Keyword: cavity
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MOIAA01 FRIB Transition to User Operations, Power Ramp Up, and Upgrade Perspectives cryomodule, operation, linac, target 1
 
  • J. Wei, H. Ao, B. Arend, S. Beher, G. Bollen, N.K. Bultman, F. Casagrande, W. Chang, Y. Choi, S. Cogan, C. Compton, M. Cortesi, J.C. Curtin, K.D. Davidson, X.J. Du, K. Elliott, B. Ewert, A. Facco, A. Fila, K. Fukushima, V. Ganni, A. Ganshyn, T.N. Ginter, T. Glasmacher, J.-W. Guo, Y. Hao, W. Hartung, N.M. Hasan, M. Hausmann, K. Holland, H.-C. Hseuh, M. Ikegami, D.D. Jager, S. Jones, N. Joseph, T. Kanemura, S.H. Kim, C. Knowles, T. Konomi, B.R. Kortum, E. Kwan, T. Lange, M. Larmann, T.L. Larter, K. Laturkar, R.E. Laxdal, J. LeTourneau, Z. Li, S.M. Lidia, G. Machicoane, C. Magsig, P.E. Manwiller, F. Marti, T. Maruta, E.S. Metzgar, S.J. Miller, Y. Momozaki, D.G. Morris, M. Mugerian, I.N. Nesterenko, C. Nguyen, P.N. Ostroumov, M.S. Patil, A.S. Plastun, L. Popielarski, M. Portillo, J. Priller, X. Rao, M.A. Reaume, K. Saito, B.M. Sherrill, M.K. Smith, J. Song, M. Steiner, A. Stolz, O. Tarasov, B.P. Tousignant, R. Walker, X. Wang, J.D. Wenstrom, G. West, K. Witgen, M. Wright, T. Xu, Y. Yamazaki, T. Zhang, Q. Zhao, S. Zhao
    FRIB, East Lansing, Michigan, USA
  • K. Hosoyama
    KEK, Ibaraki, Japan
  • P. Hurh
    Fermilab, Batavia, Illinois, USA
  • M.P. Kelly, Y. Momozaki
    ANL, Lemont, Illinois, USA
  • R.E. Laxdal
    TRIUMF, Vancouver, Canada
  • S.O. Prestemon
    LBNL, Berkeley, California, USA
  • M. Wiseman
    JLab, Newport News, Virginia, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
After project completion on scope, on cost, and ahead of schedule, the Facility for Rare Isotope Beams began operations for scientific users in May of 2022. During the first 12 months of user operations, the FRIB accelerator complex delivered 5250 beam hours, including 1528 hours to nine science experiments conducted with primary beams of 36Ar, 48Ca, 70Zn, 82Se, 124Xe, and 198Pt at beam energies >200 MeV/u; 2724 hours for beam developments, studies, and tuning; and 998 hours to industrial users and non-scientific programs using the FRIB Single Event Effect (FSEE) beam line. The ramp-up to a beam power of 400 kW is planned over a six-year period; 1 kW was delivered for initial user runs from in 2022, and 5 kW was delivered as of February 2023. Upgrade plans include doubling the primary-beam energy to 400 MeV/nucleon for enhanced discovery potential (¿FRIB 400¿). This talk reports on FRIB status and progress since SRF2021, emphasizing lessons learned during the transition from beam commissioning to machine operations, challenges and resolutions for the power ramp-up, progress with accelerator improvements, and R&D for the energy upgrade. 		 
slides icon Slides MOIAA01 [7.037 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIAA01  
About • Received ※ 20 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 03 July 2023 — Issue date ※ 19 July 2023
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MOIAA05 Commissioning of the Second JLAB C75 Cryomodule & Performance Evaluation of Installed C75 Cavities cryomodule, SRF, plasma, controls 14
 
  • M.D. McCaughan, G. Ciovati, G.K. Davis, M.A. Drury, T. Powers, A.V. Reilly
    JLab, Newport News, Virginia, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
JLAB has long been a hub of SRF technology with the CEBAF accelerator as one of its first large scale adopters. As SRF technology has advanced, the C50 and C100 programs have allowed for the extension of CEBAF’s total energy to 6 GeV and nearly 12 GeV respectively. Along with the increase in energy reach, rates of accelerating gradient degradation have been extracted for these cryomodule designs. A plan to mitigate these losses & maintain robust gradient headroom to deliver the 12 GeV program ¿ the CEBAF Performance Plan¿ established a multi-year effort of cryomodule refurbishments and replacements. Part of this plan included a cost optimization of the C50 program with more modern processing techniques and the replacement of existing cavities with larger grain boundary cavities produced from ingot Niobium (dubbed C75 for 75 MeV gain). Reports have been made on the prototype pair of C75 cavities installed in a C50 cryomodule and the first full C75 cryomodule installed in 2017 and 2021. This paper reports on the results from the qualification of the cavities for the second C75 module in both a vertical cryostat and the commissioning results of the cryomodule in the CEBAF tunnel. 		 
slides icon Slides MOIAA05 [1.810 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIAA05  
About • Received ※ 19 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 02 July 2023
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MOIXA02 PIP-II Project Overview and Status linac, cryomodule, SRF, controls 19
 
