Keyword: experiment
Paper Title Other Keywords Page
SUPCAV005 Current Status of the ALPI Linac Upgrade for the SPES Facilities at INFN LNL cavity, linac, acceleration, niobium 11
 
  • A. Tsymbaliuk, D. Bortolato, F. Chiurlotto, E. Chyhyrynets, G. Keppel, E. Munaron, C. Pira, F. Stivanello
    INFN/LNL, Legnaro (PD), Italy
  • E. Chyhyrynets
    Università degli Studi di Padova, Padova, Italy
  • A. Tsymbaliuk
    UNIFE, Ferrara, Italy
 
  The SPES project is based at INFN LNL and covers basic research in nuclear physics, radionuclide production, materials science research, nuclear technology and medicine. The Radioactive Ion Beam (RIB) produced by SPES will be accelerated by ALPI, which is a linear accelerator, equipped with superconducting quarter wave resonators (QWRs) and operating at LNL since 1990. For RIB acceleration it is mandatory to perform an upgrade of ALPI which consists of the implementation of two additional cryostats, containing 4 accelerating cavities each, in the high-ß section. The QWRs production technology is well established. The production technology of Nb/Cu QWRs should be adjusted for high-ß cavities production. In the framework of the upgrade, several vacuum systems were refurbished, optimal parameters of the biased sputtering processes of copper QWR cavities and plates were defined. The process of mechanical and chemical preparation, sputtering and cryogenic measurement of the high-ß Nb/Cu QWR cavities were adjusted. Several QWR cavities were already produced and measured. Currently, the production of the Nb/Cu sputtered QWR cavities and plates is ongoing.  
poster icon Poster SUPCAV005 [0.938 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPCAV005  
About • Received ※ 21 June 2021 — Revised ※ 07 July 2021 — Accepted ※ 12 August 2021 — Issue date ※ 29 April 2022
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SUPCAV009 First Nb3Sn Coating and Cavity Performance Result at KEK cavity, SRF, radio-frequency, superconducting-RF 27
 
  • K. Takahashi, T. Okada
    Sokendai, Ibaraki, Japan
  • H. Ito, E. Kako, T. Konomi, H. Sakai, K. Umemori
    KEK, Ibaraki, Japan
 
  At KEK, Nb3Sn vapor diffusion R&D for High-Q has just started. We have performed Nb3Sn coating on niobium samples and characterized these samples. We optimized the cavity coating parameter from the result of characterized samples. After optimizing the parameter, we have performed Nb3Sn coating on a TESLA-like single-cell Nb cavity and measured cavity performance in vertical tests. This presentation presents the result of the cavity coating and performance results.  
poster icon Poster SUPCAV009 [1.477 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPCAV009  
About • Received ※ 21 June 2021 — Accepted ※ 18 March 2022 — Issue date; ※ 16 May 2022  
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SUPCAV016 Studies on the Fundamental Mechanisms of Niobium Electropolishing cavity, niobium, SRF, electron 50
 
  • E.A.S. Viklund, D.N. Seidman
    NU, Evanston, Illinois, USA
  • L. Grassellino, S. Posen, T.J. Ring
    Fermilab, Batavia, Illinois, USA
 
  To improve the superconducting performance of niobium SRF cavities, electropolishing (EP) with a sulfuric and hydroflouric acid mixture is used. The chemistry of this reaction is complex due to the interactions between diffusion mechanisms, surface oxide structure, and multiple chemical species. Past studies on the EP process have produced a certain set of optimum parameters that have been used successfully for a long time. However, two recent developments have called the efficacy of the existing EP process into question. Since the introduction of nitrogen doping the surface quality of some cavities has been very poor. Also, EP performed at colder than standard temperatures leads to an increase in the cavity performance. To understand these questions, we perform a multivariate study on the EP process using niobium test samples electropolished at different temperatures and potentials. We find that electropolishing at lower potentials leads to rough surface features such as pitting and grain etching. Some of the surface features show similarities to features seen in niobium cavities. The effect of electropolishing temperature is not clear based on the results of this study.  
poster icon Poster SUPCAV016 [2.447 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPCAV016  
About • Received ※ 22 June 2021 — Revised ※ 21 August 2021 — Accepted ※ 29 September 2021 — Issue date ※ 15 November 2021
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SUPFDV015 Preliminary Results from Magnetic Field Scanning System for a Single-Cell Niobium Cavity cavity, SRF, niobium, MMI 96
 
