Lumped correction of systematic multipoles in large synchrotrons

Uncorrected systematic multipole components of the dipoles in synchrotrons can cause unacceptably large amplitude- and momentum-dependent tune shifts. The problem is exacerbated by the relatively high multipole content of high-field superconducting magnets. Correction of these tune shifts by lumped correction elements is described. A particularly effective method of correcting first-order tune shifts is a 'three-lump' system with an additional correction element placed at the center of each half cell as well as correctors at the ends of the half cells near the F and D quads, with the relative strengths per half cell of the correctors following Simpson's rule for three-point integration. The method is compared with end-corrector and distributed-correction methods, and its limitations in higher-order sextupole correction are considered. Application to the Superconducting Super Collider (SSC) is discussed. (author) 16 refs., 5 figs., 4 tabs