Document Type

Article

Publication Date

2017

DOI

10.1063/1.4991888

Publication Title

AIP Advances

Volume

7

Issue

12

Pages

1-5

Abstract

An apparatus and a method for etching of the inner surfaces of superconducting radio frequency (SRF) accelerator cavities are described. The apparatus is based on the reactive ion etching performed in an Ar/Cl2 cylindrical capacitive discharge with reversed asymmetry. To test the effect of the plasma etching on the cavity rf performance, a 1497 MHz single cell SRF cavity was used. The single cell cavity was mechanically polished and buffer chemically etched and then rf tested at cryogenic temperatures to provide a baseline characterization. The cavity's inner wall was then exposed to the capacitive discharge in a mixture of Argon and Chlorine. The inner wall acted as the grounded electrode, while kept at elevated temperature. The processing was accomplished by axially moving the dc-biased, corrugated inner electrode and the gas flow inlet in a step-wise manner to establish a sequence of longitudinally segmented discharges. The cavity was then tested in a standard vertical test stand at cryogenic temperatures. The rf tests and surface condition results, including the electron field emission elimination, are presented.

Comments

Published under a Creative Commons Attribution 3.0 Unported License.

(https://creativecommons.org/licenses/by/3.0/)

Original Publication Citation

Upadhyay, J., Palczewski, A., Popovic, S., Valente-Feliciano, A. M., Im, D., Phillips, H. L., & Vuskovic, L. (2017). Cryogenic rf test of the first SRF cavity etched in an rf Ar/Cl2 plasma. Aip Advances, 7(12), 5. doi:10.1063/1.4991888

ORCID

0000-0003-1364-0579 (Janardan Upadhyay), 0000-0002-3668-4841 (Svetozar Popovic)

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