Keyword: SRF
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MOPOJO03 HELEN: A Linear Collider Based on Advanced SRF Technology cavity, collider, linear-collider, linac 31
 
  • S.A. Belomestnykh, P.C. Bhat, M. Checchin, A. Grassellino, M. Martinello, S. Nagaitsev, S. Posen, A.S. Romanenko, V.D. Shiltsev, A. Valishev, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • S.A. Belomestnykh
    Stony Brook University, Stony Brook, USA
  • H. Padamsee
    Cornell University, Ithaca, New York, USA
 
  Funding: Work supported by the Fermi National Accelerator Laboratory, managed and operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
This paper discusses recently proposed Higgs-Energy LEptoN (HELEN) e+e’ linear collider based on advances superconducting radio frequency technology. The collider offers cost and AC power savings, smaller footprint (relative to the ILC), and could be built at Fermilab with an Interaction Region within the site boundaries. After the initial physics run at 250 GeV, the collider could be upgraded either to higher luminosity or to higher (up to 500 GeV) energies.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOJO03  
About • Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 04 September 2022 — Issue date ※ 15 September 2022
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MOPOPA02 Identification of the Mechanical Dynamics of the Superconducting Radio-Frequency Cavities for the European XFEL CW Upgrade cavity, controls, FEL, experiment 76
 
  • W.H. Syed, A. Bellandi, J. Branlard, A. Eichler
    DESY, Hamburg, Germany
 
  The European X-Ray Free-Electron Laser (EuXFEL) is to-date the largest X-ray research facility around the world which spans over 3.4 km. EuXFEL is currently being operated in a pulsed mode with a repetition rate of 10Hz. One upgrade scenario consists of operating the EuXFEL also in a Continuous-Wave (CW) mode of operation to improve the quality of experiments. This upgrade brings new challenges and requires new algorithms to deal with controlling a stable accelerating field inside the Superconducting Radiofrequency (SRF) accelerating cavities and keeping them on resonance in this new mode of operation. The purpose of this research work is to identify the mechanical dynamics of the cavities which will facilitate the development of the resonance controller for the CW upgrade. To this extent, experiments were conducted at a test bench. For the first time, in this work, two different types of spectrally rich excitation signals: multi-sine and stepped-sine are used to excite the mechanical dynamics of the cavities using the piezo actuator. After the analysis of experimental data, mechanical modes are successfully identified and will be used to design the controller.  
poster icon Poster MOPOPA02 [0.687 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA02  
About • Received ※ 23 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 26 August 2022 — Issue date ※ 01 September 2022
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MOPOPA13 200 MV Record Voltage of vCM and LCLS-II-HE Cryomodules Production Start Fermilab cavity, cryomodule, vacuum, plasma 95
 
  • T.T. Arkan, D. Bafia, D.J. Bice, J.N. Blowers, A.T. Cravatta, B. Giaccone, C.J. Grimm, B.D. Hartsell, J.A. Kaluzny, M. Martinello, T.H. Nicol, Y.M. Orlov, S. Posen
    Fermilab, Batavia, Illinois, USA
  • M. Checchin
    SLAC, Menlo Park, California, USA
 
  Funding: Department of Energy
The Linac Coherent Light Source (LCLS) is an X-ray science facility at SLAC National Accelerator Laboratory. The LCLS-II project (an upgrade to LCLS) is in the commissioning phase; the LCLS-II-HE (High Energy) project is another upgrade to the facility, enabling higher energy operation. An electron beam is accelerated using superconducting radio frequency (SRF) cavities built into cryomodules. It is planned to build 24 1.3 GHz standard cryomodules and 1 1.3 GHz single-cavity Buncher Capture Cavity (BCC) cryomodule for the LCLS-II-HE project. Fourteen of these standard cryomodules and one BCC are planned to be assembled and tested at Fermilab. Procurements for standard cryomodule components are nearing completion. The first LCLS-II-HE cryomodule, referred to as the verification cryomodule (vCM) was assembled and tested at Fermilab. Fermilab has completed the assembly of the second cryomodule. This paper presents LCLS-II-HE cryomodule production status at Fermilab, emphasizing the changes done based on the successes, challenges, mitigations, and lessons learned from LCLS-II; validation of the changes with the excellent vCM results.
 
poster icon Poster MOPOPA13 [1.975 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOPA13  
About • Received ※ 10 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 09 September 2022
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MOPOGE14 Current Status of the Spoke Cavity Prototyping for the JAEA-ADS Linac cavity, linac, simulation, status 180
 
  • J. Tamura, Y. Kondo, F. Maekawa, S.I. Meigo, B. Yee-Rendón
    JAEA/J-PARC, Tokai-mura, Japan
  • T. Dohmae, E. Kako, H. Sakai, K. Umemori
    KEK, Ibaraki, Japan
 
  The Japan Atomic Energy Agency (JAEA) has proposed an accelerator-driven subcritical system (ADS) to efficiently reduce high-level radioactive waste generated at nuclear power plants. One of the challenging R&D aspects of ADS is the reliability of the accelerator. In preparation for the full-scale design of the CW proton linac for the JAEA-ADS, we are now prototyping a low-beta (around 0.2) single spoke cavity. Since there is no experience in Japan in manufacturing a superconducting spoke cavity, prototyping and performance testing of the cavity is essential to ensure the feasibility of the JAEA-ADS linac. In the Japanese fiscal year 2021, we have started welding cavity parts together. By preliminarily examining the electron beam welding conditions, each press-formed niobium part was joined with a smooth welding bead. The current status of the spoke cavity prototyping for the JAEA-ADS linac is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE14  
About • Received ※ 01 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 14 September 2022 — Issue date ※ 26 September 2022
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MOPOGE21 A Superconducting 217 MHz Single Spoke Cavity for the Helmholtz Linear Accelerator at GSI cavity, simulation, linac, resonance 200
 
