IPAC2012 - List of Authors (Taborelli, M.)

Paper	Title	Page
MOPPC009	Multipactor for E-cloud Diagnostics	139
	P. Costa Pinto, F. Caspers, P. Edwards, M. Holz, M. Taborelli CERN, Geneva, Switzerland
	Electron cloud in particle accelerators can be mitigated by coating the vacuum beam pipe with thin films of low secondary electron yield (SEY). SEY of small samples can be measured in the laboratory. Verifying the performance of long pipes is more complex, since it requires their insertion in the accelerator and the subsequent measurement of the beam induced pressure rise. RF induced multipacting in a coaxial waveguide configuration is proposed as a test before insertion in the machine. The technique is applied to two main bending dipoles of the SPS, where the RF power is fed though a tungsten wire stretched along the vacuum chamber (6.4 m). A dipole with a bare stainless steel chamber shows a clear power threshold initiating an abrupt rise in reflected power and pressure. The effect is enhanced at RF frequencies corresponding to cyclotron resonances for given magnetic field. Preliminary result show that the dipole with a carbon coated vacuum chamber does not exhibit any pressure rise or reflected RF power up to the maximum available input power. In the event of a large scale coating production this technique will be a valuable resource for quality control.

TUPPC086	Conceptual Design of the CLIC damping rings	1368
	Y. Papaphilippou, F. Antoniou, M.J. Barnes, S. Calatroni, P. Chiggiato, R. Corsini, A. Grudiev, J. Holma, T. Lefèvre, M. Martini, M. Modena, N. Mounet, A. Perin, Y. Renier, G. Rumolo, S. Russenschuck, H. Schmickler, D. Schoerling, D. Schulte, M. Taborelli, G. Vandoni, F. Zimmermann CERN, Geneva, Switzerland C. Belver-Aguilar, A. Faus-Golfe IFIC, Valencia, Spain A. Bernhard KIT, Karlsruhe, Germany M.J. Boland ASCo, Clayton, Victoria, Australia A.V. Bragin, E.B. Levichev, S.V. Sinyatkin, P. Vobly, K. Zolotarev BINP SB RAS, Novosibirsk, Russia M. Korostelev Cockcroft Institute, Warrington, Cheshire, United Kingdom E. Koukovini EPFL, Lausanne, Switzerland M.A. Palmer CLASSE, Ithaca, New York, USA M.T.F. Pivi, S.R. Smith SLAC, Menlo Park, California, USA R.P. Rassool, K.P. Wootton The University of Melbourne, Melbourne, Australia L. Rinolfi JUAS, Archamps, France A. Vivoli Fermilab, Batavia, USA
	The CLIC damping rings are designed to produce unprecedentedly low-emittances of 500 nm and 5 nm normalized at 2.86 GeV, in all beam dimensions with high bunch charge, necessary for the performance of the collider. The large beam brightness triggers a number of beam dynamics and technical challenges. Ring parameters such as energy, circumference, lattice, momentum compaction, bending and super-conducting wiggler fields are carefully chosen in order to provide the target emittances under the influence of intrabeam scattering but also reduce the impact of collective effects such as space-charge and coherent synchrotron radiation. Mitigation techniques for two stream instabilities have been identified and tested. The low vertical emittance is achieved by modern orbit and coupling correction techniques. Design considerations and plans for technical system, such as damping wigglers, transfer systems, vacuum, RF cavities, instrumentation and feedback are finally reviewed.

Paper

Title

Page

Multipactor for E-cloud Diagnostics

139

P. Costa Pinto, F. Caspers, P. Edwards, M. Holz, M. Taborelli
CERN, Geneva, Switzerland

Electron cloud in particle accelerators can be mitigated by coating the vacuum beam pipe with thin films of low secondary electron yield (SEY). SEY of small samples can be measured in the laboratory. Verifying the performance of long pipes is more complex, since it requires their insertion in the accelerator and the subsequent measurement of the beam induced pressure rise. RF induced multipacting in a coaxial waveguide configuration is proposed as a test before insertion in the machine. The technique is applied to two main bending dipoles of the SPS, where the RF power is fed though a tungsten wire stretched along the vacuum chamber (6.4 m). A dipole with a bare stainless steel chamber shows a clear power threshold initiating an abrupt rise in reflected power and pressure. The effect is enhanced at RF frequencies corresponding to cyclotron resonances for given magnetic field. Preliminary result show that the dipole with a carbon coated vacuum chamber does not exhibit any pressure rise or reflected RF power up to the maximum available input power. In the event of a large scale coating production this technique will be a valuable resource for quality control.

TUPPC086

Conceptual Design of the CLIC damping rings

1368

Y. Papaphilippou, F. Antoniou, M.J. Barnes, S. Calatroni, P. Chiggiato, R. Corsini, A. Grudiev, J. Holma, T. Lefèvre, M. Martini, M. Modena, N. Mounet, A. Perin, Y. Renier, G. Rumolo, S. Russenschuck, H. Schmickler, D. Schoerling, D. Schulte, M. Taborelli, G. Vandoni, F. Zimmermann
CERN, Geneva, Switzerland
C. Belver-Aguilar, A. Faus-Golfe
IFIC, Valencia, Spain
A. Bernhard
KIT, Karlsruhe, Germany
M.J. Boland
ASCo, Clayton, Victoria, Australia
A.V. Bragin, E.B. Levichev, S.V. Sinyatkin, P. Vobly, K. Zolotarev
BINP SB RAS, Novosibirsk, Russia
M. Korostelev
Cockcroft Institute, Warrington, Cheshire, United Kingdom
E. Koukovini
EPFL, Lausanne, Switzerland
M.A. Palmer
CLASSE, Ithaca, New York, USA
M.T.F. Pivi, S.R. Smith
SLAC, Menlo Park, California, USA
R.P. Rassool, K.P. Wootton
The University of Melbourne, Melbourne, Australia
L. Rinolfi
JUAS, Archamps, France
A. Vivoli
Fermilab, Batavia, USA

The CLIC damping rings are designed to produce unprecedentedly low-emittances of 500 nm and 5 nm normalized at 2.86 GeV, in all beam dimensions with high bunch charge, necessary for the performance of the collider. The large beam brightness triggers a number of beam dynamics and technical challenges. Ring parameters such as energy, circumference, lattice, momentum compaction, bending and super-conducting wiggler fields are carefully chosen in order to provide the target emittances under the influence of intrabeam scattering but also reduce the impact of collective effects such as space-charge and coherent synchrotron radiation. Mitigation techniques for two stream instabilities have been identified and tested. The low vertical emittance is achieved by modern orbit and coupling correction techniques. Design considerations and plans for technical system, such as damping wigglers, transfer systems, vacuum, RF cavities, instrumentation and feedback are finally reviewed.