• The effect of polarization wigglers placed downstream of each IP has been looked at by particle trackings.
  • A more or less realistic field of the detector/compensation solenoids are included.
• Impact on the beam lifetime due to the large energy spread caused by the wigglers can be an issue.
  • For pilot bunches, it can be recovered by turning off the crab sextupoles.
  • However, the lifetime for colliding beams maymatter, as they have the similar energy spread by the beamstrahlung as the wigglers.
    • The effect is larger in bx* = 10 cm optics than bx* = 15 cm.
    • It can be worsened by machine errors.
• There are at least two candidates for the location of the polarimeter:
  • Upstream in the RF straight section:
    • The measurement is done though a weak bend to protect the RF.
    • The separation of two beams must compatible with requirements from the RF.
  • Upstream of an IP:
    • No interference with the other beam.
    • Relatively short available space and small bending angle.
    • May need a short wavelength laser.
    • Otherwise pushing components toward the IP by   will be necessary.