| Paper | Title | Page |
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| TUOAB02 | Low-emittance Tuning for Circular Colliders | 57 |
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| The 100 km FCC-ee e+/e− circular collider requires luminosities in the order of 1035 cm-2 s-1 and very low emittances of 0.27 nm·prad for the horizontal plane and 1 pm·prad in the vertical. In order to reach these requirements, extreme focusing of the beam is needed in the interaction regions, leading to a vertical beta function of 0.8 mm at the IP. These challenges make the FCC-ee design particularly susceptible to misalignment and field errors. This paper describes the tolerance of the machine to magnet alignment errors and the effectiveness of optics and orbit correction methods that were implemented in order to bring the vertical dispersion to acceptable values, which in turn limits the vertical emittance. Thousands of misalignment and error seeds were introduced in MADX simulations and a comprehensive correction strategy, which includes macros based upon Dispersion Free Steering (DFS), linear coupling correction based on Resonant Driving Terms (RDTs) and response matrices, was implemented. The results are summarized in this paper. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUOAB02 | |
| About • | paper received ※ 11 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | |
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| TUOBB02 | Off-momentum Optics at SuperKEKB | 71 |
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| The nano-beam scheme can squeeze the vertical beta function at the IP much smaller than the bunch length. It implies that the large chromaticity is generated in the vicinity of the final focus quadrupole magnets and the strong sextupoles are adopted to correct the chromaticity, for instance the local chromaticity corrections. While understanding of the off-momentum optics is important to optimize the dynamic aperture to make Touschek lifetime long and to reduce the luminosity degradation due to chromatic behaviors. In general, there is a discrepancy between measurements and those obtained from the optics model. The chromatic phase-advance is introduced to measure the off-momentum optics and correct by using sextupole magnets. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUOBB02 | |
| About • | paper received ※ 12 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | |
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| TUYBA03 | Beam-beam Blowup in the Presence of x-y Coupling Sources for FCC-ee | 112 |
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| FCC-ee, the lepton version of the Future Circular Collider (FCC), is a 100 Km future machine under study to be built at CERN. It acquires two experiments with a highest beam energy of 182.5 GeV. FCC-ee aims to operate at four different energies, with different luminosities to fulfill physics requirements. Beam-beam effects at such a high energy/luminosity machine are very challenging and require a deep understanding, especially in the presence of x-y coupling sources. Beam-beam effects include the beamstrahlung process, which limits the beam lifetime at high energies, as well as dynamic effects at the Interaction point (IP) which include changes in the beta functions and emittances. In this report, we will define the beam-beam effects and their behaviours in the FCC-ee highest energy lattice after introducing x-y coupling in the ring. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYBA03 | |
| About • | paper received ※ 11 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | |
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| WEXBA03 | Beam Blowup due to Lattice Coupling/Dispersion with/without Beam-beam | 207 |
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Funding: Work supported by JSPS KAKENHI Grant Number 17K05475. Also supported by the European Commission under project EuCARD–2, grant agreement 312453, and under the Horizon 2020, grant agreement 654166. A significant blowup of the vertical emittance is observed in particle tracking in lattices with random skew quadrupoles, even without beam-beam effects with the FCC-ee lattice at ttbar. A Vlasov model well explains the blowup, and agrees with the tracking. This effect will set an additional limit on the goal of tuning of the vertical emittance of the lattice of colliders, well below the value at the collision. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEXBA03 | |
| About • | paper received ※ 25 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | |
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| MOYAA01 | Several Topics on Beam Dynamics in FCC-ee | 18 |
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Funding: Work supported by the European Commission under Capacities 7th Framework Programme project EuCARD–2, grant agreement 312453, and the Horizon 2020 Programme project CREMLIN, grant agreement 654166. Several studies on the beam dynamics at FCC-ee: low emittance tuning, dynamic aperture, beam blowup with/without beam beam, will be introduced. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-MOYAA01 | |
| About • | paper received ※ 23 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | |
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| WEXBA02 | Machine Detector Interface for the e+e− Future Circular Collider | 201 |
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| The international Future Circular Collider (FCC) study~[fccweb] aims at a design of p-p, \rm e+e-, e-p colliders to be built in a new 100~km tunnel in the Geneva region. The \rm e+e- collider (FCC-ee) has a centre of mass energy range between 90 (Z-pole) and 375~GeV (t\bar{t}). To reach such unprecedented energies and luminosities, the design of the interaction region is crucial. The crab-waist collision scheme~[ref:cw] has been chosen for the design and it will be compatible with all beam energies. In this paper we will describe the machine detector interface layout including the solenoid compensation scheme. We will describe how this layout fulfills all the requirements set by the parameters table and by the physical constraints. We will summarize the studies of the impact of the synchrotron radiation, the analysis of trapped modes and of the backgrounds induced by single beam and luminosity effects giving an estimate of the losses in the interaction region and in the detector. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEXBA02 | |
| About • | paper received ※ 03 November 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | |
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| WEPAB03 | FCC-ee Operation Model, Availability & Performance | 269 |
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Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES no.~730871. This document discusses the machine parameters and expected luminosity performance for the proposed future circular lepton collider FCC-ee. Particular emphasis is put on availability, physics run time, and efficiency. Key performance assumptions are compared with the operational experience of several past and present colliders including their injectors - LHC, LEP/LEP-2, PEP-II, KEKB, BEPCII, DAΦNE, SLC and the SPS complex. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEPAB03 | |
| About • | paper received ※ 13 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | |
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