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Active lower order mode damping for the four rod LHC crab cavity

Research output: Contribution to Journal/Magazine › Journal article › peer-review

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Active lower order mode damping for the four rod LHC crab cavity. / Dexter, Amos Christopher; Burt, Graeme Campbell; Apsimon, Robert James.
In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 844, 01.02.2017, p. 62-71.

Research output: Contribution to Journal/Magazine › Journal article › peer-review

Harvard

Dexter, AC, Burt, GC & Apsimon, RJ 2017, 'Active lower order mode damping for the four rod LHC crab cavity', Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 844, pp. 62-71. https://doi.org/10.1016/j.nima.2016.11.021

APA

Dexter, A. C., Burt, G. C., & Apsimon, R. J. (2017). Active lower order mode damping for the four rod LHC crab cavity. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 844, 62-71. https://doi.org/10.1016/j.nima.2016.11.021

Vancouver

Dexter AC, Burt GC, Apsimon RJ. Active lower order mode damping for the four rod LHC crab cavity. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2017 Feb 1;844:62-71. Epub 2016 Nov 12. doi: 10.1016/j.nima.2016.11.021

Author

Dexter, Amos Christopher ; Burt, Graeme Campbell ; Apsimon, Robert James. / Active lower order mode damping for the four rod LHC crab cavity. In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2017 ; Vol. 844. pp. 62-71.

Bibtex

@article{cd955132b356428481ed72433379662c,
title = "Active lower order mode damping for the four rod LHC crab cavity",
abstract = "The high luminosity upgrade planned for the LHC requires crab cavities to rotate bunches into alignment at the interaction points. They compensate for a crossing angle near to 500~$\mu$Rad. It is anticipated that four crab cavities in succession will be utilized to achieve this rotation either side of each IP in a local crossing scheme. A crab cavity operates in a dipole mode but always has an accelerating mode that may be above or below the frequency of the operating mode. Crab cavities are given couplers to ensure that unwanted acceleration modes are strongly damped however employing standard practice these unwanted modes will always have some level of excitation. Where this excitation has a random phase it might promote bunch growth and limit beam lifetime. This paper sets out a method for active control of the phase and amplitude of the unwanted lowest accelerating mode in the crab cavities. The paper investigates the level of suppression that can be achieved as a function cavity quality factor and proximity to resonance. ",
keywords = "Active damping, Crab cavity, HL-LHC, LHC",
author = "Dexter, {Amos Christopher} and Burt, {Graeme Campbell} and Apsimon, {Robert James}",
year = "2017",
month = feb,
day = "1",
doi = "10.1016/j.nima.2016.11.021",
language = "English",
volume = "844",
pages = "62--71",
journal = "Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment",
issn = "0168-9002",
publisher = "ELSEVIER SCIENCE BV",

}

RIS

TY - JOUR

T1 - Active lower order mode damping for the four rod LHC crab cavity

AU - Dexter, Amos Christopher

AU - Burt, Graeme Campbell

AU - Apsimon, Robert James

PY - 2017/2/1

Y1 - 2017/2/1

N2 - The high luminosity upgrade planned for the LHC requires crab cavities to rotate bunches into alignment at the interaction points. They compensate for a crossing angle near to 500~$\mu$Rad. It is anticipated that four crab cavities in succession will be utilized to achieve this rotation either side of each IP in a local crossing scheme. A crab cavity operates in a dipole mode but always has an accelerating mode that may be above or below the frequency of the operating mode. Crab cavities are given couplers to ensure that unwanted acceleration modes are strongly damped however employing standard practice these unwanted modes will always have some level of excitation. Where this excitation has a random phase it might promote bunch growth and limit beam lifetime. This paper sets out a method for active control of the phase and amplitude of the unwanted lowest accelerating mode in the crab cavities. The paper investigates the level of suppression that can be achieved as a function cavity quality factor and proximity to resonance.

AB - The high luminosity upgrade planned for the LHC requires crab cavities to rotate bunches into alignment at the interaction points. They compensate for a crossing angle near to 500~$\mu$Rad. It is anticipated that four crab cavities in succession will be utilized to achieve this rotation either side of each IP in a local crossing scheme. A crab cavity operates in a dipole mode but always has an accelerating mode that may be above or below the frequency of the operating mode. Crab cavities are given couplers to ensure that unwanted acceleration modes are strongly damped however employing standard practice these unwanted modes will always have some level of excitation. Where this excitation has a random phase it might promote bunch growth and limit beam lifetime. This paper sets out a method for active control of the phase and amplitude of the unwanted lowest accelerating mode in the crab cavities. The paper investigates the level of suppression that can be achieved as a function cavity quality factor and proximity to resonance.

KW - Active damping

KW - Crab cavity

KW - HL-LHC

KW - LHC

U2 - 10.1016/j.nima.2016.11.021

DO - 10.1016/j.nima.2016.11.021

M3 - Journal article

VL - 844

SP - 62

EP - 71

JO - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

JF - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

SN - 0168-9002

ER -