  • R.P. Stanek, C. Boffo, S.K. Chandrasekaran, S.J. Dixon, E.R. Harms, L. Kokoska, I. Kourbanis, J.R. Leibfritz, O. Napoly, D. Passarelli, E. Pozdeyev, A.M. Rowe
    Fermilab, Batavia, Illinois, USA
  
  Funding: Prepared by PIP-II Project using resources of the Fermi National Accelerator Laboratory, a U.S. DOE facility, managed by Fermi Research Alliance, LLC, acting under Contract No. DE-AC02-07CH11359.
The Proton Improvement Plan II (PIP-II) project is an essential upgrade to Fermilab’s particle accelerator complex to enable the world’s most intense neutrino beam for LBNF/DUNE and a broad particle physics program for many decades to come. PIP-II will deliver 1.2 MW of proton beam power from the Main Injector, upgradeable to multi-MW capability. The central element of PIP-II is an 800 MeV superconducting radio frequency (SRF) linac, which comprises a room temperature front end followed by an SRF section. The SRF section consists of five different flavors of cavities/cryomodules, including Half Wave Resonators (HWR), Single Spoke and elliptical resonators operating at, or above, state-of-the-art parameters. The first two PIP-II cryomodules, Half Wave Resonator (HWR) and Single Spoke Resonator 1 (SSR1) were installed in the PIP-II Injector Test facility (PIP2IT) and have accelerated beam to above 17 MeV. PIP-II is the first U.S. accelerator project that will be constructed with significant contributions from international partners, including India, Italy, France, United Kingdom and Poland. The project was baselined in April 2022, and the construction phase is underway. 		 
slides icon Slides MOIXA02 [3.353 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIXA02  
About • Received ※ 07 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 16 July 2023
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MOIXA03 Proton Power Upgrade Project Progress and Plans at the Spallation Neutron Source in Oak Ridge Tennessee target, cryomodule, operation, linac 25
 
  • J.D. Mammosser, M.J. Dayton, D.D. Kraft, R. Maekawa, L. Pinion, B.E. Robertson
    ORNL RAD, Oak Ridge, Tennessee, USA
  • R. Afanador, D.L. Barnhart, M.S. Champion, B. DeGraff, M. Doleans, J. Galambos, S.W. Gold, M.N. Greenwood, G.A. Hine, M.P. Howell, S.-H. Kim, C.J. McMahan, P. Pizzol, S.E. Stewart, D.J. Vandygriff, D.M. Vandygriff
    ORNL, Oak Ridge, Tennessee, USA
  • A. Bitter, K.B. Bolz, A. Navitski, L. Zweibäumer
    RI Research Instruments GmbH, Bergisch Gladbach, Germany
  • E.F. Daly, G.K. Davis, P. Dhakal, J.F. Fischer, D. Forehand, N.A. Huque, K.M. Wilson
    JLab, Newport News, Virginia, USA
  
  Funding: Work Supported by UT-Battelle, LLC, under contract DE-AC05-00OR22725
The Proton Power Upgrade project is well underway at the Spallation Neutron Source (SNS) facility in Oak Ridge, Tennessee. This project aims at increasing the proton beam power capability from 1.4 to 2.8 MW, by adding linac energy, increasing the beam current and implementing target developments to handle the increased beam power. This talk will cover the current status of increasing the beam energy, issues encountered along the way, operational experience with the new SRF cryomodules and target improvements and results from operation with beam so far. 		 
slides icon Slides MOIXA03 [3.327 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIXA03  
About • Received ※ 09 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 08 July 2023
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MOIXA05 Operating Experience of SRF System at High Beam Current in SuperKEKB operation, HOM, SRF, luminosity 38
 
  • M. Nishiwaki, K. Akai, T. Furuya, S. Mitsunobu, Y. Morita, T. Okada
    KEK, Ibaraki, Japan
  
