Keyword: vacuum
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MOP023 Nitrogen Infusion Sample R&D at DESY cavity, niobium, SRF, HOM 77
 
  • C. Bate, A. Dangwal Pandey, A. Ermakov, B. Foster, T.F. Keller, D. Reschke, J. Schaffran, S. Sievers, N. Walker, H. Weise, M. Wenskat
    DESY, Hamburg, Germany
  • W. Hillert
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • G.D.L. Semione, V. Vonk
    DESY Nanolab, FS-NL, Hamburg, Germany
  • A. Stierle
    University of Hamburg, Hamburg, Germany
  
  The European XFEL continuous wave upgrade requires cavities with reduced surface resistance (high Q-values) for high duty cycle while maintaining high accelerating gradient for short-pulse operation. A possible way to meet the requirements is the so-called nitrogen infusion procedure. However, a fundamental understanding and a theoretical model of this method are still missing. The approach shown here is based on sample R&D, with the goal to identify key parameters of the process and establish a stable, reproducible recipe. To understand the underlying processes of the surface evolution, which gives improved cavity performance, advanced surface analysis techniques (e.g. SEM/EDX, TEM, XPS, TOF-SIMS) are utilized. Additionally, a small furnace just for samples was set up to change and explore the parameter space of the infusion recipe. Results of these analyses, their implications for the cavity R&D and next steps are presented.  
poster icon Poster MOP023 [3.759 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP023  
About • paper received ※ 23 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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MOP027 Study on Nitrogen Infusion using KEK New Furnace cavity, injection, SRF, accelerating-gradient 95
 
  • K. Umemori, E. Kako, T. Konomi, S. Michizono, H. Sakai
    KEK, Ibaraki, Japan
  • T. Okada
    Sokendai, Ibaraki, Japan
  • J. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
  
  KEK has been carried out high-Q/high-G R&D, to realize high performance of SRF cavities toward ILC. KEK constructed a new furnace, which is dedicated for N-infusion studies. We performed more than 10 times of N-infusion trials using 1.3 GHz single-cell cavities. Some results showed better Q-values up to high field, however, some results showed degraded Q-E slopes probably due to contamination. Improvement of accelerating gradient is not observed at moment. We have tried to clean the furnace and Nitrogen injection line to reduce the effect of contamination. Details of procedures of N-infusion, results of vertical tests, condition of the furnace including RGA spectrum and Nb sample analysis results are shown.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP027  
About • paper received ※ 04 July 2019       paper accepted ※ 04 July 2019       issue date ※ 14 August 2019  
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MOP051 3.9 GHz SRF Production Cavities for LCLS-II cavity, cryomodule, linac, radiation 173
 
  • S. Aderhold, A. Burrill
    SLAC, Menlo Park, California, USA
  • D.J. Bice, C.M. Ginsburg, C.J. Grimm, T.N. Khabiboulline, O.S. Melnychuk, D.A. Sergatskov, N. Solyak, G. Wu
    Fermilab, Batavia, Illinois, USA
  
  Funding: This work was supported by the US DOE and the LCLS-II Project.
The main part of the SRF linac for the Linac Coherent Light Source II (LCLS-II) at SLAC will consist of 35 cryomodules with superconducting RF cavities operating at 1.3 GHz. In addition, two cryomodules with 3.9 GHz cavities will be installed and help to linearize the longitudinal phase space of the beam. During the design verification phase, four prototype 9-cell 3.9 GHz cavities had been built by industry and then processed, including chemical surface removal and heat treatment, and tested at Fermi National Accelerator Laboratory. Based on the resulting cavity treatment recipe, 24 cavities (for two cryomodules to be installed in the linac and one spare cryomodule) have been built by industry and tested at Fermilab prior to cryomodule string assembly. We present an overview of the cavity production and the results of the vertical acceptance tests for the LCLS-II 3.9 GHz cavities. 		 
poster icon Poster MOP051 [1.015 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP051  
About • paper received ※ 02 July 2019       paper accepted ※ 03 July 2019       issue date ※ 14 August 2019  
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MOP062 Fabrication of SRF Cavity coupling, cavity, SRF, pick-up 214
 
  • K. Kanaoka, H. Hara, A. Miyamoto, K. Sennyu, T. Yanagisawa
    MHI-MS, Kobe, Japan
  • E. Kako, K. Umemori
    KEK, Ibaraki, Japan
  
  Mitsubishi Heavy Industries Machinery Systems (MHI-MS) have developed manufacturing process of superconducting cavities for a long time. In this presentation, recent progress will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP062  
About • paper received ※ 23 June 2019       paper accepted ※ 05 July 2019       issue date ※ 14 August 2019  
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MOP070 Investigation of the Critical RF Fields of Superconducting Cavity Connections cavity, simulation, niobium, impedance 230
 
  • J.C. Wolff, J.I. Iversen, D. Klinke, D. Kostin, D. Reschke, S. Sievers, A. Sulimov, J.H. Thie, M. Wiencek
    DESY, Hamburg, Germany
  • R. Wendel, J.C. Wolff
    HAW Hamburg, Hamburg, Germany
  
  To optimise the length of the drift tube of a superconducting cavity (SC), it is required to know the critical value of the RF fields to prevent a potential early quench at the flange connection in case of a drift tube length reduction. To avoid changes on the SC which has been used for the tests, all RF cryogenic experiments have been carried out by using a cylinder in the center of a 1-cell cavity drift tube to increase the field magnitude at the connection. This cylinder has been designed and optimised by RF simulations to provide a field density at the connection twice as high as at a chosen reference point near the iris. Hence also a test SC with a comparatively low gradient can be used without causing field restrictions. In this contribution an approach to investigate the field limitations of 1.3 GHz TESLA-Shape SC connections and thereby the minimal drift tube length based on simulations will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP070  
About • paper received ※ 23 June 2019       paper accepted ※ 04 July 2019       issue date ※ 14 August 2019  
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MOP076 Fundamental Power Coupler Design for a 325 MHz Balloon SSR Cavity cavity, multipactoring, simulation, cryogenics 252
 
  • R.E. Laxdal, Y. Ma, B. Matheson, B.S. Waraich, Z.Y. Yao, V. Zvyagintsev
    TRIUMF, Vancouver, Canada
  
  TRIUMF has designed, fabricated and tested the first balloon variant of the single spoke resonator at 325 MHz and β=0.3. TRIUMF has also designed a 6 kW fundamental power coupler as part of the development. The design of the coupler will be presented.  
poster icon Poster MOP076 [1.282 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP076  
About • paper received ※ 24 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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MOP078 Adjustable Power Coupler for NICA HWR Cavities cavity, simulation, coupling, collider 260
 
  • S.V. Matsievskiy, M.V. Lalayan
    MEPhI, Moscow, Russia
  • D. Bychanok
    INP BSU, Minsk, Belarus
  • M. Gusarova
    JINR, Dubna, Moscow Region, Russia
  
  Current results on input power coupler development for Half-Wave superconducting accelerating cavity proposed for Nuclotron-based Ion Collider fAcility (NICA) collider injector upgrade are discussed. Two coupler designs are considered, first one is a low-power coupler for cavity tests and the second one is a high-power operational coupler. Both devices are of coaxial type with capacitive coupling; high-power coupler utilizes single ceramic vacuum window. NICA is designed to accelerate different types of ions. Due to the variable intensity of ion sources, beam current will vary in wide range. In order to ensure efficient acceleration, power coupler must be highly adjustable in terms of coupling coefficient. This introduces excessive mechanical stress in the ceramic RF window due to the bellows deformation. In order to mitigate this effect bellows were substituted with sliding contacts. This paper discusses new coupler design and its electrical, mechanical and thermal properties.  
poster icon Poster MOP078 [1.296 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP078  
About • paper received ※ 23 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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MOP080 Latest Progress in Designs and Testings of PIP-II Power Couplers cavity, rfq, multipactoring, cryogenics 263
 
