Measurements and Correction of the PEP Interaction Region Quadrupole Magnets

Lenses for the intersection regions of PEP must be pure quadrupole over the entire magnet aperture to within 1:104. Correction of the magnet and its end fringe regions to this accuracy requires measurement of the field quality (relative field harmonic component amplitudes at the pole radius) to 1:105 through the 30th harmonic. Equipment developed for these measurements and the techniques used for field correction are described.