Multipole and phase tuning methods for insertion devices

Multipole and phase tuning of insertion devices is important for maintaining beam dynamics and reaching the high brightness goals of the Advanced Photon Source. Several general approaches are described: mechanical adjustments, end-pole shaping, and magnetic shimming. Off-axis Hall probe measurements after assembly guide magnet exchanges and local mechanical adjustments. A recent development has been the use of potential theory applied to end-pole shaping. The wide gap tuning range of the APS devices requires careful matching of device errors and correct gap dependencies in the gap/period range of 0.18 to 0.6. Shims are especially sensitive at small gaps. We describe signatures, gap dependencies, algorithms, modeling, and experimental results for these techniques. copyright 1996 American Institute of Physics