| Paper | Title | Other Keywords | Page |
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| TUT1BH2 | Study of Coherent Head-tail Instablility Due to Beam-beam Interaction in Cirular Colliders Based on Crab Waist Scheme | ion, luminosity, damping, emittance | 61 |
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| FCC-ee is being studied various collision schemes, head-on and large Piwinski angle/ crab waist schemes. We discuss beam-beam limit in the collision schemes using weak-strong and strong-strong models. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT1BH2 | ||
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| TUT3AH3 | Beam-based Impedance Measurement Techniques | ion, impedance, vacuum, damping | 112 |
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Funding: Work supported by DOE under contract No.DE-AC02- 98CH10886 Characterization of a vacuum chamber impedance is necessary to estimate stability conditions of a particle beam motion, to find a limit of the beam intensity and characteristic times of single-bunch and multi-bunch instabilities. For new accelerator projects, minimization of the vacuum chamber impedance is now the mandatory requirement. For an accelerator in operation, the impedance can be measured experimentally using various beam-based techniques. The beam-impedance interaction manifests itself in measurable beam parameters, such as betatron tunes, closed orbit, growth rates of instabilities, bunch length and synchronous phase. The beam-based techniques developed for measurement of the longitudinal and transverse impedance are discussed, including theoretical basics and experimental results. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT3AH3 | ||
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| TUT3AH5 | Electron Cloud and Ion Effects and Their Mitigation in FCC-ee | ion, electron, feedback, damping | 120 |
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| Electron cloud and fast-ion instabilities are serious issues for colliders operated with high current and many bunches. We discuss the instabilities in FCC-ee/hh based on simulations and experiences of KEKB/SuperKEKB. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT3AH5 | ||
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| TUT3AH7 | Electron Cloud and Collective Effects in the Interaction Region of FCC-ee | ion, electron, impedance, quadrupole | 130 |
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| The FCC-ee is an e+e− circular collider designed to accommodate four different experiments in a beam energy range from 91 to 350 GeV and is a part of the Future Circular Collider (FCC) project at CERN. One of the most critical aspects of this new very challenging machine regards the collective effects which can produce instabilities, thus limiting the accelerator operation and reducing its performance. The following studies are focused on the Interaction Region of the machine. This talk will present preliminary simulation results of the power loss due to the wake fields generated by the electromagnetic interaction of the beam with the vacuum chamber. A preliminary estimation of the electron cloud build-up is also reported, whose effects have been recognized as one of the main limitations for the Large Hadron Collider at CERN. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT3AH7 | ||
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| WET2H7 | LLRF Controls Including Gap Transients at KEKB and Plans for SuperKEKB | ion, cavity, controls, LLRF | 177 |
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| Features of LLRF control systems in KEKB and SuperKEKB will be reviewed, and the evaluation of the bunch gap transient effect on beam phase will be presented for SuperKEKB. The RF systems of KEKB are being reinforced to handle triple as large beam power for upgrade to SuperKEKB. Furthermore, a new LLRF control system, which is based on a recent digital control technique, has been developed. For nine RF stations, among a total of thirty, the LLRF control system has been replaced with new ones. They were worked successfully in the Phase-1 commissioning. Bunch phase shift along the bunch train due to a bunch gap transient is a concern. In KEKB operation, a rapid phase change was observed at the leading part of the train, which was not predicted. Our new simulation study clarified that the rapid phase change is caused by a transient loading in the three-cavity system of ARES. And the new simulation shows that the phase change will be much large in SuperKEKB. The main issue is the difference in beam phase change between the two rings for the asymmetry colliding. The measures by means of mitigation of the relative beam phase difference between the two rings will be also suggested. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-WET2H7 | ||
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| THS1H5 | Summary Beam-beam Session, eeFACT2016 Workshop | ion, beam-beam-effects, resonance, collider | 203 |
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| There are two talks in the beam-beam session. But beam-beam is an issue that permeates in several other sessions. So in this summary I have taken the liberty to include some materials extracted also from other sessions. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-THS1H5 | ||
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