  • I.P. Parajuli, G. Ciovati, J.R. Delayen, A.V. Gurevich
    ODU, Norfolk, Virginia, USA
  • G. Ciovati, J.R. Delayen
    JLab, Newport News, Virginia, USA
 
  One of the building blocks of modern particle accelerators is superconducting radiofrequency (SRF) cavities. Niobium is the material of choice to build such cavities, which operate at liquid helium temperature (2 - 4 K) and have some of the highest quality factors found in Nature. There are several sources of residual losses, one of them is trapped magnetic flux, which limits the quality factor in SRF cavities. The flux trapping mechanism depends on different niobium surface preparations and cool-down conditions. Suitable diagnostic tools are not yet available to study the effects of such conditions on magnetic flux trapping. A magnetic field scanning system (MFSS) for SRF cavities using Hall probes and Fluxgate magnetometer has been designed, built, and is commissioned to measure the local magnetic field trapped in 1.3 GHz single-cell SRF cavities at 4 K. In this contribution, we will present the preliminary results from MFSS for a single cell niobium cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPFDV015  
About • Received ※ 21 June 2021 — Revised ※ 13 August 2021 — Accepted ※ 08 November 2021 — Issue date ※ 27 April 2022
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MOPTEV006 Synchrotron XPS Study of Niobium Treated with Nitrogen Infusion niobium, vacuum, cavity, synchrotron 211
 
  • A.L. Prudnikava, J. Knobloch, O. Kugeler, Y. Tamashevich
    HZB, Berlin, Germany
  • V. Aristov, O. Molodtsova
    DESY, Hamburg, Germany
  • S. Babenkov
    LIDYL, Gif sur Yvette, France
  • A. Makarova
    FUB, Berlin, Germany
  • D. Smirnov
    Technische Universität Dresden, Dresden, Germany
 
  Processing of niobium cavities with the so-called ni-trogen infusion treatment demonstrates the improve-ment of efficiency and no degradation of maximal accelerating gradients. However, the chemical compo-sition of the niobium surface and especially the role of nitrogen gas in this treatment has been the topic of many debates. While our study of the infused niobium using synchrotron X-ray Photoelectron Spectroscopy (XPS) showed modification of the surface sub-oxides surprisingly there was no evidence of nitrogen con-centration build up during the 120°C baking step, irre-spectively of N2 supply. Noteworthy, that the niobium contamination with carbon and nitrogen took place during a prolonged high-temperature anneal even in a high vacuum condition (10-8-10-9 mbar). Evidently, the amount of such contamination appears to play a key role in the final cavity performance  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPTEV006  
About • Received ※ 21 June 2021 — Revised ※ 13 July 2021 — Accepted ※ 19 August 2021 — Issue date ※ 05 September 2021
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MOPTEV009 A Method for In-Situ Q0 Measurements of High-Quality SRF Resonators beat-wave, cavity, SRF, resonance 221
 
  • S.V. Kuzikov, P.V. Avrakhov, C.-J. Jing, R.A. Kostin, Y. Zhao
    Euclid TechLabs, Solon, Ohio, USA
  • C.-J. Jing, C.-J. Jing
    ANL, Lemont, Illinois, USA
  • C.-J. Jing, R.A. Kostin
    Euclid Beamlabs, Bolingbrook, USA
  • R.A. Kostin, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • T. Powers, R.A. Rimmer
    JLab, Newport News, Virginia, USA
 
  Funding: The work was supported in the part by DoE SBIR grant #DE-SC0019687.
Accelerator projects such as LCLS-II naturally require low-loss superconducting (SRF) cavities. Due to strong demand for improving intrinsic quality factor (Q0), importance of accurate cavity characterization increases. We propose a method to measure Q0 in situ for an SRF resonator installed in its cryogenic module and connected with a RF feed source via a fixed RF coupler. The method exploits measurements of a response for an SRF resonator fed by an amplitude-modulated signal. Such a signal can be synthesized as a beat-wave composed of two frequencies that are close to the resonant frequency. Analyzing the envelope of the reflected signal, one can find the difference in reflection for the chosen frequencies and use them to compute the intrinsic Q. We also develop the methodology to carry out measurements of Q0 at the nominal cavity operating voltage. We verified our method in experiments with a room temperature copper resonator and with two SRF resonators including Fermilab’s 650 MHz cavity and JLab’s 1500 MHz cavity.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPTEV009  
About • Received ※ 15 June 2021 — Revised ※ 26 August 2021 — Accepted ※ 19 February 2022 — Issue date ※ 06 April 2022
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MOPCAV006 High-Q/High-G R&D at KEK Using 9-Cell TESLA-Shaped Niobium Cavities cavity, SRF, niobium, vacuum 268
 
