On the Effect of Eddy Current Induced Field

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On the Effect of Eddy Current Induced Field

• Wanming Liu, Sergey Antipov and Wei Gai
• HEP, ANL

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Conditions

• Undulator k0.92, lu1.15cm, 100m long
• Target 0.4 r.l. Ti, 500m drift
• OMD5T-0.25T,50cm
• Eddy current induced field from Femlab
  simulation at 900rpm for 1m radius wheel of
  titanium under 5T magnetic field.
• Conductivity of target 1.5e6 and 3e6

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Bz on yz plane near the targets1.5e6
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Bz of Induced field OMD field near the target
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By of OMD field on yz plane near the target
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x-x comparison of captured positrons with and
without induced field
Induced field kicked some out but also kicked
some in. The final yield doesnt change for
s1.5e6
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Induced field, s3e6
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Induced field OMD field
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Initial x-x of captured positrons
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Summary

• For s1.5e6, since the eddy current induced field
  is small comparing with the OMD field, and also
  due to the broad band matching provided from OMD
  field, the distortion of field doesnt caused any
  noticeable change to the e yield.
• For s3e6, the eddy current induced field is
  nearly twice as much as of s1.5e6 and we noticed
  a lost of yield of about 5( from 1.27 down to
  1.20).
• Lower the conductivity will suppress the effect
  eddy current induced field.