  SuperKEKB aims for high luminosity on the order of 1035 cm-2s-1 with beam currents of 2.6 A for electron and 3.6 A for positron to search new physics beyond the Standard Model in the B meson regime. In recent operations, we achieved a new record of luminosity of 4.65×1034 cm-2s-1 with 1.1 A for electron and 1.3 A for positron. The SRF system that was designed for KEKB, the predecessor of SuperKEKB, is operating stably with the high beam currents owing to the measures against the large beam powers and the large higher-order-mode (HOM) powers. As a measure against the large beam powers, our SRF cavities have increased a coupling of high-power input couplers during the KEKB operation. As a measure against the large HOM power, newly developed SiC HOM dampers have been installed in the SuperKEKB ring. In addition, we have established the horizontal high-pressure rinse method to recover the cavity performance that has degraded due to vacuum works and accidents in the long-term operation. In this report, we will present our operation experience of SRF system under the high beam currents.  
slides icon Slides MOIXA05 [3.450 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIXA05  
About • Received ※ 19 June 2023 — Revised ※ 21 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 20 July 2023
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MOIXA06 Operational Experience with the European XFEL SRF Linac operation, FEL, linac, LLRF 43
 
  • Ch. Schmidt, M. Bousonville, J. Branlard, M. Diomede, S. Göller, D. Kostin, M. Scholz, V. Vogel (Fogel), N. Walker
    DESY, Hamburg, Germany
  
  The European X-ray Free Electron laser (EuXFEL) is a 3.4 km long research facility which generates ultrashort X-ray flashes of outstanding brilliance since 2017. Up to 27000 electron bunches per second are accelerated in a 1.3 km long superconducting radio frequency (SRF) linac to a maximum energy of 17.6 GeV. Within this time, operational experience with a pulsed RF machine has been gained and new operation modes simultaneously delivering electron bunches to 3 different SASE undulator beamlines have been successfully implemented. Recent activities on increasing the linac availability, power efficiency and duty cycle are discussed.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIXA06  
About • Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 06 July 2023
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MOPMB001 Development and Testing of Split 6 GHz Cavities With Niobium Coatings SRF, coupling, target, site 51
 
  • N.L. Leicester, G. Burt, H.S. Marks
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • E. Chyhyrynets, C. Pira
    INFN/LNL, Legnaro (PD), Italy
  • J.A. Conlon, O.B. Malyshev, B.S. Sian, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • D.J. Seal
    Lancaster University, Lancaster, United Kingdom
  
  Superconducting thin-films on a copper substrate are used in accelerator RF cavities as an alternative to bulk Nb due to the high thermal conductivity of copper and the lower production costs. Although thin-film coated RF cavities can match, or even exceed the performance of bulk Nb, there are some challenges around the deposition. The RF cavities are often produced as two half-cells with a weld across the centre where the RF surface current is highest, which could reduce cavity performance. To avoid this, a cavity can be produced in 2 longitudinally split halves, with the join parallel to the surface current. As the current doesn’t cross the join a simpler weld can be performed far from the fields, simplifying the manufacturing process, and potentially improving the cavities performance. This additionally allows for different deposition techniques and coating materials to be used, as well as easier post-deposition quality control. This paper discusses the development and testing of 6 GHz cavities that have been designed and coated at the Cockcroft Institute, using low temperature RF techniques to characterise cavities with different substrate preparations and coating techniques.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB001  
About • Received ※ 18 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 04 July 2023
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MOPMB003 Flux Expulsion Lens: Concept and Measurements FEL, niobium, site, SRF 56
 
  • D.A. Turner
    European Organization for Nuclear Research (CERN), Geneva, Switzerland
  • A. Gallifa Terricabras, T. Koettig, A. Macpherson, G.J. Rosaz, N. Stapley
    CERN, Meyrin, Switzerland
  • I. González Díaz-Palacio
    University of Hamburg, Hamburg, Germany
  • W. Hillert
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • M. Wenskat
    DESY, Hamburg, Germany
  
  A magnetic flux expulsion lens (MFEL) has been designed and built at CERN. This device uses closed topology conduction cooling of samples to quantify magnetic flux expulsion of superconductors, and allows for systematic measurements of the cooling dynamics and the magnetic response during the superconducting transition. Measurements for bulk Nb, cold worked Nb, sputtered Nb on Cu, and SIS multilayer structures are given. Preliminary results for both sample characterization of expulsion dynamics, and observation of an enhanced flux expulsion in SIS samples are also reported.  
poster icon Poster MOPMB003 [2.459 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB003  
About • Received ※ 27 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 14 July 2023
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MOPMB005 Muon Spin Rotation Studies of Bilayer Superconductors and Low Temperature Baked Niobium interface, experiment, polarization, niobium 62
 
  • M. Asaduzzaman, R.E. Laxdal, R.M.L. McFadden, E. Thoeng
    TRIUMF, Vancouver, Canada
  • M. Asaduzzaman, T. Junginger, R.M.L. McFadden
    UVIC, Victoria, Canada
  • E. Thoeng
    UBC & TRIUMF, Vancouver, British Columbia, Canada
  