  • S. Kazakov, B.M. Hanna, O.V. Pronitchev, N. Solyak
    Fermilab, Batavia, Illinois, USA
  
  Proton Improvement Plan – II (PIP-II) project is under go in Fermi National Laboratory. Main part of the project is 800 MeV proton superconducting accelerator which includes 116 superconducting cavities of 5 different types and three 162.5, 325 and 650 MHz frequencies. Key elements of accelerator which determine a reliable operation are main couplers for superconducting cavities. This paper describes the latest progress in design and testing of main couplers for PIP-II projects.  
poster icon Poster MOP080 [0.881 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP080  
About • paper received ※ 18 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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MOP085 The Destructive Effects to the RF Coupler by the Plasma Discharge plasma, cavity, experiment, coupling 285
 
  • A.D. Wu, Q.W. Chu, H. Guo, Y. He, S.C. Huang, T.C. Jiang, C.L. Li, Z.Q. Lin, F. Pan, Y.K. Song, T. Tan, W.M. Yue, S.H. Zhang, H.W. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
  
  The low temperature RF plasma was proved an effec-tive method to clean the niobium surface and relieve the field emission effect for the SRF cavities. In the case of half-wave resonators, these cavities were usually powered via the fundamental coupler with the electric coupling. Thus, coupler antennas were fixed in the intense electric field region, and this region was where the plasma rou-tinely ignited. Therefore, the ceramic window of coupler taken the risk of breakdown under the sputtering of ions and heating loads that may be caused by the plasma drift and diffusion from the electric field region. In this paper, the plasma ignition for surface cleaning on the HWR cavity and its coupler was investigated, and the power transmission, temperature raising and vacuum degradation were tested to characterize the adverse impacts on the ceramic window. Finally, the solution was proposed to figure these issues.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP085  
About • paper received ※ 22 June 2019       paper accepted ※ 02 July 2019       issue date ※ 14 August 2019  
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MOP086 Conditioning of the First Mass Production Power Couplers for the ESS Elliptical Cavities electron, pick-up, cavity, Windows 288
 
  • C. Arcambal, M. Baudrier, P. Bosland, G. Devanz, T. Hamelin, C. Marchand, M. Oublaid, G. Perreu, S. Regnaud, C. Servouin, C. Simon
    CEA-DRF-IRFU, France
  • G. Monnereau
    CEA-IRFU, Gif-sur-Yvette, France
  
  In the framework of the European Spallation Source (ESS), CEA Paris-Saclay is in charge of the delivery of 9 medium beta (β = 0.67) and 21 high beta (β = 0.86) cryomodules. Each cryomodule is composed of 4 cavities equipped with RF (Radio Frequency) power couplers (704.42 MHz, 1.1 MW maximum peak power, repetition rate=14 Hz, RF pulse width > 3.1 ms). Ten prototype power couplers have been manufactured to validate the design and the performance. Currently the mass production of the 120 couplers started and the six first pre-series medium beta couplers have been successfully conditioned. The achievement of this milestone allowed us to launch the production of the remaining 30 medium beta couplers. This paper presents the conditioning of the pre-series couplers.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP086  
About • paper received ※ 23 June 2019       paper accepted ※ 29 June 2019       issue date ※ 14 August 2019  
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MOP094 Design Strategy of the PIP-II Cryomodules cryomodule, cavity, interface, cryogenics 307
 
  • V. Roger, S.K. Chandrasekaran, 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
The Proton Improvement Plan II (PIP-II) is the first U.S. accelerator project that will have significant contributions from international partners. Research institutions in India, Italy, UK and France will build major components of the particle accelerator. The High Beta 650 MHz (HB650) prototype cryomodule is being designed jointly between Fermilab (USA), CEA (France), STFC (UK) and RRCAT (India). The assembly of this prototype cryomodule will be done at Fermilab whereas the production cryomodules will be assembled in UK. Concerning the Low Beta 650 MHz (LB650) cryomodules, they will be designed and assembled at CEA. To reduce the cost of the project and to increase the quality it is essential to define a design strategy for each cryomodule which includes a degree of standardization. In this way, the lessons learned of each prototype cryomodule will have a great impact not only on one cryomodule type but on all cryomodules. An international joint design brings also additional challenges to the project: which unit system should be used? Should a common project lifecycle management system be used for all partners? How to transport the cryomodules overseas. 		 
poster icon Poster MOP094 [1.117 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP094  
About • paper received ※ 21 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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MOP099 Design of Crab Cavity Cryomodule for HL-LHC cryomodule, cavity, cryogenics, operation 320
 
  • T. Capelli, K. Artoos, A.B. Boucherie, K. Brodzinski, R. Calaga, S.J. Calvo, E. Cano-Pleite, O. Capatina, F. Carra, L. Dassa, F. Eriksson, M. Garlasché, A. Krawczyk, R. Leuxe, P. Minginette, E. Montesinos, B. Prochal, M. Sosin, M. Therasse
    CERN, Geneva, Switzerland
  • T.J. Jones, N. Templeton
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • A. Krawczyk, B. Prochal
    IFJ-PAN, Kraków, Poland
  • S.M. Pattalwar
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: Research supported by the HL-LHC project
Crab cavities are a key element to achieve the HL-LHC performance goals. There are two types of cavities Double Quarter Wave (DQW) for vertical crabbing, and Radiofrequency Dipole (RFD) for horizontal crabbing. Cavities are hosted in a cryomodule to provide optimal conditions for their operation at 2K while minimizing the external thermal loads and stray magnetic fields. One crab cryomodule contains more than thirteen thousand components and the assembly procedure for the first DQW prototype was carefully planned and executed. It was installed in the SPS accelerator at CERN in 2018 and successfully tested with proton beams. A review has thus been performed right after completion of the assembly in order to gather all the experience acquired and improve accordingly the design of the next generation of crab cryomodules. A second cryomodule with two RFD cavities is currently under production. This paper presents the lessons learnt from the first assembly and their implementation to the design of the future crab cryomodules. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP099  
About • paper received ※ 21 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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MOP101 Design and Manufacturing Challenges of the SSR1 Current Leads for PIP-II cryomodule, focusing, instrumentation, cryogenics 329
 
  • S. Cheban, D. Passarelli, V. Roger
    Fermilab, Batavia, Illinois, USA
  
  The SSR1 cryomodule contains eight 325 MHz superconducting single spoke cavities and four solenoid-based focusing lenses operating at 2 K. The focusing lens for SSR1 cryomodule, is a superconducting magnet surrounded by a helium box which will be filled with liquid helium. The magnet assembly is composed of one solenoid with operating current 70 A and 2 quadrupoles correctors with operating current 45 A. The conduction cooled current leads will be used to power magnets. The details of current leads design, fabrication and room temperature qualification will be presented. Main emphasis will be put on the design and production process challenges and possible solutions to fulfilled operation requirement under low temperature conditions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP101  
About • paper received ※ 28 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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TUP004 Latest Cryogenic Test Results of the Superconducting β=0.069 CH-cavities for the HELIAC-project cavity, linac, cryomodule, heavy-ion 392
 
  • M. Basten, M. Busch, T. Conrad, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, M. Heilmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, J. Salvatore, A. Schnase, S. Yaramyshev
    GSI, Darmstadt, Germany
  • K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu
    HIM, Mainz, Germany
  • K. Aulenbacher, S. Lauber
    IKP, Mainz, Germany
  • F.D. Dziuba, J. List
    KPH, Mainz, Germany
  
