Keyword: cryogenics
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MOAA02 Recent Progress with EU-XFEL cryomodule, cavity, linac, operation 14
 
  • D. Reschke
    DESY, Hamburg, Germany
  
  The superconducting accelerator of the European XFEL consists of the injector part and the main linac. The injector includes one 1.3 GHz accelerator module and one 3.9 GHz third-harmonic module, while the main linac will consist of 100 accelerator modules, operating at an average design gradient of 23.6 MV/m. The fabrication and surface treatment by industry as well as RF acceptance tests of the required 808 superconducting 1.3 GHz cavities are close to an end by the time of SRF15. The accelerator module assembly, testing and installation in the tunnel is in full swing. First steps of commissioning have been made. The status and results of cavity and module RF tests at 1.3 GHz and 3.9 GHz are presented.  
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MOBA05 Nature of Quality Factor Degradation in SRF Cavities due to Quench cavity, superconductivity, simulation, electron 41
 
  • M. Checchin
    Fermilab, Batavia, Illinois, USA
  
  Superconductive quench is a well-known phenomenon that causes magnetic flux trapping in superconducting accelerating cavities increasing the radio-frequency surface resistance. This paper is addressed to the understanding of the quench-induced losses nature. We present the proof that the real origin of quench-related quality factor degradation is consequence only of ambient magnetic field trapped at the quench spot. Also, we show how the quality factor can be fully recovered after it was highly deteriorated quenching several times in presence of external magnetic field. Such phenomenon was found to be completely reliable up to certain values of applied magnetic field, above that the cavity quality factor cannot be fully recovered anymore.  
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MOPB003 Superconducting Cavity for the Measurements of Frequency, Temperature, RF Field Dependence of the Surface Resistance cavity, plasma, coupling, experiment 70
 
  • H. Park, S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • H. Park
    JLab, Newport News, Virginia, USA
  
  In order to better understand the contributions of the various physical processes to the surface resistance of superconductors the ODU Center for Accelerator Science is developing a half-wave resonator capable of operating between 325 MHz and 1.3 GHz. This will allow the measurement of the temperature and rf field dependence of the surface resistance on the same surface over the range of frequency of interest for particle accelerators and identify the various sources of power dissipation.  
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MOPB055 Characterization of Nitrogen Doping Recipes for the Nb SRF Cavities niobium, cavity, SRF, electron 223
 
  • Y. Trenikhina, A. Grassellino, O.S. Melnychuk, A. Romanenko
    Fermilab, Batavia, Illinois, USA
  
  For the future development of the nitrogen doping technology, it’s vital to understand the mechanisms behind the performance benefits of N-doped cavities as well as the performance limitations, such as quench field. Following various doping recipes, cavity cutouts and flat niobium samples have been evaluated with XRD, SEM, SIMS and TEM in order to relate structural and compositional changes in the niobium near-surface to SRF performance. Annealing of Nb cavities with nitrogen for various durations and at various temperatures lead to a layer containing inclusions of non-superconducting Nb nitride phases, followed by unreacted Nb with an elevated N-interstitials concentration. We found that EP of the N-treated cavities removes the unwanted niobium nitride phases, confirming that performance benefits are originating from the elevated concentration of N interstitials. The role of low temperature Nb hydride precipitants in the performance limitation of N-doped cavities was evaluated by TEM temperature dependent studies. Finally, extended characterization of the original cavity cutouts from the N-doped RF tested cavity sheds some light on quenching mechanisms.  
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MOPB063 Design of the Superconducting LINAC for SARAF cryomodule, cavity, solenoid, linac 250
 
  • C. Madec
    CEA, Gif-sur-Yvette, France
  • N. Bazin, L. Boudjaoui, R. Cubizolles, G. Ferrand, P. Hardy, C. Pes, N. Sellami
    CEA/IRFU, Gif-sur-Yvette, France
  • P. Bertrand
    GANIL, Caen, France
  • P. Brédy, B. Gastineau, N. Pichoff
    CEA/DSM/IRFU, France
  
  CEA is committed to delivering a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5mA beam of either protons from 1.3 MeV to 35 MeV or deuterons from 2.6 MeV to 40.1 MeV. The SCL consists 4 cryomodules equipped with warm diagnostics. The first two identical cryomodules host 6 half-wave resonator (HWR) low beta cavities (β = 0.091), 176 MHz. As the last two identical welcome 7 HWR high-beta cavities (β = 0.181), 176 MHz. The beam is focused through the superconducting solenoids located between cavities housing steering coils. A Beam Position Monitor is placed upstream each solenoid. A diagnostic box containing a beam profiler, a bunch length monitor and a vacuum pump will be inserted between 2 consecutive cryomodules. The HWR cavities, the solenoid package and the cryomodules are being designed. These studies will be presented in this poster.  
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MOPB090 Analysis of Degraded Cavities in Prototype Modules for the European XFEL cavity, accelerating-gradient, SRF, radiation 355
 
  • S. Aderhold
    Fermilab, Batavia, Illinois, USA
  • S. Aderhold, D. Kostin, A. Matheisen, A. Navitski, D. Reschke
    DESY, Hamburg, Germany
  
