SRF2011 - List of Authors (Dole, N.)

Paper

Title

Page

Detailed Nb Surface Morphology Evolution During Electropolishing for SRF Cavity Production

802

H. Tian, C.E. Reece
JLAB, Newport News, Virginia, USA
S.R. Brankovic, N. Dole
University of Houston, Houston TX, USA

Electropolishing is currently an important part of attaining the best performance of SRF cavities. We endeavor to develop sufficient understanding of the process dynamics to gain predictive power over specific topographies subjected to controlled electropolishing conditions. This work examines the evolution of highly reproducible Nb surface morphology produced by centrifugal barrel polishing of fine-grain and single-crystal material as this material is electropolished under different well-controlled conditions. The morphology evolution of Nb surface has been described using a combined approach of scaling analysis and predictions of the electropolishing theory. Our results shows that electropolishing at low temperature helps to smooth out the surface feature scales within the diffusion layer and to reduce the kinetics-controlled surface etching. A preliminary computational model has been developed that simulates the evolution of specific topography of a niobium surface under parametrized conditions. This work is expected to lead to the direct linking of starting surface morphology specification, specific processing protocol, and consistently attained finished surface condition.

Poster THPO038 [0.895 MB]

Paper	Title	Page
THPO038	Detailed Nb Surface Morphology Evolution During Electropolishing for SRF Cavity Production	802
	H. Tian, C.E. Reece JLAB, Newport News, Virginia, USA S.R. Brankovic, N. Dole University of Houston, Houston TX, USA
	Electropolishing is currently an important part of attaining the best performance of SRF cavities. We endeavor to develop sufficient understanding of the process dynamics to gain predictive power over specific topographies subjected to controlled electropolishing conditions. This work examines the evolution of highly reproducible Nb surface morphology produced by centrifugal barrel polishing of fine-grain and single-crystal material as this material is electropolished under different well-controlled conditions. The morphology evolution of Nb surface has been described using a combined approach of scaling analysis and predictions of the electropolishing theory. Our results shows that electropolishing at low temperature helps to smooth out the surface feature scales within the diffusion layer and to reduce the kinetics-controlled surface etching. A preliminary computational model has been developed that simulates the evolution of specific topography of a niobium surface under parametrized conditions. This work is expected to lead to the direct linking of starting surface morphology specification, specific processing protocol, and consistently attained finished surface condition.
	Poster THPO038 [0.895 MB]