  The upcoming FAIR (Facility for Antiproton and Ion Research) project at GSI will use the existing UNILAC (UNIversal Linear Accelerator) as an injector, reducing the beam time for the ambitious Super Heavy Element (SHE) program. To keep the UNILAC user program competitive a new superconducting (sc) continuous wave (cw) high intensity heavy ion LINAC should provide ion beams with max. duty factor above the coulomb barrier. The fundamental sc 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. The latest milestones towards the new cw LINAC HELIAC (HELmholtz LInear ACcelerator) have been the successful tests and commissioning of the first demonstrator section with heavy ion beam in 2017 and 218 as well as the successful test under cryogenic conditions of the second CH-cavity in 2018. Now the third CH-cavity has been tested at cryogenic temperatures of 4 Kelvin at the Institute for Applied Physics (IAP) at Goethe University Frankfurt (GUF). The results of these measurements as well as the status of the HELIAC-project will be presented.  
poster icon Poster TUP004 [0.958 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP004  
About • paper received ※ 22 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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TUP013 Non-Evaporative Getter-Based Differential Pumping System for SRILAC at RIBF SRF, linac, cavity, operation 419
 
  • H. Imao
    RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
  • O. Kamigaito, N. Sakamoto, T. Watanabe, Y. Watanabe, K. Yamada
    RIKEN Nishina Center, Wako, Japan
  • K. Oyamada
    SHI Accelerator Service Ltd., Tokyo, Japan
  
  Upgrades of the RIKEN heavy-ion linac (RILAC) involving a new superconducting linac (SRILAC) are undergoing to promote super-heavy element searches at the RIKEN radioactive isotope beam factory (RIBF). Stable ultra-high vacuum (<10-8 Pa) and particulate-free conditions are strictly necessary for keeping the performance of the superconductive radio frequency (SRF) cavities of the SRILAC. It is crucially important to develop neighboring warm sections to prevent contamination from the existing old RILAC and beamlines built almost four decades ago. In the present study, non-evaporative getter-based differential pumping systems were newly developed to achieve the pressure reduction from the existing beamline vacuum (10-5–10-6 Pa ) to the ultra-high vacuum within very limited length (<80 cm) ensuring the large beam aperture of more than 40 mm. They are also equipped with compact electrostatic particle removers. We will describe and discuss details of the design, construction and performance of the system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP013  
About • paper received ※ 03 July 2019       paper accepted ※ 14 August 2019       issue date ※ 14 August 2019  
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TUP019 Status of High Temperature Vacuum Heat Treatment Program at IPN Orsay cavity, SRF, niobium, MMI 438
 
  • M. Fouaidy, F. Chatelet, V. Delpech, F. Galet, D. Le Dréan, R. Martret, G. Olry, T. Pépin-Donat
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • M. Baudrier, P. Carbonnier, E. Fayette, X. Hanus, Th. Proslier, D. Roudier, P. Sahuquet, C. Servouin
    CEA-DRF-IRFU, France
  • E. Cenni, L. Maurice
    CEA-IRFU, Gif-sur-Yvette, France
  • D. Longuevergne
    FLUO, Orsay, France
  
  In the framework of ESS, a vacuum furnace dedicated to High Temperature Heat Treatment under Vacuum (VH2T2) of SRF bulk Nb cavities was developed and commissioned in May 2016. This furnace is currently used for interstitial hydrogen removal (10h00 @ 650 °C) of two type of cavities: 1) the whole series of 26 ESS 352 MHz spoke resonators equipped with their Ti LHe tank well, 2) some prototypes of ESS high beta and medium beta cavities. Up to know IPN Orsay VH2T2 (10h00 @ 650 °C) was successfully applied to more than 16 cavities. In this paper we will first report about these VH2T2 tests. Finally, we have just started testing nitrogen infusion and nitrogen doping processes on samples and 1.3 GHz cavities: the preliminary results will be discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP019  
About • paper received ※ 03 July 2019       paper accepted ※ 04 July 2019       issue date ※ 14 August 2019  
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TUP031 Heat Treatment for Jacketed Half-wave Resonator Cavity cavity, cryomodule, SRF, ECR 482
 
  • Y. Jung, B.H. Choi, D.H. Gil, M.O. Hyun, H. Kim, J.W. Kim, M.S. Kim, D.Y. Lee, J. Lee, S. Lee
    IBS, Daejeon, Republic of Korea
  
  Vertical tests of a prototype half-wave resonator cavity are being tested. The performance of the cavities, such as quality factor and accelerating electrical field, are measured and compared to the target design value. In previous study, we reported the effect of the heat treatment on a prototype bare HWR cavity. We baked a jacketed HWR cavity to improve a performance for 10 h at 650°C. In this study, we will report the effect of the heat treatment on the jacketed HWR cavity.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP031  
About • paper received ※ 23 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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TUP033 Modal Analysis of the EXFEL 1.3 GHz Cavity and Cryomodule Main Components and Comparison with Measured Data cavity, cryomodule, FEL, linac 488
 
  • S. Barbanotti, A. Bellandi, J. Branlard, K. Jensch
    DESY, Hamburg, Germany
  
  Future upgrades of the European X-ray Free Electron Laser (EXFEL) may require driving the linac at higher duty factor, possibly extending to Continuous Wave (CW) mode. An R&D program has started at DESY, to prepare for a CW upgrade. Cryomodules are being tested in CW mode in our CryoModule Test Bench (CMTB) to study the performance and main issues for such an operation mode. Sensitivity to vibration causing microphonics is one of the main concerns for the CW operation in mode. Therefore a detailed analysis is being performed to evaluate the frequency spectrum of the EXFEL cryomodule main components: the cavity itself, the cavity string, the cold mass and the vacuum vessel. Finite Element Modal Analyses have been performed and the results compared with data measured at the CMTB. This paper summarizes the main results and conclusions of such a study.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP033  
About • paper received ※ 18 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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TUP034 Microphonics Testing of LCLS II Cryomodules at Jefferson Lab cavity, cryomodule, background, cryogenics 493
 
  • T. Powers, N.C. Brock, G.K. Davis
    JLab, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
Jefferson Lab is partnering with Fermilab to build the 36 cryomodules for the LCLS II accelerator that will be installed at SLAC. The cavities have design loaded-Q of 4×107, which means that it has a control bandwidth of 16 Hz. The JLab prototype cryomodule was instrumented with a series of seven accelerometers, and impulse hammer response measurements were made while the cryomodule was being built and after it was installed in the JLab cryomodule test facility. This was done so that we could understand the shapes of the modes of the structure. These results were compared to impulse hammer testing from the outside of the cryomodule and to individual cavity frequency shifts when the cryomodule was cold. The prototype cryomodule had excessive microphonics of 150 Hz peak due to a thermos-acoustic oscillation. Design modifications were implemented and subsequently the cryomodules had microphonics on the order of 10 to 20 Hz. Results of the modal analysis as well as the background microphonics observed when operated under various cryogenic conditions and with different modifications will be presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP034  
About • paper received ※ 21 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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TUP037 Construction of Superconducting Linac Booster for Heavy-Ion Linac at RIKEN Nishina Center cryomodule, linac, controls, booster 502
 
  • K. Yamada, T. Dantsuka, H. Imao, O. Kamigaito, K. Kusaka, H. Okuno, K. Ozeki, N. Sakamoto, K. Suda, T. Watanabe, Y. Watanabe
    RIKEN Nishina Center, Wako, Japan
  • H. Hara, A. Miyamoto, K. Sennyu, T. Yanagisawa
    MHI-MS, Kobe, Japan
  • E. Kako, H. Nakai, H. Sakai, K. Umemori
    KEK, Ibaraki, Japan
  
