Paper |
Title |
Page |
MPPT033 |
Development of a Superconducting Helical Undulator for a Polarised Positron Source
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2295 |
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- Y. Ivanyushenkov, F.S. Carr
CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
- D.P. Barber
DESY, Hamburg
- E. Baynham, T.W. Bradshaw, J. Rochford
CCLRC/RAL, Chilton, Didcot, Oxon
- J.A. Clarke, O.B. Malyshev, D.J. Scott, B.J.A. Shepherd
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
- P. Cooke, J.B. Dainton, T. Greenshaw
Liverpool University, Science Faculty, Liverpool
- G.A. Moortgat-Pick
Durham University, Durham
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A method of producing a polarised positron beam from e+e- pair production in a target by circularly polarised ?-radiation is being investigated. Polarised photons are to be generated by the passage of a high energy electron beam (250 GeV as anticipated in the International Linear Collider - ILC) through a helical undulator. For production of 20 MeV photons, an undulator with a period of 14 mm, a bore of approximately 4 mm and magnetic field on axis of 0.75 T is required. First prototypes have been constructed using both superconducting and permanent magnet technologies which are capable of producing the necessary magnetic field configuration in the undulator. This paper details the design, construction techniques and field measurement results of the first superconducting prototype and compares the results with simulation.
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MPPT079 |
Commissioning of an APPLE-II Undulator at Daresbury Laboratory for the SRS
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4051 |
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- J.A. Clarke, F.E. Hannon, D.J. Scott, B.J.A. Shepherd, N.G. Wyles
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
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A new variable polarisation undulator of the APPLE-II type has been designed and constructed at Daresbury Laboratory. Initial magnet testing of the 56mm period device was followed by an intensive period of shimming to improve the field quality. After this was successfully completed the undulator was installed into the SRS and tests made of the effect of the device upon the electron beam. This beam commissioning was completed in a very short space of time with the beamline being given full control of the gap and phase of the magnet within a few weeks of installation. This paper summarises the measurement of the magnet and the shimming techniques employed to improve the field quality. It also describes the effect of the device upon the stored 2 GeV electron beam and the measures taken to minimise these effects during user operations.
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