  In-between the fabrication and the operation in an accelerator the performance of superconducting RF cavities is typically tested several times. Although the assembly is done under very controlled conditions in a clean room, it is observed from time to time that a cavity with good performance in the vertical acceptance test shows deteriorated performance in the accelerator module afterwards. This work presents the analysis of several such cavities that have been disassembled from modules of the prototype phase for the European XFEL for detailed investigation like additional rf tests, optical inspection and replica.  
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MOPB104 Flux Expulsion Variation in SRF Cavities cavity, niobium, factory, SRF 404
 
  • S. Posen, M. Checchin, A.C. Crawford, A. Grassellino, M. Martinello, O.S. Melnychuk, A. Romanenko, D.A. Sergatskov
    Fermilab, Batavia, Illinois, USA
  
  Treating a cavity with nitrogen doping significantly increases Q0 at medium fields, reducing cryogenic costs for high duty factor linear accelerators such as LCLS II. N-doping also makes cavities more sensitive to increased residual resistance due to trapped magnetic flux, making it critical to either have extremely effective magnetic shielding, or to prevent flux from being trapped in the cavity during cooldown. In this paper, we report on results of a study of flux expulsion. We discuss possible ways in which flux can be pinned in the inner surface, outer surface, or bulk of a cavity, and we present experimental results studying these mechanisms. We show that grain structure appears to play a key role and that a cavity that expelled flux poorly changed to expelling flux well after a high temperature furnace treatment. We further show that after furnace treatment, this cavity exhibited a significant improvement in quality factor when cooled in an external magnetic field. We conclude with implications for SRF accelerators with high Q0 requirements.  
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TUAA06 Recent Progress of ESS Spoke and Elliptical Cryomodules cryomodule, cavity, SRF, linac 474
 
  • G. Olry
    IPN, Orsay, France
  
  The ESS accelerator high level requirements are to provide a 2.86 ms long proton pulse at 2 GeV at repetition rate of 14 Hz. This represents 5 MW of average beam power with a 4% duty cycle on target. In a framework of collaboration between IPN Orsay, CEA Saclay and ESS, prototype spoke and medium and high beta elliptical cavities and cryomodules have been studied, constructed and tested. After a description of the ESS project and the accelerator layout, this paper will focus on the recent progress towards realization of the detailed design, the manufacturing of the first components of the prototype cryomodules and the first test results of some of the main critical elements such as SRF cavities and cold tuning systems.  
slides icon Slides TUAA06 [17.400 MB]  
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TUBA01 Status of the SRF Systems at HIE-ISOLDE cavity, cryomodule, vacuum, solenoid 481
 
  • W. Venturini Delsolaro, L. Arnaudon, K. Artoos, C. Bertone, J.A. Bousquet, N. Delruelle, M. Elias, J.A. Ferreira Somoza, F. Formenti, J. Gayde, J.L. Grenard, Y. Kadi, G. Kautzmann, Y. Leclercq, M. Mician, A. Miyazaki, E. Montesinos, V. Parma, G.J. Rosaz, K.M. Schirm, E. Siesling, A. Sublet, M. Therasse, L. Valdarno, D. Valuch, G. Vandoni, L.R. Williams, P. Zhang
    CERN, Geneva, Switzerland
  
  The HIE-ISOLDE project has been approved by CERN in 2009 and gained momentum after 2011. The final energy goal of the upgrade is to boost the radioactive beams of REX-ISOLDE from the present 3 MeV/u up to 10 MeV/u for A/q up to 4.5. This is to be achieved by means of a new superconducting linac, operating at 101.28 MHz and 4.5 K with independently phased quarter wave resonators (QWR). The QWRs are based on the Nb sputtering on copper technology, pioneered at CERN and developed at INFN-LNL for this cavity shape. Transverse focusing is provided by Nb-Ti superconducting solenoids. The cryomodules hosting the active elements are of the common vacuum type. In this contribution we will report on the recent advancements of the HIE-ISOLDE linac technical systems involving SRF technology. The paper is focused on the cavity production, on the experience with the assembly of the first cryomodule (CM1), and on the results of the first hardware commissioning campaign.  
slides icon Slides TUBA01 [27.129 MB]  
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TUPB006 The CLS SRF Cryogenic System Upgrade cryomodule, cavity, storage-ring, SRF 539
 
  • C.N. Regier
    CLS, Saskatoon, Saskatchewan, Canada
  
  The Canadian Light Source currently makes use of a 500 MHz CESR-B type SRF cavity in its storage ring. While the performance of this cavity has generally been good, the reliability of the cryostat and cryogenic system has suffered a few setbacks over the 10 years of operation. The position of CLS as a user facility requires reliable beam to be consistently delivered. For this reason CLS is undertaking an upgrade project to improve system reliability and reduce downtime due to planned and unplanned maintenance. The upgrade is to include a redundant helium compressor, and new cryogenic infrastructure. In addition, the spare CESR-B cryomodule will be installed and operating in the storage ring. This talk reviews the problems with the current system to date, and discusses the proposals for the upgrade of the system.  
poster icon Poster TUPB006 [0.622 MB]  
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TUPB007 Progress in the Elliptical Cavities and Cryomodule Demonstrators for the ESS LINAC cryomodule, cavity, vacuum, linac 544
 
