Paper | Title | Page |
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TPAT079 | Importance of the Linear Coupling and Multipole Compensation of Long-Range Beam-Beam Interactions In Tevatron | 4039 |
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Funding: The US Department of Energy under Grant No. DE-FG02-04ER41288. In Tevatron, serious long-range beam-beam effects are due to many parasitic collisions that are distributed around the ring. Because of this non-localized nature of long-range beam-beam interactions, the multipole compensation with one-turn or sectional maps aims a global compensation of long-range beam-beam interactions. Since nonlinear beam dynamics in a storage ring can usually be described by a one-turn map that contains all global information of system nonlinearities, by minimizing nonlinear terms of the maps order-by-order with a few groups of multipole correctors, one could reduce the nonlinearity globally. Since a large beam separation is typical at parasitic points, in the phase-space region that is relevant to the beam, long-range beam-beam interactions can be expanded into a Taylor series around the beam separation and be included into the one-turn map for the global compensation. To examine the effect of this multipole compensation scheme, the emittance growth of both p and pbar beam in Tevatron were studied with a beam-beam simulation. The result showed that the multipole compensation can significantly reduces the emittance growth of the pbar beam due to long-range beam-beam interactions. |