Transverse behaviour of the LHC proton beam in the SPS: an update

Arduini, G.; Cornelis, K.; Höfle, Wolfgang; Rumolo, G.; Zimmermann, Frank

doi:10.1109/pac.2001.987215

Cited by 11 publications

(10 citation statements)

References 3 publications

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“…Using a higher number of interaction sections might help in this sense but the study is still being carried on. The large emittance growth seems to be consistent with the experimental observations [1].…”

Section: Resultssupporting

confidence: 90%

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Simulation of single bunch instabilities driven by electron cloud in the SPS

Rumolo

Zimmermann²

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

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Photoemission, or gas ionization, and secondary emission can give rise to a quasi-stationary electron cloud inside the beam pipe through a beam-induced multipacting process. We investigate single bunch instabilities driven by a quasi-stationary electron cloud by means of a computer simulation. The model that we apply makes use of two sets of macroparticles for both the bunch particles and for the electrons, which interact at one or more locations along the beam orbit. Two different schemes have been implemented for the electron cloud field calculation (PIC and soft-Gaussian), and their efficiencies are compared. The code is used to simulate possible instability mechanisms in the SPS. The options of a broad-band wake-field and space charge induced tune spread have been also introduced in order to follow the bunch evolution under the combined effect of the electron-cloud and a broad-band impedance.

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Section: Resultssupporting

confidence: 90%

“…The instability starts at currents which are just above the threshold of beam-induced multipacting [1], and its progression along a bunch train is reminiscent of the vertical blow up observed at KEKB. The latter has been attributed to a single-bunch instability driven by an electron cloud [2].…”

Section: Introductionmentioning

confidence: 84%

Simulation of single bunch instabilities driven by electron cloud in the SPS

Rumolo

Zimmermann²

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

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“…About 0.01 in vertical tune shift observed in the measurement, but no appreciable shift detected in horizontal, which is not understood yet [24].…”

Section: −18mentioning

confidence: 62%

RHIC Vacuum Pressure Bump

Zhang¹

2002

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Effects of the beam loss, ion and electron gas desorption on the RHIC vacuum pressure bump have been reviewed. The beam loss and ion desorption are probably not the dominant factors in the RHIC vacuum problem. On the other hand, electron desorption, given the electron multipacting, can cause serious vacuum problem. In general, the electron multipacting was not predicted for the RHIC according to the present understanding of the mechanism. However, beam loss created ions can extend electron lifetime during the bunch gap, and electron multipacting becomes possible at the RHIC. Also, the pressure rise in the RHIC Gold beam run was much worse than the usual electron cloud induced vacuum pressure rise, which was observed in many machines. One possibility is that the beam loss created ions have raised the electron density saturation limit and, therefore, contributed to further pressure rise. Some complications in diagnostics of electron multipacting by coherent tune shift in bunches will be discussed. Electron collection may indicate the coincidence between the electron multipacting and the pressure rise. It also can help to determine the electron density.

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“…The estimated electron cloud densities can be compared with simulation results. Such comparisons were also done for the low energy ring of KEKB [3] and the SPS [4,5].…”

Section: Introductionmentioning

confidence: 99%

Electron Cloud Measurements and Simulation for RHIC

Fischer¹,

Brennan²,

Blaskiewicz³

et al. 2002

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Intense ion beams in RHIC lead to a rise in the vacuum pressure. Electron clouds can contribute to such a process. To measure electron cloud densities the coherent tune shift along the bunch train was observed with different bunch spacings and intensities. From the measured coherent tune shift electron cloud densities are computed and compared with densities obtained in electron cloud simulations.

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Transverse behaviour of the LHC proton beam in the SPS: an update

Cited by 11 publications

References 3 publications

Simulation of single bunch instabilities driven by electron cloud in the SPS

Simulation of single bunch instabilities driven by electron cloud in the SPS

RHIC Vacuum Pressure Bump

Electron Cloud Measurements and Simulation for RHIC

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