A new closed orbit correction procedure for the CERN SPS

Using well-known correction techniques and algorithms, a procedure has been devised to correct the closed orbit of the CERN SPS (Super Proton Synchrotron). The option to steer beam lines has been included, allowing the establishment and optimization of the first turn in the machine. As a new feature, this correction procedure can take into account limited corrector strength. Apart from necessary enhancements to the algorithms, a data interface between the programs involved has been defined to achieve high flexibility and language independence and to increase efficiency. The correction procedure is described in detail, and the performance is discussed using results from simulations and its first application during the lepton commissioning period and pp¯ collider run in 1988. Initial tests during the machine development periods for lepton commissioning were successful in correcting the first turn and the closed orbit of the particles