  • R. Katayama, A. Araki, H. Ito, E. Kako, T. Konomi, S. Michizono, M. Omet, K. Umemori
    KEK, Ibaraki, Japan
 
  We will report on the current progress of High-Q/High-G R&D using three 1.3 GHz 9-cell TESLA shape niobium superconducting cavities at the High Energy Accelerator Research Organization (KEK). These cavities are made of bulk niobium of fine grain material with RRR >300 and have been annealed at 900 degrees for 3 hours. The cavity performances were evaluated at the Superconducting RF Test Facility at KEK (KEK-STF) after 2-step bake (70-75°C 4 h + 120°C 48 h), electropolishing at low temperature, and fast cooling procedure were applied to these cavities. In this study, obtained results will be compared with the baseline measurement for the standard recipe at KEK.  
poster icon Poster MOPCAV006 [1.876 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPCAV006  
About • Received ※ 22 June 2021 — Revised ※ 14 January 2022 — Accepted ※ 22 February 2022 — Issue date ※ 28 February 2022
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MOPCAV011 Fabrication Process of Single Spoke Resonator Type-2 (SSR2) for RISP cavity, niobium, SRF, superconducting-cavity 283
 
  • M.O. Hyun, J. Joo, H.C. Jung, Y. Kim
    IBS, Daejeon, Republic of Korea
 
  Funding: This paper was supported by the Rare Isotope Science Project (RISP), which is funded by the Ministry of Science and ICT (MSIT) and National Research Foundation (NRF) of the Republic of Korea.
Rare Isotope Science Project (RISP) in the Institute of Basic Science (IBS), South Korea, is now constructing superconducting linear accelerator 3 (SCL3) for low-energy beam experiment and also making prototypes of superconducting cavity, RF power coupler, tuner, and cryomodule of superconducting (SC) linear accelerator 2 (SCL2) for high-energy beam experiment. Single spoke resonator type-1 (SSR1) and type-2 (SSR2) superconducting cavities are now on the prototyping stage. This paper explains about SSR2 fabrication process from press-forming to electron beam welding (EBW) with RRR300 niobium sheets.
 
poster icon Poster MOPCAV011 [1.949 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPCAV011  
About • Received ※ 22 June 2021 — Revised ※ 26 August 2021 — Accepted ※ 26 August 2021 — Issue date ※ 22 April 2022
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MOPFAV004 First Vertical Test of a Prototype Crab Cavity for HL-LHC at FREIA Laboratory in Uppsala University cavity, SRF, MMI, dipole 313
 
  • A. Miyazaki, K. Fransson, K.J. Gajewski, L. Hermansson, R.J.M.Y. Ruber
    Uppsala University, Uppsala, Sweden
 
  We developed and commissioned a new vertical test stand at FREIA Laboratory for the High-Lumi LHC project. The first cold test was performed with a prototype crab cavity (Double-Quarter-Wave cavity) and the obtained result met the project specification. This opened a new opportunity at Uppsala University for SRF science and engineering. In this poster, the result of the first cold test and plans for future experiments are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPFAV004  
About • Received ※ 21 June 2021 — Revised ※ 14 August 2021 — Accepted ※ 21 August 2021 — Issue date ※ 07 October 2021
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MOPFDV002 High Density Mapping Sytems for SRF Cavities cavity, SRF, cryogenics, superconducting-cavity 323
 
  • Y. Fuwa
    JAEA/J-PARC, Tokai-mura, Japan
  • R.L. Geng
    JLab, Newport News, Virginia, USA
  • Y. Iwashita, Y. Kuriyama
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
 
