TUPCAV —  Tuesday Poster Cavities   (29-Jun-21   11:10—12:10)
Paper Title Page
TUPCAV001 Vertical Electro-Polishing of 704 MHz Resonators Using Ninja Cathode: First Results 431
  • F. Éozénou, M. Baudrier, E. Cenni, E. Fayette, L. Maurice, C. Servouin
    CEA-DRF-IRFU, France
  • V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • H. Hayano, H. Ito, S. Kato, T. Kubo, H. Monjushiro, T. Saeki
    KEK, Ibaraki, Japan
  • G. Jullien
    CEA-IRFU, Gif-sur-Yvette, France
  Vertical Electro-Polishing (VEP) of elliptical cavities using rotating Ninja cathodes (Marui Company patented technology) has continually been improved since 2012 and successfully applied for 1300MHz multicell ILC-type resonators. The goal of the presented study is to apply this technology to 704 MHz ESS-type resonators with both better Q0 and accelerating gradients in mind. We intend to demonstrate the superiority of VEP compared to standard Buffer Chemical Polishing (BCP), for possible applications such as MYRRHA accelerator. We describe here the promising results achieved on β=0.86 single-cell cavity after 200 µm uniform removal. The cavity quenched at 27 MV/m without any heat treatment. The surface resistance achieved was less than 5nΩ at 1.8K. Substantial performance improvement is expected after heat treatment of the cavity and additional 20 µm VEP sequence. A cathode for 5-Cell ESS cavity is concomitantly under design stage.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV001  
About • Received ※ 21 June 2021 — Revised ※ 16 August 2021 — Accepted ※ 23 August 2021 — Issue date ※ 17 March 2022
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TUPCAV002 HOM Excitation in Spoke Resonator for SRF Studies 435
  • D. Longuevergne, N. Bippus, F. Chatelet, V. Delpech, N. Hu, C. Joly, T. Pépin-Donat, F. Rabehasy, L. Renard
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • M. Baudrier
    CEA-DRF-IRFU, France
  • E. Cenni, L. Maurice
    CEA-IRFU, Gif-sur-Yvette, France
  The excitation of Higher Order Modes (HOM) or Lower Order Modes (LOM) has been performed for years on multi-cell superconducting accelerating cavities as a mean to coarsely locate a quench, a defective area or ignite a plasma for surface cleaning. Moreover, such multi-mode testing is very useful to understand more accurately the frequency dependence of the surface resistance in a wide range of surface magnetic fields (0<B<150mT). In that sense, several type of dedicated non-accelerating resonators like Quadrupole Resonator (QPR), Half- or Quarter- Wave resonators have been built to specifically study new superconducting materials or new surface or heat treatments. What is proposed in this paper is to perform such multi-mode analysis (352 MHz, 720 MHz and 1300 MHz) in an existing accelerating cavity, in particular a Spoke Resonator. Baseline results will be presented and perspectives of such technique will be discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV002  
About • Received ※ 22 June 2021 — Revised ※ 19 July 2021 — Accepted ※ 23 August 2021 — Issue date ※ 15 April 2022
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TUPCAV003 1.3 GHz Seamless Copper Cavities via CNC Spinning Technique 440
  • F. Sciarrabba, O. Azzolini, G. Keppel, C. Pira
    INFN/LNL, Legnaro (PD), Italy
  • I. Calliari, R. Guggia, L. Pezzato, M. Pigato
    UNIPD, Padova, Italy
  The spinning process is an established technology for the production of seamless resonant cavities. The main drawback is that, so far, a manual process is adopted, so the quality of the product is subject to the worker’s skills. The Compute Numerical Controlled (CNC) applied to the spinning process can be used to limit this problem and increase the reproducibility and geometrical accuracy of the cavities obtained. This work reports the first 1.3 GHz SRF seamless copper cavities produced by CNC spinning at the Laboratori Nazionali di Legnaro of INFN. For this purpose, metrological analysis were conducted to verify the geometrical accuracy of the cavities after different steps of forming and thermal treatments; axial profile and wall thickness measurements were carried out, investigating different zones of the cavity profile. The cavities were also characterized through mechanical and microstructural analysis, to identify the effect of the automatic forming process applied to the production process of the 1.3 GHz SRF seamless copper cavities.  
poster icon Poster TUPCAV003 [1.025 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV003  
About • Received ※ 21 June 2021 — Revised ※ 12 July 2021 — Accepted ※ 23 August 2021 — Issue date ※ 24 December 2021
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TUPCAV004 Deflecting Cavities for Proton Beam Spreader in CiADS Project 445
  • Y.L. Huang, Y. He, H. Jia, Y.S. Qin, Z.J. Wang, Z.L. Zhang
    IMP/CAS, Lanzhou, People’s Republic of China
  Funding: Large Research Infrastructures "China initiative Accelerator Driven System’(Grant No.2017-000052-75-01-000590 ) and National Natural Science Foundation of China (Grant NO. 11805249)
Chinese initiative Accelerator Driven Subcritical System (CiADS) is supposed to accelerate continuous 162.5 MHz, 10 mA (or higher) proton beam to 500 MeV (or higher energy) with a superconducting driver linac. More application scenarios based on this high power intensity proton linac are now under considerations. Beam spreader system based on deflecting cavities for multiple users simultaneous operation are discussed in this paper, as well as the RF structure options for the equal eight- and nigh- beam-line split schemes.