  • F.D. Dziuba, K. Aulenbacher, W.A. Barth, V. Gettmann, T. Kürzeder, J. List, M. Miski-Oglu
    HIM, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, F.D. Dziuba
    KPH, Mainz, Germany
  • K. Aulenbacher, W.A. Barth, M. Basten, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, S. Yaramyshev
    GSI, Darmstadt, Germany
  • T. Conrad, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
 
  Funding: Work supported by GSI, HIM, BMBF Contr. No. 05P18UMRB2
A new superconducting (SC) continuous wave (CW) linac, providing high efficient heavy ion acceleration above the coulomb barrier, is going to be built at GSI to fulfill the upcoming demands in the research field of super heavy element (SHE) synthesis. The so called HELIAC (HElmholtz LInear ACcelerator) delivers ion beams in the energy range of 3.5 MeV/u and 7.3 MeV/u with a mass to charge ratio (A/z) of up to 6. Superconducting multi-gap crossbar-H-mode (CH) cavities with a resonance frequency of 217 MHz are used for beam acceleration. In addition, SC single spoke buncher cavities should ensure longitudinal beam matching to the corresponding CH sections. Therefore, the first 217 MHz single spoke cavity with beta 0.07 has been developed at HIM/GSI and built at an industrial partner. In this paper the design of the cavity and first RF measurements during manufacturing are presented.
 
poster icon Poster MOPOGE21 [2.619 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPOGE21  
About • Received ※ 18 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 31 August 2022
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MOPORI18 Overview of STFC Daresbury Laboratory Vacuum Operations for the Testing of ESS High Beta Cavities. cavity, vacuum, operation, detector 268
 
  • S. Wilde, K.J. Middleman, M.D. Pendleton, J.O.W. Poynton
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • D.A. Mason, G. Miller, J. Mutch
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • K.J. Middleman
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  This paper describes the vacuum systems and operations that are used at the STFC Daresbury Laboratory SuRF lab during cold RF testing of ESS high beta RF accelerating cavities. Dedicated slow pump slow vent (SPSV) systems are used to perform vacuum acceptance testing of each cavity before, during and after cold RF testing. Details of the vacuum systems, support facilities, acceptance criteria and test results will be discussed in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI18  
About • Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 02 September 2022 — Issue date ※ 09 September 2022
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TU1AA02 Compact, Turn-Key SRF Accelerators cavity, cryomodule, operation, controls 290
 
  • N.A. Stilin, A.T. Holic, M. Liepe, T.I. O’Connell, J. Sears, V.D. Shemelin, J. Turco
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  The development of simpler, compact Superconducting RF (SRF) systems represents a new subject of research in accelerator science. These compact accelerators rely on advancements made to both Nb3Sn SRF cavities and commercial cryocoolers, which together allow for the removal of liquid cryogenics from the system. This approach to SRF cavity operation, based on novel conduction cooling schemes, has the potential to drastically extend the range of application of SRF technology. By offering robust, non-expert, turn-key operation, such systems enable the use of SRF accelerators for industrial, medical, and small-scale science applications. This presentation will provide an overview of the significant progress being made at Cornell, Jefferson Lab, and Fermilab (FNAL), including stable cavity operation at 10 MV/m. It will also introduce the primary challenges of this new field and their potential solutions, along with an overview of the various applications which could benefit the most from this technology.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA02  
About • Received ※ 29 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 14 October 2022
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TU1AA03 R&D Towards High Gradient CW SRF Cavities cavity, niobium, cryomodule, vacuum 295
 
  • D. Bafia, P. Berrutti, B. Giaccone, A. Grassellino, D.V. Neuffer, S. Posen, A.S. Romanenko
    Fermilab, Batavia, Illinois, USA
 
  This talk will discuss Fermilab’s recent progress in the surface engineering of superconducting radio-frequency (SRF) cavities geared toward producing simultaneously high quality factors and high accelerating gradients in cryomodules. We investigate possible microscopic mechanisms that drive improved performance by carrying out sequential RF tests on cavities subjected to low temperature baking. We compare performance evolution to observations made with material science techniques and find correlations with material parameters. We also discuss other key advancements that enable high gradient operation in cryomodules.  
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slides icon Slides TU1AA03 [2.007 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA03  
About • Received ※ 20 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 16 October 2022
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TU1AA04 SWELL and Other SRF Split Cavity Development cavity, HOM, GUI, vacuum 300
 
  • F. Peauger
    CERN, Meyrin, Switzerland
 
  An innovative superconducting cavity topology has been recently proposed at CERN and at Lancaster University. It integrates longitudinal slots crossing perpendicularly the RF surface. The RF current lines run along the slots, inducing no perturbation of the accelerating mode. Thanks to this approach, the cavity can be built using halves or quadrants, which is well appropriate to precise manufacturing techniques. This configuration allows direct access to the RF surface, thus facilitating the surface preparation and thin film deposition process in the case of cavities based on Nb/Cu technology. The contact faces between the cavity parts are moved to the slots’ ends where the electromagnetic fields are extremely low, thus relaxing the constraints on the quality of the assembly joints. This paper covers the latest development of a 600 MHz slotted elliptical cavity called SWELL, which has been proposed as an alternative option for the FCC-ee RF system as well as a simplified SWELL version of a single cell 1.3 GHz elliptical cavity and a new 6 GHz split resonator made of two halves for superconducting thin film characterization.
Acknowledgement of U. Van Rienen from Rostock University for the use of their GPU based workstations for RF simulations.
 