  High density mapping systems for superconducting cavities are prepared. They include sX-map, XT-map and B-map. Each strip of the sX-map system has 32 X-ray sensors approximately 10 mm apart, which can be installed under the stiffener rings to show uniform higher sensitivities. This is suitable to get X-ray distribution around iris areas. The XT-map system enables temperature distribution mapping of cavity cells with high spatial resolution at approximately 10 mm intervals in both azimuth and latitude. It also gives X-ray distribution on cells, as well. Magnetic field distributions can be obtained by B-map system using AMR sensors. Since all these systems are based on the technology of multiplexing at cryogenic side, less number of wires can carry the huge number of signals. The systems are described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPFDV002  
About • Received ※ 02 July 2021 — Revised ※ 19 December 2021 — Accepted ※ 22 January 2022 — Issue date ※ 02 May 2022
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MOPFDV003 Measuring Flux Trapping Using Flat Samples cavity, simulation, controls, HOM 326
 
  • F. Kramer, S. Keckert, J. Knobloch, O. Kugeler
    HZB, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
 
  With modern superconducting cavities flux trapping is a limiting factor for the achievable quality factor. Flux trapping is influenced by various parameters such as geometry, material, and cooldown dynamics. At SRF2019 we presented data showing the magnetic field surrounding a cavity. We now present supplemental simulations for this data focusing on geometric effects. As these simulations are inconclusive, we have designed a new setup to measure trapped flux in superconducting samples which is presented as well. The advantages compared to a cavity test are the simpler sample geometry, and quicker sample production, as well as shorter measurement times. With this setup we hope to identify fundamental mechanisms of flux trapping, including geometry effects, different materials, and different treatments. First results are presented along with the setup itself.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPFDV003  
About • Received ※ 21 June 2021 — Accepted ※ 03 April 2022 — Issue date; ※ 02 May 2022  
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MOPFDV008 SRF Levitation and Trapping of Nanoparticles cavity, SRF, vacuum, niobium 331
 
  • R.L. Geng
    ORNL, Oak Ridge, Tennessee, USA
  • P. Dhakal, B.J. Kross, F. Marhauser, J.E. McKisson, J. Musson, H. Wang, A. Weisenberger, W.Z. Xi
    JLab, Newport News, Virginia, USA
 
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences & Office of Nuclear Physics.
A proposal has been conceived to levitate and trap mesoscopic particles using radio frequency (RF) fields in a superconducting RF(SRF) cavity. Exploiting the intrinsic characteristics of an SRF cavity, this proposal aims at overcoming a major limit faced by state-of-the-art laser trapping techniques. The goal of the proposal is to establish a foundation to enable observation of quantum phenomena of an isolated mechanical oscillator interacting with microwave fields. An experiment supported by LDRD funding at JLab has started to address R&D issues relevant to these new research directions using existing SRF facilities at JLab. The success of this experiment would establish its groundbreaking relevance to quantum information science and technology, which may lead to applications in precision force measurement sensors, quantum memories, and alternative quantum computing implementations with promises for superior coherence characteristics and scalability well beyond the start-of-the-art. In this contribution, we will introduce the proposal and basic consideration of the experiment.
 
poster icon Poster MOPFDV008 [0.595 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPFDV008  
About • Received ※ 10 June 2021 — Accepted ※ 30 September 2021 — Issue date; ※ 02 May 2022  
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TUPFDV002 SIMS Sample Holder and Grain Orientation Effects niobium, SRF, cavity, simulation 401
 
  • J.W. Angle, M.J. Kelley
    Virginia Polytechnic Institute and State University, Blacksburg, USA
  • M.J. Kelley, E.M. Lechner, A.D. Palczewski, C.E. Reece
    JLab, Newport News, Virginia, USA
  • F.A. Stevie
    NCSU AIF, Raleigh, North Carolina, USA
 
  SIMS analyses for ’N-doped’ materials are becoming increasingly important. A major hurdle to acquiring quantitative SIMS results for these materials is the uncertainty of instrument calibration due to changes in sample height either from sample topography or from the sample holder itself. The CAMECA sample holder design allows for many types of samples to be analyzed. However, the cost is that the holder faceplate can bend, introducing uncertainty into the SIMS results. Here we designed and created an improved sample holder which is reinforced to prevent faceplate deflection and thereby reduce uncertainty. Simulations show that the new design significantly reduces deflection from 10 µm to 5 nm. Measurements show a reduction of calibration (RSF) uncertainty from this source from 4.1% to 0.95%. Grain orientation has long been suspected to affect RSF determination as well. A bicrystal implant standard consisting of [111] and [001] grains were repeatedly rotated 15° in between analyses. It was observed that 20% of the analyses performed on [111] grains exhibited anomalously high RSF values likely due to the changing of the grain normal with respect to the primary Cs+ beam.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPFDV002  
About • Received ※ 21 June 2021 — Revised ※ 11 July 2021 — Accepted ※ 21 August 2021 — Issue date ※ 05 January 2022
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TUPFDV008 Instrumentation R&D for the Studies of SRF Thin-Film Structures at KEK and Kyoto University cavity, SRF, superconductivity, controls 421
 