poster icon Poster TUPCAV004 [1.074 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV004  
About • Received ※ 21 June 2021 — Revised ※ 16 August 2021 — Accepted ※ 23 August 2021 — Issue date ※ 13 May 2022
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TUPCAV005 Toward Qualifications of HB and LB 650MHz Cavities for the Prototype Cryomodules for the PIP-II Project 448
  • M. Martinello, D.J. Bice, C. Boffo, S.K. Chandrasekaran, G.V. Eremeev, F. Furuta, T.N. Khabiboulline, K.E. McGee, A.V. Netepenko, J.P. Ozelis, A.I. Sukhanov, G. Wu
    Fermilab, Batavia, Illinois, USA
  • M. Bagre, V. Jain, A. Puntambekar, S. Raghvendra, P. Shrivastava
    RRCAT, Indore (M.P.), India
  • M. Bertucci, A. Bosotti, C. Pagani, R. Paparella
    INFN/LASA, Segrate (MI), Italy
  • P. Bhattacharyya, S. Ghosh, S. Ghosh, A. Mandal, S. Seth, S. Som
    VECC, Kolkata, India
  • M.P. Kelly, T. Reid
    ANL, Lemont, Illinois, USA
  • S.H. Kim, K.E. McGee, P.N. Ostroumov
    FRIB, East Lansing, Michigan, USA
  • K.K. Mistri, P.N. Prakash
    IUAC, New Delhi, India
  High-beta (HB) and low-beta (LB) 650 MHz cryomodules are key components of the Proton Improvement Plan II (PIP-II) project. In this contribution we present the results of several 5-cell HB650 cavities that have been processed and tested with the purpose of qualifying them for the prototype cryomodule assembly, which will take place later this year. We also present the first results obtained in LB650 single-cell cavities process optimization. Taking advantage of their very similar geometry, we are also analyzing the effect of different surface treatments in FRIB’s 5-cell medium-beta 644MHz cavities. Cavities processed with N-doping and mid-T baking showed very promising results in term of both Q-factors and accelerating gradient for these low-beta structures.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV005  
About • Received ※ 01 July 2021 — Accepted ※ 02 November 2021 — Issue date; ※ 16 May 2022  
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TUPCAV006 Nb₃Sn Films Depositions from Targets Synthesized via Liquid Tin Diffusion 452
  • M. Zanierato, O. Azzolini, E. Chyhyrynets, V.A. Garcia Diaz, G. Keppel, C. Pira, F. Stivanello
    INFN/LNL, Legnaro (PD), Italy
  The deposition of Nb3Sn on copper cavities is inter-esting for the higher thermal conductivity of copper compared to common Nb substrates. The better heat exchange would allow the use of cryocoolers reducing cryogenic costs and the risk of thermal quench [1]. Magnetron sputtering technology allows the deposi-tion of Nb3Sn on substrates different than Nb, however the coating of substrates with complex geometry (such as elliptical cavities) may require targets with non-planar shape, difficult to realize with classic powder sintering techniques. In this work, the possibility of using the Liquid Tin Diffusion (LTD) technique to produce sputtering targets is explored. The LTD tech-nique is a wire fabrication technology, already devel-oped in the past at LNL for SRF applications [2], that allows the deposition of very thick and uniform coat-ing on Nb substrates even with complex geometry [3]. Improvements in LTD process, proof of concept of a single use LTD target production, and characterization of the Nb3Sn film coated by DC magnetron sputtering with these innovative targets are reported in this work.  
