| Paper | Title | Page |
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| A Nearly Independent, Low-Rigidity Transport Lattice Embedded into a High-Rigidity Lattice | ||
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The linac optics of the CEBAF recirculating accelerator simultaneously transports up to five beams of different rigidity within a common channel. The focusing strength of the linac lattice is limited by the single-particle stability boundary of that structure for the lowest required rigidity. The focusing progressively weakens (and beta increases) for increasing rigidity. The CEBAF FODO lattice performs well over moderate rigidity ratios. In studying ways to increase the linac focusing strength for the higher acceleration passes, we devised a lattice consisting of two coincident structures. The low-rigidity part, reasonably described as an 'embedded lattice,' consists of strong symmetric triplets. Lattice elements for the higher-rigidity beams are located at the small-beta waists of the triplet structure, rendering them ineffective upon the low-rigidity beam well beyond the usual envelope stability limit for that beam. The residual focusing strength for the high-rigidity beam can be much greater than is possible for a simple FODO structure. The triplets are themselves ineffective upon the high-rigidity beams. CEBAF optics and analogues are used to illustrate. |