  • Y. Fuwa
    JAEA/J-PARC, Tokai-mura, Japan
  • H. Hayano, H. Ito, R. Katayama, T. Kubo, T. Saeki
    KEK, Ibaraki, Japan
  • Y. Iwashita, Y. Kuriyama
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
 
  We have been developing SRF instrumentations by which the effective lower critical magnetic field Hc1,eff of superconducting-material sample is evaluated through the method of the third-order harmonic voltage measurement mainly for the studies of new SRF thin-film structures. Recently, the quad coil system, which enables us to measure four samples simultaneously in a single batch of an experiment, has been developed. In order to study the creation of thin-film structures inside the SRF cavity, we developed 3-GHz-shaped coupon cavities and an XT-map system for the performance tests of 3 GHz cavities. This article reports the details of these works.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPFDV008  
About • Received ※ 01 July 2021 — Revised ※ 19 December 2021 — Accepted ※ 02 April 2022 — Issue date ※ 02 May 2022
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TUPCAV001 Vertical Electro-Polishing of 704 MHz Resonators Using Ninja Cathode: First Results cavity, cathode, niobium, linac 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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TUPCAV003 1.3 GHz Seamless Copper Cavities via CNC Spinning Technique cavity, SRF, ECR, superconductivity 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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TUPCAV015 Performance of a Low Frequency QWR-Based SRF Gun cavity, electron, simulation, multipactoring 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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TUPTEV003 Progress of MgB2 Deposition Technique for SRF Cavities at LANL cavity, SRF, superconductivity, radio-frequency 482
 
  • P. Pizzol, L. Civale, D.N. Kelly, I. Nekrashevich, A. Poudel, H.R. Salazar, R.K. Schulze, T. Tajima
    LANL, Los Alamos, New Mexico, USA
 
  Since its discovery in 2001, Magnesium Diboride (MgB2) has had the potential to become a material for cavity manufacturing. Having a transition temperature (Tc) at ~39 K, there is a potential to operate the cavity at ~20 K with cryocoolers. This will open up a variety of applications that benefit from compact high-efficiency superconducting accelerators. We have found a 2-step deposition technique as a viable technique for cavity coating, i.e., coating of a pure boron layer with chemical vapor deposition using a diborane gas in the first step and react it with Mg vapor in the second step. In this paper, we will show some recent results with up to Tc ~38 K using a small furnace and describe a new coating system under construction with a new 3-zone furnace to coat a 1.3-GHz single-cell cavity.  
poster icon Poster TUPTEV003 [0.451 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPTEV003  
About • Received ※ 21 June 2021 — Accepted ※ 16 October 2021 — Issue date; ※ 02 May 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTEV013 Managing Sn-Supply to Tune Surface Characteristics of Vapor-Diffusion Coating of Nb3Sn cavity, SRF, niobium, superconductivity 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
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WEPFAV004 Status of the Cryogenic Infrastructure for MESA cryomodule, cryogenics, SRF, operation 539
 
  • T. Stengler, K. Aulenbacher, F. Hug, D. Simon
    KPH, Mainz, Germany
 
  Funding: supported by the German Research Foundation (DFG): EXC 2118/2019
The Institute of Nuclear Physics at the Johannes Gutenberg University Mainz, Germany is currently constructing the Mainz Energy-recovering Superconducting Accelerator (MESA). The centerpiece of the MESA consists of two superconducting cryomodules of the ELBE/Rossendorf type, which are operated at 1.8 K. Furthermore, accelerator elements for polarimetry, a 10 T solenoid, and the external SRF test facility of the Helmholtz Institute Mainz have to be supplied with 4 K helium. One challenge here is to supply the components located throughout the accelerator according to their requirements and to establish a 16mbar system for 1.8 K operation. To ensure the required supply of helium at the different temperature levels, the existing helium liquefier has to be upgraded. The cryogenic infrastructure has to be adapted to the accelerator. The concept of the future cryogenic distribution network is presented in this paper and the design of the cryogenic facilities including the modifications is described in detail.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-WEPFAV004  
About • Received ※ 21 June 2021 — Accepted ※ 21 August 2021 — Issue date; ※ 10 April 2022  
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WEPFDV005 Tensile Tests of Large Grain Ingot Niobium at Liquid He Temperature niobium, cavity, SRF, radio-frequency 562
 
