Keyword: accelerating-gradient
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TUPO049 Nitrogen Doping Study With 1.3 GHz Single Cell Superconducting Cavities cavity, vacuum, niobium, experiment 442
 
  • S. Chen, M. Chen, L.W. Feng, J.K. Hao, L. Lin, K.X. Liu, S.W. Quan, F. Wang, F. Zhu
    PKU, Beijing, People’s Republic of China
 
  Nitrogen doping studies were carried out at Peking University. A series of 1.3 GHz single cell cavities fabricated with OTIC large grain niobium material were annealed and doped in the furnace of Peking University, and electropolished by a simple EP device. Light doping recipe and heavy doping recipe are both adopted for comparison. The results and analysis are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO049  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TUPO065 Improvement of Cavity Performance by Nitrogen Doping at KEK cavity, ECR, SRF, solenoid 480
 
  • T. Okada, Y. Hori, E. Kako, T. Konomi, H. Sakai, K. Umemori, Y. Yamamoto
    Sokendai, Ibaraki, Japan
  • T. Dohmae, Y. Hori, E. Kako, T. Konomi, T. Saeki, T. Saeki, H. Sakai, K. Umemori, Y. Yamamoto
    KEK, Ibaraki, Japan
  • J. Kamiya
    JAEA/J-PARC, Tokai-mura, Japan
  • S. Kurosawa, K. Takeishi
    JAEA, Ibaraki-ken, Japan
 
  Nitrogen doping experiments in single-cell and 3-cell niobium cavities were carried out at KEK. After annealing at 800 deg C for 3 hours, pure nitrogen gas with a pressure of 3 Pa for 20 minutes and 3 minutes were introduced for doping in a furnace in J-PARC, respectively. Removing surface in 5 um and 20 um by electropolishing were performed prior to the vertical tests, respectively. Increases of a quality factor at 2K and reduction of the BCS resistance with respect to an accelerating gradient were observed in both cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO065  
About • paper received ※ 12 September 2018      issue date ※ 18 January 2019  
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TUPO076 An Innovative Nb3Sn Film Approach and Its Potential for SRF Applications cavity, SRF, site, cathode 513
 
  • E.Z. Barzi, D. Turrioni, C. Ciaccia
    Fermilab, Batavia, Illinois, USA
  • G.V. Eremeev, R.L. Geng, R.A. Rimmer, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  • S. Falletta
    Politecnico di Torino, Torino, Italy
  • H. Hayano, T. Saeki
    KEK, Ibaraki, Japan
  • H. Ito
    Sokendai, Ibaraki, Japan
  • A. Kikuchi
    NIMS, Tsukuba, Ibaraki, Japan
 
  Funding: Work supported by U.S. DOE contract No. DE-AC02-07CH11359
A novel electro-chemical technique to produce Nb3Sn films on Nb substrates was developed and optimized at Fermilab. The Nb3Sn phase is obtained in a two-electrode cell, by electrodeposition from aqueous solutions of Sn layers and Cu intermediate layers onto Nb substrates. Subsequent thermal treatments in inert atmosphere are realized at a maximum temperature of 700°C to obtain the Nb3Sn superconducting phase. Several superconduct-ing Nb3Sn films were obtained on Nb substrates by study-ing and optimizing most parameters of the electro-plating process. Samples were characterized at Fermilab, NIMS, KEK and JLAB, including EPMA analyses, DC and in-ductive tests of critical temperature Tc0, and lower critical field Hc1(4.2 K) by SQUID. In parallel to sample devel-opment and fabrication at FNAL, at JLAB and KEK effort was put into etching and electro-polishing techniques adequate to remove the Cu and bronze phases from the samples’ outer surface. This is necessary prior to meas-urements at JLAB of the surface impedance of flat sam-ples in a setup that make use of an RF host cavity.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO076  
About • paper received ※ 21 September 2018      issue date ※ 18 January 2019  
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TUPO113 Beam Dynamics Studies Through Dielectric THz Accelerating Structures GUI, simulation, vacuum, linac 569
 
  • R. Apsimon, G. Burt, A.L. Healy, S.P. Jamison
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • R.B. Appleby, E.J.H. Smith
    UMAN, Manchester, United Kingdom
  • A. Latina
    CERN, Geneva, Switzerland
 
