Multipole components and their minimization in deflecting cavities with standard type couplers

Ambattu, Praveen and Burt, Graeme and Grudiev, A. and Dolgashev, V. and Dexter, Amos (2013) Multipole components and their minimization in deflecting cavities with standard type couplers. Physical Review Special Topics: Accelerators and Beams, 16 (6). ISSN 1098-4402

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Deflecting cavities are used in particle accelerators for the manipulation of charged particles by deflecting or crabbing (rotating) them. For short deflectors, the effect of the power coupler on the deflecting field can become significant. The particular power coupler type can introduce multipole rf field components and coupler-specific wakefields. Coupler types that would normally be considered like standard on-cell coupler, waveguide coupler, or mode-launcher coupler could have one or two rf feeds. The major advantage of a dual-feed coupler is the absence of monopole and quadrupole rf field components in the deflecting structure. However, a dual-feed coupler is mechanically more complex than a typical single-feed coupler and needs a splitter. For most applications, deflecting structures are placed in regions where there is small space hence reducing the size of the structure is very desirable. This paper investigates the multipole field components of the deflecting mode in single-feed couplers and ways to overcome the effect of the monopole component on the beam. Significant advances in performance have been demonstrated. Additionally, a novel coupler design is introduced which has no monopole field component to the deflecting mode and is more compact than the conventional dual-feed coupler.

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Journal Article
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Physical Review Special Topics: Accelerators and Beams
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Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
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08 Oct 2014 09:00
Last Modified:
11 May 2022 03:53