HB2016 - List of Keywords (betatron)

Paper	Title	Other Keywords	Page
MOPR020	Space Charge Effects of High Intensity Beams at BRing	resonance, emittance, simulation, injection	101
	J. Li, J.C. Yang IMP/CAS, Lanzhou, People's Republic of China
	Funding: Work supported by NSFC (Grant No. 11475235) Space charge effects perform one of the main intensity limitations for low energy synchrotron. Large tune spread and crossing resonance stop-bands can hardly be avoided for intensive heavy ion beam at high intensity. Several subjects like Betatron and structure resonance, and tune spread are discussed. Simulations are carried out for 238U³⁴⁺ focusing on emittance and intensity change during RF capture at the injection energy at the booster ring of the High Intensity heavy ion Accelerator Facility (HIAF). lijie@impcas.ac.cn
	Poster MOPR020 [1.157 MB]
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TUPM1X01	Broadband Feedback System for Instability Damping in the SNS Ring	operation, feedback, accumulation, extraction	288
	N.J. Evans ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy The transverse feedback system in the Accumulator Ring of the Spallation Neutron Source~(SNS) is intended to damp broadband (≈40-120~MHz), coherent betatron motion due to e-p interaction. The SNS feedback system is based on an analog delay-line model with some signal conditioning and tuning parameters implemented digitally. This system provides a simple setup with two primary knobs, phase and gain, as well as an equalizer. This simplicity comes at the cost of some flexibility normally found in a standard mode-by-mode design, namely mode-by-mode phase, and gain control. In this paper we discuss the design, tuning, evaluation, and operation of the SNS feedback damper, and discuss the tradeoffs implicit in the design of the system.
	Slides TUPM1X01 [2.352 MB]
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THPM6X01	Space Charge Effects in FFAG	space-charge, closed-orbit, lattice, emittance	499
	M. Haj Tahar, F. Méot BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Understanding space charge effects in FFAG is crucial in order to assess their potential for high power applications. This paper shows that, to carry out parametric studies of these effects in FFAG, the average field index of the focusing and defocusing magnets are the natural parametrization. Using several classes of particle distribution functions, we investigate the effects of space charge forces on the non-linear beam dynamics of FFAG and provide stability diagrams for an FFAG-like lattice. The method developed in this study is mainly applicable to systems with slowly varying parameters, i.e slow acceleration.
	Slides THPM6X01 [2.171 MB]
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THPM7X01	Use of RF Quadrupole Structures to Enhance Stability in Accelerator Rings	quadrupole, octupole, simulation, synchrotron	505
	M. Schenk, A. Grudiev, K.S.B. Li, K. Papke CERN, Geneva, Switzerland
	The beams required for the high luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN call for efficient mechanisms to suppress transverse collective instabilities. In addition to octupole magnets installed for the purpose of Landau damping, we propose to use radio frequency (rf) quadrupole structures to considerably enhance the aforementioned stabilising effect. By means of the PyHEADTAIL macroparticle tracking code, the stabilising mechanism introduced by an rf quadrupole is studied and discussed. As a specific example, the performance of an rf quadrupole system in presence of magnetic octupoles is demonstrated for HL-LHC. Furthermore, potential performance limitations such as the excitation of synchro-betatron resonances are pointed out. Finally, efforts towards possible measurements with the CERN Super Proton Synchrotron (SPS) are discussed aiming at studying the underlying stabilising mechanisms experimentally.
	Slides THPM7X01 [37.755 MB]
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Paper

Title

Other Keywords

Page

MOPR020

Space Charge Effects of High Intensity Beams at BRing

resonance, emittance, simulation, injection

101

J. Li, J.C. Yang
IMP/CAS, Lanzhou, People's Republic of China

Funding: Work supported by NSFC (Grant No. 11475235)
Space charge effects perform one of the main intensity limitations for low energy synchrotron. Large tune spread and crossing resonance stop-bands can hardly be avoided for intensive heavy ion beam at high intensity. Several subjects like Betatron and structure resonance, and tune spread are discussed. Simulations are carried out for 238U³⁴⁺ focusing on emittance and intensity change during RF capture at the injection energy at the booster ring of the High Intensity heavy ion Accelerator Facility (HIAF).
lijie@impcas.ac.cn

Poster MOPR020 [1.157 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPM1X01

Broadband Feedback System for Instability Damping in the SNS Ring

operation, feedback, accumulation, extraction

288

N.J. Evans
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy
The transverse feedback system in the Accumulator Ring of the Spallation Neutron Source~(SNS) is intended to damp broadband (≈40-120~MHz), coherent betatron motion due to e-p interaction. The SNS feedback system is based on an analog delay-line model with some signal conditioning and tuning parameters implemented digitally. This system provides a simple setup with two primary knobs, phase and gain, as well as an equalizer. This simplicity comes at the cost of some flexibility normally found in a standard mode-by-mode design, namely mode-by-mode phase, and gain control. In this paper we discuss the design, tuning, evaluation, and operation of the SNS feedback damper, and discuss the tradeoffs implicit in the design of the system.

Slides TUPM1X01 [2.352 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPM6X01

Space Charge Effects in FFAG

space-charge, closed-orbit, lattice, emittance

499

M. Haj Tahar, F. Méot
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Understanding space charge effects in FFAG is crucial in order to assess their potential for high power applications. This paper shows that, to carry out parametric studies of these effects in FFAG, the average field index of the focusing and defocusing magnets are the natural parametrization. Using several classes of particle distribution functions, we investigate the effects of space charge forces on the non-linear beam dynamics of FFAG and provide stability diagrams for an FFAG-like lattice. The method developed in this study is mainly applicable to systems with slowly varying parameters, i.e slow acceleration.

Slides THPM6X01 [2.171 MB]

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPM7X01

Use of RF Quadrupole Structures to Enhance Stability in Accelerator Rings

quadrupole, octupole, simulation, synchrotron

505

M. Schenk, A. Grudiev, K.S.B. Li, K. Papke
CERN, Geneva, Switzerland

The beams required for the high luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN call for efficient mechanisms to suppress transverse collective instabilities. In addition to octupole magnets installed for the purpose of Landau damping, we propose to use radio frequency (rf) quadrupole structures to considerably enhance the aforementioned stabilising effect. By means of the PyHEADTAIL macroparticle tracking code, the stabilising mechanism introduced by an rf quadrupole is studied and discussed. As a specific example, the performance of an rf quadrupole system in presence of magnetic octupoles is demonstrated for HL-LHC. Furthermore, potential performance limitations such as the excitation of synchro-betatron resonances are pointed out. Finally, efforts towards possible measurements with the CERN Super Proton Synchrotron (SPS) are discussed aiming at studying the underlying stabilising mechanisms experimentally.

Slides THPM7X01 [37.755 MB]

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)