  As conventional RF accelerating schemes approach the physical limit of accelerating gradient, the accelerator community is increasingly looking at novel accelerating techniques to overcome these limitations. Moving from the RF to the THz frequency range, higher acceleration gradients of high energy beams can be achieved in compact structures. Beam dynamics studies are crucial as part of the design of novel accelerating structures to maximise the output beam current as well as the accelerating gradient. In this paper we present beam dynamics simulations through dielectric lined waveguide structures using novel techniques to simulate broadband signals for particle tracking studies in RF-Track. The beam parameters through the structure are optimised and we study the dynamics of general broadband accelerating structures.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO113  
About • paper received ※ 13 September 2018      issue date ※ 18 January 2019  
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THPO066 First High Power Test of the ESS High Beta Elliptical Cavity cavity, SRF, linac, superconductivity 841
 
  • H. Li, L. Hermansson, M. Jobs, R.J.M.Y. Ruber, R. Santiago Kern
    Uppsala University, Uppsala, Sweden
  • G. Devanz, T. Hamelin
    CEA/DSM/IRFU, France
 
  ESS, the European Spallation Source, will adopt elliptical multi-cell superconducting cavities with a beta value of 0.86 to accelerate the proton beam up to 2 GeV at the last section of the linac. A 5-cell high-beta cavity for ESS project was tested with high power at FREIA Laboratory. A pulse mode test stand based on a self-excited loop was used in this test. The qualification of the cavity package involved a 5-cell elliptical cavity, a fundamental power coupler, a cold tuning system, LLRF system and a RF station. These tests represented an important verification before the series production. This paper presents the test configuration, RF conditioning history, first high power performance and experience of this cavity package.  
slides icon Slides THPO066 [1.437 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO066  
About • paper received ※ 14 September 2018      issue date ※ 18 January 2019  
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THPO072 Cryogenic Tests of the Superconducting β=0.069 CH-cavities for the HELIAC-project cavity, heavy-ion, linac, cryogenics 855
 
  • M. Basten, M. Busch, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    HIM, Mainz, Germany
  • W.A. Barth, M. Heilmann, S. Yaramyshev
    GSI, Darmstadt, Germany
 
  In the future the existing UNILAC (UNIversal Linear Accelerator) at GSI will be most exclusively used as an injector for FAIR to provide short pulse high intensity heavy ion beams at low repetition rates [Barth3]. A new superconducting (sc) continuous wave (cw) high intensity heavy ion Linac should provide ion beams with max. duty factor above the coulomb barrier for the Super Heavy Element (SHE) program at GSI. The fundamental Linac design comprises a low energy beam transport (LEBT)-section followed by a sc Drift Tube Linac (DTL) consisting of sc Crossbar-H-mode (CH) structures for acceleration up to 7.3 MeV/u [*]. After the successful test and commissioning of the first demonstrator section with heavy ion beam from the HLI in 2017 [**], the next two sc CH-structures have been constructed and the first one has been extensively tested at cryogenic temperatures at the Institute for Applied Physics (IAP) at Goethe University Frankfurt (GUF). The results of the final cold test of the first CH-structure as well as the next steps realizing a new sc cw heavy ion LINAC at GSI will be presented.
[*]W. Barth et al., "Further investigations for a superconducting cw-Linac at GSI"
[**]W. Barth et al., "First high intensity heavy ion beam tests with a superconducting multi gap CH-cavity"
 
poster icon Poster THPO072 [1.150 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO072  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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THPO115 Consolidation and Extension of the High-gradient LINAC RF Technology at PSI FEL, linac, cavity, polarization 937
 
  • P. Craievich, M. Bopp, H.-H. Braun, A. Citterio, H. Fitze, T. Garvey, T. Kleeb, F. Löhl, F. Marcellini, M. Pedrozzi, J.-Y. Raguin, L. Rivkin, K. Rolli, R. Zennaro
    PSI, Villigen PSI, Switzerland
 
  For SwissFEL a novel production process for high-gradient, high-precision C-band accelerating structures had been developed at PSI and was implemented for series production in collaboration with industry. The copper parts of the structures are machined and brazed relying on a ultra-high precision manufacturing process and tight mechanical tolerances; no RF tuning methods are applied during or after production. So far none of the structures of the series production failed during RF power conditioning and operation in the SwissFEL facility. After completing the series production for SwissFEL PSI started collaborations with CERN, ELETTRA and DESY for applying the production process and related know-how to other frequencies, namely S-band (3 GHz) and X-band (12 GHz). This paper gives an overview on the ongoing and planned R\&D activities and results obtained so far.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO115  
About • paper received ※ 11 September 2018      issue date ※ 18 January 2019  
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