HB2016 - List of Authors (Mether, L.)

Paper	Title	Page
TUAM4X01	Electron Cloud in the CERN Accelerator Complex	266
	G. Rumolo, H. Bartosik, E. Belli, G. Iadarola, K.S.B. Li, L. Mether, A. Romano CERN, Geneva, Switzerland M. Schenk EPFL, Lausanne, Switzerland
	Operation with closely spaced bunched beams causes the build up of an Electron Cloud (EC) in both the LHC and the two last synchrotrons of its injector chain (PS and SPS). Pressure rise and beam instabilities are observed at the PS during the last stage of preparation of the LHC beams. The SPS was affected by coherent and incoherent emittance growth along the LHC bunch train over many years, before scrubbing has finally suppressed the EC in a large fraction of the machine. When the LHC started regular operation with 50 ns beams in 2011, EC phenomena appeared in the arcs during the early phases, and in the interaction regions with two beams all along the run. Operation with 25 ns beams (late 2012 and 2015), which is nominal for LHC, has been hampered by EC induced high heat load in the cold arcs, bunch dependent emittance growth and degraded beam lifetime. Dedicated and parasitic machine scrubbing is presently the weapon used at the LHC to combat EC in this mode of operation. This talk summarises the EC experience in the CERN machines (PS, SPS, LHC) and highlight the dangers for future operation with more intense beams as well as the strategies to mitigate or suppress the effect.
	Slides TUAM4X01 [9.785 MB]
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WEAM4X01	Numerical Modeling of Fast Beam Ion Instabilities	368
	L. Mether, G. Iadarola, G. Rumolo CERN, Geneva, Switzerland
	The fast beam ion instability may pose a risk to the operation of future electron accelerators with beams of high intensity and small emittances, including several structures of the proposed CLIC accelerator complex. Numerical models can be used to identify necessary vacuum specifications to suppress the instability, as well as requirements for a possible feedback system. Vacuum requirements imposed by the instability have previously been estimated for linear CLIC structures, using the strong-strong macroparticle simulation tool FASTION. Currently, efforts are being made to improve the simulation tools, and allow for equivalent studies of circular structures, such as the CLIC damping rings, on a multi-turn scale. In this contribution, we review the recent code developments, and present first simulation results.
	Slides WEAM4X01 [3.379 MB]
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WEAM5X01	Beam-Dynamics Issues in the FCC	373
	F. Zimmermann, W. Bartmann, M. Benedikt, M.I. Besana, R. Bruce, O.S. Brüning, X. Buffat, F. Burkart, H. Burkhardt, S. Calatroni, F. Cerutti, S.D. Fartoukh, M. Fiascaris, C. Garion, B. Goddard, B.J. Holzer, W. Höfle, J.M. Jowett, R. Kersevan, R. Martin, L. Mether, A. Milanese, T. Pieloni, S. Redaelli, G. Rumolo, B. Salvant, M. Schaumann, D. Schulte, E.N. Shaposhnikova, L.S. Stoel, C. Tambasco, R. Tomás, D. Tommasini CERN, Geneva, Switzerland J.L. Abelleira, E. Cruz Alaniz, A. Seryi JAI, Oxford, United Kingdom R.B. Appleby UMAN, Manchester, United Kingdom P. Bambade, A. Faus-Golfe, J. Molson LAL, Orsay, France J. Barranco EPFL, Lausanne, Switzerland J.-L. Biarrotte, A. Lachaize IPN, Orsay, France O. Boine-Frankenheim, U. Niedermayer TEMF, TU Darmstadt, Darmstadt, Germany M. Boscolo, F. Collamati, A. Drago INFN/LNF, Frascati (Roma), Italy A. Chancé CEA, Gif-sur-Yvette, France B. Dalena, J. Payet CEA/IRFU, Gif-sur-Yvette, France J.D. Fox, G. Stupakov SLAC, Menlo Park, California, USA G. Guillermo Cantón CINVESTAV, Mérida, Mexico S. Khan, B. Riemann DELTA, Dortmund, Germany V. Kornilov GSI, Darmstadt, Germany T.M. Mitsuhashi, K. Ohmi KEK, Ibaraki, Japan
	Funding: European Commission under the Capacities 7th Framework Programme project EuCARD-2, grant agreement 312453, and the HORIZON 2020 project EuroCirCol, grant agreement 654305. Also by the German BMBF. The international Future Circular Collider (FCC) study is designing hadron, lepton and lepton-hadron colliders based on a new 100 km tunnel in the Geneva region. The main focus and ultimate goal of the study are high-luminosity proton-proton collisions at a centre-of-mass energy of 100 TeV, using 16 T Nb3Sn dipole magnets. Specific FCC beam dynamics issues are related to the large circumference, the high brightness - made available by radiation damping -, the small geometric emittance, unprecedented collision energy and luminosity, the huge amount of energy stored in the beam, large synchrotron radiation power, plus the injection scenarios. In addition to the FCC-hh proper, also a High-Energy LHC (HE-LHC) is being explored, using the FCC-hh magnet technology in the existing LHC tunnel, which can yield a centre-of-mass energy around 25 TeV.
	Slides WEAM5X01 [10.402 MB]
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Paper