  At RIKEN Nishina Center, the RIKEN Heavy-Ion Linac (RILAC) is undergoing an upgrade of its acceleration voltage in order to allow it further investigation of new super-heavy elements. In this project, a new superconducting (SC) booster linac, so-called SRILAC, is being developed and constructed. The SRILAC consists of 10 TEM quarter-wavelength resonators made of pure niobium sheets which operate at 4 K. The target performance of each cavity is set as Q0 of 1×109 with its accelerating gradient of 6.8 MV/m. Recently we succeeded to develop high performance SC-cavities which satisfies the requirement with a wide margin. The cryomodule assembly is under way, and installation of cryomodules and He liquefaction system will be completed by the end of FY2018. The cooling-down test is scheduled in the Q1 of FY2019. This contribution makes a report on the construction status of the SRILAC.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP037  
About • paper received ※ 02 July 2019       paper accepted ※ 04 July 2019       issue date ※ 14 August 2019  
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TUP046 Low Frequency, Low Beta Cavity Performance Improvement Studies cavity, niobium, SRF, factory 527
 
  • P. Kolb, R.E. Laxdal, Z.Y. Yao
    TRIUMF, Vancouver, Canada
  
  In recent years, new discoveries such as N2 doping and infusion lead to a significant increases in Q0 and accelerating gradient for 1.3 GHz, β=1 elliptical cavities. To understand and to adapt these treatments for lower frequency, \beta < 1 cavities, two coaxial test cavities, one quarter-wave resonator (QWR) and one half-wave resonator (HWR), have been built and put through a systematic study of these new treatments to show the effectiveness of these treatments at different frequencies. These cavities are tested in their fundamental mode and several higher order modes to study the frequency dependence of new cavity treatments such as N2 doping and infusion. Results of these studies are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP046  
About • paper received ※ 22 June 2019       paper accepted ※ 29 June 2019       issue date ※ 14 August 2019  
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TUP070 The SRF Thin Film Test Facility in LHe-Free Cryostat cavity, cryogenics, SRF, controls 610
 
  • O.B. Malyshev, J.A. Conlon, P. Goudket, N. Pattalwar, S.M. Pattalwar
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G. Burt
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  
  An ongoing programme of development superconducting thin film coating for SRF cavities requires a facility for a quick sample evaluation at the RF conditions. One of the key specifications is a simplicity of the testing procedure, allowing an easy installation and quick turnover of the testing samples. Choked test cavities operating at 7.8 GHz with three RF chokes have been designed and tested at DL in a LHe cryostat verifying that the system could perform as required. Having a sample and a cavity physically separate reduces the complexity involved in changing samples (major causes of low throughput rate and high running costs for other test cavities) and also allows direct measurement of the RF power dissipated in the sample via power calorimetry. However, changing a sample and preparation for a test requires about two-week effort per sample. In order to simplify the measurements and achieve a faster turnaround, a new cryostat cooled with a closed-cycle refrigerator has been designed, built and tested. Changing a sample, cooling down and testing can be reduced to 2-3 days per sample. Detailed design and results of testing of this facility will be reported at the conference.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP070  
About • paper received ※ 21 June 2019       paper accepted ※ 02 July 2019       issue date ※ 14 August 2019  
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TUP072 The Development of Niobium Sputtering on Copper Cavities at IHEP cavity, niobium, SRF, photon 613
 
  • J. Dai, P. He, Z.Q. Li, Y. Ma, F.Y. Yang, P. Zhang
    IHEP, Beijing, People’s Republic of China
  
  A R&D program focusing on niobium sputtering on copper cavities started at IHEP in 2017. Single-cell 1.3 GHz elliptical cavity shape has been initially chosen as sputtering substrate. A magnetron sputtering system have been developed in 2018. In addition, a surface treatment facility to polish the copper substrate before sputtering has been developed and commissioned. This paper will present the Nb/Cu coating activities at IHEP.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP072  
About • paper received ※ 19 June 2019       paper accepted ※ 04 July 2019       issue date ※ 14 August 2019  
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TUP081 Status of the HL-LHC Crab Cavity Tuner cavity, cryomodule, GUI, SRF 646
 
  • K. Artoos, L. Arnaudon, R. Calaga, E. Cano-Pleite, O. Capatina, T. Capelli, D.F. Cartaxo dos Santos, M. Garlasché, D.C. Glenat, A. Krawczyk, R. Leuxe, P. Minginette, J.S. Swieszek
    CERN, Geneva, Switzerland
  • T.J. Jones
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • A. Krawczyk, B. Prochal
    IFJ-PAN, Kraków, Poland
  • J.A. Mitchell
    Lancaster University, Lancaster, United Kingdom
  • S. Verdú-Andrés
    BNL, Upton, New York, USA
  
  Funding: Research supported by the HL-LHC project
The resonance frequency of the HL-LHC Double Quarter Wave (DQW) and Radio Frequency Dipole (RFD) crab cavities is set to the operating frequency of 400.79 MHz by deforming the cavities. For both types of cavities, the tuning principle foresees a symmetric mechanical deformation of parts of the cavities in vertical direction, with the tuner motor placed outside on top of the vacuum vessel. The tuner design was successfully tested on the DQW prototype cryomodule with two cavities in 2018 in the SPS at CERN. This paper describes the design of DQW and RFD crab tuners. The experience and results of assembly and cold testing is given together with some required improvements. Finally, the final series crab tuners preparation is reported. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP081  
About • paper received ※ 21 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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TUP084 Testing of the Piezo-actuators at High Dynamic Rate Operational Conditions SRF, cavity, operation, linac 656
 
  • Y.M. Pischalnikov, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
  
  Reliability of the piezo-actuators that deployed into SRF cavity tuner and operated at high dynamic rate operational conditions made significant impact on the overall performance of the SRF linacs. We tested at FNAL piezo-actuators P-P-844K075 that were developed at Physik Instrumente for LCLS II project. Even these actuators were developed for CW linac we tested them at high dynamic rate inside cryogenic/insulated vacuum environment. Results of the tests will be presented. Different modes of the piezo-actuators failure will be discussed.  
poster icon Poster TUP084 [3.168 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP084  
About • paper received ※ 23 June 2019       paper accepted ※ 04 July 2019       issue date ※ 14 August 2019  
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TUP086 Frequency Tuning System Based on Mobile Plungers For Superconductive Coaxial Half Wave Resonators cavity, simulation, linac, SRF 664
 
  • D. Bychanok, S. Huseu, S.A. Maksimenko
    INP BSU, Minsk, Belarus
  • A.V. Butenko, E. Syresin
    JINR, Dubna, Moscow Region, Russia
  • E.A. Gurnevich
    Belarussian State University, Scientific Research Institute of Nuclear Problems, Minsk, Belarus
  • M. Gusarova, M.V. Lalayan, S.M. Polozov
    MEPhI, Moscow, Russia
  
  The design of a prototype of the frequency tuning system (FTS) for superconductive coaxial half wave cavities (HWR) [1] developed for the Nuclotron-based Ion Collider fAcility (NICA) injector is presented. The proposed system is based on mobile plungers placed in the technological holes in the end caps of the resonator. The FTS allows controlling the penetration depth of plungers, which is monotonically related to the resonant frequency shift of the cavity. The developed FTS includes slow/fast tuner parts and is more compact and simple in comparison to traditional mechanical systems, which deform reversibly the HWR by applying an effort on the beam ports [2]. The similar plunger-based tuner design was considered for QWR cavities in [3]. The results of numerical simulations of the resonant frequency for a wide range of plunger parameters are presented and discussed. The most important parameters for effective frequency shift are estimated.
[1] S. Matsievskiy et al., RuPAC’18. doi:10.18429/JACoW-RUPAC2018-WEPSB48
[2] N. Misiara et al., LINAC’16. doi:10.18429/JACoW-LINAC2016-MOPRC026
[3] D. Longuevergne et al., ‘‘A cold tuner system with mobile plunger’’, in Proc. SRF2013, paper THIOD04. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP086  
About • paper received ※ 22 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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TUP092 Experiences of Superconducting Radio Frequency Coldmass Production for the FRIB Linear Accelerator cavity, cryomodule, solenoid, SRF 675
 