  Funding: Financial support was provided by an Natural Sciences and Engineering Research Council of Canada (NSERC)
Muon spin rotation (muSR) results have shown that vortex penetration into Nb can be delayed up to the superheating field Hsh by a single layer of a material with larger London penetration depth. For low temperature baked (LTB) Nb an increase in the vortex penetration field Hvp has also been observed. While clearly exceeding the lower critical field Hc1, Hvp was found to remain significantly below Hsh for LTB niobium (Superconductor Science and Technology 30 (12), 125012). Further, magnetometry experiments suggested that there is no interface barrier in LTB Nb and that the apparent Hvp increase as observed by muSR was due to surface pinning (Scientific Reports 12 (1), 5522). By varying the implantation depth of ~4.1 MeV muons using moderating foils, new muSR measurements confirm that the apparent Hvp increase in LTB Nb is indeed due to surface pinning, while for a Nb₃Sn/Nb bilayer we find an interface barrier for flux penetration. These results confirm the potential of using superconducting bilayers to achieve a flux free Meissner state up to the superheating field of the substrate. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB005  
About • Received ※ 17 June 2023 — Revised ※ 21 June 2023 — Accepted ※ 25 June 2023 — Issue date ※ 21 July 2023
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MOPMB006 SIMS Characterization of Nitrogen Doping of LCLS-II-HE Production Cavities SRF, niobium, vacuum, controls 67
 
  • C.E. Reece, M.J. Kelley, E.M. Lechner
    JLab, Newport News, Virginia, USA
  • J.W. Angle
    Virginia Polytechnic Institute and State University, Blacksburg, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177 and Office of High Energy Physics grant DE-SC-0014475.
The thermal diffusion of nitrogen into the surface of niobium has been shown to yield superior low-loss SRF performance. An effective solution was identified and promptly employed in the production of cryomodules for LCLS-II. With added experience and R&D, a modified process was chosen for use in the upgrade for LCLS-II-HE. Largely motivated by this circumstance, supporting research has significantly refined the technique for making calibrated secondary ion mass spectrometry (SIMS) measurements of the N concentration depth profiles produced by production processes. Standardized reference samples were included with four HE production cavities in their N-doping furnace runs. We report the calibrated dynamic SIMS depth profiles of N, C, and O for these samples, together with the cryogenic acceptance test performance of the associated cavities. Interpretation and comparison with similar samples acquired in other furnaces highlights the importance of intentional process quality control of furnace conditions. 		 
poster icon Poster MOPMB006 [1.380 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB006  
About • Received ※ 16 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 18 July 2023
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MOPMB008 In-Situ Quality Factor Measurements of SRF Cavities at S-DALINAC linac, SRF, coupling, resonance 70
 
  • R. Grewe, M. Arnold, A. Brauch, M. Dutine, L.E. Jürgensen, N. Pietralla, F. Schließmann, D. Schneider
    TU Darmstadt, Darmstadt, Germany
  
  Funding: Work supported by DFG (GRK 2128) and the State of Hesse within the Research Cluster ELEMENTS (Project ID 500/10.006)
The Superconducting Darmstadt Linear Accelerator (S-DALINAC) is a thrice recirculating electron accelerator wich can be operated in a multi-turn energy recovery mode*. The design parameters for kinetic energy and beam current are up to 130 MeV and up to 20 uA respectively. The injector consists of a six-cell capture cavity and two 20-cell srf cavities. The main linac consists of eight 20-cell cavities. The cavities are operated at a temperature of 2 K with a frequency of 2.9972(1) GHz. Monitoring of the srf cavities is important for the overall performance of the accelerator. A key parameter for the rating of the srf cavity performance is the intrinsic quality factor Q. At the S-DALINAC it is measured for selected cavities during the yearly maintenance procedures. The unique design of the rf input coupler allows for a wide tuning range for the input coupling strength. This makes in-situ quality factor measurements using the decay time measurement method** possible. The contribution illustrates the principal design of the input couplers and the benefits it yields for Q measurements. Recent results including the progression of the quality factors over time will be presented.
*Felix Schliessmann et al., Nat. Phys. 19, 597-602 (2023).
**Tom Powers, Proc. of SRF’05, Cornell University, Ithaca, New York, USA, 2005, p.40. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB008  
About • Received ※ 19 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 04 August 2023
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MOPMB009 Plasma Electrolytic Polishing Technology Progress Development for Nb and Cu Substrates Preparation cathode, plasma, experiment, SRF 75
 
