Correction of skew-quadrupole errors in RHIC

The correction scheme for skew-quadrupole (α1) errors in the Relativistic Heavy Ion Collider is presented. The α1 errors result from fabrication and from installation errors. At the selected betatron tune of νx = 28.826 and νy = 28.820, the principal resonances driven by α1 errors are νx - νy = 0, the sum resonances near νx + νy which cause residual tune splitting and distortion of beta function, and νy = 28 and 29 which cause vertical dispersion. Skew quadrupole correctors located in the insertions and arcs will be used to correct the coupling and sum resonances and, if required, separate correctors in the arcs could be used for vertical dispersion correction. The study of the α1 correction system confirmed that correction is possible at β* = 2 m and β* = 6 m and that the required corrector strengths are consistent with those specified for RHIC