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slides icon Slides TU1AA04 [4.217 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA04  
About • Received ※ 14 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022
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TU1AA06 Next-Generation Nb3Sn Superconducting RF Cavities cavity, accelerating-gradient, radio-frequency, superconducting-RF 305
 
  • N.M. Verboncoeur, G. Gaitan, M. Liepe, R.D. Porter, L. Shpani, N.A. Stilin, Z. Sun
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Nb3Sn currently is the most promising alternative material for next-generation, higher-performance SRF cavities. Significant recent progress has been made in further increasing efficiency, maximum field, and demonstrating readiness for first applications in actual accelerators. This paper will present an overview of worldwide recent progress in making this material a viable option for further accelerators.  
slides icon Slides TU1AA06 [6.559 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU1AA06  
About • Received ※ 31 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 04 September 2022 — Issue date ※ 09 September 2022
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TU2AA01 Overview of ADS Projects in the World linac, proton, status, target 310
 
  • B. Yee-Rendón
    JAEA/J-PARC, Tokai-mura, Japan
 
  Accelerator-driven subcritical systems (ADS) offer an advantageous option for the transmutation of nuclear waste. ADS employs high-intensity proton linear accelerators (linacs) to produce spallation neutrons for a subcritical reactor. Besides the challenges of any megawatt proton machine, ADS accelerator must operate with stringent reliability to avoid thermal stress in the reactor structures. Thus, ADS linacs have adopted a reliability-oriented design to satisfy the operation requirements. This work provides a review and the present status of the ADS linacs in the world.  
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slides icon Slides TU2AA01 [2.951 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TU2AA01  
About • Received ※ 23 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 14 October 2022
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TUPOJO15 Commissioning of UKRI-STFC SRF Vertical Test and HPR Reprocessing Facility cavity, MMI, cryogenics, vacuum 380
 
  • M.D. Pendleton, A.E.T. Akintola, R.K. Buckley, G. Collier, K.D. Dumbell, M.J. Ellis, S. Hitchen, P.C. Hornickel, G. Hughes, C.R. Jenkins, A.J. May, P.A. McIntosh, K.J. Middleman, A.J. Moss, S.M. Pattalwar, J.O.W. Poynton, P.A. Smith, A.E. Wheelhouse, S. Wilde
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G. Jones, M. Lowe, D.A. Mason, G. Miller, C. Mills, J. Mutch, A. Oates, J.T.G. Wilson
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
 
  Mark Pendleton, et al. The UK’s first and only vertical test facility and associated cleanroom reprocessing suite has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The facility is capable of 2 K testing of 3 jacketed SRF cavities in a horizontal configuration per 2-week test cycle. We report on the associated cryogenic, RF, UHV, mechanical, cleanroom, and HPR infrastructure. SRF cavity workflows have been developed to meet the requirements of the ESS high beta cavity project within a newly developed quality management system, SuraBee, in accordance with ISO9001. To support standardisation of measurements across the collaboration, reference cavities have been measured for cross-reference between CEA, DESY, and UKRI-STFC. We further report on commissioning objectives, observations, and continuous improvement activities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO15  
About • Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 05 September 2022 — Issue date ※ 08 September 2022
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TUPOJO18 Cavity Qualification and Production Update for SNS-PPU Cryomodules at Jefferson Lab cavity, cryomodule, proton, neutron 387
 
  • P. Dhakal, E. Daly, J.F. Fischer, N.A. Huque
    JLab, Newport News, Virginia, USA
  • M.P. Howell
    ORNL, Oak Ridge, Tennessee, USA
  • J.D. Mammosser
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The Proton Power Upgrade (PPU) project at Oak Ridge National Lab’s Spallation Neutron Source (SNS) currently being constructed will double the proton beam power capability from 1.4 to 2.8 MW by adding seven cryomodules, each containing four six-cell high-beta (β = 0.81) superconducting radio frequency cavities. Research Instruments, located in Germany, built and processed the cavities at the vendor site, including electropolishing as the final active chemistry step. Twenty-eight cavities for seven cryomodules and an additional four cavities for a spare cryomodules were delivered to Jefferson Lab and first qualification tests were completed on all cavities as received from the vendor. The performance largely exceeded the requirements on quality factor and accelerating gradient. Here we present the status of initial cavity qualification tests, rework on unqualified cavities and final cavity qualification with helium vessel prior to installation in cryomodules. In addition, an update on cryomodule production is presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO18  
About • Received ※ 23 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 09 September 2022
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TUPOJO22 Progress of PIP-II Activities at IJCLab cavity, HOM, experiment, niobium 402
 
  • P. Duchesne, N. Gandolfo, D. Le Dréan, D. Longuevergne, R. Martret, T. Pépin-Donat, F. Rabehasy, S. Roset, L.M. Vogt
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • P. Berrutti, M. Parise, D. Passarelli
    Fermilab, Batavia, Illinois, USA
 