  • E. Chyhyrynets, O. Azzolini, R. Caforio, D. Fonnesu, D. Ford, G. Keppel, C. Pira, A. Salmaso, F. Stivanello
    INFN/LNL, Legnaro (PD), Italy
  • G. Marconato
    Università degli Studi di Padova, Padova, Italy
  
  Funding: Work supported by the INFN CSNV experiment SAMARA. Fundings from the EU’s Horizon 2020 Research and Innovation programme under Grant Agreement N 101004730. PNRR MUR project PE0000023-NQSTI.
Superconducting radio frequency (SRF) cavity performance is highly dependent on surface preparation. Conventionally, electropolishing (EP) is used to achieve a clean surface and low roughness for both Nb and Cu substrates, but it requires harsh and corrosive solutions like concentrated acids. Plasma Electrolytic Polishing (PEP) is a promising alternative that uses only diluted salt solutions and has several advantages over EP. PEP can replace intermediate steps like mechanical or chemical polishing, thanks to its superior removal rate of up to 2-8 um/min of Nb and 3-30 um/min of Cu. It achieves Ra roughness of 100 nm for both substrates and has a higher smoothing effect than EP. PEP is also suitable for normal conducting cavities and other accelerator components, including couplers. We demonstrate the effectiveness of PEP on SRF substrates and analyse substrate defect evaluation. We demonstrate the application of PEP onto SRF substrates and analyse the substrate’s defect evaluation. The ongoing work includes Nb bulk and Nb on Cu QPR treatments and RF tests in collaboration with HZB. 		 
poster icon Poster MOPMB009 [11.877 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB009  
About • Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 17 July 2023
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MOPMB010 Analysis of Semiconductor Components as Temperature Sensors for Cryogenic Investigation of SRF Materials controls, cryogenics, experiment, SRF 80
 
  • A. Cierpka, S. Keckert, J. Knobloch, F. Kramer, O. Kugeler
    HZB, Berlin, Germany
  
  Temperature mapping systems have been used for many years to detect local heating in an SRF cavity surface or materials sample. They require a large number of temperature sensors. Most often, low-cost Allen-Bradley resistors are used for this purpose. Since they have poor sensitivity and reproducibility above 4 K, sensor alternatives that combine the precision of Cernox sensors with the low-cost of Allen-Bradley resistors would be highly desirable. In this work various semiconductor components that exhibit a temperature dependent electrical response, such as diodes and LEDs were analyzed with respect to sensitivity, reproducibility and response speed in a temperature range between 6.5 K and 22 K. In this range, many diodes and LEDs were found to be more sensitive than Cernox sensors. However, in some components the response time was slow - possibly due to poor thermal contact.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB010  
About • Received ※ 08 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 17 July 2023
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MOPMB011 Deposition and Characterisation of V₃Si films for SRF Applications SRF, site, target, vacuum 84
 
  • C. Benjamin, J.A. Conlon, O.B. Malyshev, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G. Burt, O.B. Malyshev, D.J. Seal, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G. Burt, D.J. Seal
    Lancaster University, Lancaster, United Kingdom
  • N.L. Leicester, H.S. Marks
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • L.G.P. Smith
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730.
A15 superconducting materials, like V₃Si and Nb₃Sn, are potential alternatives to Nb for next generation thin film SRF cavities when operated at 4 K. Their relatively high Tc and superconducting properties could allow for higher accelerating gradients and elevated operating temperatures. We present work on the deposition of V₃Si thin films on planar Cu substrates and an open structure 6 GHz cavity, using physical vapour deposition (PVD) and a V₃Si single target. The surface structure, composition and DC superconducting properties of two planar samples were characterised via secondary electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX) and in a magnetic field penetration facility. Furthermore, the first deposition using PVD of a V₃Si film on a 6 GHz split cavity and the RF performance is presented. 		 
poster icon Poster MOPMB011 [7.496 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB011  
About • Received ※ 16 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 19 July 2023
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MOPMB012 Investigation, Using Nb Foils to Characterise the Optimal Dimensions of Samples Measured by the Magnetic Field Penetration Facility SRF, experiment, ECR, niobium 88
 
