Cavities - Fabrication
quality assurance
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MOP005 The Facility for Rare Isotope Beams Superconducting Cavity Production Status and Findings Concerning Surface Defects 31
 
  • C. Compton
    NSCL, East Lansing, Michigan, USA
  • H. Ao, J. Asciutto, K. Elliott, W. Hartung, S.H. Kim, E.S. Metzgar, S.J. Miller, J.T. Popielarski, L. Popielarski, K. Saito, T. Xu
    FRIB, East Lansing, Michigan, USA
  • J. Craft
    SLAC, Menlo Park, California, USA
 
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB), located on the campus of Michigan State University (MSU) will require 324 Superconducting Radio Frequency (SRF) cavities in the driver linac. Four types of cavities of two classes, quarter-wave (β=0.041 and 0.085) and half-wave (β=0.29 and 0.53), will be housed in 46 cryomodules. To date, FRIB has tested over 300 cavities in vertical Dewar tests as part of the certification procedures. Incoming cavities, fabricated in industry, are sequenced through acceptance inspection and checked for non-conformance. If accepted, the cavities are processed, assembled onto a vertical test stand, and cold tested. A large database of cavity surface images has been collected with the aid of a borescope camera. Borescope inspection is a standard step that is performed at incoming inspection, post-acid bulk etch, and after failed tests (if necessary) for each cavity, in order to locate any non-conformances. Findings of surface defects relating to degraded cavity performance will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP005  
About • paper received ※ 02 July 2019       paper accepted ※ 13 August 2019       issue date ※ 14 August 2019  
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THP099 The ESS Database for Elliptical Cavities 1152
 
  • P. Pierini, C.G. Maiano
    ESS, Lund, Sweden
  • A. Bosotti, D. Sertore
    INFN/LASA, Segrate (MI), Italy
  • E. Cenni
    CEA-IRFU, Gif-sur-Yvette, France
  • M. Wang
    IHEP, Beijing, People’s Republic of China
 
  The large inkind scope of the elliptical superconducting RF linac of the ESS facility implies the handling of handover conditions between the cavities fabrication and testing phases performed at INFN and STFC, to the assembly of cryomodules at CEA and later to ESS in Lund. The performance qualification at the module test stand, and later the commissioning and operation phases require the availability of the cavity performance and frequency data under all environmental conditions during preparation (e.g. temperature, vacuum in beam line/He vessel/vacuum vessel, tuner state). Availability of the data needs to be guaranteed for the long term maintainability of the accelerator. For these reasons a cavity database has been set up at ESS, integrating the data contained in the handover documentation from the inkind partners and extending it during the activities at ESS after receiving the modules. The database has been used to analyze the preparation steps of the prototype demonstrator cryomodule for the tests at ESS, by benchmarking with the data collected during the tests at CEA, and is currently used during the series cavities handover phases.  
poster icon Poster THP099 [10.434 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP099  
About • paper received ※ 03 July 2019       paper accepted ※ 04 July 2019       issue date ※ 14 August 2019  
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THP100 Insight into DESY’s Test Laboratory for Niobium Raw Material and Semi-finished Products 1157
 
  • J.I. Iversen, A. Brinkmann, A. Ermakov, A. Muhs, J. Ziegler
    DESY, Hamburg, Germany
 
  DESY has started setting up a test laboratory for niobium more than 20 years ago. The initial application was to assure required surface quality of niobium sheets before its forming to half cells for the 1.3 GHz SRF Tesla shape cavities. As a first test equipment DESY developed a basic eddy current test device which was refined continuously. Since that time the laboratory grew with the requirements on R&D activities for niobium raw material and its semi-finished products. To be able to assure the Quality of niobium products needed for the European XFEL series cavity production, the Lab’s infrastructure was updated significantly. Now the capabilities of the test laboratory cover the investigation of the fundamental physical properties of various materials including for example mechanical properties, surface, microstructure and chemical composition analysis. The Quality Assurance for the European XFEL was performed successfully on an outstanding level and in the meantime the laboratory was used for several other projects like LCLS-II and ESS. We present DESY’s test infrastructure as well as applied methods for the Quality Assurance and R&D activities and we report about experiences.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP100  
About • paper received ※ 25 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 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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THP102 Uncertainty Quantification of a Quadrupole-Resonator for Radio Frequency Characterization of Superconductors 1168
 
  • P. Putek, S. Gorgi Zadeh, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  • W. Hillert
    ELSA, Bonn, Germany
  • W. Hillert, M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • M. Wenskat
    DESY, Hamburg, Germany
  • U. van Rienen
    University of Rostock, Rostock, Germany
 
  Funding: This work has been supported by the German Federal Ministry for Research and Education BMBF under contract 05H18HRRB1.
To explore the fundamental properties of superconducting materials used in modern particle accelerators, high precision surface resistance measurements in a dedicated testing equipment is of key importance. The quadrupole resonator, originally developed at CERN, and then successfully modified at the Helmholtz-Zentrum Berlin, is ideally suited for characterization of samples at temperatures of 1.8 K to > 20 K, RF fields of up to 120 mT and frequencies of 433 MHz, 866 MHz and 1.3 GHz. In the past years, this set-up has been subject of intensive research on both its capabilities and limitations. Yet, one of the main challenges is the accuracy of the surface resistance measurement, which is determined by both the uncertainty in the RF measurement and manufacturing imperfections related to the production tolerances such as quenching and chemical polishing processes, etc. In this contribution, we focus on the influence of key geometrical parameters on operating the quadrupole resonator at the third mode, since the surface resistance measurement shows some unexpected behavior for this frequency.
* Design and Fabrication of a Quadrupole-Resonator for Sample R&D by M. Wenskat, W. Hillert, et al.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP102  
About • paper received ※ 25 June 2019       paper accepted ※ 29 June 2019       issue date ※ 14 August 2019  
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