The superconducting interaction region magnet positioning system for the CESR Phase III upgrade

Due to the extraordinary sensitivity of beams to misalignments of the superconducting high gradient interaction region magnets for the Phase III upgrade, a beam-based alignment and active positioning scheme has been designed and is being constructed. Using cams and kinematic mounting, the magnetic centers of the four quadrupole magnets will be independently positioned over a radial range of 1 mm with a resolution below 10 /spl mu/m. Beam measurements of the closed orbit will determine where to set the position. In principle realignment can be done while beams are stored. The positioning system must withstand considerable dynamic forces due to the interaction of the CLEO detector solenoid field with the current in the dipole windings. It is located almost entirely within the CLEO detector and has a special transition from non-magnetic to magnetic materials so as not to disturb the uniformity of the solenoid field. It allows for retraction of the CLEO pole from the detector without interference.