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Author Degiovanni, A.; Wuensch, W.; Giner Navarro, J.
Title (down) Comparison of the conditioning of high gradient accelerating structures Type Journal Article
Year 2016 Publication Physical Review Accelerators and Beams Abbreviated Journal Phys. Rev. Accel. Beams
Volume 19 Issue 3 Pages 032001 - 6pp
Keywords
Abstract Accelerating gradients in excess of 100 MV/m, at very low breakdown rates, have been successfully achieved in numerous prototype CLIC accelerating structures. The conditioning and operational histories of several structures, tested at KEK and CERN, have been compared and there is clear evidence that the conditioning progresses with the number of rf pulses and not with the number of breakdowns. This observation opens the possibility that the optimum conditioning strategy, which minimizes the total number of breakdowns the structure is subject to without increasing conditioning time, may be to never exceed the breakdown rate target for operation. The result is also likely to have a strong impact on efforts to understand the physical mechanism underlying conditioning and may lead to preparation procedures which reduce conditioning time.
Address [Degiovanni, Alberto; Wuensch, Walter] CERN, European Org Nucl Res, CH-1211 Geneva, Switzerland, Email: walter.wuensch@cern.ch
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9888 ISBN Medium
Area Expedition Conference
Notes WOS:000400274700001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3090
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Author Senes, E.; Argyropoulos, T.; Tecker, F.; Wuensch, W.
Title (down) Beam-loading effect on breakdown rate in high-gradient accelerating cavities: An experiment at the Compact Linear Collider Test Facility at CERN Type Journal Article
Year 2018 Publication Physical Review Accelerators and Beams Abbreviated Journal Phys. Rev. Accel. Beams
Volume 21 Issue 10 Pages 102001 - 8pp
Keywords
Abstract Radio frequency breakdown rate is a crucial performance parameter that ensures that the design luminosity is achieved in the CLIC linear collider. The required low breakdown rate for CLIC, of the order of 10(-7) breakdown pulse(-1) m(-1), has been demonstrated in a number of 12 GHz CLIC prototype structures at gradients in excess of the design 100 MV/m accelerating gradient, however without the presence of the accelerated beam and associated beam loading. The beam loading induced by the approximately 1 A CLIC main beam significantly modifies the field distribution inside the structures, and the effect on breakdown rate is potentially significant so needs to be determined. A dedicated experiment has been carried out in the CLIC Test Facility CTF3 to measure this effect, and the results are presented.
Address [Senes, Eugenio] John Adams Inst, Denys Wilkinson Bldg,Keble Rd, Oxford OX1 3RH, England, Email: eugenio.senes@cern.ch
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9888 ISBN Medium
Area Expedition Conference
Notes WOS:000447731900003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3768
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Author Fuster-Martinez, N.; Bruce, R.; Hofer, M.; Persson, T.; Redaelli, S.; Tomas, R.
Title (down) Aperture measurements with ac dipoles and movable collimators in the Large Hadron Collider Type Journal Article
Year 2022 Publication Physical Review Accelerators and Beams Abbreviated Journal Phys. Rev. Accel. Beams
Volume 25 Issue 10 Pages 101002 - 13pp
Keywords
Abstract This paper presents a first experimental demonstration of a new nondestructive method for aperture measurements based on ac dipoles. In high intensity particle colliders, such as the CERN Large Hadron Collider (LHC), aperture measurements are crucial for a safe operation while optimizing the optics in order to reduce the size of the colliding beams and hence increase the luminosity. In the LHC, this type of measurements became mandatory during beam commissioning and the current method used is based on the destructive blowup of bunches using a transverse damper. The new method presented in this paper uses the ac-dipole excitation to generate adiabatic forced oscillations of the beam in order to create losses to identify the smallest aperture in the machine without blowing up the beam emittance. A precise and tuneable control of the oscillation amplitude enables the beams to be reused for several aperture measurements, as well as for other subsequent commissioning activities. Measurements performed with the new method are presented and compared with the current LHC transverse damper method for two different beam energies and two different operational optics.
Address [Fuster-Martinez, N.] CSIC UV, Inst Fis Corpuscular, Valencia 46908, Spain, Email: nuria.fuster@ific.uv.es
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:000875736400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5397
Permanent link to this record