Author: Junginger, T.
Paper Title Page
SUPFDV007 Magnetic Field Penetration of Niobium Thin Films Produced by the ARIES Collaboration 77
  • D.A. Turner
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • G. Burt, K.D. Dumbell, O.B. Malyshev, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  • E. Chyhyrynets, C. Pira
    INFN/LNL, Legnaro (PD), Italy
  • T. Junginger
    TRIUMF, Vancouver, Canada
  • T. Junginger
    UVIC, Victoria, Canada
  • S.B. Leith, M. Vogel
    University Siegen, Siegen, Germany
  • O.B. Malyshev, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • A. Medvids, P. Onufrijevs
    Riga Technical University, Riga, Latvia
  • R. Ries
    Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
  • E. Seiler
    IEE, Bratislava, Slovak Republic
  • A. Sublet
    CERN, Meyrin, Switzerland
  • J.T.G. Wilson
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  Superconducting (SC) thin film coatings on Cu substrates are already widely used as an alternative to bulk Nb SRF structures. Using Cu allows improved thermal stability compared to Nb due to having a greater thermal conductivity. Niobium thin film coatings also reduce the amount of Nb required to produce a cavity. The performance of thin film Nb cavities is not as good as bulk Nb cavities. The H2020 ARIES WP15 collaboration studied the impact of substrate polishing and the effect produced on Nb thin film depositions. Multiple samples were produced from Cu and polished with various techniques. The polished Cu substrates were then coated with a Nb film at partner institutions. These samples were characterised with surface characterisation techniques for film morphology and structure. The SC properties were studied with 2 DC techniques, a vibrating sample magnetometer (VSM) and a magnetic field penetration (MFP) facility. The results conclude that both chemical polishing and electropolishing produce the best DC properties in the MFP facility. A comparison between the VSM and the MFP facility can be made for 10 micron thick samples, but not for 3 micron thick samples.  
poster icon Poster SUPFDV007 [1.064 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPFDV007  
About • Received ※ 21 June 2021 — Accepted ※ 28 October 2021 — Issue date ※ 09 April 2022  
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TUOFDV08 First \betaNMR Results on SRF Samples at TRIUMF 365
  • E. Thoeng, J.R. Adelman, A. Chatzichristos, M. Dehn, D. Fujimoto, V.L. Karner, R. Kiefl, W.A. MacFarlane, J.O. Ticknor
    UBC & TRIUMF, Vancouver, British Columbia, Canada
  • M. Asaduzzaman, T. Junginger
    UVIC, Victoria, Canada
  • D.L. Cortie
    University of Wollongong, Institute of Superconducting and Electronic Materials, Wollongong, New South Wales, Australia
  • S.R. Dunsiger, T. Junginger, P. Kolb, R.E. Laxdal, C.D.P. Levy, R. Li, R.M.L. McFadden, I. McKenzie, G. Morris, M. Stachura
    TRIUMF, Vancouver, Canada
  The \betaNMR (\beta-detected nuclear magnetic resonance) facility at TRIUMF offers the possibility of depth-resolved probing of the Meissner state over the first §I{100}{\nano\meter} below a sample surface. The measurement can give the attenuation of the applied magnetic field, as a function of depth. The technique can be especially important when probing layered systems like the dirty/clean S-S (superconductor-superconductor) bi-layer and S-I-S (Superconductor-Insulator-Superconductor) structures. The TRIUMF SRF (Superconducting RF) group has recently completed first measurements at beta-NMR on Nb samples with various treatments. The results and method will be reported.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2021-TUOFDV08  
About • Received ※ 09 July 2021 — Revised ※ 29 September 2021 — Accepted ※ 07 May 2022 — Issue date ※ 08 May 2022
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Results and Analysis from Multi-mode Coaxial Cavity Tests  
  • P. Kolb, T. Junginger, R.E. Laxdal, Z.Y. Yao
    TRIUMF, Vancouver, Canada
  • T. Junginger
    UVIC, Victoria, Canada
  TRIUMF fabricated two coaxial test cavities (one QWR and one HWR) in order to investigate the characterization of TEM-mode cavities with standard and novel surface treatments. The cavities are intended as the TEM mode equivalent to the 1.3 GHz single cell cavity, which is the essential tool for high frequency cavity research. Given these coaxial structure, the cavities allow testing at the fundamental mode and higher harmonics, giving unique insight into the role of RF frequency on fundamental loss mechanisms from intrinsic and extrinsic sources. This talk will report the results related to the various heat treatments: 120OC bake, Mid-T bake, and Infusion. The characterization will be over a broad frequency range. In addition initial flux expulsion studies from built in Helmholtz coils will also be presented.  
slides icon Slides THOFDV01 [6.094 MB]  
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