Experience with magnetic shielding of a large scale accelerator

It is not unusual to place multiple accelerators in a common enclosure to save on civil construction costs. This often complicates operations, especially if accelerators are affecting each other. At Fermilab, the influence of a rapidly cycling Main Injector (MI) synchrotron on an antiproton storage ring (Recycler), placed in a common tunnel, was initially found to be unacceptable for a reliable operation of the Recycler. Initial closed orbit excursions in the Recycler ring during the MI ramp were in excess of 5 mm (rms). This paper describes a shielding technique, used to reduce these orbit excursions by a factor of five