  Since 2018, IJCLab is involved in PIP-II project on the design and development of accelerator components for the SSR2 (Single Spoke Resonator type 2) section of the superconducting linac. First pre-production components have been fabricated, surface processing and cavity qualification in vertical cryostat are on-going. IJCLab has upgraded its facilities by developing a new set-up to perform rotational BCP. The progress of all processing and testing activities for PIP-II project will be reported and, in particular, a dedicated study to qualify removal uniformity compared to static BCP will be presented.  
poster icon Poster TUPOJO22 [1.997 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO22  
About • Received ※ 23 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 01 September 2022
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TUPOJO23 Accelerated Lifetime Test of Spoke Cavity Cold Tuning Systems for Myrrha cavity, cryomodule, operation, vacuum 406
 
  • N. Gandolfo, S. Blivet, F. Chatelet, V. Delpech, D. Le Dréan, G. Mavilla, M. Pierens, H. Saugnac
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
 
  Within the framework of MINERVA, the first Phase of MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) project, IN2P3 labs are in charge of the developments of several accelerator elements. Among those, a fully equipped Spoke cryomodule prototype was constructed, it integrates two superconducting single spoke cavities operating at 2K, the RF power couplers and the associated cold tuning systems. The extreme reliability specified for this project motivated to conduct ALT (Accelerated Lifetime Test) on two extra cold tuning systems in cryomodule like environment. Thus, by gathering information from experimental data, many aspects can be enhanced like maintenance plan consolidation, determination of aging indicators and design optimization of the whole system and its sub components. This paper describes the complete ALT process from the studying elements and the test environment design, to the experimental results and findings.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO23  
About • Received ※ 15 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022
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TUPOPA25 Design, Manufacturing, Assembly, Testing, and Lessons Learned of the Prototype 650 MHz Couplers vacuum, cryomodule, cavity, multipactoring 462
 
  • J. Helsper, S.K. Chandrasekaran, F. Furuta, B.M. Hanna, S. Kazakov, J.P. Ozelis, K.S. Premo, N. Solyak, G. Wu
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work supported, in part, by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under U.S. DOE Contract No. DE-AC02-07CH11359.
Six 650 MHz high-power couplers will be integrated into the prototype High Beta 650 MHz (HB650) cryomodule for the PIP-II project at Fermilab. The design of the coupler is described, including design optimizations from the previous generation. This paper then describes the coupler life-cycle, including manufacturing, assembly, testing, conditioning and the lessons learned at each stage.
 
poster icon Poster TUPOPA25 [2.695 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA25  
About • Received ※ 24 August 2022 — Revised ※ 25 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 02 September 2022
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TUPOGE07 Magnetic Field Measurements and Shielding at the UKRI-STFC Daresbury Laboratory SRF Vertical Test Facility cavity, shielding, simulation, MMI 495
 
  • A.E.T. Akintola, A.R. Bainbridge, S. Hitchen, A.J. May, S.M. Pattalwar, P.A. Smith
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • M. Lowe, D.A. Mason, A.D. Shabalina
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
 
  A novel vertical test facility has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The cryostat is designed to test 3 jacketed superconducting RF cavities in a horizontal configuration in a single cool-down run at 2 K. A 2-year program is currently underway to test ESS high-beta cavities. Upon completion of this program, the facility will undertake a testing program for PIP-II HB650 cavities. In the current configuration, a solution combining passive and active magnetic shielding has been validated for the ESS requirement of field attenuation to the level of <1 uT, although continuous field measurements are not provided. This paper reports the implementation of passive and active shielding, along with simulation and experimental measurements thereof.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE07  
About • Received ※ 22 August 2022 — Revised ※ 27 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 01 September 2022
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TUPOGE09 Steady-State Cryogenic Operations for the UKRI-STFC Daresbury SRF Vertical Test Facility cavity, cryogenics, operation, MMI 501
 
  • A.J. May, A.E.T. Akintola, R.K. Buckley, G. Collier, K.D. Dumbell, S. Hitchen, P.C. Hornickel, G. Hughes, C.R. Jenkins, S.M. Pattalwar, M.D. Pendleton, P.A. Smith
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  A novel vertical test facility has been developed, commissioned, and entered steady-state operations at the UKRI-STFC Daresbury Laboratory. The cryostat is designed to test 3 jacketed superconducting RF cavities in a horizontal configuration in a single cool-down run at 2 K. The cavities are cooled with superfluid helium filled into their individual helium jackets. This reduces the liquid helium consumption by more than 70% in comparison with the conventional facilities operational elsewhere. The facility is currently undertaking a 2-year program to qualify 84 high-beta SRF cavities for the ESS (European Spallation Source) as part of the UK’s in-kind contribution. This paper reports on the steady-state operations, along with a detailed discussion of the cryogenic performance of the facility, including that of the cryoplant.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE09  
About • Received ※ 13 August 2022 — Revised ※ 21 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 04 September 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOGE10 A Final Acceptance Test Kit for Superconducting RF Cryomodules cryomodule, cavity, vacuum, cryogenics 504
 
  • A.J. May, A.E.T. Akintola, S.M. Pattalwar, A. White
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  UKRI-STFC Daresbury Laboratory is currently undertaking several projects involving assembly of superconducting RF cryomodules, including HL-LHC crab cavities and PIP-II HB650 cavities. As part of the final acceptance tests before shipping of the modules, extensive leak testing, pressure testing, and thermal cycling with gaseous and liquid must be performed. A Final Acceptance Test kit (FAT-kit) has been developed to support these tests. The FAT-kit, designed as a single portable unit, sits as an interface module between the cryomodule under test and the required utilities (liquid cryogen supply and return, gaseous cryogen supply and return, warm gas supply and return, vacuum pumps, leak detectors, etc.). The kit features a valve manifold to make or break connections to, from, and between circuits in the cryomodule, safety groupings to provide protection for the circuits as required, and various instrumentation. We report here on the design and commissioning of the kit.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE10  
About • Received ※ 23 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 15 September 2022
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TUPOGE13 Niobium to Titanium Electron Beam Welding for SRF Cavities niobium, cavity, vacuum, linac 515
 
