SRF2011 - List of Authors (Garich, H.M.)

Paper

Title

Page

Development and Scale-Up of an HF Free Electropolishing Process in Single-Cell Niobium SRF Cavities

397

M.E. Inman, H.M. Garich, S.T. Snyder, E.J. Taylor
Faraday Technology, Inc., Clayton, USA
L.D. Cooley, C.A. Cooper, A.M. Rowe
Fermilab, Batavia, USA

The performance of niobium SRF cavities is strongly dependent on a microscopically smooth and clean surface, achieved using buffered chemical polishing or electropolishing, which require a viscous electrolyte containing hydrofluoric acid to achieve niobium oxide breakdown and current distribution control. An ideal polishing process would include: electrolyte free of hydrofluoric acid; control of surface roughness to less than 0.1 micron; surface free from contamination; current distribution control enabling uniform polishing; removal of at least 100 microns. Faraday is working with Fermilab to develop and scale-up the FARADAYIC Electropolishing process to achieve these conditions. FARADAYIC Electropolishing combines pulse reverse electric fields and low viscosity aqueous electrolytes to control current distribution and oxide formation during metal removal. Recent results on coupon polishing will be presented including polishing rates up to 1 micron/min, control of electrolyte temperature to below 20 C, and surface finishes less than 0.2 microns over 4 mm length scales. Construction of a single-cell cavity electropolishing apparatus at Faraday are discussed.

Poster TUPO017 [1.931 MB]

Paper	Title	Page
TUPO017	Development and Scale-Up of an HF Free Electropolishing Process in Single-Cell Niobium SRF Cavities	397
	M.E. Inman, H.M. Garich, S.T. Snyder, E.J. Taylor Faraday Technology, Inc., Clayton, USA L.D. Cooley, C.A. Cooper, A.M. Rowe Fermilab, Batavia, USA
	The performance of niobium SRF cavities is strongly dependent on a microscopically smooth and clean surface, achieved using buffered chemical polishing or electropolishing, which require a viscous electrolyte containing hydrofluoric acid to achieve niobium oxide breakdown and current distribution control. An ideal polishing process would include: electrolyte free of hydrofluoric acid; control of surface roughness to less than 0.1 micron; surface free from contamination; current distribution control enabling uniform polishing; removal of at least 100 microns. Faraday is working with Fermilab to develop and scale-up the FARADAYIC Electropolishing process to achieve these conditions. FARADAYIC Electropolishing combines pulse reverse electric fields and low viscosity aqueous electrolytes to control current distribution and oxide formation during metal removal. Recent results on coupon polishing will be presented including polishing rates up to 1 micron/min, control of electrolyte temperature to below 20 C, and surface finishes less than 0.2 microns over 4 mm length scales. Construction of a single-cell cavity electropolishing apparatus at Faraday are discussed.
	Poster TUPO017 [1.931 MB]