  • F. Peauger, C. Arcambal, S. Berry, N. Berton, P. Bosland, E. Cenni, J.-P. Charrier, G. Devanz, F. Éozénou, F. Gougnaud, A. Hamdi, X. Hanus, P. Hardy, V.M. Hennion, T. Joannem, F. Leseigneur, D. Loiseau, C. Madec, L. Maurice, O. Piquet, J. Plouin, J.P. Poupeau, B. Renard, D. Roudier, P. Sahuquet, C. Servouin
    CEA/DSM/IRFU, France
  • C. Darve, N. Elias
    ESS, Lund, Sweden
  • G. Olivier
    IPN, Orsay, France
  
  The European Spallation Source (ESS) accelerator is a large superconducting linac under construction in Lund, Sweden. A collaboration between CEA Saclay, IPN Orsay and ESS-AB is established to design the elliptical cavities cryomodule of the linac. It is foreseen to build and test two cryomodule demonstrators within the next two years. We present the design evolution and the fabrication status of the cryomodule components housing four cavities. The latest test results of two prototype cavities are shown. The cryomodule assembly process and the on-going testing infrastructures at CEA Saclay are also described.  
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TUPB008 A New Cryogenic Control System for the Vertical Test Area at Jefferson Lab controls, PLC, SRF, operation 549
 
  • G.K. Davis, T. Goodman, P. Kushnick, T. Powers, C.M. Wilson
    JLab, Newport News, Virginia, USA
  
  Funding: DOE
The Vertical Test Area at Jefferson Lab, consisting of eight vertical dewars, recently received a major upgrade by replacing the original (1995) cryogenic control system. A new, state-of-the-art, distributed control system (DC S) based on Programmable Logic Controllers (PLCs) was installed and commissioned. The new system increases facility throughput, reliability and cryogenic efficiency, while improving safety. The system employs a touchscreen graphical user interface and a highly redundant architecture on an Ethernet backbone. 		 
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TUPB013 Fermilab Cryomodule Test Stand Design and Plans cryomodule, controls, cavity, SRF 566
 
  • E.R. Harms, C.M. Baffes, K. Carlson, B.E. Chase, A.L. Klebaner, M.J. Kucera, J.R. Leibfritz, M.W. McGee, P.S. Prieto, J. Reid, R.P. Stanek, D. Sun, M.J. White
    Fermilab, Batavia, Illinois, USA
  
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
A facility dedicated to SRF cryomodule testing is under construction at Fermilab. The test stand has been designed to be flexible enough to cool down and power test full length TESLA-style 8-cavity cryomodules as well cryomodules for low-β acceleration. We describe the design considerations, status, and near future plans for utilization of the test stand. 		 
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TUPB017 1.3 GHz SRF Technology R&D Progress of IHEP cavity, cryomodule, vacuum, HOM 581
 
  • J.Y. Zhai, Y.L. Chi, J.P. Dai, X.W. Dai, J. Gao, R. Ge, D.Y. He, T.M. Huang, X. Huang, S. Jin, S.P. Li, H.Y. Lin, B. Liu, Z.C. Liu, Q. Ma, Z.H. Mi, W.M. Pan, X.H. Peng, L.R. Sun, Y. Sun, Z. Xue, S.W. Zhang, Z. Zhang, H. Zhao, T.X. Zhao, H.J. Zheng, Z.S. Zhou
    IHEP, Beijing, People's Republic of China
  
  IHEP started the 1.3GHz SRF technology R&D in 2006 and recently enters the stage of integration and industrialization. After successfully making several single cell and 9-cell cavities of different shape and material, we designed and assembled a short cryomodule containing one large grain low loss shape 9-cell cavity with an input coupler and a tuner etc. This module will perform horizontal test in 2016 with the newly commissioned 1.3GHz 5MW klystron and the 2K cryogenic system. Beam test with a DC photocathode gun is also foreseen in the near future. We report here the problems, key findings and improvements in cavity dressing, clean room assembly, cryomodule assembly and the liquid nitrogen cool down test. A fine grain TESLA 9-cell cavity is also under fabrication in a company as the industrialization study.  
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TUPB026 Cryogenic Performance of the HNOSS Test Facility at Uppsala University cavity, operation, vacuum, controls 612
 
  • R. Santiago Kern, K.J. Gajewski, L. Hermansson, R.J.M.Y. Ruber
    Uppsala University, Uppsala, Sweden
  • P. Bujard, T. Junquera, J.P. Thermeau
    Accelerators and Cryogenic Systems, Orsay, France
  
