. Malysheva
    Liverpool University, Science Faculty, Liverpool
  • G.A. Moortgat-Pick
    CERN, Geneva
 
  An undulator positron source has been recently selected by the International Linear Collider (ILC) community as a baseline. For the ILC a helical undulator capable of producing 10 MeV photons and with a period as close as possible to 10 mm is required. The HeliCal collaboration in the UK is looking at the merits of both permanent magnet and superconducting technologies for the design of a helical undulator. For the superconducting option, several prototypes have been built and tested. This paper details the design, construction and test results of the first superconducting prototypes.  
MOPLS072 Status of the HeLiCal Contribution to the Polarised Positron Source for the International Linear Collider 715
 
  • J.A. Clarke, O.B. Malyshev, D.J. Scott
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • I.R. Bailey, P. Cooke, J.B. Dainton, L.I. Malysheva
    Liverpool University, Science Faculty, Liverpool
  • D.P. Barber
    DESY, Hamburg
  • E. Baynham, T.W. Bradshaw, A.J. Brummitt, F.S. Carr, Y. Ivanyushenkov, J. Rochford
    CCLRC/RAL, Chilton, Didcot, Oxon
  • G.A. Moortgat-Pick
    Durham University, Durham
 
  The baseline positron source for the International Linear Collider is a helical undulator-based design, which can generate unprecedented quantities of polarised positrons. A major thrust of the global design in this area is led by the UK-based HeLiCal collaboration. The collaboration takes responsibility for the design and prototyping of the helical undulator itself, which is a highly demanding short period device with very small aperture, and also leads the start to end simulations of the polarised particles to ensure that the high polarisation levels generated are maintained from the source, right through the beam transport systems and up to the interaction point itself. This paper will provide an update on the work of the collaboration, focusing on these two topic areas, and will also discuss future plans.  
WEPLS032 Spin Tracking at the ILC 2454
 
  • G.A. Moortgat-Pick, I.R. Bailey, D.P. Barber, J.A. Clarke, J.B. Dainton, O.B. Malyshev, G.A. Moortgat-Pick, D.J. Scott
    Cockcroft Institute, Warrington, Cheshire
  • E. Baynham, T.W. Bradshaw, A.J. Brummitt, F.S. Carr, Y. Ivanyushenkov, J. Rochford
    CCLRC/RAL, Chilton, Didcot, Oxon
  • P. Cooke, L.I. Malysheva
    Liverpool University, Science Faculty, Liverpool
 
  Polarized beams will play a key role in the physics programme at the International Linear Collider (ILC). It is expected that the electron and positron sources will be able to produce beams with polarizations of about 90% and 60% respectively. However, to obtain accurate measurements it is essential to have precise knowledge and control of the polarization at the interaction point itself. It follows that the theoretical calculations used for spin tracking must be guaranteed to match the anticipated 0.1% relative measurement uncertainty of the polarimeters. To meet this need, the heLiCal collaboration is developing a computer simulation to track the evolution of the polarization of bunches of electrons and positrons from the sources to the interaction point. We have studied the beam spin dynamics throughout the ILC including spin precession and radiative spin-flip processes in the positron source, damping rings, beam delivery system and the interaction region. We present the result of these studies with special emphasis on the impact of new theoretical calculations for the CAIN bunch-bunch simulation including full spin correlations and higher-order contributions.  
MOPLS118 Magnetic Modelling of a Short-period Superconducting Helical Undulator for the ILC Positron Source 840
 
  • J. Rochford, E. Baynham, T.W. Bradshaw, F.S. Carr
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • I.R. Bailey, L.I. Malysheva
    Cockcroft Institute, Warrington, Cheshire
  • D.P. Barber
    DESY, Hamburg
  • A.J. Brummitt, Y. Ivanyushenkov
    CCLRC/RAL, Chilton, Didcot, Oxon
  • J.A. Clarke, O.B. Malyshev, D.J. Scott
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • P. Cooke, J.B. Dainton
    Liverpool University, Science Faculty, Liverpool
  • G.A. Moortgat-Pick
    Durham University, Durham
 
  A positron source utilising undulators is now defined as the baseline option for the International Linear Collider (ILC). The ILC requires a short period undulator, as close to 10mm as possible, that is capable of producing 10 MeV photons. The HeliCal collaboration in the UK has undertaken a programme to design, develop and produce a prototype undulator. As part of the programme, the group has used the OPERA software package to perform the magnetic design of the undulator. The design has addressed several issues, including the effect of magnetic material for the undulator former, optimal winding geometry, the magnetic flux inside the superconductor and its variation with undulator period and the winding bore. This paper summarizes the results of both the 2d and the 3d magnetic simulations.