poster icon Poster TUPCAV006 [5.032 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV006  
About • Received ※ 21 June 2021 — Revised ※ 12 July 2021 — Accepted ※ 23 August 2021 — Issue date ※ 02 September 2021
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TUPCAV009 AMR Sensors Studies and Development for Cavities Tests Magnetometry at CEA 457
  • J. Plouin, E. Cenni, L. Maurice
    CEA-DRF-IRFU, France
  Studying flux expulsion during superconducting cavities test increases the need for exhaustive magnetometric cartography. The use of Anistropic Magneto Resistance (AMR) sensors, much cheaper than commercial fluxgates, allows the use of tens of sensors simultaneously. Such sensors are developed and sold for room temperature application but are resistant to cryogenic temperatures. However, they need proper calibration, which is more difficult at cryogenic temperature. Actually, this calibration uses the flip of the magnetization of the anisotropic ferromagnetic element, which coercitive field is increased at low temperature. We will present the development of method and software carried out at CEA for the use of such sensors, as well as the preliminary design of a rotating magnetometric device destined to elliptical cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV009  
About • Received ※ 22 June 2021 — Revised ※ 13 January 2022 — Accepted ※ 22 February 2022 — Issue date ※ 22 February 2022
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TUPCAV010 Application of the ASME Boiler and Pressure Vessel Code in the Design of SRF Cavities at Fermilab 460
  • C.S. Narug, M. Parise, D. Passarelli
    Fermilab, Batavia, Illinois, USA
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
Jacketed Superconducting Radio Frequency (SRF) cavities structurally comprise of an inner niobium vessel surrounded by a liquid helium containment vessels. The pressure of the helium bath and/or its volume might be such that a jacketed SRF cavity shall be considered a system of pressure vessels. Thus, methods described in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) should be used to analyze the structural soundness of jacketed SRF cavities. This paper will report the use of the set of rules developed at Fermilab for the design of SRF cavities, such as jacketed 1.3 GHz cavities for LCLS-II HE and jacketed Single Spoke Resonator type~2 (SSR2) for PIP-II, to ensure a similar level of safety as prescribed by the ASME BPVC.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV010  
About • Received ※ 22 June 2021 — Accepted ※ 23 August 2021 — Issue date; ※ 12 December 2021  
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TUPCAV013 STC Qualification Tests of PIP-II HB650 Cavities 465
  • A.I. Sukhanov, S.K. Chandrasekaran, G.V. Eremeev, F. Furuta, S. Kazakov, T.N. Khabiboulline, T.H. Nicol, Y.M. Pischalnikov, O.V. Prokofiev, V. Roger, G. Wu, V.P. Yakovlev, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
  Design of the high beta 650 MHz prototype cryomodule for PIP-II is currently undergoing at Fermilab. The cryomodule includes six 5-cell elliptical SRF cavities with accelerating voltage up to 20 MV and low heat dissipation (Q0 > 3.3 · 10zEhNZeHn). Characterization of performance of fully integrated jacketed cavities with high power coupler and tuner is crucial for the project. Such a characterization of jacketed cavity requires a horizontal test cryostat. The Fermilab Spoke Test Cryostat (STC) has been upgraded to accommodate testing of 650 MHz cavities. Commissioning of upgraded STC has been reported at SRF’19 conference. In this paper we present results of testing of the prototype HB650 cavity in upgraded STC facility. We characterize cavity performance and qualify it for the prototype HB650 cryomodule assembly.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV013  
About • Received ※ 21 June 2021 — Accepted ※ 21 August 2021 — Issue date; ※ 04 October 2021  
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TUPCAV014 Design of a Third Harmonic Cavity With Low R/Q for the ESR in BNL EIC 469
  • B.P. Xiao
    BNL, Upton, New York, USA
  Funding: The work is supported by by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
For the electron Storage Ring (ESR) of Brookhaven National Lab Electron Ion Collider (BNL EIC), beam loading is a great concern due to the high beam current together with abortion gap, especially for harmonic cavities due to higher operational frequency. There were attempts to use feedback/feedforward control, using multiple cavities with counter-phasing. A straightforward way to lower beam loading effect is to design a cavity with low R/Q. In this paper, we show such a design for the 3rd harmonic cavity for BNL EIC ESR.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV014  
About • Received ※ 22 June 2021 — Revised ※ 12 November 2021 — Accepted ※ 11 February 2022 — Issue date ※ 22 February 2022
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TUPCAV015 Performance of a Low Frequency QWR-Based SRF Gun 472
  • G. Chen, M.V. Fisher, M. Kedzie, M.P. Kelly, T.B. Petersen, T. Reid
    ANL, Lemont, Illinois, USA
  • X. Lu, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
Superconducting radio-frequency (SRF) electron guns are generally considered to be an effective way of producing beams with high brightness and high repetition rates (or continuous wave). In this work, the 199.6 MHz quarter wave resonator (QWR)-based Wisconsin Free Electron Laser (WiFEL) superconducting electron gun was recently refurbished and tested at Argonne (ANL). The field performance of the e-gun was fully characterized. During this time, multipacting (MP) conditioning was performed for over 20 hours to overcome the hard MP barrier observed in the accelerating voltage range of 8 to 40 kV; the presence of multipacting is expected to operationally important for future e-guns. Here we simulated and studied the effect using CST* Microwave Studio and Particle Studio and compare with the measured data.
* CST Studio Suite, version 2020, https://www.cst.com.
poster icon Poster TUPCAV015 [4.870 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV015  
About • Received ※ 21 June 2021 — Revised ※ 20 December 2021 — Accepted ※ 22 February 2022 — Issue date ※ 23 March 2022
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