  • L.G.P. Smith, D.A. Turner
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • G. Burt, O.B. Malyshev, D.A. Turner
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G. Burt
    Lancaster University, Lancaster, United Kingdom
  • T. Junginger
    TRIUMF, Vancouver, Canada
  • T. Junginger
    UVIC, Victoria, Canada
  • O.B. Malyshev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  SRF cavities made of bulk Nb are reaching their theoretical limits in the maximum accelerating gradient, Eacc, where Eacc is limited by the maximum magnetic field, Bmax, that can be applied on the surface of the accelerating cavity wall. To increase Eacc, Bmax, which can be applied to the surface, must also be increased. The A15 materials or multilayer structures are the potential solution to increase Bmax. Since coating and RF testing of full size RF cavities is both expensive and time consuming, one need to evaluate new ideas in superconducting thin films quickly and at low cost. A magnetic field penetration experiment has been designed and built at Daresbury Laboratory to test small superconducting samples. The facility produces a parallel DC magnetic field, which applied from one side of the sample to the other similar to that in an RF cavity. The facility applies an increasing magnetic field at a set temperature to determine the field of full flux penetration which can give an insight into the quality and structure of the superconducting structure. The facility has been characterised using both type I and II superconductors and is now producing results from novel materials.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB012  
About • Received ※ 18 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 17 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMB013 Influence of the Coating Parameters on the Tc of Nb₃Sn Thin Films on Copper Deposited via DC Magnetron Sputtering site, niobium, SRF, cathode 92
 
  • D. Fonnesu, O. Azzolini, R. Caforio, E. Chyhyrynets, D. Ford, V.A. Garcia, G. Keppel, C. Pira, A. Salmaso, F. Stivanello
    INFN/LNL, Legnaro (PD), Italy
  • G. Marconato
    Università degli Studi di Padova, Padova, Italy
  
  Funding: The I.FAST project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730. Work supported by the INFN CSNV experiment SAMARA.
The I.FAST collaboration aims at pushing the performance of particle accelerators by developing sustainable innovative technologies. Among its goals, the development of thin film-coated copper elliptical accelerating cavities covers both the optimization of the manufacturing of seamless substrates and the development of functional coatings able to conform to the 3D cavity geometry while delivering the needed performance. For the latter, the optimization of the deposition recipe is central to a successful outcome. The work presented here focuses on the deposition of Nb₃Sn films on flat, small copper samples. The films are deposited via DCMS from a planar stoichiometric Nb₃Sn commercial target. The results of the film characterization are presented here. The observed dependencies between the film properties and, in particular, Tc(90%-10%) = (17.9±0.1)K is reported for Nb₃Sn on sapphire and Tc(90%-10%) = (16.9±0.2)K for Nb₃Sn on copper with a 30 micron thick niobium buffer layer. 		 
poster icon Poster MOPMB013 [1.749 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB013  
About • Received ※ 18 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 02 July 2023
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MOPMB014 NbTi Thin Film SRF Cavities for Dark Matter Search target, SRF, photon, cryogenics 96
 
  • G. Marconato
    Università degli Studi di Padova, Padova, Italy
  • D. Alesini, A. D’Elia, D. Di Gioacchino, C. Gatti, C. Ligi, G. Maccarrone, A. Rettaroli, S. Tocci
    LNF-INFN, Frascati, Italy
  • O. Azzolini, R. Caforio, E. Chyhyrynets, D. Fonnesu, D. Ford, V.A. Garcia, G. Keppel, C. Pira, A. Salmaso, F. Stivanello
    INFN/LNL, Legnaro (PD), Italy
  • C. Braggio
    Univ. degli Studi di Padova, Padova, Italy
  • D. D’Agostino, U. Gambardella
    INFN-Salerno, Baronissi, Salerno, Italy
  • S. Posen
    Fermilab, Batavia, Illinois, USA
  
  Funding: Resources from U.S. DOE, Ofce of Science, NQISRC, SQMS contract No DE-AC02-07CH11359. Also from EU’s Horizon 2020 Research and Innovation programme, Grant Agreement No 101004730; INFN CSNV exp. SAMARA
The search for dark matter is now looking at ALPs (axion-like particles) as a very promising candidate to understand our universe. Within this framework, we explore the possibility to use NbTi thin film coatings on Cu resonating cavities to investigate the presence of axions in the range of 35-45 µeV mass by coupling the axion to a very strong magnetic field inside the cavity, causing its conversion to a photon which is subsequently detected. In this work the chemical treatments and DC magnetron sputtering details of the preparation of 9 GHz, 7 GHz, and 3.9 GHz resonant cavities and their quality factor measurements at different applied magnetic fields are presented. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB014  
About • Received ※ 18 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 26 July 2023
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MOPMB015 Development of a Plasma-Enhanced Chemical Vapor Deposition System for High-Performance SRF Cavities SRF, plasma, vacuum, controls 100
 
  • G. Gaitan, A.T. Holic, W.I. Howes, G. Kulina, P. Quigley, J. Sears, Z. Sun
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • M. Liepe
    Cornell University, Ithaca, New York, USA
  • B.W. Wendland
    University of Minnesota, Minnesota, USA
  