  • M. Parise, J. Bernardini, 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.
Titanium and niobium are the main materials used for the fabrication of Superconducting Radio Frequency (SRF) cavities. These two metals are usually joined , using various welding techniques, using a third material in between. This contribution focuses on the development of an innovative electron beam welding technique capable of producing a strong bond between these two different materials. Several samples are produced and tested to assess the mechanical strength at room and cryogenic temperature as well as the composition of the resulting welded joint. Also, the first units of the Single Spoke Resonator type 2 (SSR2) cavities for the Proton Improvement Plan-II (PIP-II [1]) have been fabricated joining directly various grades of titanium to niobium and results gathered through the fabrication will be reported.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE13  
About • Received ※ 14 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 02 September 2022
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TUPOGE14 Beamline Volume Relief Analysis for the PIP-II SSR2 Cryomodule at Fermilab cryomodule, cavity, vacuum, radiation 519
 
  • M. Parise, J. Bernardini, 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 beam volume of the Pre-Production Single Spoke Resonator type 2 (ppSSR2) cryomodule [1] for the Proton Improvement Plan-II (PIP-II) [2] project will be protected against over-pressurization using a burst disk. This contri- bution focuses on the analysis of the relief of such trapped volume during a catastrophic scenario with multiple systems failures. An analytical model, able to predict the pressure in the beam volume depending of the various boundary condi- tions, has been developed and will be presented along with the results.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE14  
About • Received ※ 24 August 2022 — Revised ※ 31 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 02 September 2022
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TUPOGE16 Standardization and First Lessons Learned of the Prototype HB650 Cryomodule for PIP-II at Fermilab cryomodule, vacuum, interface, cavity 526
 
  • V. Roger, J. Bernardini, S.K. Chandrasekaran, C.J. Grimm, O. Napoly, J.P. Ozelis, M. Parise, D. Passarelli
    Fermilab, Batavia, Illinois, USA
  • N. Bazin, R. Cubizolles
    CEA-IRFU, Gif-sur-Yvette, France
 
  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 prototype High Beta 650 MHz cryomodule (pHB650 CM) has been designed by an integrated design team, consisting of Fermilab (USA), CEA (France), STFC UKRI (UK), and RRCAT (India). The manufacturing and assembly of this prototype cryomodule is being done at Fermilab, whereas the production cryomodules will be manufactured and assembled by STFC-UKRI. As the first PIP-II cryomodule for which standardization was applied, the design, manufacturing and assembly of this cryomodule led to significant lessons being learnt and experiences gathered. These were incorporated into the design of the pre-production Single Spoke Resonator Type 2 cryomodule (ppSSR2 CM) and the pre-production Low Beta 650 MHz cryomodule (ppLB650 CM). This paper presents the pHB650 CM lessons learned and experiences gathered from the design to the lower coldmass assembly and how this cryomodule has a positive impact on all the next Proton Improvement Plan-II (PIP-II) cryomodules due to the standardization set up among SSR and 650 cryomodules.
 
poster icon Poster TUPOGE16 [1.478 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE16  
About • Received ※ 11 August 2022 — Revised ※ 17 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022
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TUPOGE17 Fabrication Experience of the Pre-Production PIP-II SSR2 Cavities at Fermilab cavity, niobium, operation, target 529
 
  • M. Parise, D. Passarelli, V. Roger
    Fermilab, Batavia, Illinois, USA
  • P. Duchesne, D. Longuevergne
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
 
  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, [1]) linac will in- clude 35 Single Spoke Resonators type 2 (SSR2). A total of eight pre-production SSR2 jacketed cavities will be procured and five installed in the first pre-production cryomodule. The mechanical design of the jacketed cavity has been finalized and it will be presented in this paper along with fabrication and processing experience. The importance of interfaces, quality controls and procurement aspects in the design phase will be remarked as well as lessons learned during the fabri- cation process. Furthermore, development studies will be presented together with other design validation tests.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOGE17  
About • Received ※ 14 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 04 September 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOPA15 Anomaly Detection Based Quench Detection System for CW Operation of SRF Cavities cavity, experiment, operation, superconductivity 775
 
  • G. Martino, A. Bellandi, J. Branlard, A. Eichler, H. Schlarb
    DESY, Hamburg, Germany
  • S. Aderhold, A.L. Benwell, D. Gonnella, S.L. Hoobler, J. Nelson, R.D. Porter, A. Ratti, L.M. Zacarias
    SLAC, Menlo Park, California, USA
  • L.R. Doolittle
    LBNL, Berkeley, California, USA
  • G. Fey
    Hamburg University of Technology, Hamburg, Germany
 
  Funding: This work is supported by DASHH (Data Science in Hamburg - HELMHOLTZ Graduate School for the Structure of Matter) under Grant No.: HIDSS-0002.
Superconducting radio frequency (SRF) cavities are used in modern particle accelerators to take advantage of their very high quality factor (Q). A higher Q means that a higher RF field can be sustained, and a higher acceleration can be produced in the cavity for length unity. However, in certain situations, e.g., too high RF field, the SRF cavities can experience quenches that risk creating damage due to the rapid increase in the heat load. This is especially negative in continuous wave (CW) operation due to the impossibility of the system to recover during the off-load period. The design goal of a quench-detection system is to protect the system without being a limiting factor during the operation. In this paper, we compare two different classification approaches for improving a quench detection system. We perform tests using traces recorded from LCLS-II and show that the ARSENAL classifier outperforms a CNN classifier in terms of accuracy.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA15  
About • Received ※ 24 August 2022 — Accepted ※ 25 August 2022 — Issue date ※ 23 September 2022  
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THPOPA21 Narrow Bandwidth Active Noise Control for Microphonics Rejection in Superconducting Cavities at LCLS-II cavity, controls, resonance, FPGA 785
 
