Author: Caforio, R.
Paper Title Page
SUPTEV002 Application of Plasma Electrolytic Polishing onto SRF Substrates 116
 
  • E. Chyhyrynets, O. Azzolini, R. Caforio, V.A. Garcia Diaz, G. Keppel, C. Pira, F. Stivanello, M. Zanierato
    INFN/LNL, Legnaro (PD), Italy
 
  Funding: Work supported by the INFN CSNV experiment TEFEN. This project has received funding from the Euro-pean Union’s Horizon 2020 Research and Innovation programme under GA No 101004730.
A new promising approach of SRF substrates surface treatment has been studied - Plasma Electrolytic Polishing (PEP). The possible application of PEP can be used not only on conventional elliptical resonators, but also on other components of SRF such as, for example, couplers or Quadrupole resonators (QPRs). However, SRF application of PEP represents a challenge since it requires a different approach to treat the inner surface of elliptical cavities respect to electropolishing. In this work, the main problematics and possible solutions, the equipment, and the polishing system requirements will be shown. A proposed polishing system for 6 GHz elliptical cavities and QPRs will be shown and discussed.
 
poster icon Poster SUPTEV002 [2.710 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPTEV002  
About • Received ※ 21 June 2021 — Revised ※ 08 July 2021 — Accepted ※ 12 August 2021 — Issue date ※ 22 April 2022
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SUPTEV003 Cu/Nb QPR Surface Preparation Protocol in the Framework of ARIES Project 121
 
  • E. Chyhyrynets, O. Azzolini, R. Caforio, V.A. Garcia Diaz, G. Keppel, C. Pira, F. Stivanello
    INFN/LNL, Legnaro (PD), Italy
 
  Funding: Work supported by the INFN CSNV experiment TEFEN. This project has received funding from the European Union’s Horizon 2020 Research and Innovation Pro-gramme under Grant Agreement no. 730871.
The Quadrupole Resonator is a powerful tool for SRF R&D on thin films. It allows to perform Q vs E measurements on flat sample rather than a curved surface of a cavity. For the investigation of SC coatings on copper substrates, e-beam welded Cu/Nb samples have been prepared for the QPR. However, the presence of two metals, in particular at the interface makes proper polishing of both surfaces challenging due the different chemical behaviour of both components. In this work we present the protocol developed for surface preparation of the coexisting Cu and Nb phases and the results obtained for 5 different samples. The work was performed in the framework of the ARIES project.
 
poster icon Poster SUPTEV003 [2.506 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPTEV003  
About • Received ※ 21 June 2021 — Revised ※ 08 July 2021 — Accepted ※ 12 August 2021 — Issue date ※ 27 September 2021
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THOTEV06 Plasma Electrolytic Polishing as a Promising Treatment Replacement of Electropolishing in the Copper and Niobium Substrate Preparation for SRF 718
 
  • C. Pira, O. Azzolini, R. Caforio, E. Chyhyrynets, V.A. Garcia, G. Keppel, F. Stivanello
    INFN/LNL, Legnaro (PD), Italy
 
  Superconducting radio frequency (SRF) cavities performances strongly depend on the substrate preparation. Currently, the conventional protocol of SRF surface preparation includes electropolishing (EP) as the main treatment achieving low roughness, clean and non-contaminated surfaces, both for bulk Nb and Cu substrates. Harsh and non-environmentally friendly solutions are typically used: HF and H2SO4 mixture for Nb, and H3PO4 with Butanol mixtures for EP of Cu. This research is focused on the application of a relatively new technique "Plasma Electrolytic Polishing" (PEP) for the SRF needs. PEP technology is an evolution of EP with a list of advantages that SRF community can benefit from. PEP requires diluted salt solutions moving to a greener approach in respect to EP. PEP can in principle substitute, or completely eliminate, intermediate steps, like mechanical and/or (electro) chemical polishing. Thanks to the superior removing rate in the field (up to 3.5 µm/min of Nb, and 10 µm/min of Cu) in one single treatment roughness below 100 nm Ra has been obtained both for Nb and Cu. In the present work a proof of concept is shown on Nb and Cu planar samples.  
slides icon Slides THOTEV06 [7.197 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-THOTEV06  
About • Received ※ 21 June 2021 — Accepted ※ 18 October 2021 — Issue date; ※ 01 May 2022  
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