  Funding: This work was supported by the U.S. National Science Foundation under Award PHY-1549132, the Center for Bright Beams
Next-generation, thin-film surfaces employing Nb₃Sn, NbN, NbTiN, or other compound superconductors are essential for reaching enhanced RF performance levels in SRF cavities. However, optimized, advanced deposition processes are required to enable high-quality films of such materials on large and complex-shaped cavities. For this purpose, Cornell University is developing a plasma-enhanced chemical vapor deposition (CVD) system that facilitates coating on complicated geometries with a high deposition rate. This system is based on a high-temperature tube furnace with a high-vacuum, gas, and precursor delivery system, and uses plasma to significantly reduce the required processing temperature and promote precursor decomposition. Here we present an update on the development of this system, including final system design, safety considerations, assembly, and commissioning. 		 
poster icon Poster MOPMB015 [1.951 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB015  
About • Received ※ 16 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 01 July 2023 — Issue date ※ 16 July 2023
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MOPMB016 Successful Al₂O₃ Coating of Superconducting Niobium Cavities by Thermal ALD niobium, SRF, HOM, experiment 104
 
  • G.K. Deyu, W. Hillert, M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • R.H. Blick, I. González Díaz-Palacio, R. Zierold
    University of Hamburg, Hamburg, Germany
  
  Funding: This work is supported by the BMBF under the research Grant 05K19GUB.
Al₂O₃ is one of the potential insulator materials in the superconductor-insulator-superconductor (SIS) multilayer coatings of superconducting radio-frequency (SRF) cavities for pushing their performance limits. We report on the successful coating of two 1.3 GHz Tesla-shaped SRF cavities with 18 nm and 36 nm layers of Al₂O₃ deposited by thermal atomic layer deposition (ALD). The coating recipe was developed by thermal atomic layer deposition (ALD). The coating recipe was optimized with respect to different the applied process parameters such as exposure and purge times, substrate temperature and flow rates. After a proof-of-principle Al₂O₃ coating of a cavity, second the cavity maintained its maximum achievable accelerating field of more than 40 MV/m and no deterioration was observed [1]. On the contrary, an improvement of the surface resistance above 10 MV/m has been observed, which is now further under investigation.
[1].Wenskat, Marc, et al. "Successful Al₂O₃ coating of superconducting niobium cavities with thermal ALD." Superconductor Science and Technology 36.1 (2022): 015010. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB016  
About • Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 28 June 2023
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MOPMB017 Development of a Thermal Conductance Instrument for Niobium at Cryogenic Temperatures niobium, ECR, cryogenics, operation 109
 
  • C. Saribal, C. Martens
    University of Hamburg, Hamburg, Germany
  • W. Hillert, M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  
  Funding: University of Hamburg
Particle accelerators form an important tool in a variety of research fields. In an effort to reduce operation costs while maintaining high energies, their accelerating structures are steadily improved towards higher accelerating fields and lower RF losses. Stable operation of such a cavity generally requires Joule-heating, generated in its walls, to be conducted to an outer helium bath. Therefore, it is of interest to experimentally evaluate how present and future cavity treatments affect thermal characteristics. We present an instrument for measuring the thermal performance of SRF cavity materials at cryogenic temperatures. Pairs of niobium disks are placed inside of a liquid helium bath and a temperature gradient is generated across them to obtain total thermal resistance for temperatures below 2 Kelvin. To get an idea of the instruments sensitivity and how standard cavity treatments influence thermal resistance, samples are tested post fabrication, polishing and 800 °C baking. The first tests show the commissioning of our newly set up system and if it is feasible to observe relevant changes and evaluate new and promising cavity treatments such as SIS structures. 		 
poster icon Poster MOPMB017 [3.217 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB017  
About • Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 01 July 2023
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MOPMB019 Numerical Calculations of Superheating Field in Superconductors with Nanostructured Surfaces simulation, radio-frequency, SRF, superconductivity 114
 
  • M.R.P. Walive Pathiranage
    VMI, Lexington, USA
  • A.V. Gurevich
    ODU, Norfolk, Virginia, USA
  
  Funding: This work was supported by DOE under Grant DE-SC 100387-020 and by Virginia Military Institute (VMI) under Jackson-Hope Grant for faculty travel and for New Directions in Teaching and Research Grants.
We report calculations of a dc superheating field Hs in superconductors with nanostructured surfaces. Particularly, we performed numerical simulations of the Ginzburg-Landau (GL) equations for a superconductor with an inhomogeneous profile of impurity concentration, a thin superconducting layer on top of another superconductor, and S-I-S multilayers. The superheating field was calculated taking into account the instability of the Meissner state at a finite wavelength along the surface depending on the value of the GL parameter. Simulations were done for the materials parameters of Nb and Nb₃Sn at different values of the GL parameter and the mean free paths. We show that the impurity concentration profile at the surface and thicknesses of superconducting layers in S-I-S structures can be optimized to reach the maximum Hs, which exceeds the bulk superheating fields of both Nb and Nb₃Sn. For example, a S-I-S structure with 90 nm thick Nb₃Sn layer on Nb can boost the superheating field up to ~ 500 mT, while protecting the SRF cavity from dendritic thermomagnetic avalanches caused by local penetration of vortices. 		 
poster icon Poster MOPMB019 [1.214 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB019  
About • Received ※ 17 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 16 July 2023
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MOPMB020 A Comprehensive Picture of Hydride Formation and Dissipation site, superconductivity, SRF, niobium 119
 