  Funding: Knut and Alice Wallenbergs foundation
The FREIA Laboratory at Uppsala University, Sweden, is developing part of the RF system and testing the superconducting double spoke cavitites for ESS. During 2014 it was equipped with HNOSS, a versatile horizontal cryostat system for testing superconducting cavities. HNOSS is designed for high power RF testing of up to two superconducting accelerating cavities equipped with helium tank, fundamental power coupler and tuning system. In particular it will be used to characterise the performance of spoke cavities like used in the accelerator for the ESS project. HNOSS is connected to a cryogenic plant providing liquid helium and a sub-atmospheric pumping system enabling operation in the range 1.8 to 4.5~K. We present a brief description of the major components, installation and results from the recent operation and tests. 		 
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TUPB048 Fermilab Nb3Sn R&D Program niobium, cavity, SRF, accelerating-gradient 678
 
  • S. Posen, M. Merio, A. Romanenko, Y. Trenikhina
    Fermilab, Batavia, Illinois, USA
  
  A substantial program has been initiated at FNAL for R&D on Nb3Sn coated cavities. Since early 2015, design, fabrication, and commissioning has been ongoing on a coating chamber, designed for deposition via vapor diffusion. The volume of the chamber will be large enough to accommodate not just R&D cavities, but full production-style cavities such as TeSLA 9-cells. In this contribution, we overview the development of the chamber and we introduce the R&D program planned for the coming years. We discuss research paths that may yield increased maximum fields and reduced residual resistances as well as new applications that could be explored with larger coated cavities.  
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TUPB064 Superconducting Thin Film Test Cavity Commissioning cavity, vacuum, niobium, resonance 731
 
  • P. Goudket, K.D. Dumbell, L. Gurran, O.B. Malyshev, N. Pattalwar, S.M. Pattalwar, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G. Burt, L. Gurran
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • G. Burt, L. Gurran
    Lancaster University, Lancaster, United Kingdom
  • P. Goudket, O.B. Malyshev, S.M. Pattalwar, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • T.J. Jones, E.S. Jordan
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  
  A radiofrequency (RF) cavity and cryostat dedicated to the measurement of superconducting coatings at GHz frequencies was designed to evaluate surface resistive losses on a flat sample. The test cavity consists of two parts: a cylindrical half-cell made of bulk niobium (Nb) and a flat Nb disc. The two parts can be thermally and electrically isolated via a vacuum gap, whereas the electromagnetic fields are constrained through the use of RF chokes. Both parts are conduction cooled hence the cavity halves are suspended in vacuum during operation. The flat disc can be replaced with a sample, such as a Cu disc coated with a film of niobium or any other superconducting material. The RF test provides simple cavity Q-factor measurements as well as calorimetric measurements of the losses on the sample. The advantage of this method is the combination of a compact cavity with a simple planar sample. The paper describes the RF, mechanical and cryogenic design, and initial commissioning of the system with notes on how any issues arising are to be addressed.  
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TUPB065 Cryogenic RF Characterization of Superconducting Materials at SLAC With Hemispherical Cavities cavity, niobium, SRF, factory 735
 
  • P.B. Welander, M.A. Franzi, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  
  For the characterization of SRF materials, we have commissioned a second-generation, X-band cavity cryostat that can rapidly analyze thin-film coatings or bulk samples. The system operates at 11.4 GHz, at temperatures down to 4 K, and utilizes two interchangeable hemispherical cavities (one Cu, one Nb) that can accommodate 51 mm-diameter samples on the flat side. The cavities are designed to operate with a TE032-like mode where the magnetic field is strongest on the sample surface. As a result, the sample accounts for 33% of the overall cavity loss, despite comprising less than 8% of the total surface area. For low-power testing we utilize a programmable network analyzer, while for high-power testing we connect the cavity to a 50 MW XL-4 klystron. With the Nb cavity we can measure surface resistances down to 0.7 microhm, while with the Cu cavity we can measure quenching fields up to 360 mT. X-band operation permits a compact cavity and cryostat design with a reasonable sample size, while the closed-cycle pulse-tube cryorefrigerator allows for rapid sample cycling. We will discuss cryostat design, cavity modeling, measurement limits, and recent sample testing results.  
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TUPB071 Development and Testing of a 325 MHz beta0 = 0.82 Single-Spoke Cavity cavity, linac, vacuum, impedance 744
 
  • C.S. Hopper, J.R. Delayen, H. Park
    ODU, Norfolk, Virginia, USA
  • J.R. Delayen, H. Park
    JLab, Newport News, Virginia, USA
  
  A single-spoke cavity operating at 325 MHz with geometric beta of 0.82 has been developed and tested. Initial results* showed high levels of field emission which limited the achievable gradient. Several rounds of helium processing significantly improved the cavity performance. Here we discuss the development process and report on the improved results.
*C.S. Hopper, HyeKyoung Park, and J.R. Delayen, “Cryogenic Testing of High-Velocity Spoke Cavities,” Proc. of the 27th Linear Accelerator Conference, Geneva, Switzerland, TUPP109, (2014). 		 
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TUPB081 Multi-Cell Temperature Mapping and Conclusions cavity, SRF, monitoring, controls 783
 
