Large aperture quadrupoles for RHIC interaction regions

The ultimate luminosity performance of the Relativistic Heavy Ion Collider (RHIC) depends on the field quality in the large aperture (130 mm) superconducting quadrupoles in the interaction regions. In this paper we discuss the design features that are incorporated to obtain a good field quality. Coil midplane gap and pole shims may be adjusted to remove certain field harmonics due to systematic errors in construction. Iron tuning shims will be inserted at eight strategic locations in the assembled magnets to correct the measured values of harmonics in each magnet. The performance of two prototype magnets and upgrades under consideration will be discussed.<
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