Author: Tiskumara, J.K.
Paper Title Page
SUPTEV011 Nb3Sn Coating of Twin Axis Cavity for SRF Applications 146
 
  • J.K. Tiskumara, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • G.V. Eremeev
    Fermilab, Batavia, Illinois, USA
  • U. Pudasaini, C.E. Reece
    JLab, Newport News, Virginia, USA
 
  The twin axis cavity with two identical accelerating beams has been proposed for energy recovery linac (ERL) applications. Nb3Sn is a superconducting material with a higher critical temperature and a higher critical field as compared to Nb, which promises a lower operating cost due to higher quality factors. Two niobium twin axis cavities were fabricated at JLab and were proposed to be coated with Nb3Sn. Due to their more complex geometry, the typical coating process used for basic elliptical cavi-ties needs to be improved to coat these cavities. This development advances the current coating system at JLab for coating complex cavities. Two twin axis cavities were coated recently for the first time. This contribution dis-cusses initial results from coating of twin axis cavities, RF testing and witness sample analysis with an overview of the current challenges towards high performance Nb3Sn coated twin axis cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPTEV011  
About • Received ※ 22 June 2021 — Revised ※ 19 December 2021 — Accepted ※ 21 February 2022 — Issue date ※ 01 April 2022
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TUPTEV013 Managing Sn-Supply to Tune Surface Characteristics of Vapor-Diffusion Coating of Nb3Sn 516
 
  • U. Pudasaini, C.E. Reece
    JLab, Newport News, Virginia, USA
  • J.K. Tiskumara
    ODU, Norfolk, Virginia, USA
 
  Funding: Authored by Jefferson Science Associates under contract no. DE¬AC05¬06OR23177
Nb3Sn promises better RF performance (Q and Eacc) than niobium at any given temperature because of superior superconducting properties. Nb3Sn-coated SRF cavities are now produced routinely by growing a few microns thick Nb3Sn films inside Nb cavities via the tin vapor diffusion technique. Sn evaporation and consumption during the growth process notably affect the quality of the coating. Aiming at favorable surface characteristics that could enhance the RF performance, many coatings were produced by varying Sn sources and temperature profiles. Coupon samples were examined using different material characterization techniques, and a selected few sets of coating parameters were used to coat 1.3 GHz single-cell cavities for RF testing. The Sn supply’s careful tuning is essential to manage the microstructure, roughness, and overall surface characteristics of the coating. We summarize the material analysis of witness samples and discuss the performance of several Nb3Sn-coated single-cell cavities linked to Sn-source characteristics and observed Sn consumption during the film growth process.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPTEV013  
About • Received ※ 21 June 2021 — Revised ※ 09 October 2021 — Accepted ※ 15 December 2021 — Issue date ※ 22 February 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)