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MULTI-PASS BEAM-BREAKUP: THEORY AND CALCULATION ∗

Multi-pass, multi-bunch beam-breakup has been long known to be a potential limiting factor for the current in linac-based recirculating accelerators. New understanding of theoretical and computational aspects of the phenomenon are presented here. We also describe a detailed simulation study of BBU in the proposed 5 GeV Energy Recovery Linac light source at Cornell University.