Author: Antoine, C.Z.
Paper Title Page
FROFDV06 Synthesis of Nb and Alternative Superconducting Film to Nb for SRF Cavity as Single Layer 893
 
  • R. Valizadeh, P. Goudket, A.N. Hannah, O.B. Malyshev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • C.Z. Antoine
    CEA-DRF-IRFU, France
  • C.Z. Antoine
    CEA-IRFU, Gif-sur-Yvette, France
  • E. Chyhyrynets, C. Pira
    INFN/LNL, Legnaro (PD), Italy
  • P. Goudket, O.B. Malyshev, D.J. Seal, B.S. Sian, D.A. Turner
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • O. Kugeler, D.B. Tikhonov
    HZB, Berlin, Germany
  • S.B. Leith, A.O. Sezgin, M. Vogel
    University Siegen, Siegen, Germany
  • A. Medvids, P. Onufrijevs
    Riga Technical University, Riga, Latvia
  • D.J. Seal, B.S. Sian, D.A. Turner
    Lancaster University, Lancaster, United Kingdom
  • G.B.G. Stenning
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • A. Sublet, G. Vandoni, L. Vega Cid, W. Venturini Delsolaro, P. Vidal Garcia
    CERN, Geneva, Switzerland
 
  "Bulk niobium (Nb) has been the material of choice for superconducting RF (SRF) cavities but for further improvement in cavity RF performance, one may have to turn to films of Nb and to other superconducting materials deposited on copper as thermal and mechanical support. Other materials known as A15, such as Nb3Sn or V3Si and B1 such as NbTiN and NbN are much easier to synthesise in thin films rather than being made as bulk cavity. The potential benefits of using materials other than Nb would be a higher Tc, a potentially higher critical held Hc, leading to potentially significant cryogenics cost reduction if the cavity operation temperature is 4.2 K or higher. We report on optimising deposition parameters and effect of substrate treatment prior to deposition for successful synthesising of Nb and the alternative superconducting thin film with high superconducting properties (Tc and Hsh) on flat substrates and QPR samples in single layer. The DC and RF SC properties have been tested using PPMS and QPR measurements. This work is part of the H2020 ARIES collaboration. We further report on preparation of RF cavities employing these alternative material for future cavity production."  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-FROFDV06  
About • Received ※ 21 June 2021 — Accepted ※ 05 January 2022 — Issue date; ※ 28 April 2022  
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SUPTEV016 Samples for 3rd Harmonic Magnetometry Assessment of NbTiN-Based SIS Structures 164
 
  • D.R. Beverstock, J.R. Delayen, I.H. Senevirathne, J.K. Spradlin, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  • C.Z. Antoine
    CEA-IRFU, Gif-sur-Yvette, France
  • J.R. Delayen, I.H. Senevirathne
    ODU, Norfolk, Virginia, USA
  • D. Manos
    The College of William and Mary, Williamsburg, Virginia, USA
 
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. NSF Grants PHY-1734075 and PHY-1416051, and DOE Awards DE-SC0010081 and DE-SC0019399.
In the quest for alternative superconducting materials to bring accelerator cavity performance beyond the bulk niobium (Nb) intrinsic limits, a promising concept uses superconductor-insulator-superconductor (SIS) thin film structures that allows magnetic flux shielding in accelerator cavities to higher fields [1]. Candidate materials for such structures are NbTiN as the superconductor and AlN as the insulator. We have demonstrated high quality NbTiN and AlN deposited by reactive DC magnetron sputtering (DCMS), both for individual layers and multilayers. Interface quality has been assessed for bilayer stacks with 250 nm NbTiN layers and AlN thicknesses from 30 nm down to1 nm. These SIS structures show continued sharp interfaces with total average roughness under 2 nm. The Hfp enhancement of the films will be examined with a 3rd harmonic magnetometry. The system is being designed and built in a continuing collaboration with CEA Saclay. It can measure 25 to 50 mm samples on a temperature controlled stage. This contribution presents an overview of the design of the 3rd harmonic magnetometer and the material properties assessment of standalone films and multilayer nanostructures.
[1] A. Gurevich, Applied Physics Letters, vol. 88, p. 012511, 2006.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPTEV016  
About • Received ※ 22 June 2021 — Accepted ※ 10 November 2021 — Issue date; ※ 16 May 2022  
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MOPFDV001 Investigation of an Alternative Path for SRF Cavity Fabrication and Surface Processing 319
 
  • O. Hryhorenko, D. Longuevergne
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • C.Z. Antoine
    CEA-IRFU, Gif-sur-Yvette, France
  • F. Brisset
    ICMMO, Orsay, France
  • T. Dohmae
    KEK, Ibaraki, Japan
 