  • K. Elliott, B.W. Barker, C. Donald, E.S. Metzgar, L. Popielarski, D.R. Victory, J.D. Whaley, M.S. Wilbur
    FRIB, East Lansing, Michigan, USA
  
  Funding: *Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and the National Science Foundation under Cooperative Agreement PHY-1102511.
The superconducting radio frequency (SRF) portion of the Facility for Rare Isotope Beams (FRIB) linear accelerator consists of 46 cryomodules of 6 different types. Each cryomodule contains a coldmass consisting of a string of SRF resonators. There are four different types of resonators; a β=0.041 quarter wavelength resonator (QWR), a β=0.085 QWR, a β=0.29 half wavelength resonator (HWR), and a β=0.53 HWR. In total there are 324 SRF resonators in the FRIB linear accelerator. This paper provides a summary of experiences from the assembly of all FRIB coldmass types in a clean room environment. 		 
poster icon Poster TUP092 [1.481 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP092  
About • paper received ※ 23 June 2019       paper accepted ※ 14 August 2019       issue date ※ 14 August 2019  
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TUP094 Improvements to LCLS-II Cryomodule Transportation cavity, cryomodule, ISOL, SRF 684
 
  • N.A. Huque, E. Daly, P.D. Owen
    JLab, Newport News, Virginia, USA
  • B.D. Hartsell, J.P. Holzbauer
    Fermilab, Batavia, Illinois, USA
  
  The Linear Coherent Light Source (LCLS-II) is currently being constructed at the SLAC National Laboratory. A total of 35 cryomodules will be fabricated at Jefferson Lab (JLab) in Virginia and Fermi National Laboratory (FNAL) in Illinois and transported via road to SLAC. A shipping frame with an inner bed isolated by springs was designed to protect the CMs from shocks and vibrations during shipments. Successful road testing of the JLab prototype paved the way for production CM shipments. The initial production shipments lead to several catastrophic failures in beamline vacuum in the cryomodules. The failures were determined to be due to fatigue in Fundamental Power Coupler (FPC) bellows due to excessive motion during shipment. A series of instrumented CM shipping tests and component tests were undertaken to develop a solution. A modified spring layout was tested and implemented, which reduced shocks on the CMs. FPC coupler bellows restraints were tested on a shaker table and on a CM during shipping; they were able to reduce bellows motion by a factor of three. The updated shipping system is currently in use and has successfully delivered six cryomodules to SLAC from JLab and FNAL.  
poster icon Poster TUP094 [0.958 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP094  
About • paper received ※ 23 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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TUP095 Lessons Learned Assembling the SSR1 Cavities String for PIP-II cavity, solenoid, cryomodule, SRF 690
 
  • D. Passarelli, D.J. Bice, M. Parise, T.J. Ring, G. Wu
    Fermilab, Batavia, Illinois, USA
  • S. Berry
    CEA-DRF-IRFU, France
  
  The string assembly of the prototype Single Spoke Resonator type 1 (SSR1) cryomodule for PIP-II at Fermilab was successfully completed. Lessons learned from the preparation, assembly and the quality control activities of the final fully integrated assembly will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP095  
About • paper received ※ 28 June 2019       paper accepted ※ 29 June 2019       issue date ※ 14 August 2019  
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TUP096 Optimization of Clean Room Infrastructure and Procedure During LCLS-II Cryomodule Production at Fermilab cavity, cryomodule, detector, linac 695
 
  • G. Wu, S.D. Adams, T.T. Arkan, M.A. Battistoni, D.J. Bice, M.B. Chlebek, E.R. Harms, B.M. Kuhn, A.M. Rowe
    Fermilab, Batavia, Illinois, USA
  • S. Berry, O. Napoly
    CEA-DRF-IRFU, France
  
  Funding: The work is supported by Fermilab which is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Optimization of Fermilab string assembly procedure and infrastructure has yielded a significant improvement of cryomodule particulate counts. Late production of LCLS-II cryomodules were tested at CMTF at Fermilab and showed little to no x-ray up to administrative limit. The paper describes the field emission measurement instrumentation, field emission results of LCLS-II cyomodules, clean room infrastructure upgrade and procedure optimization. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP096  
About • paper received ※ 23 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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TUP101 LCLS-II Cryomodules Production Experience and Lessons Learned at Fermilab cryomodule, cavity, FEL, linac 709
 
  • T.T. Arkan, J.N. Blowers, C.M. Ginsburg, C.J. Grimm, J.A. Kaluzny, T.H. Nicol, Y.O. Orlov, K.S. Premo, R.P. Stanek, G. Wu
    Fermilab, Batavia, Illinois, USA
  
  LCLS-II is a planned upgrade project for the linear coherent light source (LCLS) at SLAC. The LCLS-II Linac will consist of thirty-five 1.3 GHz and two 3.9 GHz superconducting RF continuous wave (CW) cryomodules that Fermilab and Jefferson Lab are currently producing in collaboration with SLAC. The LCLS-II 1.3 GHz cryomodule design is based on the European XFEL pulsed-mode cryomodule design with modifications needed for CW operation. Two prototype cryomodules had been assembled and tested. After prototype cryomodule tests, both laboratories have increased their cryomodule production rate to meet the challenging LCLS-II project installation schedule requirements of approximately one cryomodule per month per laboratory. To date, Fermilab has completed the assembly and testing of sixteen 1.3 GHz cryomodules. Fermilab has successfully shipped five CMs to SLAC and will continue to ship with a two-week throughput. The first 3.9 GHz cryomodule assembly is scheduled to start in June 2019; production readiness verifications are in progress. This paper presents LCLS-II cryomodule assembly and production experience, emphasizing the challenges, the mitigations and lessons learned  
poster icon Poster TUP101 [0.834 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP101  
About • paper received ※ 20 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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TUP104 Improvement of a Clean Assembly Work for Superconducting RF Cryomodule and Its Application to the KEK-STF Cryomodule cryomodule, cavity, controls, SRF 721
 
  • H. Sakai, E. Kako, T. Konomi, K. Umemori, Y. Yamamoto
    KEK, Ibaraki, Japan
  • T. Ebisawa, A. Kasugai
    QST, Aomori, Japan
  
  We usually encountered the degradation of the superconducting RF cavities on the cryomodule test even though the performance of these cavities was good on the vertical test. In reality, the degradation of Q-values of two cavities of cERL main-linac were observed after cryomodule assembly in KEK [1] and STF cryomodule also met the degradation after the cryomodule assembly [2]. Some dusts and invisible particles might enter the cavity and generate field emission during the assembly work. Field emission is the most important cause of this degradation. In this paper, first we introduce some trials for the improved clean assembly work to SRF cavity by re-examining our clean assembly work and vacuum work. For example, slow pumping system with vacuum particle monitor was developed to know and control the particle movement during slow pumping and venting. Next we show the application of this improved work to the STF re-assemble cryomodule work in KEK.
[1} H. Sakai et al., SRF’13, Paris, France, p.855, 2013.
[2] Y. Yamamoto et al., IPAC’16, Busan, Korea, p.2158, 2016. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP104  
About • paper received ※ 20 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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TUP105 Preparation of the Cryomodule Assembly for the Linear IFMIF Prototype Accelerator (LIPAc) in Rokkasho cryomodule, cavity, operation, SRF 726
 