  • M. Yamanaka
    KEK, Ibaraki, Japan
  • K. Enami
    Tsukuba University, Ibaraki, Japan
 
  Tensile tests at liquid He temperature were performed using specimen taken from high purity large grain niobium ingot produced by CBMM. The measured RRR is 242. The ingot is 260 mm in diameter and sliced by a multi wire saw to 2.8 thickness. 5 specimens were cut off from one sliced disk. 3 disks were set in same phase to obtain same grain distribution. 3 specimens each of 5 grain patterns 5, 15 in total were used for the tensile test. The tensile test stand using a cryostat and liquid He was manufactured by ourselves. The measured tensile strength varied 379 to 808 MPa. The average value is 611 MPa. The tensile strength at room temperature is 84 MPa. The strength becomes high at low temperature like a fine grain niobium. The specimen includes a grain boundary, and causes the variation of strength. The different result was obtained in same grain patterns. The relationship between crystal orientation and strength is discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-WEPFDV005  
About • Received ※ 08 June 2021 — Accepted ※ 12 September 2021 — Issue date; ※ 02 May 2022  
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WEPCAV010 Comparison of Electromagnetic Properties During Fabrication of Copper and Niobium Prototypes of 325 MHz Coaxial Half-Wave Resonator cavity, niobium, controls, electron 609
 
  • D. Bychanok, V. Bayev, S. Huseu, S.A. Maksimenko, A.E. Sukhotski, E. Vasilevich
    INP BSU, Minsk, Belarus
  • A.V. Butenko, E. Syresin
    JINR, Dubna, Moscow Region, Russia
  • M. Gusarova, M.V. Lalayan, S.M. Polozov
    MEPhI, Moscow, Russia
  • V.S. Petrakovsky, A.I. Pokrovsky, A. Shvedov, S.V. Yurevich
    Physical-Technical Institute of the National Academy of Sciences of Belarus, Minsk, Belarus
  • Y. Tamashevich
    HZB, Berlin, Germany
 
  The main fabrication stages of niobium and copper prototypes of coaxial half-wave resonators (HWR) operating at frequency 325 MHz for the Nuclotron-based Ion Collider fAcility (NICA) injector are presented and discussed. Results of intermediate measurements and electromagnetic properties control for niobium and copper cavities of equivalent geometrical characteristics are compared and analyzed. The comparison of electromagnetic properties of Cu- and Nb-prototypes allows estimating specific features and differences of intermediate "warm" measurements of niobium and copper cavities. The presented results will be used for further development and production of superconductive niobium cavities with a similar design for the NICA-project.  
poster icon Poster WEPCAV010 [3.180 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-WEPCAV010  
About • Received ※ 21 June 2021 — Revised ※ 12 August 2021 — Accepted ※ 27 December 2021 — Issue date ※ 05 May 2022
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THPFDV006 Seebeck Coefficient Measurement at Cryogenic Temperatures for the LCLS-II HE Project cryomodule, niobium, cryogenics, cavity 768
 
  • M. Ge, A.T. Holic, M. Liepe, J. Sears
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Reducing thermoelectric currents during cooldown is important to maintain high-quality factors (Q0) of the cavities in the LCLS-II HE cryomodules. The temperature-dependent Seebeck coefficients of the materials used in the cryomodules are needed for quantitative estimations of thermoelectric currents. In this work, we present a setup for cryogenic Seebeck coefficient measurements as well as the measured Seebeck coefficients of high-pure niobium at cryogenic temperatures between 4K and 200K.  
poster icon Poster THPFDV006 [0.505 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-THPFDV006  
About • Received ※ 29 June 2021 — Revised ※ 10 August 2021 — Accepted ※ 21 August 2021 — Issue date ※ 26 November 2021
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THPCAV003 Impact of Vertical Electropolishing with Flipping System on Removal Uniformity and Surface State: Study with 9-Cell Niobium Coupon Cavity cavity, cathode, niobium, status 783
 
  • K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • H. Hayano, S. Kato, H. Monjushiro, T. Saeki
    KEK, Ibaraki, Japan
 
