Correction of the first order beam transport of the SLC Arcs

Correction of the first order transport of the SLC (Stanford Linear Collider) Arcs has been made possible by a technique which allows the full 4*4 transport matrix across any section of Arc to be experimentally determined. By the introduction of small closed bumps into each achromat it is possible to substantially correct first order optical errors, and notably the cross plane coupling at the exit of the Arcs. The careful analysis of the errors of the 4*4 matrix reconstruction allows correction of the Arc R matrix to an accuracy equivalent to 10 mu m random magnet misalignments.<>