  • A. Bellandi, J. Branlard
    DESY, Hamburg, Germany
  • S. Aderhold, A.L. Benwell, A. Brachmann, J.A. Diaz Cruz, D. Gonnella, S.L. Hoobler, J. Nelson, A. Ratti, L.M. Zacarias
    SLAC, Menlo Park, California, USA
  • J.A. Diaz Cruz
    UNM-ECE, Albuquerque, USA
  • R.D. Porter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  LCLS-II is an X-Ray Free Electron Laser (XFEL) under commissioning at SLAC, being the first Continuous Wave (CW) hard XFEL in the world to come into operation. To accelerate the electron beam to an energy of 4 GeV, 280 superconducting cavities of the TESLA types are used. A Loaded Q (QL) value of 4x107 is used to drive the cavities at a power level of a few kilowatts. For this QL value, the RF cavity bandwidth is equal to 32 Hz. Therefore, keeping the cavity resonance frequency within such bandwidth is imperative to avoid a significant increase in the required RF power. In superconducting accelerators, resonance frequency variations are produced by mechanical microphonic vibrations of the cavities. One source of microphonics noise is rotary machinery such as vacuum pumps or HVAC equipment. A possible method to reject these disturbances is to use Narrowband Active Noise Control (NANC) techniques. Such a technique was already tested at DESY/CMTB and Cornell/CBETA. This proceeding presents the implementation of a NANC controller in the LCLS-II Low Level RF (LLRF) control system. Tests on the rejection of LCLS-II microphonics disturbances are also presented.  
poster icon Poster THPOPA21 [1.843 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOPA21  
About • Received ※ 24 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 02 September 2022 — Issue date ※ 26 September 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOGE02 Investigation of HiPIMS-Coated S(I)S Structures for SRF Cavities cavity, site, niobium, radio-frequency 805
 
  • A.Ö. Sezgin, X. Jiang, M. Vogel
    University Siegen, Siegen, Germany
  • C.Z. Antoine
    CEA-IRFU, Gif-sur-Yvette, France
  • S. Keckert, J. Knobloch, O. Kugeler, D.B. Tikhonov
    HZB, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
  • O.B. Malyshev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • R. Ries, E. Seiler
    Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
  • L.G.P. Smith
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
 
  The sustainable next generation particle accelerators require innovative solutions to overcome the current technological challenges set by existing bulk niobium superconducting radio-frequency (SRF) cavities. Thin film-based multilayer structures in the form of superconductor-insulator-superconductor (SIS) may be the long-sought-after breakthrough for higher performance SRF cavities by enhancing both accelerating gradients and quality factors. In order to understand better the underlying mechanisms of SIS structures to be coated onto (S)RF cavities, we study various material properties with the resultant superconducting properties of high-power im-pulse magnetron sputtering (HiPIMS)-coated S(I)S structures of Nb-(AlN)-NbN with different thicknesses which are designed to be coated mainly on OFHC copper (Cu) samples for more efficient SRF cavities. This contribution presents materials properties of the aforementioned HiPIMS-coated S(I)S structures as well as the superconducting and RF behaviours of these multilayers which are assessed comparatively via DC and AC magnetization techniques.  
poster icon Poster THPOGE02 [0.747 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE02  
About • Received ※ 25 August 2022 — Revised ※ 30 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022
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THPOGE05 Some Interesting Observations During Vertical Test on ESS-HB-704 SRF Cavities cavity, accelerating-gradient, operation, MMI 812
 
  • K.D. Dumbell, A.E.T. Akintola, R.K. Buckley, M.J. Ellis, S. Hitchen, P.C. Hornickel, C.R. Jenkins, J. Lewis, A.J. May, P.A. McIntosh, K.J. Middleman, A.J. Moss, S.M. Pattalwar, M.D. Pendleton, P.A. Smith, A.E. Wheelhouse, S. Wilde
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • M.D. Hancock, J. Hathaway, C. Hodgkinson, G. Jones, M. Lowe, D.A. Mason, G. Miller, J. Mutch, A. Oates, J.T.G. Wilson
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
 
  The vertical test stand in use at Daresbury has three cavities loaded horizontally at different heights. The jacketed cavities are supplied with liquid helium from a header tank at the top of the configuration. A few cavities have been tested in different positions and the results have been analysed. The pressure of the helium inside the jacketed cavities is affected by the height of the liquid helium column above the jacket and using results from earlier analysis during cool-down enables the pressure of the cavity to be determined from the frequency of operation. Analysis of the effects may allow for corrections to the frequency to be made. In addition to the above observations there have also been some challenges in the operation at higher power as the phase of the self-excited loop driving the system, has been seen to change. This paper discusses some of the observation, analysis of those observations and challenges that are being addressed in the continuing use of this facility.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE05  
About • Received ※ 10 August 2022 — Revised ※ 13 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 15 September 2022
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THPOGE09 Split Thin Film SRF 6 GHz Cavities cavity, niobium, cryogenics, ISOL 814
 
