Correction of skew-quadrupole errors in RHIC

The correction scheme for skew-quadrupole (a/sub 1/) errors in the Relativistic Heavy Ion Collider is presented. The a/sub 1/ errors result from fabrication and from installation errors. At the selected betatron tune of nu /sub x/=28.826 and nu /sub y/-28.820, the principal resonances driven by a/sub 1/ errors are nu /sub x/- nu /sub y/=0, the sum resonances near nu /sub x/+ nu /sub y/ which cause residual tune splitting and distortion of beta function, and nu /sub y/=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.<
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