  • F. Furuta, R.G. Eichhorn, G.M. Ge, D. Gonnella, D.L. Hartill, G.H. Hoffstaetter, J.J. Kaufman, M. Liepe, E.N. Smith
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Multi-cell temperature mapping (T-map) system has been developed and applied on SRF Nb cavities vertical tests (VT) at Cornell. It has nearly two thousand thermometers and achieved a 1mK resolution of niobium surface temperature rinsing in superfluid helium . We have upgraded the system to be capable of monitoring the temperature profiles of quench spot on cavity. The recent results of T-map during cavity tests and details will be reported.  
poster icon Poster TUPB081 [4.421 MB]  
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TUPB083 Test Characterization of Superconducting Spoke Cavities at Uppsala University cavity, superconductivity, accelerating-gradient, pick-up 791
 
  • H. Li, A.K. Bhattacharyya, V.A. Goryashko, L. Hermansson, R.J.M.Y. Ruber, R. Santiago Kern
    Uppsala University, Uppsala, Sweden
  • D.S. Dancila
    Uppsala University, Department of Engineering Sciences, Uppsala, Sweden
  • G. Olry
    IPN, Orsay, France
  
  As part of the development of the ESS spoke linac, the FREIA Laboratory at Uppsala University, Sweden, has been equipped with a superconducting cavity test facility. The cryogenic tests of a single and double spoke cavity developed by IPN Orsay have been performed in the new HNOSS horizontal cryostat system. The cavities are equipped with a low power input antenna and a pick-up antenna. Different measurement methods were investigated to measure the RF signal coupling from the cavity. Results from the tests confirm the possibility to transport the cavities from France to Sweden without consequences. We present the methods and preliminary study results of the cavity performance.  
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TUPB099 Magnetic Foils for SRF Cryomodule cavity, shielding, SRF, niobium 844
 
  • G. Wu, S. Aderhold, S.K. Chandrasekaran, A.C. Crawford, A. Grassellino, C.J. Grimm, J.P. Ozelis, D.A. Sergatskov, A. Vostrikov
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by FRA under DOE contract DE-AC02-07CH11359
High quality factor niobium cavities require minimal residual magnetic field around the high magnetic field region. A typical global magnetic shield takes more material and provides less effective magnetic screening. On the other hand, local magnetic shield has to introduce complex geometries to cover access ports and instrumentation and thermal straps. Local magnetic source and thermal current will increase residual field seen by SRF cavities regardless the complexity of local magnetic shield. Magnetic foils that is cryogenic compatible provides a great benefit to reduce residual magnetic field. This paper will describe the evaluation of such magnetic foils in both vertical and horizontal test. 		 
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TUPB108 Connection of EU-XFEL Cryomodules, Caps, Boxes in EU-XFEL Main Linac and Injector: Welding of Cryo-Pipes and Assembly of Beam-Line Absorbers Under Requirements of PED Regulation linac, cryomodule, vacuum, operation 883
 
  • S. Barbanotti, C. Buhr, H. Hintz, K. Jensch, L. Lilje, W. Maschmann, P. Pierini, A. Wagner
    DESY, Hamburg, Germany
  • P. Pierini
    INFN/LASA, Segrate (MI), Italy
  
  The European X-ray Free Electron Laser (EU-XFEL) cold linac consists of 100 assembled cryomodules, 6 feed-/end-boxes and 6 string connection boxes fixed to the ceiling of the accelerator tunnel; the injector consists of a radio frequency gun, one 1.3 GHz and one 3.9 GHz cryomodule, one feed- and one end-cap lying on ground supports. The components are connected together in the tunnel, after cold testing, transport, final positioning and alignment. The cold linac is a pressure equipment and is therefore subjected to the requirements of the Pressure Equipment Directive (PED). This paper describes the welding and subsequent non-destructive testing of the cryo-pipes (with a deeper look at the technical solutions adopted to satisfy the PED requirements), the assembly of the beam line absorbers and the final steps before closing the connection with a DN1000 bellows. A special paragraph will be dedicated to the connection of the injector components, where the lack of space makes this installation a particularly challenging task.  
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TUPB113 JLab Cryomodule Assembly Infrastructure Modifications for LCLS-II cavity, cryomodule, vacuum, controls 898
 
  • E. Daly, J. Armstrong, G. Cheng, M.A. Drury, J.F. Fischer, D. Forehand, K. Harding, J. Henry, K. Macha, J.P. Preble, A.V. Reilly, K.M. Wilson
    JLab, Newport News, Virginia, USA
  
  Funding: This work was supported by the LCLS-II Project and the U.S. Department of Energy, Contract DE-AC02-76SF00515.
The Thomas Jefferson National Accelerator Facility is currently engaged, along with several other DOE national laboratories, in the Linac Coherent Light Source II project (LCLS II). The SRF Institute at Jefferson Lab will be building 1 prototype and 17 production cryomodules based on the TESLA / ILC / XFEL design. Each cryomodule will contain eight nine cell cavities with coaxial power couplers operating at 1.3 GHz. New and modified infrastructure and assembly tooling is required to construct cryomodules in accordance with LCLS-II requirements. The approach for modifying assembly infrastructure included evaluating the existing assembly infrastructure implemented at laboratories world-wide in support of ILC and XFEL production activities and considered compatibility with existing infrastructure at JLab employed for previous cryomodule production projects. These modifications include capabilities to test cavities, construct cavity strings in a class 10 cleanroom environment, assemble cavity strings into cryostats, and prepare cryomodules for cryogenic performance testing. This paper will give a detailed description of these modifications. 		 
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TUPB115 Improvements of the Mechanical, Vacuum and Cryogenic Procedures for European XFEL Cryomodule Testing cryomodule, vacuum, operation, detector 906
 