  We have been developing a vertical electropolishing (VEP) method for niobium superconducting RF cavities using a novel setup that allows periodic flipping of the cavity to put it upside down in the VEP process. The purpose of using the novel setup named as flipping system is to achieve uniform removal and smooth surface of the cavity. Previously, we have already introduced the VEP system and showed the preliminary results of VEP performed with the flipping system. In this article, we report VEP results obtained with a nine-cell coupon cavity. The results include detail on coupon currents with I-V curves for coupons, and impact of the cavity flipping on removal uniformity and surface morphology of the cavity.  
poster icon Poster THPCAV003 [1.261 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-THPCAV003  
About • Received ※ 19 June 2021 — Revised ※ 10 August 2021 — Accepted ※ 22 October 2021 — Issue date ※ 23 November 2021
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THPCAV005 Status of the INFN-LASA Contribution to the PIP-II Linac cavity, SRF, linac, simulation 787
 
  • R. Paparella, M. Bertucci, M. Bonezzi, A. Bosotti, D. Cardelli, A. D’Ambros, G. Fornasier, A.T. Grimaldi, L. Monaco, D. Sertore
    INFN/LASA, Segrate (MI), Italy
  • C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
 
  The international effort for the PIP-II project at Fermilab has been joined by INFN with its planned contribution to the PIP-II proton linac in the low-beta section. INFN-LASA is finalizing its commitment to deliver in kind the full set of the LB650 cavities, 36 plus spares resonators with 5-cell cavities at 650 MHz and geometrical beta 0.61. All cavities, designed by INFN-LASA, will be produced and surface treated in industry to reach the unprecedented performances required by PIP-II, qualified through vertical cold test at state-of-the art infrastructures and delivered as ready for the linac at the string assembly site. The status of INFN contribution to PIP-II, the development of infrastructures and prototypes as well as the ongoing activities toward the start of series production are summarized in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-THPCAV005  
About • Received ※ 21 June 2021 — Accepted ※ 09 October 2021 — Issue date; ※ 08 May 2022  
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THPCAV007 Thermal Mapping Studies on Nb/Su SRF Cavities cavity, SRF, interface, cryogenics 796
 
  • A. Bianchi, M. Chiodini, G. Vandoni, W. Venturini Delsolaro
    CERN, Meyrin, Switzerland
 
  A thermal mapping system is one of the most useful diagnostic tools to identify the mechanisms responsible of performance degradation in superconducting radio frequency (SRF) cavities. Unlike most of the thermal mapping systems currently in operation, we want to develop a system for mapping copper coated SRF cavities. This thermal mapping system, based on contact thermometry, will operate in both superfluid and normal liquid helium for the study of thin film cavities on copper built at CERN. This paper describes the R&D studies to design and develop the system. The characterisation of thermometers and the validation of their thermal contact are presented. Thanks to the use of some heaters with the aim of reproducing the presence of heat losses in a SRF cavity, temperature profiles on a copper surface will be shown at different conditions of the helium bath. In addition, preliminary results on magnetic field sensors, based on the anisotropic magnetoresistance effect, will be reported in view of their possible implementation in the thermal mapping system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-THPCAV007  
About • Received ※ 18 June 2021 — Revised ※ 23 August 2021 — Accepted ※ 25 November 2021 — Issue date ※ 12 May 2022
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THPTEV011 Experimental Validation of the Use of Cold Cathode Gauge inside the Cryomodule Insulation Vacuum vacuum, operation, cryomodule, linac 848
 
  • H. Jenhani, P. Carbonnier
    CEA-IRFU, Gif-sur-Yvette, France
 
  The Proton Improvement Plan - II (PIP-II) project is underway at Fermilab with an international collaboration involving CEA in the development and testing of 650 MHz cryomodules. The risk analysis related to cryomodule operation proposed to add a vacuum gauge on the power coupler to prevent the untimely rupture of its ceramic. Due to the advanced design of the cryomodules, the gauge needs to be integrated inside the insulation vacuum to reduce the impact of this new modification. The lack of experience feedback on a similar operating condition requires an experimental validation before the implementation. This article details the experimental tests carried out before the approval of this solution.  
poster icon Poster THPTEV011 [0.659 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-THPTEV011  
About • Received ※ 21 June 2021 — Revised ※ 16 August 2021 — Accepted ※ 23 November 2021 — Issue date ※ 15 January 2022
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