  • T. Ebisawa, A. Kasugai, K. Kondo, S. Maebara, K. Sakamoto
    QST, Aomori, Japan
  • N. Bazin, S. Berry
    CEA-DRF-IRFU, France
  • P. Cara
    IFMIF/EVEDA, Rokkasho, Japan
  • H. Dzitko, G. Phillips
    F4E, Germany
  • E. Kako, H. Sakai, K. Umemori
    KEK, Ibaraki, Japan
  
  The staged installation and commissioning of LIPAc is ongoing at Rokkasho Fusion Institute of QST, Japan for validating the low energy section of the IFMIF deuteron accelerator up to 9 MeV. The LIPAc Superconducting Radio Frequency accelerator (SRF) cryomodule is assembled under the responsibility of the EU Home Team, and the assembly work recently started at Rokkasho in March 2019. To fulfil the cleanliness requirements for the assembly process, QST took the responsibility to prepare the infrastructure of a cleanroom and associated devices. In this present paper, the details of the preparation work for the cryomodule assembly made by QST will be presented.  
poster icon Poster TUP105 [2.116 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP105  
About • paper received ※ 17 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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WETEA5 FRIBCavity and Cryomodule Performance, Comparison with the Design and Lessons Learned cryomodule, alignment, solenoid, cavity 742
 
  • S.J. Miller, H. Ao, B. Bird, B. Bullock, N.K. Bultman, F. Casagrande, C. Compton, J. Curtin, K. Elliott, A. Facco, V. Ganni, I. Grender, W. Hartung, J.D. Hulbert, S.H. Kim, P. Manwiller, E.S. Metzgar, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, M.A. Reaume, K. Saito, M. Shuptar, J. Simon, B.P. Tousignant, D.R. Victory, J. Wei, J.D. Wenstrom, K. Witgen, M. Xu, T. Xu
    FRIB, East Lansing, Michigan, USA
  • A. Facco
    INFN/LNL, Legnaro (PD), Italy
  • M.P. Kelly
    ANL, Lemont, Illinois, USA
  • M. Wiseman
    JLab, Newport News, Virginia, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and the National Science Foundation under Cooperative Agreement PHY-1102511.
The superconducting driver linac for the Facility for Rare Isotope Beams (FRIB) requires the production of 46 cryomodules. Design is complete on all six cryomodule types which utilize four superconducting radio frequency (SRF) cavity designs and superconducting solenoids. The FRIB cryomodules utilize an innovative bottom up approach to achieve alignment tolerance and simplify production assembly. The cryomodule testing includes qualification of the resonator performance, fundamental power couplers, tuners, and cryogenic systems. FRIB beam commissioning has been performed on 15 cryomodules in the FRIB and validates the FRIB cryomodule bottom up assembly and alignment method. This paper will report the FRIB cryomodule design, performance, and the alignment results and their impact on beam commissioning. 		 
slides icon Slides WETEA5 [14.640 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-WETEA5  
About • paper received ※ 21 June 2019       paper accepted ※ 29 June 2019       issue date ※ 14 August 2019  
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WETEB1 Development of Superconducting Quarter-Wave Resonator and Cryomodule for Low-Beta Ion Accelerators at RIKEN Radioactive Isotope Beam Factory cavity, cryomodule, linac, SRF 750
 
  • N. Sakamoto, T. Dantsuka, M. Fujimaki, H. Imao, O. Kamigaito, K. Kusaka, H. Okuno, K. Ozeki, K. Suda, A. Uchiyama, T. Watanabe, Y. Watanabe, K. Yamada
    RIKEN Nishina Center, Wako, Japan
  • H. Hara, A. Miyamoto, K. Sennyu, T. Yanagisawa
    MHI-MS, Kobe, Japan
  • E. Kako, H. Nakai, H. Sakai, K. Umemori
    KEK, Ibaraki, Japan
  
  A prototype cryomodule with a superconducting quarter- wave resonator (SC QWR) has been developed at RIKEN Radioactive Isotope Beam Factory (RIBF). During the last SRF conference, we presented the performance of our first SC QWR and the first cool-down test of its cryomodule. Since then, we have continued our efforts to improve cavity performance and succeeded in recovering deteriorated Q0. In this paper, we report what we constructed and learned from the prototype, including design issues with the cavity and its cryomodule. Design issues related to the new SC QWRs and their cryomodules for the SC linac booster of the RIKEN Heavy-Ion Linac (RILAC) are described as well.  
slides icon Slides WETEB1 [120.252 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-WETEB1  
About • paper received ※ 24 June 2019       paper accepted ※ 05 July 2019       issue date ※ 14 August 2019  
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WETEB3 CEBAF C100 Fault Classification based on Time Domain RF Signals cavity, cryomodule, controls, operation 763
 
  • T. Powers, A.D. Solopova
    JLab, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
The CEBAF 12 GeV upgrade project, which was completed and commissioned in 2014, included the construction and installation of 80 new 7-cell superconducting cavities that were configured in 10 cryomodules. In 2018, the software and hardware in the digital low level RF systems were configured such that a fault would trigger an acquisition process which records waveform records of 17 of the RF signals for each of the 8 cavities within the cryomodule for subsequent analysis. These waveforms are especially useful in C100 cryomodules as there is a 10% mechanical coupling between adjacent cavities. When one cavity has a fault and the gradient is reduced quickly, it will mechanically deform due relaxation of the Lorentz force effects. This deformation change causes perturbations in the adjacent cavities which, in turn, causes a cascade of cavity faults that are difficult to understand without the time domain data. This contribution will describe the types of faults encountered during operation and their signatures in the time domain data, as well as how is being used to modify the setup of the machine and implement improvements to the cryomodules. 		 
slides icon Slides WETEB3 [3.169 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-WETEB3  
About • paper received ※ 21 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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WETEB8 The Fundamental Power Coupler for CEPC Booster Cavity cavity, booster, simulation, multipactoring 789
 
  • T.M. Huang, F. Bing, R. Guo, H.Y. Lin, Q. Ma, W.M. Pan, J.Y. Zhai, Z. Zhang
    IHEP, Beijing, People’s Republic of China
  
  Funding: Supported by National natural Science Foundation of China ( 11475203)
96 Tesla type 1.3GHz 9-cell superconducting cavities, housed in eight 12m-long cryomodules, will be adopted for CEPC booster. Each cavity equips with one variable coupling, double-window fundamental power coupler (FPC). The FPC will operate at RF power up to 20 kW at quasi-CW mode. A variable coupling from 4·106 to 107 is required to meet different operation modes of Higgs, W and Z. A new coupler that employs a 50 Ω coaxial line with bellow structures, a cylindrical warm window, a coaxial planar cold window and a coupling adjusting actuator has been designed. Then two prototypes have been fabricated and high power tested up to CW 70 kW successfully. In this paper, the design, fabrication and high power test of the prototype FPCs will be presented. 		 
slides icon Slides WETEB8 [9.971 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-WETEB8  
About • paper received ※ 23 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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THP007 In-Situ EXAFS Investigations of Nb-Treatments in N2 at Elevated Temperatures experiment, niobium, cavity, lattice 842
 
  • P. Rothweiler, B. Bornmann, J. Klaes, D. Lützenkirchen-Hecht, R. Wagner, S. von Polheim
    University of Wuppertal, Wuppertal, Germany
  
