Review of single bunch instabilities driven by an electron cloud

Zimmermann, F.

doi:10.1103/physrevstab.7.124801

Cited by 91 publications

(56 citation statements)

References 29 publications

(64 reference statements)

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“…It has been shown both theoretically and experimentally [3] that the e-cloud density build-up depends on the SEY function (E) and to minimize the effects of e-cloud, the max value should be less than a certain threshold value, but in most cases max < 1 would be a sufficient condition [3,15].…”

Section: Introductionmentioning

confidence: 99%

“…In high intensity particle accelerators with positively charged beams such as the LHC [1,2,3], KEKB [4], DAFNE [5], RHIC [6], PEP=II [7], etc., the beam induced electron multipacting (BIEM) and electron cloud (e-cloud) effects can significantly affect the quality of the beam and machine operation [8,9]. E-cloud was first observed on the proton/antiproton collider VAPP in the Budker Institute of Nuclear Physics in 1965 [10,11].…”

Section: Introductionmentioning

confidence: 99%

“…making grooves) [3,16]; (c) Coating with low SEY materials (such as TiN [17], NEG [18] and amorphous carbon (a-C) [19]); (d) Coating with low SEY microstructure (ex. : copper black, gold black; columnar NEG) [20,21,22]; (f) Various combinations of above.…”

Section: Introductionmentioning

confidence: 99%

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Reduction of secondary electron yield for E-cloud mitigation by laser ablation surface engineering

Valizadeh

Malyshev

Wang

et al. 2017

Applied Surface Science

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Developing a surface with low Secondary Electron Yield (SEY) is one of the main ways of mitigating electron cloud and beam-induced electron multipacting in high-energy charged particle accelerators. In our previous publications, a low SEY< 0.9 for as-received metal surfaces modified by a nanosecond pulsed laser was reported. In this paper, the SEY of laser-treated blackened copper has been investigated as a function of different laser irradiation parameters. We explore and study the influence of micro-and nano-structures induced by laser surface treatment in air of copper samples as a function of various laser irradiation parameters such as peak power, laser wavelength ( = 355 nm and 1064 nm), number of pulses per point (scan speed and repetition rate) and fluence, on the SEY. The surface chemical composition was determined by x-ray photoelectron spectroscopy (XPS) which revealed that heating resulted in diffusion of oxygen into the bulk and induced the transformation of CuO to sub-stoichiometric oxide. The surface topography was examined with high resolution scanning electron microscopy (HRSEM) which showed that the laser-treated surfaces are dominated by microstructure grooves and nanostructure features.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Reduction of secondary electron yield for E-cloud mitigation by laser ablation surface engineering

Valizadeh

Malyshev

Wang

et al. 2017

Applied Surface Science

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“…Two excellent reviews, covering the phenomenology, measurements, simulations and historical development, have been recently given by Frank Zimmermann [16,17]. In this article we focus on the mechanisms of electron-cloud buildup and dissipation for hadronic beams, particularly those with very long, intense, bunches.…”

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confidence: 99%

Electron-cloud build-up in hadron machines

Furman¹

2004

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The first observations of electron-proton coupling effect for coasting beams and for long-bunch beams were made at the earliest proton storage rings at the Budker Institute of Nuclear Physics (BINP) in the mid-60's [1]. The effect was mainly a form of the two-stream instability. This phenomenon reappeared at the CERN ISR in the early 70's, where it was accompanied by an intense vacuum pressure rise. When the ISR was operated in bunched-beam mode while testing aluminum vacuum chambers, a resonant effect was observed in which the electron traversal time across the chamber was comparable to the bunch spacing [2]. This effect ("beam-induced multipacting"), being resonant in nature, is a dramatic manifestation of an electron cloud sharing the vacuum chamber with a positively-charged beam. An electron-cloud-induced instability has been observed since the mid-80's at the PSR (LANL) [3]; in this case, there is a strong transverse instability accompanied by fast beam losses when the beam current exceeds a certain threshold. The effect was observed for the first time for a positron beam in the early 90's at the Photon Factory (PF) at KEK, where the most prominent manifestation was a coupled-bunch instability that was absent when the machine was operated with an electron beam under otherwise identical conditions [4]. Since then, with the advent of ever more intense positron and hadron beams, and the development and deployment of specialized electron detectors [5][6][7][8][9], the effect has been observed directly or indirectly, and sometimes studied systematically, at most lepton and hadron machines when operated with sufficiently intense beams. The effect is expected in various forms and to various degrees in accelerators under design or construction.The electron-cloud effect (ECE) has been the subject of various meetings [10][11][12][13][14][15]. Two excellent reviews, covering the phenomenology, measurements, simulations and historical development, have been recently given by Frank Zimmermann [16,17]. In this article we focus on the mechanisms of electron-cloud buildup and dissipation for hadronic beams, particularly those with very long, intense, bunches. Primary sources of electrons and secondary electron emissionDepending upon the type of machine, the EC is seeded by primary electrons from three main sources: photoelectrons, ionization of residual gas, and electrons generated when stray beam particles hit the chamber walls. In addition, for HIF drivers, an important expected source of electrons is a combination of two of the above, namely: gas will be desorbed by stray ions striking the chamber walls which will subsequently be ionized by the beam. These electrons get kicked by successive bunches mostly in the * Published as Sec. 2.9 of the ICFA Beam Dynamics Newsletter No. 33, July 2004, p. 70. 2 direction perpendicular to the beam; as they strike the walls of the chamber, they generate secondary electrons which add to the existing electron population.Of all hadron machines presently existing or under construction...

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“…At high proton-beam energies, beam-induced synchrotron radiation is an important source of heating, of beam-related vacuum pressure increase, and of primary photoelectrons, which can give rise to an electron cloud [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Examining mitigation schemes for synchrotron radiation in high-energy hadron colliders

Guillermo

Sagan

Zimmermann

2018

Phys. Rev. Accel. Beams

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At high proton-beam energies, beam-induced synchrotron radiation is an important source of heating, of beam-related vacuum pressure increase, and of primary photoelectrons, which can give rise to an electron cloud. We use the Synrad3D code developed at Cornell to simulate the photon distributions in the arcs of several existing, planned, or proposed highest-energy hadron colliders to analyze the efficiency of several techniques developed, or proposed, to mitigate the negative effects of synchrotron radiation, such as a sawtooth surface and slots in the beam screen.

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Review of single bunch instabilities driven by an electron cloud

Cited by 91 publications

References 29 publications

Reduction of secondary electron yield for E-cloud mitigation by laser ablation surface engineering

Reduction of secondary electron yield for E-cloud mitigation by laser ablation surface engineering

Electron-cloud build-up in hadron machines

Examining mitigation schemes for synchrotron radiation in high-energy hadron colliders

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