  • J. Świerbleski, M. Bednarski, B. Dzieza, W. Gaj, L. Grudnik, P. Halczynski, A. Kotarba, A. Krawczyk, K. Myalski, T. Ostrowicz, B. Prochal, J. Rafalski, M. Sienkiewicz, M. Skiba, M. Wartak, M. Wiencek, J. Zbroja, P. Ziolkowski
    IFJ-PAN, Kraków, Poland
  
  The European X-ray Free Electron Laser is under construction at DESY, Hamburg. The linear accelerator part of the laser consists of 100 SRF cryomodules. Before installation in the tunnel the cryomodules undergo a series of performance tests at the AMTF Hall. Testing procedures have been implemented based on TTF (Tesla Test Facility) experience. However, the rate of testing and number of test benches is greater than in the TTF infrastructure. To maintain the goal testing rate of one module per week, improvement to the existing procedures were implemented at AMTF. Around 50% of the testing time is taken by connection of the cryomodule to the test bench, performing all necessary checks and cool down. Most of the preparation procedures have been optimized to decrease mounting time. This paper describes improvements made to the mechanical connections, vacuum checks and cryogenics operation.  
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TUPB117 Cavities and Cryomodules Managing System at AMTF cavity, cryomodule, status, vacuum 910
 
  • M. Wiencek, K. Krzysik, J. Świerbleski
    IFJ-PAN, Kraków, Poland
  • J. Chodak
    DESY, Hamburg, Germany
  
  800 SRF cavities and 100 SRF cryomodules are under test in the AMTF Hall at DESY, Hamburg. Testing of such a large volume of components requires a management system which can store the measurement data. In addition the system should simplify tasks which are recurrent. In the case of the system developed at AMTF, communication with external databases has also been developed. An added complication is that not all the test procedures are identical for each component, and therefore the management system keeps track of all work done for each of the individual components. In the case of the vertical acceptance tests for the 800 SRF cavities, the management system provides an interface for specifying a decision of the next step each cavity (e.g. send for module assembly or retreatment). This paper describes the most important parts of this system.  
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TUPB118 Improvements of the RF Test Procedures for European XFEL Cryomodule Testing cryomodule, cavity, HOM, LLRF 914
 
  • M. Wiencek, K. Kasprzak, D. Konwisorz, S. Myalski, K. Turaj, A. Zwozniak
    IFJ-PAN, Kraków, Poland
  
  The testing of the 100 SRF cryomodules for E-XFEL is currently ongoing at the AMTF Hall, located at DESY, Hamburg. Cold tests for the cryomodules have been developed based on TTF (Tesla Test Facility) experience. However, to be able to test the cryomodules with required test rate of one a week, some improvements to the measurements had to be made. The goal of these improvements was to reduce the time needed for testing without losing any of the important data for the cryomodule. Currently, after testing more than 30% of the cryomodules, gathered experience is now allowing us to skip or combine some of the measurements. This paper describes changes in the cold test procedures which have been made since the testing of the first serial cryomodules delivered by IRFU.  
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TUPB120 The Cryogenic Infrastructure for SRF Testing at TRIUMF SRF, cryomodule, ISAC, TRIUMF 919
 
  • R.R. Nagimov, P.R. Harmer, D. Kishi, A. Koveshnikov, R.E. Laxdal, H. Liu, N. Muller
    TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
  
  Funding: Canada Foundation for Innovation, British Columbia Knowledge Development Fund, and National Research Council Canada.
At the moment TRIUMF operates one superconductive radio-frequency (SRF) accelerator and is building the second one. The superconducting heavy ion linear accelerator of the Isotope Separation and Acceleration (ISAC) facility utilizes medium beta quarter wave cavities cooled down to 4 K. The Advanced Rare IsotopE Laboratory (ARIEL) is a major expansion of the ISAC facility. ARIEL SRF electron linear accelerator (e-linac) operates nine-cell TESLA type cavities at 2 K. Both accelerators have dedicated cryogenic systems including liquid helium plants and distribution systems. In addition to accelerator cryogenic support, ISAC cryoplant provides liquid helium for the SRF testing facility at both 4 K and 2 K temperatures. TRIUMF’s SRF development involves both SRF testing facility and accelerators cryogenic support systems. This paper presents the details of the SRF testing cryogenic systems as well as recent commissioning results of the new e-linac cryogenic system. 		 
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WEA1A05 Nanostructure of the Penetration Depth in Nb Cavities: Debunking the Myths and New Findings niobium, cavity, electron, SRF 937
 
  • Y. Trenikhina, A. Romanenko
    Fermilab, Batavia, Illinois, USA
  • J. Kwon, J.-M. Zuo
    UIUC, Urbana, USA
  