  Funding: We gratefully acknowledge financial support by the German Federal Ministry of Education and Research (BMBF) under project No. 05H15PXRB1.
Smooth polycrystalline Nb metal foils were exposed to dilute N2 and Kr atmospheres at elevated temperatures of up to 900°C. Transmission mode X-ray absorption spectroscopy (EXAFS) experiments were used to study the resulting changes of the atomic short range order structure in-situ. EXAFS data were collected prior to any heat treatment as well as during the different process steps at elevated temperatures with a time resolution of about 1 s, and the samples were also studied after cooling to room temperature. In general, only very small changes of the Nb-EXAFS data could be detected after the processing in N2-atmospheres, and no evidence for bulk formation of Nb-nitrides was found. In contrast, the quantitative EXAFS data evaluation revealed slightly distorted Nb-Nb coordinations, suggesting that N-atoms are increasingly incorporated on octahedral interstitial sites in the host lattice with increasing N2-exposure. For the treatments in Kr-atmospheres, simultaneous measurements are feasible at both the K-edge of the Nb host and the Kr dopant. Those studies gave clear evidence for a Kr uptake during the heat treatment, and will be discussed in more detail at the conference. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP007  
About • paper received ※ 23 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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THP025 Overview of Superconducting RF Cavity Reliability at Diamond Light Source cavity, operation, GUI, storage-ring 885
 
  • C. Christou, P. Gu, P.J. Marten, S.A. Pande, A.F. Rankin, D. Spink, L.T. Stant, A. Tropp
    DLS, Oxfordshire, United Kingdom
  
  Diamond Light Source has been providing beam for users since January 2007. The electron beam in the storage ring is normally driven by two superconducting CESR-B cavities, with two similar cavities available as spares. Day-to-day reliability of the cavities, measured by storage ring MTBF, has improved enormously over the years. A full analysis of how this improvement has been achieved is given, with particular attention paid to cavity voltage and vacuum pressure management, and the scheduling and procedure of cavity conditioning. The benefits and risks of full and partial warm-ups of the cavities are discussed, and details and impacts of cavity failure and repair are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP025  
About • paper received ※ 21 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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THP026 Initial Operation of the LCLS-II Electron Source gun, cavity, cathode, operation 891
 
  • C. Adolphsen, A.L. Benwell, G.W. Brown, M.P. Dunning, S. Gilevich, K. Grouev, X. Liu, J.F. Schmerge, T. Vecchione, F.Y. Wang, F. Zhou
    SLAC, Menlo Park, California, USA
  • G. Huang, M.J. Johnson, T.H. Luo, F. Sannibale, S.P. Virostek
    LBNL, Berkeley, California, USA
  
  Funding: This work supported under DOE Contract DE-AC02-76SF00515
The Early Injector Commissioning program for LCLS-II aims to demonstrate CW electron beam production this year in the first two meters of the injector that includes the room-temperature 185.7 MHz single-cell gun and the 1.3 GHz two-cell buncher cavity. These cavities were designed and built by LBNL based on their experience with similar ones for their Advanced Photo-Injector Experiment (APEX) program. With the 258 nm laser system and Cs2Te cathodes, bunches of up to 300 pC are expected at rates as high as 1 MHz. The paper presents results from this program including the vacuum levels achieved, RF processing and field control experience, dark current measurements and laser and beam characterization. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP026  
About • paper received ※ 26 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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THP034 The First Tests on Vertical Cryostat GERSEMI at FREIA Facility controls, cryogenics, operation, MMI 921
 
  • J.P. Thermeau
    Laboratoire APC, Paris, France
  • K.J. Gajewski, L. Hermansson, R.J.M.Y. Ruber, R. Santiago Kern
    Uppsala University, Uppsala, Sweden
  • T. Junquera, O. Kochebina
    Accelerators and Cryogenic Systems, Orsay, France
  
  A new vertical cryostat, called Gersemi, installed at FREIA Laboratory at Uppsala University, Sweden, is designed to test superconducting magnets and radio-frequency cavities and operates at temperatures between 1.8 K and 4.2 K. Two different inserts can be used to test different superconducting equipment: a helium saturated bath insert for cavities without a helium vessel and a λ-plate insert for magnet testing in superfluid helium pressurized bath. The cold vessel cryostat has an internal diameter of 1.1 m and a useful height of 3.5 m. A valve box supplies the cryostat with the cryogens (LN2, LHe, SHe) and is linked to a gas reheater. The last one is connected to a helium recovery circuit and to a helium pumping system (4.5 g/s at 16 mbar). The Gersemi vertical cryostat is a part of FREIA cryogenic facility which also contains a helium liquefier and a horizontal cryostat inside of a bunker allowing the test of superconducting cavity cryomodules. The first results of the cryogenic tests on this equipment are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP034  
About • paper received ※ 23 June 2019       paper accepted ※ 04 July 2019       issue date ※ 14 August 2019  
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THP053 Analysis of the Results of the Tests of IFMIF Accelerating Units cavity, cryomodule, SRF, linac 992
 
  • N. Bazin, S. Chel, M. Desmons, G. Devanz, H. Jenhani, O. Piquet
    CEA-DRF-IRFU, France
  
  The prototype IFMIF-EVEDA cryomodule encloses eight superconducting 175 MHz β=0.09 Half-Wave Resonators (HWR). They are designed together with the power coupler to accelerate a high intensity deuteron beam (125 mA) from to 5 to 9 MeV. Two cavity packages, complete with tuning system and power couplers, have been tested in a dedicated horizontal test cryostat - SaTHoRI (Satellite de Tests HOrizontal des Résonateurs IFMIF). The successful operational equivalent tests and tuning of the SRF accelerating units is reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP053  
About • paper received ※ 21 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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THP055 Magnetic Field Induced by Thermo Electric Current in LCLS-II Cryomodules cavity, cryomodule, SRF, niobium 1003
 
  • G. Wu, S.K. Chandrasekaran
    Fermilab, Batavia, Illinois, USA
  
  Funding: The work is supported by Fermilab which is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Seebeck effect of metals play an important role in cryomodule design. As cryomodule cools down from room temperature down to nominal cavity operating temperature, components in a cryomodule experiences different temperatures. Some components such as power couplers cross from room temperature to 2 K. Thermo electric current forms loops circulating through and around cavities. Such current loops will generate additional magnetic field that could be trapped into cavity wall during superconducting transition as well as during cavity quench. These trapped field can degrade cavity quality factor and increase heat load. Simple circuit model is proposed and compared to calculated trapped field during cryomodule tests. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP055  
About • paper received ※ 26 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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THP058 Conditioning Experience of the ESS Spoke Cryomodule Prototype cavity, cryomodule, operation, hardware 1011
 
  • A. Miyazaki, K. Fransson, K.J. Gajewski, L. Hermansson, H. Li, R.J.M.Y. Ruber, R. Santiago Kern, R. Wedberg
    Uppsala University, Uppsala, Sweden
  
  The prototype cryomodule for the ESS double spoke cavities is tested in the FREIA laboratory at Uppsala University. One of the goals of this test is to establish an efficient way to assess one series cryomodule within a due time (about one month). In 2017, the dedicated high-power test for dressed cavities in the horizontal cryostat (HNOSS) revealed that one of the possible challenges is a conditioning process of the coupler and cavity multipacting. Each process should not damage any components of the cryomodule but at the same time it should be finished in a reasonable time scale. More importantly, unlike the previous tests in the vertical or horizontal cryostat, conditioning two cavities in one cryomodule in due time may require parallel processing in some part of the procedure. This study will be the first practical experience of double spoke cavity conditioning in a cryomodule, and will lead to a standard conditioning recipe for future projects containing superconducting spoke cavities. In this presentation, a preliminary result of cryomodule testing will be shown with a special focus on the conditioning processes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP058  
About • paper received ※ 01 July 2019       paper accepted ※ 03 July 2019       issue date ※ 14 August 2019  
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THP068 Evaluation of Low Heat Conductivity RF Cables cavity, insertion, cryogenics, SRF 1045
 
