The Accumulator Ring for the proposed Spallation Neutron

Source (SNS) [1] is to accept a 1 ms beam pulse from a 1 GeV Proton Linac at a repitition rate of 60 Hz. For each beam pulse, 1014 protons (some 1000 turns) are to be accu-mulated via charge-exchange injection and then promptly extracted to an external target for the production of neu-trons by spallation. At this very high intensity, stringent limits (less than two parts in 10,000 per pulse) on beam loss during accumulation must be imposed in order to keep ac-tivation of ring components at an acceptable level. To stay within the desired limit, the effects of random and system-atic field errors in the ring require careful attention. This paper describes our studies of these effects and the mag-netic corrector schemes for their compensation.