Development of gas cluster ion beam surface treatments for reducing field emission and breakdown in RF cavities

D. R. Swenson, A. T. Wu, E. Degenkolb, Z. Insepov

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Citations (Scopus)

Abstract

Sub-micron-scale surface roughness and contamination cause field emission that can lead to high voltage breakdown of electrodes, and these are limiting factors in the development of high gradient RF technology. We are studying various Gas Cluster Ion Beam (GCIB) treatments to smooth, clean, etch and/or chemically alter electrode surfaces to allow higher fields and accelerating gradients, and to reduce the time and cost of conditioning high voltage electrodes. For this paper, we have processed Nb, Stainless Steel, and Ti electrode materials using beams of Ar, O2, or NF3 +O 2 clusters with accelerating potentials up to 35 kV. Using a Scanning Field Emission Microscope (SFEM), we have repeatedly seen a dramatic reduction in the number of field emission sites on Nb coupons treated with GCIB. Smoothing effects on Stainless steel and Ti substrates have been evaluated using AFM imaging and show that 200-nm wide polishing scratch marks are greatly attenuated. A 150-mm diameter GCIB treated stainless steel electrode has now shown virtually no DC field emission current at gradients over 20 MV/m.

Original languageEnglish
Title of host publicationADVANCED ACCELERATOR CONCEPTS
Subtitle of host publication12th Advanced Accelerator Concepts Workshop
Pages370-377
Number of pages8
DOIs
Publication statusPublished - 2006
EventADVANCED ACCELERATOR CONCEPTS: 12th Advanced Accelerator Concepts Workshop - Lake Geneva, WI, United States
Duration: Jul 10 2006Jul 15 2006

Publication series

NameAIP Conference Proceedings
Volume877
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

OtherADVANCED ACCELERATOR CONCEPTS: 12th Advanced Accelerator Concepts Workshop
CountryUnited States
CityLake Geneva, WI
Period7/10/067/15/06

Keywords

  • Cluster-surface interactions
  • Field emission
  • Gas cluster ion beam
  • RF breakdown
  • Superconducting RF cavity

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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