  • G. Cheng, G. Ciovati, M.L. Morrone
    JLab, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
New potential applications of superconducting radio-frequency can be envisioned with conduction cooling of the cavities using cryocoolers. In this case, the total heat load to the cryocoolers have to be carefully managed to assure sufficient margin to operate the cavity at an acceptable accelerating gradient. The static and dynamic heat load from rf cables connected to the cavity can be a significant contribution to the total heat load. In this contribution we report the results from measurements of the temperature profile at 1.3 GHz for two low heat conductivity rf cables, as a function of the rf power and with one end of the cable in thermal contact with a liquid helium bath at 4.3 K. A parametric model of the two cables was developed with ANSYS to match the temperature profiles and calculate the heat load at the cold end of the cable. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP068  
About • paper received ※ 21 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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THP087 2 K SUPERFLUID HELIUM CRYOGENIC VERTICAL TEST STAND OF PAPS cavity, cryogenics, superconducting-cavity, SRF 1107
 
  • L.R. Sun, R. Ge, R. Han, Y.C. Jiang, S.P. Li, C.C. Ma, M.J. Sang, M.F. Xu, R. Ye, J.H. Zhang, X.Z. Zhang, Z.Z. Zhang, T.X. Zhao
    IHEP, Beijing, People’s Republic of China
  
  Platform of Advanced Photon Source Technology R&D (PAPS) in the Institute of High Energy Physics (IHEP) is an ongoing project, which aimed to provide a comprehensive research and testing platform for the particle accelerator, X-ray detection and optics. As one of the important parts of the platform, cryogenic vertical test stand for the superconducting cavities is composed of three big vertical test cryostats with 2 different inner diameters, which can provide 4.5K liquid helium, 2K superfluid helium and the lowest 1.5K environments according to the cavities test requirements. The cryogen-ic vertical test stands also focus on current international ¿hot spot¿ fast cool down to the superconducting cavi-ties, maximum liquid helium mass flow rate can be reached to 80g/s. Because of the big size of the cryostats and certain scale, the finished cryogenic vertical test stand can meet several different type cavities test, such as 1.3GHz 9cell, Spoke, elliptical, etc. And also can provide the cavities¿ mass vertical testing for the large scale superconducting accelerators.  
poster icon Poster THP087 [1.182 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP087  
About • paper received ※ 20 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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THP091 Upgrade of the Fermilab Spoke Test Cryostat for Testing of PIP-II 650 MHz 5-Cell Elliptical Cavities cavity, MMI, cryogenics, interface 1124
 
  • A.I. Sukhanov, S.K. Chandrasekaran, B.M. Hanna, T.H. Nicol, J.P. Ozelis, Y.M. Pischalnikov, D. Plant, O.V. Prokofiev, O.V. Pronitchev, V. Roger, W. Schappert, I. Terechkine, V.P. Yakovlev
    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 > 3·10zEhNZeHn). 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. Existing horizontal testing facilities at Fermilab, Horizontal Test Stand (HTS) and Spoke Test Cryostat (STC), are not large enough to accommodate jacketed 650 MHz 5-cell cavity. An upgrade of the STC is proposed to install extension to the cryostat and modify cryogenic connections and RF infrastructure to provide testing of 650 MHz cavities. In this paper we describe STC upgrade and commissioning of the upgraded facility. We discuss mitigation of issues and problems specific for testing of high Q0 650 MHz cavities, which require low residual magnetic field and low acoustic and mechanical vibrations environment.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP091  
About • paper received ※ 23 June 2019       paper accepted ※ 30 June 2019       issue date ※ 14 August 2019  
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THP101 Commissioning of a Cleanroom for SRF Activities at the Helmholtz Institute Mainz cavity, SRF, operation, heavy-ion 1162
 
  • T. Kürzeder, K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, R.G. Heine, S. Lauber, J. List, M. Miski-Oglu
    HIM, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, S. Lauber, J. List, M. Miski-Oglu, S. Yaramyshev
    GSI, Darmstadt, Germany
  • K. Aulenbacher, F.D. Dziuba, S. Lauber
    IKP, Mainz, Germany
  • J. Conrad
    TU Darmstadt, Darmstadt, Germany
  • R.G. Heine, F. Hug, J. List, T. Stengler
    KPH, Mainz, Germany
  
  A newly built cleanroom is under commissioning at the Helmholtz-Institute Mainz (HIM). In its ISO-class 6 area vacuum components and cavities can be cleaned in different ultrasonic baths and in a dedicated conductance rinsing bath. In the ISO-class 4 area a large vacuum oven offers the possibility for comprehensive drying. A high pressure rinsing cabinet (HPR) has been installed between the two cleanroom areas to be loaded and unloaded from both sides. Complete cold-strings have to be mounted in the ISO-class 4 area and to be rolled out of the cleanroom on a rail system installed on the floor. All installations and tools have been integrated to treat and assemble superconducting 217 MHz multigap crossbar cavities for the Helmholtz Linear Accelerator (HELIAC), which is under development by HIM and GSI. Those crossbar cavities have a diameter of 650 mm and a weight of up to 100 kg. The cleanroom will be also used for the Mainz Energy-Recovering Superconducting Accelerator (MESA) project, processing the TESLA/XFEL type 9-cell cavities and other beamline components. This paper reports on the commissioning of the cleanroom and shows the features of the different installations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP101  
About • paper received ※ 23 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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THP106 An SRF Test Stand in High Intensity and High Energy Proton Beams cavity, cryogenics, cryomodule, SRF 1187
 
  • G. Vandoni, K. Artoos, V. Baglin, K. Brodzinski, R. Calaga, O. Capatina, S.D. Claudet, L.P. Delprat, S. Mehanneche, E. Montesinos, C. Pasquino, J.S. Swieszek
    CERN, Meyrin, Switzerland
  
  In the framework of HL-LHC, a new infrastructure was installed in 2018, to test SRF structures in the proton beams of the SPS. Scope of the test stand is to study the operational performance of crab cavities for HL-LHC – more generally, SRF cavities – through a wide range of proton beam parameters up to high energy and current, under safe conditions for equipment and personnel. The SPS beam instrumentation is used to monitor orbit centering, RF phase scans, bunch rotation. To minimize impact on beam time, infrastructure and services allow for full remote control. Critical aperture restrictions is overcome by placing the test structure and its ancillaries on a motorized table for lateral translation in- and out of beam. Two articulated Y-shaped vacuum chambers connect the test cryomodule on a beam by-pass. A new cryogenic refrigerator is installed in a split scheme, with an underground cold box fed from a surface compressor. The two Inductive Output Tubes (IOT) power amplifiers deliver up to 60 kW cw via coaxial transmission lines to the two cavities and charges and circulators, the latter installed on the translation table. Interlocks and safety equipment complete the test stand.  
poster icon Poster THP106 [3.982 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP106  
About • paper received ※ 23 June 2019       paper accepted ※ 01 July 2019       issue date ※ 14 August 2019  
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FRCAB7 Plasma Processing to Reduce Field Emission in LCLS-II 1.3 GHz SRF Cavities plasma, cavity, radiation, HOM 1231
 
  • B. Giaccone, J. Zasadzinski
    IIT, Chicago, Illinois, USA
  • P. Berrutti, B. Giaccone, A. Grassellino, M. Martinello
    Fermilab, Batavia, Illinois, USA
  • M. Doleans
    ORNL, Oak Ridge, Tennessee, USA
  • D. Gonnella, G. Lanza, M.C. Ross
    SLAC, Menlo Park, California, USA
  
  Plasma cleaning for LCLS-II 9-cell 1.3 GHz cavities is under study at Fermilab. Starting from ORNL method, we have developed a new technique for plasma ignition using HOMs. Plasma processing is being applied to contaminated and field emitting cavities, here are discussed the first results in terms of Q and radiation vs E measured before and after treatment. Further studies are ongoing to optimize plasma parameters and to acquire statistics on plasma cleaning effectiveness.  
slides icon Slides FRCAB7 [14.701 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAB7  
About • paper received ※ 23 June 2019       paper accepted ※ 04 July 2019       issue date ※ 14 August 2019  
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