  The preparation of SRF cavities includes a lengthy, costly, and safety issued electrochemical polishing (EP or BCP) step to remove the damaged layer coming from the cavity fabrication. We have shown that most of the damage layer is originated from the rolling process during the preparation of the sheet material, while subsequent deep drawing tends to leave only µm thick damage layer. We propose a 2-steps mechanical process that allows us to easily get rid of the thick damage layer on the sheets before cavity forming. The process has been established on samples and extended to large disks ready for 1.3 GHz half-cell forming. The polished sheets will be then sent to KEK for half-cell forming and subsequent surface and material analysis before proceeding to half-cell welding. Former studies on the sample demonstrated that damages induced by forming can successfully be removed by recrystallization and less than 10 µm final chemistry.  
poster icon Poster MOPFDV001 [2.303 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPFDV001  
About • Received ※ 25 June 2021 — Revised ※ 11 July 2021 — Accepted ※ 21 August 2021 — Issue date ※ 15 May 2022
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WEPFDV007 Main Highlights of ARIES WP15 Collaboration 571
 
  • O.B. Malyshev, P. Goudket, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • C.Z. Antoine
    CEA-IRFU, Gif-sur-Yvette, France
  • O. Azzolini, E. Chyhyrynets, G. Keppel, C. Pira, F. Stivanello
    INFN/LNL, Legnaro (PD), Italy
  • G. Burt, D.J. Seal, D.A. Turner
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • G. Burt, B.S. Sian
    Lancaster University, Lancaster, United Kingdom
  • O. Kugeler, D.B. Tikhonov
    HZB, Berlin, Germany
  • S.B. Leith, A.O. Sezgin, M. Vogel
    University Siegen, Siegen, Germany
  • A. Medvids, P. Onufrijevs
    Riga Technical University, Riga, Latvia
  • R. Ries, E. Seiler
    Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
  • B.S. Sian
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Sublet, G. Vandoni, L. Vega Cid, W. Venturini Delsolaro, P. Vidal Garcia
    CERN, Geneva, Switzerland
  • D.A. Turner
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
 
  Funding: European Commission’s ARIES collaboration H2020 Research and Innovation Programme under Grant Agreement no. 730871
An international collaboration of research teams from CEA (France), CERN (Switzerland), INFN/LNL (Italy), HZB and USI (Germany), IEE (Slovakia), RTU (Latvia) and STFC/DL (UK), are working together on better understanding of how to improve the properties of superconducting thin films (ScTF) for RF cavities. The collaboration has been formed as WP15 in the H2020 ARIES project funded by EC. The systematic study of ScTF covers: Cu substrate polishing with different techniques (EP, SUBU, EP+SUBU, tumbling, laser), Nb, NbN, Nb3Sn and SIS film deposition and characterisation, Laser post deposition treatments, DC magnetisation characterisation, application of all obtained knowledge on polishing, deposition and characterisation, Laser post deposition treatments, DC magnetisation characterisation, application to the QPR samples for testing the films at RF conditions. The preparation, deposition and characterisation of each sample involves 3-5 partners enhancing the capability of each other and resulting in a more complete analysis of each film. The talk will give an overview of the collaborative research and will be an introduction to the detailed talks given by the team members.
 
poster icon Poster WEPFDV007 [2.008 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-WEPFDV007  
About • Received ※ 19 June 2021 — Accepted ※ 12 February 2022 — Issue date; ※ 10 April 2022  
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FROFDV07
Material Engineering of ALD- Deposited Multilayer to Improve the Superconducting Performances of RF Cavities Under Intense RF Fields  
 
  • Y. Kalboussi
    CEA, DES-ISAS-DM2S, Université Paris-Saclay, Gif-sur-Yvette, France
  • C.Z. Antoine, B. Delatte
    CEA-IRFU, Gif-sur-Yvette, France
  • S. Bira, D. Longuevergne
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • D. Dragoe
    ICMMO, Orsay, France
  • J. Leroy
    CEA/DRF/IRAMIS/SIS2M, Gif sur Yvette, France
  • Th. Proslier
    CEA-DRF-IRFU, France
  • S. Tusseau-Nenez
    Ecole Polytechnique, Palaiseau, France
 
  We are exploring an original approach to improve the performance of bulk Niobium RF cavities through surface engineering with ALD superconducting multilayer capable of screening efficiently the magnetic fields and therefore inhibiting vortices penetration in Niobium cavities. As a first step for the multilayer, we aim at replacing the deleterious niobium native oxide by a clean interface between an insulator synthesized by ALD (Al2O3, Y2O3 and MgO) and the Niobium metal. To that end I will present the results obtained on both flat niobium samples and 1.3 GHz elliptical cavities. Our study shows that ALD deposited films are a good diffusion barrier, resist to thermal treatments and reduce significantly the presence of the niobium native oxide on the surface. Low SEY material such as TiN was also deposited on top of the insulator film to reduce multipacting phenomena. RF test on ALD coated cavities shows already a slight improvement of the superconducting performances. In parallel we started synthesizing superconducting NbTiN alloys by ALD. I will present preliminary results on the superconducting properties of NbTiN films grown on AlN by ALD with various compositions on Nbiobium.  
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