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Vacuum electrical breakdown conditioning study in a parallel plate electrode pulsed DC system

Conditioning of a metal structure in a high-voltage system is the progressive development of resistance to vacuum arcing over the operational life of the system. This is, for instance, seen during the initial operation of radio frequency (rf) cavities in particle accelerators. It is a relevant topic...

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Autores principales: Korsbäck, Anders, Morales, Laura Mercadé, Profatilova, Iaroslava, Djurabekova, Flyura, Rodriguez Castro, Enrique, Wuensch, Walter, Ahlgren, Tommy, Calatroni, Sergio
Lenguaje:eng
Publicado: 2019
Materias:
Acceso en línea:https://dx.doi.org/10.1103/PhysRevAccelBeams.23.033102
http://cds.cern.ch/record/2676692
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author Korsbäck, Anders
Morales, Laura Mercadé
Profatilova, Iaroslava
Djurabekova, Flyura
Rodriguez Castro, Enrique
Wuensch, Walter
Ahlgren, Tommy
Calatroni, Sergio
author_facet Korsbäck, Anders
Morales, Laura Mercadé
Profatilova, Iaroslava
Djurabekova, Flyura
Rodriguez Castro, Enrique
Wuensch, Walter
Ahlgren, Tommy
Calatroni, Sergio
author_sort Korsbäck, Anders
collection CERN
description Conditioning of a metal structure in a high-voltage system is the progressive development of resistance to vacuum arcing over the operational life of the system. This is, for instance, seen during the initial operation of radio frequency (rf) cavities in particle accelerators. It is a relevant topic for any technology where breakdown limits performance and where conditioning continues for a significant duration of system run time. Projected future linear accelerators require structures with accelerating gradients of up to 100  MV/m. Currently, this performance level is achievable only after a multimonth conditioning period. In this work, a pulsed dc system applying voltage pulses over parallel disk electrodes was used to study the conditioning process, with the objective of obtaining insight into its underlying mechanics and, ultimately, to find ways to shorten the conditioning process. Two kinds of copper electrodes were tested: as-prepared machine-turned electrodes (“hard” copper) and electrodes that additionally had been subjected to high-temperature treatments (“soft” copper). The conditioning behavior of the soft electrodes was found to be similar to that of comparably treated accelerating structures, indicating a similar conditioning process. The hard electrodes reached the same ultimate performance as the soft electrodes much faster, with a difference of more than an order of magnitude in the number of applied voltage pulses. Two distinctly different distributions of breakdown locations were observed on the two types of electrodes. Considered together, our results support the crystal structure dislocation theory of breakdown and suggest that the conditioning of copper in high field systems such as rf accelerating structures is dominated by material hardening.
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institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2019
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spelling cern-26766922023-03-14T18:37:26Zdoi:10.1103/PhysRevAccelBeams.23.033102http://cds.cern.ch/record/2676692engKorsbäck, AndersMorales, Laura MercadéProfatilova, IaroslavaDjurabekova, FlyuraRodriguez Castro, EnriqueWuensch, WalterAhlgren, TommyCalatroni, SergioVacuum electrical breakdown conditioning study in a parallel plate electrode pulsed DC systemphysics.app-phConditioning of a metal structure in a high-voltage system is the progressive development of resistance to vacuum arcing over the operational life of the system. This is, for instance, seen during the initial operation of radio frequency (rf) cavities in particle accelerators. It is a relevant topic for any technology where breakdown limits performance and where conditioning continues for a significant duration of system run time. Projected future linear accelerators require structures with accelerating gradients of up to 100  MV/m. Currently, this performance level is achievable only after a multimonth conditioning period. In this work, a pulsed dc system applying voltage pulses over parallel disk electrodes was used to study the conditioning process, with the objective of obtaining insight into its underlying mechanics and, ultimately, to find ways to shorten the conditioning process. Two kinds of copper electrodes were tested: as-prepared machine-turned electrodes (“hard” copper) and electrodes that additionally had been subjected to high-temperature treatments (“soft” copper). The conditioning behavior of the soft electrodes was found to be similar to that of comparably treated accelerating structures, indicating a similar conditioning process. The hard electrodes reached the same ultimate performance as the soft electrodes much faster, with a difference of more than an order of magnitude in the number of applied voltage pulses. Two distinctly different distributions of breakdown locations were observed on the two types of electrodes. Considered together, our results support the crystal structure dislocation theory of breakdown and suggest that the conditioning of copper in high field systems such as rf accelerating structures is dominated by material hardening.Conditioning of a metal structure in a high-voltage system is the progressive development of resistance to vacuum arcing over the operational life of the system. This is, for instance, seen during the initial operation of radio frequency (rf) cavities in particle accelerators. It is a relevant topic for any technology where breakdown limits performance, and where conditioning continues for a significant duration of system runtime. Projected future linear accelerators require structures with accelerating gradients of up to 100 MV/m. Currently, this performance level is only achievable after a multi-month conditioning period. In this work, a pulsed DC system applying voltage pulses over parallel disk electrodes was used to study the conditioning process, with the objective of obtaining insight into its underlying mechanics, and ultimately, to find ways to shorten the conditioning process. Two kinds of copper electrodes were tested: As-prepared machine-turned electrodes ("hard" copper), and electrodes that additionally had been subjected to high temperature treatments ("soft" copper). The conditioning behaviour of the soft electrodes was found to be similar to that of comparably treated accelerating structures, indicating a similar conditioning process. The hard electrodes reached the same ultimate performance as the soft electrodes much faster, with a difference of more than an order of magnitude in the number of applied voltage pulses. Two distinctly different distributions of breakdown locations were observed on the two types of electrodes. Considered together, our results support the crystal structure dislocation theory of breakdown, and suggest that the conditioning of copper in high field systems such as rf accelerating structures is dominated by material hardening.arXiv:1905.03996oai:cds.cern.ch:26766922019-05-10
spellingShingle physics.app-ph
Korsbäck, Anders
Morales, Laura Mercadé
Profatilova, Iaroslava
Djurabekova, Flyura
Rodriguez Castro, Enrique
Wuensch, Walter
Ahlgren, Tommy
Calatroni, Sergio
Vacuum electrical breakdown conditioning study in a parallel plate electrode pulsed DC system
title Vacuum electrical breakdown conditioning study in a parallel plate electrode pulsed DC system
title_full Vacuum electrical breakdown conditioning study in a parallel plate electrode pulsed DC system
title_fullStr Vacuum electrical breakdown conditioning study in a parallel plate electrode pulsed DC system
title_full_unstemmed Vacuum electrical breakdown conditioning study in a parallel plate electrode pulsed DC system
title_short Vacuum electrical breakdown conditioning study in a parallel plate electrode pulsed DC system
title_sort vacuum electrical breakdown conditioning study in a parallel plate electrode pulsed dc system
topic physics.app-ph
url https://dx.doi.org/10.1103/PhysRevAccelBeams.23.033102
http://cds.cern.ch/record/2676692
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