Cumulative beam break-up study of the spallation neutron source superconducting linac

D. Jeon; L. Merminga; G. Krafft; B. Yunn; R. Sundelin; J. Delayen; S. Kim; M. Doleans

doi:10.1016/S0168-9002(02)01576-0

Cumulative beam break-up study of the spallation neutron source superconducting linac

D. Jeon, L. Merminga, G. Krafft, B. Yunn, R. Sundelin, J. Delayen, S. Kim, M. Doleans

Research output: Contribution to journal › Article › peer-review

12 Scopus citations

Abstract

Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H^- beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H^- beam and the HOM frequency spread resulting from manufacturing tolerances. As little as ±0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of ±0.1 MHz HOM is small, and hence conservative compared with measured values of σ = 0.00109(f_HOM - f₀)/f₀ obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat load. It is therefore prudent to have HOM dampers to avoid the danger of quenching a cavity.

Original language	English
Pages (from-to)	85-94
Number of pages	10
Journal	Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume	495
Issue number	2
DOIs	https://doi.org/10.1016/S0168-9002(02)01576-0
State	Published - Dec 11 2002
Externally published	Yes

Funding

SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the US Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge.

Funders	Funder number
U.S. Department of Energy

Keywords

Beam breakup
Cumulative
HOM
Instability
Superconducting linac

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10.1016/S0168-9002(02)01576-0

Cite this

Jeon, D., Merminga, L., Krafft, G., Yunn, B., Sundelin, R., Delayen, J., Kim, S., & Doleans, M. (2002). Cumulative beam break-up study of the spallation neutron source superconducting linac. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 495(2), 85-94. https://doi.org/10.1016/S0168-9002(02)01576-0

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title = "Cumulative beam break-up study of the spallation neutron source superconducting linac",

abstract = "Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H- beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H- beam and the HOM frequency spread resulting from manufacturing tolerances. As little as ±0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of ±0.1 MHz HOM is small, and hence conservative compared with measured values of σ = 0.00109(fHOM - f0)/f0 obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat load. It is therefore prudent to have HOM dampers to avoid the danger of quenching a cavity.",

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Jeon, D, Merminga, L, Krafft, G, Yunn, B, Sundelin, R, Delayen, J, Kim, S & Doleans, M 2002, 'Cumulative beam break-up study of the spallation neutron source superconducting linac', Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 495, no. 2, pp. 85-94. https://doi.org/10.1016/S0168-9002(02)01576-0

Cumulative beam break-up study of the spallation neutron source superconducting linac. / Jeon, D.; Merminga, L.; Krafft, G. et al.
In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 495, No. 2, 11.12.2002, p. 85-94.

Research output: Contribution to journal › Article › peer-review

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T1 - Cumulative beam break-up study of the spallation neutron source superconducting linac

AU - Jeon, D.

AU - Merminga, L.

AU - Krafft, G.

AU - Yunn, B.

AU - Sundelin, R.

AU - Delayen, J.

AU - Kim, S.

AU - Doleans, M.

PY - 2002/12/11

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N2 - Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H- beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H- beam and the HOM frequency spread resulting from manufacturing tolerances. As little as ±0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of ±0.1 MHz HOM is small, and hence conservative compared with measured values of σ = 0.00109(fHOM - f0)/f0 obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat load. It is therefore prudent to have HOM dampers to avoid the danger of quenching a cavity.

AB - Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H- beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H- beam and the HOM frequency spread resulting from manufacturing tolerances. As little as ±0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of ±0.1 MHz HOM is small, and hence conservative compared with measured values of σ = 0.00109(fHOM - f0)/f0 obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat load. It is therefore prudent to have HOM dampers to avoid the danger of quenching a cavity.

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Cumulative beam break-up study of the spallation neutron source superconducting linac

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