Field measurement of superconducting quadrupole magnets for TRISTAN mini-beta insertions

Eight superconducting quadrupole magnets for TRISTAN minibeta insertions (QCS) have been measured by the rotating coil method before installation in the TRISTAN electron-positron colliding ring. Following the alignment of the magnet to the measuring system by use of a movable QCS-support, harmonics and field gradients were measured as functions of current and the median plane was determined for each magnet. Details of the measuring systems and results of the measurements are presented. The results of the field measurements show that the relative errors of the integral field gradient can be kept within +or-0.001 for all the magnets and that the higher multipole components are small enough for the tolerance required to the QCS.<>