SRF2011 - List of Authors (Mammosser, J.D.)

Paper	Title	Page
TUPO031	Update on the R&D of Vertical Buffered Electropolishing on Nb Samples and SRF Single Cell Cavities	442
	A.T. Wu, J.D. Mammosser, R.A. Rimmer JLAB, Newport News, Virginia, USA S. Jin, L. Lin, X.Y. Lu, K. Zhao PKU/IHIP, Beijing, People's Republic of China
	Electropolishing (EP) has become a popular choice as the final step of the surface removal process during the fabrication of Nb superconducting radio frequency (SRF) cavities. One of the major reasons for the choice is that Nb SRF cavities treated by EP tend to have a better chance to reach an accelerating gradient of 30MV/m or higher. This advantage of EP over BCP can at least be partially attributed to the smoother Nb surfaces that EP can produce. Recently a Nb surface removal technique called buffered electropolishing (BEP) was developed at JLab, which could produce the smoothest surface finish. In this contribution, R&D efforts of vertical BEP on Nb small samples and SRF single cell cavities since the last SRF conference in 2009 will be updated. It is shown that under a suitable condition, BEP can have a Nb removal rate as high as 10 μm/mim that is more than 25 and 5 times quicker than those of EP and BCP(112) respectively. Possible mechanisms responsible for the high Nb removal rate are proposed. Clues on the optimization of vertical BEP and EP treatments on Nb SRF cavities from recent experimental results obtained on a Nb single cell demountable cavity will be discussed. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.

Paper

Title

Page

Update on the R&D of Vertical Buffered Electropolishing on Nb Samples and SRF Single Cell Cavities

442

A.T. Wu, J.D. Mammosser, R.A. Rimmer
JLAB, Newport News, Virginia, USA
S. Jin, L. Lin, X.Y. Lu, K. Zhao
PKU/IHIP, Beijing, People's Republic of China

Electropolishing (EP) has become a popular choice as the final step of the surface removal process during the fabrication of Nb superconducting radio frequency (SRF) cavities. One of the major reasons for the choice is that Nb SRF cavities treated by EP tend to have a better chance to reach an accelerating gradient of 30MV/m or higher. This advantage of EP over BCP can at least be partially attributed to the smoother Nb surfaces that EP can produce. Recently a Nb surface removal technique called buffered electropolishing (BEP) was developed at JLab, which could produce the smoothest surface finish. In this contribution, R&D efforts of vertical BEP on Nb small samples and SRF single cell cavities since the last SRF conference in 2009 will be updated. It is shown that under a suitable condition, BEP can have a Nb removal rate as high as 10 μm/mim that is more than 25 and 5 times quicker than those of EP and BCP(112) respectively. Possible mechanisms responsible for the high Nb removal rate are proposed. Clues on the optimization of vertical BEP and EP treatments on Nb SRF cavities from recent experimental results obtained on a Nb single cell demountable cavity will be discussed.
Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.