TY - GEN
T1 - Development of gas cluster ion beam surface treatments for reducing field emission and breakdown in RF cavities
AU - Swenson, D. R.
AU - Wu, A. T.
AU - Degenkolb, E.
AU - Insepov, Z.
N1 - Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2006
Y1 - 2006
N2 - 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.
AB - 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.
KW - Cluster-surface interactions
KW - Field emission
KW - Gas cluster ion beam
KW - RF breakdown
KW - Superconducting RF cavity
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U2 - 10.1063/1.2409158
DO - 10.1063/1.2409158
M3 - Conference contribution
AN - SCOPUS:33847078848
SN - 0735403783
SN - 9780735403789
T3 - AIP Conference Proceedings
SP - 370
EP - 377
BT - ADVANCED ACCELERATOR CONCEPTS
T2 - ADVANCED ACCELERATOR CONCEPTS: 12th Advanced Accelerator Concepts Workshop
Y2 - 10 July 2006 through 15 July 2006
ER -