Transverse feedback system in the CERN SPS

Vos, L.

doi:10.1063/1.42135

Cited by 9 publications

(6 citation statements)

References 1 publication

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“…Analytical calculations [16] made recently fit fairly well to the measurements. The upward drift of the SEY (δ) observed if the SPS is not operated with LHC-type beams is not an issue since measurements confirmed that the SEY recovered its initial value after 4 hours of operation with LHC-type beams above the electron cloud threshold.…”

Section: Conclusion and Discussionmentioning

confidence: 53%

Electron cloud studies and analyses at SPS for LHC-type beams

Jiménez

Arduini

Baglin

et al.

Proceedings of the 2003 Bipolar/BiCMOS Circuits and Technology Meeting (IEEE Cat. No.03CH37440)

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A summary of the main results obtained so far from the electron cloud studies using strip detectors, pick-ups, COLDEX and a 100 MHz coaxial resonator will be presented. The spatial and energy distributions of the electrons in the cloud measured by the strip detectors will be detailed and compared to the results obtained with a conventional retarding field detector. The evidence of the scrubbing effect and of the NEG coatings as remedies to reduce the electron cloud activity will also be shown.In a second part, the improved hardware of the experiments will be presented together with the program of measurements foreseen for the 2003 SPS run.

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Section: Conclusion and Discussionmentioning

confidence: 53%

Electron cloud studies and analyses at SPS for LHC-type beams

Jiménez

Arduini

Baglin

et al.

Proceedings of the 2003 Bipolar/BiCMOS Circuits and Technology Meeting (IEEE Cat. No.03CH37440)

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“…The vertical impedance of one SPS MKE kicker has been estimated using Burov-Lebedev formalism [12,13]. In 2002, a BB impedance is assumed, deduced from analytical estimates of the inductive part confirmed by measurements [14]:…”

Section: Sps Impedance Estimate and Tmci Threshold With Moses From 20mentioning

confidence: 99%

Transverse Mode-Coupling Instability in the CERN Super Proton Synchrotron

Métral¹,

Arduini²,

Benedetto³

et al. 2005

AIP Conference Proceedings

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A vertical single-bunch instability has been observed in 2003 right after injection at 26 GeV/c in the CERN Super Proton Synchrotron (SPS). High-intensity proton bunches (~1.2 10 11 p/b) with low longitudinal emittance (~0.2 eVs) are affected by heavy losses after less than one synchrotron period. Such phenomenon has already been observed with leptons in many machines, e.g. in the SPS, or with protons at transition, e.g. in the CERN Proton Synchrotron (PS). However, to the authors' knowledge, it is the first time with protons far from transition. The absence of transverse mode-coupling instability in hadron machines is generally explained by three mechanisms: (i) the intensity threshold for the longitudinal microwave instability is generally lower than for the transverse mode-coupling instability, (ii) the intensity threshold due to mode-coupling between the two lowest azimuthal modes increases with space charge, and (iii) the intensity threshold increases with bunch length (in the long-bunch regime). In this talk measurements performed in the SPS are compared to analytical and simulation predictions.

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“…As part of the SPS upgrade as LHC injector the transverse impedance is being reduced by shielding of more than 1000 vacuum pumping ports, which represented about two thirds of the total impedance [1], and by removing lepton components. About 20% of the pumping ports were already shielded during the winter shut down 1999/2000.…”

Section: Introductionmentioning

confidence: 99%

“…The 2000 measurements aimed to (1) reproduce the 1999 data, (2) possibly discern a first small improvement, (3) further develop machine set up and measurement procedure, (4) quantify contributions from space charge, and (5) explore complementary measurement approaches.…”

Section: Introductionmentioning

confidence: 99%

Measurements of the SPS transverse impedance in 2000

Arduini

Burkhardt

Cornelis

et al.

PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268)

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We report on measurements of coherent tune shifts, head-tail growth rates, and current-dependent betatron phase advances at the CERN SPS in the year 2000. Comparing results obtained at two different energies shows that there is no notable contribution from space charge. Within the measurement resolution the impedance is the same as in 1999, consistent with the expected small effect from changes to only a small number of pumping ports. In 2000, data were taken over an expanded range of chromaticities, which increases the sensitivity to the impedance frequency distribution. Measurements of the current-dependent phase advance around the ring help localizing the most important impedance sources.

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Transverse feedback system in the CERN SPS

Cited by 9 publications

References 1 publication

Electron cloud studies and analyses at SPS for LHC-type beams

Electron cloud studies and analyses at SPS for LHC-type beams

Transverse Mode-Coupling Instability in the CERN Super Proton Synchrotron

Measurements of the SPS transverse impedance in 2000

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