Title

Page

Electron Cloud in the CERN Accelerator Complex

266

G. Rumolo, H. Bartosik, E. Belli, G. Iadarola, K.S.B. Li, L. Mether, A. Romano
CERN, Geneva, Switzerland
M. Schenk
EPFL, Lausanne, Switzerland

Operation with closely spaced bunched beams causes the build up of an Electron Cloud (EC) in both the LHC and the two last synchrotrons of its injector chain (PS and SPS). Pressure rise and beam instabilities are observed at the PS during the last stage of preparation of the LHC beams. The SPS was affected by coherent and incoherent emittance growth along the LHC bunch train over many years, before scrubbing has finally suppressed the EC in a large fraction of the machine. When the LHC started regular operation with 50 ns beams in 2011, EC phenomena appeared in the arcs during the early phases, and in the interaction regions with two beams all along the run. Operation with 25 ns beams (late 2012 and 2015), which is nominal for LHC, has been hampered by EC induced high heat load in the cold arcs, bunch dependent emittance growth and degraded beam lifetime. Dedicated and parasitic machine scrubbing is presently the weapon used at the LHC to combat EC in this mode of operation. This talk summarises the EC experience in the CERN machines (PS, SPS, LHC) and highlight the dangers for future operation with more intense beams as well as the strategies to mitigate or suppress the effect.

Slides TUAM4X01 [9.785 MB]

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEAM4X01

Numerical Modeling of Fast Beam Ion Instabilities

368

L. Mether, G. Iadarola, G. Rumolo
CERN, Geneva, Switzerland

The fast beam ion instability may pose a risk to the operation of future electron accelerators with beams of high intensity and small emittances, including several structures of the proposed CLIC accelerator complex. Numerical models can be used to identify necessary vacuum specifications to suppress the instability, as well as requirements for a possible feedback system. Vacuum requirements imposed by the instability have previously been estimated for linear CLIC structures, using the strong-strong macroparticle simulation tool FASTION. Currently, efforts are being made to improve the simulation tools, and allow for equivalent studies of circular structures, such as the CLIC damping rings, on a multi-turn scale. In this contribution, we review the recent code developments, and present first simulation results.

Slides WEAM4X01 [3.379 MB]

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reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEAM5X01

Beam-Dynamics Issues in the FCC

373

F. Zimmermann, W. Bartmann, M. Benedikt, M.I. Besana, R. Bruce, O.S. Brüning, X. Buffat, F. Burkart, H. Burkhardt, S. Calatroni, F. Cerutti, S.D. Fartoukh, M. Fiascaris, C. Garion, B. Goddard, B.J. Holzer, W. Höfle, J.M. Jowett, R. Kersevan, R. Martin, L. Mether, A. Milanese, T. Pieloni, S. Redaelli, G. Rumolo, B. Salvant, M. Schaumann, D. Schulte, E.N. Shaposhnikova, L.S. Stoel, C. Tambasco, R. Tomás, D. Tommasini
CERN, Geneva, Switzerland
J.L. Abelleira, E. Cruz Alaniz, A. Seryi
JAI, Oxford, United Kingdom
R.B. Appleby
UMAN, Manchester, United Kingdom
P. Bambade, A. Faus-Golfe, J. Molson
LAL, Orsay, France
J. Barranco
EPFL, Lausanne, Switzerland
J.-L. Biarrotte, A. Lachaize
IPN, Orsay, France
O. Boine-Frankenheim, U. Niedermayer
TEMF, TU Darmstadt, Darmstadt, Germany
M. Boscolo, F. Collamati, A. Drago
INFN/LNF, Frascati (Roma), Italy
A. Chancé
CEA, Gif-sur-Yvette, France
B. Dalena, J. Payet
CEA/IRFU, Gif-sur-Yvette, France
J.D. Fox, G. Stupakov
SLAC, Menlo Park, California, USA
G. Guillermo Cantón
CINVESTAV, Mérida, Mexico
S. Khan, B. Riemann
DELTA, Dortmund, Germany
V. Kornilov
GSI, Darmstadt, Germany
T.M. Mitsuhashi, K. Ohmi
KEK, Ibaraki, Japan

Funding: European Commission under the Capacities 7th Framework Programme project EuCARD-2, grant agreement 312453, and the HORIZON 2020 project EuroCirCol, grant agreement 654305. Also by the German BMBF.
The international Future Circular Collider (FCC) study is designing hadron, lepton and lepton-hadron colliders based on a new 100 km tunnel in the Geneva region. The main focus and ultimate goal of the study are high-luminosity proton-proton collisions at a centre-of-mass energy of 100 TeV, using 16 T Nb3Sn dipole magnets. Specific FCC beam dynamics issues are related to the large circumference, the high brightness - made available by radiation damping -, the small geometric emittance, unprecedented collision energy and luminosity, the huge amount of energy stored in the beam, large synchrotron radiation power, plus the injection scenarios. In addition to the FCC-hh proper, also a High-Energy LHC (HE-LHC) is being explored, using the FCC-hh magnet technology in the existing LHC tunnel, which can yield a centre-of-mass energy around 25 TeV.

Slides WEAM5X01 [10.402 MB]

Export •

reference for this paper to ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)