Development of Gas Cluster Ion Beam Surface Treatments for Reducing Field Emission and Breakdown in RF cavities

Journal Article · Mon Nov 27 00:00:00 EST 2006 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2409158· OSTI ID:20898695

Swenson, D R; Degenkolb, E ^[1]; Wu, A T ^[2]; Insepov, Z ^[3]

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1. Beam Physics, Epion Corporation, 37 Manning Road, Billerica MA 01821 (United States)
2. Jefferson National Laboratory, 12000 Jefferson Ave., Newport News VA 23606 (United States)
3. Argonne National Laboratory, 9700 South Cass Ave., Argonne IL 60439 (United States)

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 +O2 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.

• OSTI ID: 20898695
• Journal Information: AIP Conference Proceedings, Vol. 877, Issue 1; Conference: 12. advanced accelerator concepts workshop, Lake Geneva, WI (United States), 10-15 Jul 2006; Other Information: DOI: 10.1063/1.2409158; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
ARGON
ATOMIC FORCE MICROSCOPY
BREAKDOWN
ELECTRIC POTENTIAL
ELECTRODES
ELECTRON MICROSCOPY
ETCHING
FIELD EMISSION
ION BEAMS
ION PAIRS
NIOBIUM
OXYGEN
POLISHING
RF SYSTEMS
ROUGHNESS
STAINLESS STEELS
SURFACE CLEANING
SURFACE TREATMENTS
TITANIUM