  Nanoscale defect structure within the magnetic penetration depth of ~100 nm is key to the performance limitations of niobium superconducting radio frequency (SRF) cavities. Using a unique combination of advanced thermometry during cavity RF measurements, and TEM structural and compositional characterization of the samples extracted from cavity walls at both room and cryogenic temperatures, we directly discover the existence of nanoscale hydrides in SRF cavities limited by the high field Q slope, and show the decreased hydride formation after 120C baking. Crucially, in extended studies we demonstrate that adding 800C hydrogen degassing - both with AND without light BCP afterwards - restores the hydride formation to the pre-120C bake level correlating perfectly with the observed high field Q slope behavior. We also show absence of niobium oxides along the grain boundaries and the modifications of the surface oxide upon 120C bake, which contradicts some of the widely used models of niobium surface.  
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WEBA04 Performances of Spiral2 Low and High Beta Cryomodules cryomodule, linac, cavity, ion 967
 
  • C. Marchand, P. Bosland, G. Devanz, O. Piquet
    CEA/IRFU, Gif-sur-Yvette, France
  • P.-E. Bernaudin, R. Ferdinand
    GANIL, Caen, France
  • Y. Gómez Martínez
    LPSC, Grenoble Cedex, France
  • D. Longuevergne, G. Olry
    IPN, Orsay, France
  
  All SPIRAL2 cryomodules (twelve with one quarter wave resonator (QWR) at β=0.07 and seven with two QWRs at β=0.12) have been produced and qualified, and are now in installation phase on the LINAC at GANIL. After a general introduction on the LINAC, we will first remember and compare the different design choices taken for the two families of cryomodules. We will then present a summary of the techniques used for the preparation and integration of the cavities in the cryomodules, and compare the achieved performances with design parameters. At last, we describe the status of the LINAC installation as of end of August 2015.  
slides icon Slides WEBA04 [4.577 MB]  
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THBA06 Overview on Magnetic Field Management and Shielding in High Q Modules cryomodule, cavity, shielding, linac 1043
 
  • G. Wu
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by FRA under DOE contract DE-AC02-07CH11359
Maintaining very high cavity Q0 in linac applications creates new challenges for cryomodule design. Magnetic shielding from both external fields and internal fields is required and its importance to thermal gradients during Tc transition is now emerging. This presentation will describe the design challenges and possible mitigation strategies with examples from various applications or laboratories including FRIB, LCLS-II, PIP-II, Cornell University and KEK. 		 
slides icon Slides THBA06 [1.839 MB]  
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THPB047 Analysis of a 750 MHz SRF Dipole Cavity cavity, dipole, simulation, cathode 1200
 
  • A. Castilla, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • A. Castilla, J.R. Delayen
    JLab, Newport News, Virginia, USA
  • A. Castilla
    DCI-UG, León, Mexico
  
  Funding: Authored by Jefferson Science Associates, LLC under U. S. DOE Contract No. DE-AC05-06OR23177.
There is a growing interest in using rf transverse deflecting structures for a plethora of applications in the current and future high performance colliders. In this paper, we present the results of a proof of principle superconducting rf dipole, designed as a prototype for a 750 MHz crabbing corrector for the Medium Energy Electron-Ion Collider (MEIC), which has been successfully tested at 4.2 K and 2 K at the Jefferson Lab’s Vertical Testing Area (VTA). The analysis of its rf performance during cryogenic testing, along with Helium pressure sensitivity, Lorentz detuning, surface resistance, and multipacting processing analysis are presented in this work. Detailed calculations of losses at the port flanges are included for completeness of the cavity’s cryogenic performance studies. 		 
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THPB109 ESS Spoke Cryomodule and Test Valve Box cryomodule, vacuum, linac, operation 1400
 
  • D. Reynet, S. Bousson, S. Brault, P. Duchesne, P. Duthil, N. Gandolfo, G. Olry, M. Pierens, E. Rampnoux
    IPN, Orsay, France
  • C. Darve
    ESS, Lund, Sweden
  
  ESS project aims being the world’s most powerful neutron source feeding multidisplinary researches. The superconducting part of the ESS linear accelerator includes 28 b=0.5 352.2 MHz SRF niobium double Spoke cavities. Paired in 13 cryomodules and held at 2K in a saturated helium bath those cavities will generate of an accelerating field of 9MV/m. The prototype Spoke cryomodule holds two cavities and their RF power couplers and integrates all the interfaces necessary to be operational within the linac machine. It is now being fabricated and its assembly will be performed with dedicated tooling and procedures in and out of the clean room. This prototype will be tested by the end of 2015 at IPNO site and then at full power at FREIA (Uppsala university) test stand. A valve box has thus been designed to take into account the specific features of this prototype cryomodule and of the cryogenic environments of both test sites. This valve box is also considered as a prototype of the cryogenic distribution of the linac Spoke section. This element will then be used for the tests of the series cryomodules. We propose to present this prototype Spoke cryomodule for ESS and the test valve box.  
poster icon Poster THPB109 [2.852 MB]  
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THPB119 LCLS-II 1.3 GHz Cryomodule Design – Modified TESLA-Style Cryomodule for CW Operation cryomodule, vacuum, cavity, operation 1417
 