  • B.S. Sian, G. Burt, D.J. Seal
    Lancaster University, Lancaster, United Kingdom
  • G. Burt, O.B. Malyshev, D.J. Seal, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • O.B. Malyshev, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • H.S. Marks
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
 
  Many current accelerators use cavities that are manufactured as two half cells that are electron beam welded together, the weld is across the peak surface current of the cavity. This weld can lead to large increases in surface resistance and limit the performance of thin film coated cavities. Many problems with the coating process for thin film Superconducting Radio Frequency (SRF) cavities are also due to this weld. Thin film SRF cavities can perform as well as bulk niobium cavities if the cavity is manufactured seamlessly, without any weld, as they have a more uniform surface, however, they are much more difficult and expensive to manufacture. A cavity with a split longitudinally, parallel to the direction of the electric field, would not need to be welded. These seamless cavities are easier to manufacture and coat. This opens the possibilities to coat with new materials and multilayer coatings. These cavities may allow SRF cavities to operate at significantly better parameters (higher quality factor and maximum accelerating field) than current state of the art cavities. This work discusses development and testing of longitudinally split seamless cavities at Daresbury Laboratory.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE09  
About • Received ※ 25 August 2022 — Revised ※ 28 August 2022 — Accepted ※ 12 September 2022 — Issue date ※ 15 October 2022
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THPOGE10 RF Characterisation of Bulk Niobium and Thin Film Coated Planar Samples at 7.8 GHz cavity, site, operation, superconducting-RF 818
 
  • D.J. Seal, G. Burt, O.B. Malyshev, B.S. Sian, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G. Burt, D.J. Seal, B.S. Sian
    Lancaster University, Lancaster, United Kingdom
  • E. Chyhyrynets, C. Pira
    INFN/LNL, Legnaro (PD), Italy
  • O. Hryhorenko, D. Longuevergne
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • O.B. Malyshev, E.A. Marshall, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • H.S. Marks
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
 
  Research is ongoing into the use of superconducting thin films to replace bulk niobium for future radio frequency (RF) cavities. A key part of this research requires measuring the RF properties of candidate films. However, coating and testing thin films on full-sized cavities is both costly and time-consuming. Instead, films are typically deposited on small, flat samples and characterised using a test cavity. A cost-effective facility for testing such samples has recently been built and commissioned at Daresbury Laboratory. The facility allows for low power surface resistance measurements at a resonant frequency of 7.8 GHz, temperatures down to 4 K and sample surface magnetic fields up to 1 mT. A brief overview of this facility as well as recent results from measurements of both bulk Nb and thin film coated samples will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE10  
About • Received ※ 11 August 2022 — Revised ※ 19 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 16 September 2022
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THPOGE13 Design of Production PIP-II SSR1 Cavities cavity, GUI, cryomodule, niobium 822
 
  • C.S. Narug, J. Bernardini, M. Parise, D. Passarelli
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work supported by the Fermi National Accelerator Laboratory, managed and operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The testing and manufacturing process of the PIP-II Single Spoke Resonators Type 1 (SSR1) prototype jacketed cavity presented opportunities for refinement of the production series. Experience from the prototype cavity and the design of other cavities at Fermilab were used. The mechanical design of the production jacketed cavity has been modified from the prototype design to allow for improvements in overall performance, structural behavior, and manufacturability of the weld joints.
 
poster icon Poster THPOGE13 [1.199 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE13  
About • Received ※ 14 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 02 September 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOGE15 Measuring the Seebeck Coefficient at Cryogenic Temperatures for LCLS-II-HE Project niobium, cryogenics, experiment, cryomodule 825
 
  • L. Shpani, M. Ge, A.T. Holic, M. Liepe, J. Sears, N.M. Verboncoeur
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: This work is supported by the DOE LCLS-II HE Project.
The Seebeck effect plays a crucial role during the cooldown procedure in SRF based accelerators, like LCLS-II at SLAC. The temperature-dependent Seebeck coefficient quantitatively measures the strength of electric potential induced by thermal gradients in metals. This effect is present in cryomodules and drives thermoelectric currents generating magnetic fields. These fields can get trapped in cavities and cause additional dissipation in RF fields. We have therefore designed and commissioned an experimental setup that does continuous measurements of the Seebeck coefficient for cryogenic temperatures ranging from 200K down to below 10K. We present results of the measurements of this coefficient for materials commonly used in cryomodules, such as niobium, titanium, niobium-titanium, silicon bronze, and stainless steel.
 
poster icon Poster THPOGE15 [0.959 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE15  
About • Received ※ 27 August 2022 — Revised ※ 04 September 2022 — Accepted ※ 26 September 2022 — Issue date ※ 29 September 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOGE16 Evaluation of Single-Cell Cavities Made of Forged Ingot Niobium at Jefferson Lab cavity, niobium, radio-frequency, cryomodule 828
 
  • P. Dhakal, G. Ciovati, G.R. Myneni
    JLab, Newport News, Virginia, USA
  • G. Ciovati, B.D. Khanal
    ODU, Norfolk, Virginia, USA
  • G.R. Myneni
    BSCE, Yorktown, Virginia, USA
 
  Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Currently, fine grain niobium (Nb) (grain size ~ 50 um) and large grain Nb (grain size of a few cm) are being used for the fabrication of superconducting radio frequency (SRF) cavities. Medium grain forged ingot with grain size of a few hundred um may be beneficial for cost-effectiveness as well as providing better performance for future SRF-based accelerators. Forged ingot Nb with medium grain size is a novel production method to obtain Nb discs used for the fabrication of superconducting radio frequency cavities. We have fabricated two 1.5 GHz single cell cavities made from forged Nb ingot with a residual resistivity ratio of ~100. The cavities were chemically and mechanically polished and heat-treated in the temperature range of 650-1000 C before the rf test. One of the cavities reached an accelerating gradient of 34 MV/m with a quality factor Q > 1e10, while the second cavity was limited at 14 MV/m, likely due to a weld defect at the equator.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE16  
About • Received ※ 22 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 03 September 2022 — Issue date ※ 15 September 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOGE19 Field Shielding of NbTiN Based Multilayer Structure for Accelerating Cavities cavity, niobium, site, shielding 836
 
  • I.H. Senevirathne, J.R. Delayen, A.V. Gurevich
    ODU, Norfolk, Virginia, USA
  • D.R. Beverstock
    The College of William and Mary, Williamsburg, Virginia, USA
  • D.R. Beverstock, J.R. Delayen, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
 
  Funding: NSF Grants PHY-1734075 and PHY-1416051, and DOE Awards DE-SC0010081 and DE-SC0019399
Over the past few decades, bulk niobium (Nb) has been the material of choice for superconducting radio frequen-cy (SRF) cavities used in particle accelerators to achieve higher accelerating gradients and lower RF losses. Multi-layer (SIS) structures consisting of alternating thin layers of superconductor(S) and insulator(I) deposited on a bulk Nb have been proposed to enhance the peak surface magnetic field and sustain a higher accelerating gradient. In this study, multilayers based NbTiN and AlN deposited on bulk Nb are used to test the proposed enhancement using the DC magnetic Hall probe technique. The tech-nique detects a penetrating magnetic field through the multilayer sample as it is placed under an external mag-netic field produced by a magnetic coil. This work re-ports the characterization and measurements of the mag-netic field of full flux penetration through single layers of NbTiN and bilayers of NbTiN/AlN on bulk Nb.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE19  
About • Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 08 September 2022 — Issue date ※ 15 September 2022
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THPOGE22 Medium Temperature Treatments of Superconducting Radio Frequency Cavities at DESY cavity, niobium, factory, accelerating-gradient 840
 
  • L. Steder, C. Bate, H. Remde, D. Reschke, J. Schaffran, L. Trelle, H. Weise, M. Wiencek
    DESY, Hamburg, Germany
  • M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
 
  Over the last years several different approaches to increase the performance of superconducting radio frequency (SRF) cavities by heat treatments have been developed and tested. At DESY, the R&D aims for cavities with enlarged quality factors while maintaining high accelerating gradients, since an envisaged upgrade of the European XFEL requires both. For this purpose, medium temperature (mid-T) treatments around 300 °C seem to be very promising. Lately, the furnace infrastructure at DESY was refurbished and now a niobium-retort furnace capable of carrying 1.3 GHz nine-cell cavities can be used for R&D studies. Vertical test results of single-cell cavities treated in this furnace at medium temperatures are presented and compared to four cavities treated similarly in a furnace at the company Zanon Research & Innovation Srl (Zanon). All mentioned cavities show enlarged quality factors but at the same time reduced gradients compared to their reference measurements before the mid-T treatment. The DESY treatments were accompanied by small niobium samples for surface analyses, which are also presented. Furthermore, the influence of post-treatment high pressure water rinsings is studied.  
slides icon Slides THPOGE22 [1.277 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE22  
About • Received ※ 19 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 27 August 2022 — Issue date ※ 15 September 2022
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THPOGE23 Vertical Electro-Polishing of 704 MHz Resonators Using Ninja Cathode: Gradients Over 40 MV/m Achieved on ESS Single-Cell Cavity cavity, cathode, niobium, linac 844
 
  • F. Éozénou, M. Baudrier, E. Cenni, E. Fayette, L. Maurice, C. Servouin
    CEA-DRF-IRFU, France
  • H. Hayano, H. Ito, S. Kato, T. Kubo, H. Monjushiro, T. Saeki
    KEK, Ibaraki, Japan
  • Y.I. Ida, K. Nii, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • G. Jullien
    CEA-IRFU, Gif-sur-Yvette, France
 
  CEA, KEK and Marui Galvanizing Company have been collaborating to apply the Vertical Electropolishing (VEP) process of elliptical SRF cavities to a 704MHz single-cell ESS-type cavity, using a rotating so called and patented "Ninja" cathode. First presented results* were promising with a gradient of 27MV/m achieved, without any heat treatment applied. The performance has been pushed further since. The cavity has undergone a heat treatment at 650°C during 10h, followed by a final VEP sequence and a baking at 120°C during 48h hours. The achieved gradient at 2K was 44MV/m (power limitation), and the quality factor Q0 exceeding 5·1010 up to 10 MV/m. The superiority of VEP compared to standard "BCP" chemical treatment is demonstrated and we intend now to scale the process to 5-Cell β=0.86 ESS cavity. We also intend to push further the performance by applying "2-step baking" (75°C and 120°C) proposed by FNAL, which was successfully applied at CEA Saclay on 1300MHz single-cell resonators with gradients above 50MV/m achieved after VEP bulk treatment.
* TUPCAV001, SRF 2021
 
slides icon Slides THPOGE23 [0.868 MB]  
poster icon Poster THPOGE23 [0.918 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE23  
About • Received ※ 24 August 2022 — Revised ※ 01 September 2022 — Accepted ※ 09 September 2022 — Issue date ※ 16 September 2022
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