Speaker
Michael Tiefenback
(Jefferson Lab)
Description
Operation of CEBAF with positrons using the standard electron beam direction (clockwise as viewed from above) requires inverting the polarity of the recirculation arc and Spreader/Recombiner dipoles. Retaining the focusing optics used for electrons requires inverting the quadrupole gradients. The hardware readily supports reversed polarity, and no observations are known to suggest any change of field vs. current calibration after restoring the (unipolar) dipoles to electron polarity. Depending upon residual calibration errors and beam diagnostic capabilities, it may be useful to reverse the leads not only of the dipoles, but also of the quadrupoles. These and related operational issues will be discussed.
Primary author
Michael Tiefenback
(Jefferson Lab)