  • T.J. Peterson, T.T. Arkan, C.M. Ginsburg, Y. He, J.A. Kaluzny, M.W. McGee, Y.O. Orlov
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported, in part, by the US DOE and the LCLS-II Project.
We will present the design of the 1.3 GHz cryomodule for the Linear Coherent Light Source upgrade (LCLS-II) at SLAC. Fermilab is responsible for the design of this cryomodule, a modified TESLA-style cryomodule to accommodate continuous wave (CW) mode operation and LCLS-II beam parameters, consisting of eight 1.3 GHz superconducting RF cavities, a corrector magnet package, and instrumentation. Thirty-five of these cryomodules, approximately half built at Fermilab and half at Jefferson Lab, will become the main accelerating elements of the 4 GeV linac. The modifications and special features of the cryomodule include: thermal and cryogenic design to handle high heat loads in CW operation, magnetic shielding and cool-down configurations to enable high quality factor (Q0) performance of the cavities, liquid helium management to address the different liquid levels in the 2-phase pipe with 0.5% SLAC tunnel longitudinal slope, support structure design to meet California seismic design requirements, and with the overall design consistent with space constrains in the existing SLAC tunnel. The prototype cryomodule assembly will begin in August 2015 and is to be completed in early 2016. 		 
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FRAA06 Construction and Performance of FRIB Quarter Wave Prototype Cryomodule cryomodule, vacuum, alignment, solenoid 1446
 
  • S.J. Miller, B. Bird, G.D. Bryant, B. Bullock, N.K. Bultman, F. Casagrande, C. Compton, A. Facco, P.E. Gibson, J.D. Hulbert, D. Morris, J. Popielarski, L. Popielarski, M.A. Reaume, R.J. Rose, K. Saito, M. Shuptar, J.T. Simon, B.P. Tousignant, J. Wei, K. Witgen, T. Xu
    FRIB, East Lansing, Michigan, USA
  • A. Facco
    INFN/LNL, Legnaro (PD), Italy
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The driver linac for the Facility for Rare Isotope Beams (FRIB) will require the production of 48 cryomodules. FRIB has completed the fabrication and testing of a β=0.085 quarter-wave cryomodule as a pre-production prototype. This cryomodule qualified the performance of the resonators, fundamental power couplers, tuners, and cryogenic systems of the β=0.085 quarter-wave design. In addition to the successful systems qualification; the ReA6 cryomodule build also verified the FRIB bottom up assembly and alignment method. The lessons learned from the ReA6 cryomodule build, as well as valuable fabrication, sourcing, and assembly experience are applied to the design and fabrication of FRIB production cryomodules. This paper will report the results of the β=0.085 quarter-wave cryomodule testing, fabrication, and assembly; production implications to future cryomodules will also be presented. Authors: 		 
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FRBA01 Technical and Logistical Challenges for IFMIF-LIPAC Cryomodule Construction cryomodule, cavity, vacuum, solenoid 1453
 
  • H. Dzitko, N. Bazin, A. Bruniquel, P. Charon, S. Chel, G. Devanz, G. Disset, P. Gastinel, P. Hardy, J. Neyret, J. Relland, B. Renard, N. Sellami, M.R. Vallcorba-Carbonell
    CEA/IRFU, Gif-sur-Yvette, France
  • N. Berton, P. Contrepois, V.M. Hennion, H. Jenhani, O. Piquet
    CEA/DSM/IRFU, France
  • D. Gex, G. Phillips
    F4E, Germany
  • A. Kasughai
    Japan Atomic Energy Agency (JAEA), International Fusion Energy Research Center (IFERC), Rokkasho, Kamikita, Aomori, Japan
  • J. Knaster
    IFMIF/EVEDA, Rokkasho, Japan
  • D. Regidor, F. Toral
    CIEMAT, Madrid, Spain
  
  This paper provides an overview of the final design and fabrication status of the IFMIF cryomodule, including the design issues, and deals with the strategies implemented in order to mitigate the main technical and logistical risks identified. The seismic constraints as well as licensing requirements, transportation issue and assembly process are also addressed. The IFMIF cryomodule presented here will be part of the LIPAc project (Linear IFMIF Prototype Accelerator). It is a full scale prototype of one of the IFMIF accelerators, from the injector to the first cryomodule, aiming at validating the technical options for the future accelerator-based D-Li neutron source to produce high intensity high energy neutron flux for testing of candidate materials for use in fusion energy reactors. The cryomodule contains all the equipment to transport and accelerate a 125 mA deuteron beam from an input energy of 5 MeV up to 9 MeV. It consists of a horizontal cryostat of about 6 m long, 3 m high and 2 m wide, which includes 8 superconducting HWRs for beam acceleration working at 175 MHz and at 4.5 K, 8 power couplers to provide RF power to cavities, and 8 Solenoid Packages as focusing elements.  
slides icon Slides FRBA01 [9.263 MB]  
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