Paper |
Title |
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TUPOR010 |
Simulation of Instability at Transition Energy with a New Impedance Model for CERN PS |
1674 |
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- N. Wang
IHEP, Beijing, People's Republic of China
- S. Aumon, N. Biancacci, M. Migliorati, G. Sterbini, N. Wang
CERN, Geneva, Switzerland
- M. Migliorati
INFN-Roma1, Rome, Italy
- S. Persichelli
University of Rome La Sapienza, Rome, Italy
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Instabilities driven by the transverse impedance are proven to be one of the limitations for the high intensity reach of the CERN PS. Since several years, fast single bunch vertical instability at transition energy has been observed with the high intensity bunch serving the neu-tron Time-of-Flight facility (n-ToF). In order to better understand the instability mechanism, a dedicated meas-urement campaign took place. The results were compared with macro-particle simulations with PyHEADTAIL based on the new impedance model developed for the PS. Instability threshold and growth rate for different longitu-dinal emittances and beam intensities were studied.
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DOI • |
reference for this paper
※ DOI:10.18429/JACoW-IPAC2016-TUPOR010
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THPOR001 |
Tolerance Studies and Dispersion Free Steering for Extreme Low Emittance in the FCC-ee Project |
3759 |
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- S. Aumon, A. Doblhammer, B. Härer, B.J. Holzer
CERN, Geneva, Switzerland
- B. Härer
KIT, Karlsruhe, Germany
- K. Oide
KEK, Ibaraki, Japan
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The FCC-ee study is investigating the design of a 100 km e+/e− circular collider for precision measurements and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 1035 cm-2s-1. In order to reach such performances, an extreme focusing of the beam is required in the interaction regions with a low vertical beta function of 2 mm at the IP. Moreover, the FCC-ee physics program requires very low emittances never achieved in a collider with 2 nm for εx and 2 pm for εy, reducing the coupling ratio to 1/1000. With such requirements, any field errors and sources of coupling will introduce spurious vertical dispersion which degrades emittances, limiting the luminosity of the machine. This paper describes the tolerance study and the impact of errors will affect the vertical emittance. In order to preserve the FCC-ee performances, in particular εy, a challenging correction scheme is proposed to keep the coupling and the vertical emittance as low as possible.
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DOI • |
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※ DOI:10.18429/JACoW-IPAC2016-THPOR001
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THPOR022 |
Design of Beam Optics for the FCC-ee Collider Ring |
3821 |
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- K. Oide, K. Ohmi, D. Zhou
KEK, Ibaraki, Japan
- M. Aiba
PSI, Villigen PSI, Switzerland
- S. Aumon, M. Benedikt, H. Burkhardt, A. Doblhammer, B. Härer, B.J. Holzer, J.M. Jowett, M. Koratzinos, L.E. Medina Medrano, Y. Papaphilippou, J. Wenninger, F. Zimmermann
CERN, Geneva, Switzerland
- A.P. Blondel
DPNC, Genève, Switzerland
- A.V. Bogomyagkov, I. Koop, E.B. Levichev, P.A. Piminov, D.N. Shatilov, D.B. Shwartz, S.V. Sinyatkin
BINP SB RAS, Novosibirsk, Russia
- M. Boscolo
INFN/LNF, Frascati (Roma), Italy
- Y. Cai, M.K. Sullivan, U. Wienands
SLAC, Menlo Park, California, USA
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A design of beam optics will be presented for the FCC-ee double-ring collider. The main characteristics are 45 to 175 GeV beam energy, 100 km circumference with two IPs/ring, 30 mrad crossing angle at the IP, crab-waist scheme with local chromaticity correction system, and "tapering" of the magnets along with the local beam energy. An asymmetric layout near the interaction region suppresses the critical energy of synchrotron radiation toward the detector at the IP less than 100 keV, while keeping the geometry as close as to the FCC-hh beam line. A sufficient transverse/longitudinal dynamic aperture is obtained to assure the lifetime with beamstrahlung and top-up injection. The synchrotron radiation in all magnets, the IP solenoid and its compensation, nonlinearity of the final quadrupoles are taken into account.
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DOI • |
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※ DOI:10.18429/JACoW-IPAC2016-THPOR022
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