| Paper | Title | Other Keywords | Page |
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| TUYAA01 | High Currents Effects in DAΦNE | vacuum, feedback, cavity, electron | 82 |
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| DAΦNE, the Italian lepton collider, operates routinely with high intensity electron and positron colliding beams. The high current multi-bunch beams are stored in two independent rings, each of them 97 m long, and are distributed in 100 ’ 110 contiguous buckets out of the 120 available, spaced by only 2.7 ns. Since its construction, DAΦNE has been operated in different configurations which, overall, allowed to store current up to 1.4 A and 2.45 A in the positron and in the electron beam respectively. Still today DAΦNE holds the record for the highest electron beam current ever stored in particle factories and modern synchrotron radiation sources. The DAΦNE experience in terms of beam dynamics optimization aimed at achieving the high intensity beams is presented, with special emphasis on the e-cloud related issues, which represent the dominant effect limiting the positron beam current. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYAA01 | ||
| About • | paper received ※ 24 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | ||
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| TUYAA03 | Impedances and Collective Effects for JLEIC | electron, cavity, dipole, proton | 90 |
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Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. JLEIC is the high luminosity and high polarization electron-ion collider (EIC) currently under design at Jefferson Lab. Its luminosity performance relies on the beam stability under high-intensity electron and ion beam operation. The impedance budget analysis and the estimations of beam instabilities are currently underway. In this paper, we present the update status of our back-of-envelope estimations for these collective instabilities, and identify area or parameter regimes where special attentions for instability mitigations are required. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYAA03 | ||
| About • | paper received ※ 22 October 2018 paper accepted ※ 08 March 2019 issue date ※ 21 April 2019 | ||
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| TUYBA04 | Some Issues on Beam-beam Interaction at CEPC | luminosity, dynamic-aperture, simulation, factory | 116 |
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Funding: Project 11775238 supported by NSFC In this paper, the beam-beam study in CEPC CDR is briefly introduced. Some issues related with beam-beam interaction will be emphasized. The bunch lengthening due to impedance and beamstrahlung is simulated in a more self-consistent method. It is found that there exist very narrow stable working point space at W-mode during the CDR design study. We’ll show wider tune scan result. It is found that there exist some disagreement between dynamic aperture and beam lifetime. We try to define the so-called diffusion rate map to explain the cause. Some initial result for different lattice solution is shown. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYBA04 | ||
| About • | paper received ※ 26 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | ||
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| WEOAB04 | Single Bunch Instabilities and NEG Coating for FCC-ee | electron, collider, simulation, vacuum | 234 |
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| The high luminosity electron-positron collider FCC-ee is part of the Future Circular Collider (FCC) study at CERN and it has been designed to cover the beam energy range from 45.6 GeV to 182.5 GeV to study the properties of the Higgs boson and other particles. Electron cloud build up simulations on the Z resonance revealed the necessity of minimising the Secondary Electron Yield (SEY) of the pipe walls by applying a Ti-Zr-V Non-Evaporable Getter (NEG) coating in the entire ring. Beam dynamics simulations at 45.6 GeV pointed out that minimising the thickness of this layer is mandatory to reduce the resistive wall (RW) impedance, thus increasing the single bunch instability thresholds and ensuring beam stability during operation. However, reducing the coating thickness can affect the performance of the material and therefore the SEY. For this reason, an extensive measurement campaign was performed at CERN to characterise NEG thin films with thicknesses below 250 nm in terms of activation performance and SEY measurements. This paper also presents the FCC-ee longitudinal impedance model which includes all the current machine components. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEOAB04 | ||
| About • | paper received ※ 12 November 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | ||
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