  • N. Sitaraman, T. Arias
    Cornell University, Ithaca, New York, USA
  • A.V. Harbick, M.K. Transtrum
    Brigham Young University, Provo, USA
  • M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: This work was supported by the U.S. National Science Foundation under Award PHY-1549132, the Center for Bright Beams.
Research linking surface hydrides to Q-disease, and the subsequent development of methods to eliminate surface hydrides, is one of the great successes of SRF cavity R\&D. We use time-dependent Ginzburg-Landau to extend the theory of hydride dissipation to sub-surface hydrides. Just as surface hydrides cause Q-disease behavior, we show that sub-surface hydrides cause high-field Q-slope (HFQS) behavior. We find that the abrupt onset of HFQS is due to a transition from a vortex-free state to a vortex-penetration state. We show that controlling hydride size and depth through impurity doping can eliminate HFQS. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB020  
About • Received ※ 30 June 2023 — Revised ※ 18 July 2023 — Accepted ※ 19 August 2023 — Issue date ※ 19 August 2023
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MOPMB021 Correlating Lambda Shift Measurements with RF Performance in Mid-T Heat Treated Cavities SRF, niobium, radio-frequency, ECR 124
 
  • R. Ghanbari, G.K. Deyu, W. Hillert, R. Monroy-Villa, M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • C. Bate, D. Reschke, L. Steder, J.C. Wolff
    DESY, Hamburg, Germany
  
  Funding: This work was supported by the BMBF under the research grants 05K19GUB and 05H2021.
Heat treatment procedures have been identified as cru-cial for the performance of niobium SRF cavities, which are the key technology of modern accelerators. The so called "mid-T heat treatments", invert the dependence of losses on the applied accelerating field (anti-Q slope) and significantly reduce the absolute value of losses. The mechanism behind these improvements is still under investigation, and further research is needed to fully understand the principle processes involved. Anomalies in the frequency shift near the transition temperature (Tc), known as "dip" can provide insight into fundamental material properties and allow us to study the relation-ship of frequency response with surface treatments. Therefore, we have measured the frequency versus temperature of multiple mid-T heat treated cavities with different recipes and studied the correlation of SRF properties with frequency shift features. The maximum quality factor correlates with two such shift features, namely the dip magnitude per temperature width and the total frequency shift. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB021  
About • Received ※ 20 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 August 2023
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MOPMB022 Recent mid-T Single-Cell Treatments R&D at DESY niobium, SRF, vacuum, controls 129
 
  • C. Bate, D. Reschke, J. Schaffran, L. Steder, L. Trelle, H. Weise
    DESY, Hamburg, Germany
  
  The challenge of improving the performance of SRF cavities is being faced worldwide. One approach is to modify the superconducting surface properties through certain baking procedures. Recently a niobium retort furnace placed directly under an ISO4 clean room has been refurbished at DESY. Thanks to an inter-vacuum chamber and cryopumps, with high purity values in the mass spectrum it is working in the UHV range of 2·10-8 mbar. The medium temperature (mid-T) heat treatments around 300°C are promising and successfully deliver reproducible very high Q₀ values of 2-5·1010 at medium field strengths of 16 MV/m. Since the first DESY and ZRI mid-T campaign yielded promising results, further results of 1.3 GHz single-cell cavities are presented here after several modified treatments of the mid-T recipe. In addition, samples were added to each treatment, the RRR value change was examined, and surface analyses were subsequently performed. The main focus of the sample study is the precise role of the changes in the concentration of impurities on the surface. In particular, the change in oxygen content due to diffusion processes is suspected to be the cause of enhancing the performance.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB022  
About • Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 01 July 2023
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MOPMB023 Magnetic Flux Expulsion in TRIUMF’s Multi-Mode Coaxial Cavities simulation, SRF, experiment, controls 135
 
  • R.R. Gregory, T. Junginger, M.W. McMullin
    UVIC, Victoria, Canada
  • T. Junginger, P. Kolb, R.E. Laxdal, M.W. McMullin, Z.Y. Yao
    TRIUMF, Vancouver, Canada
  
  The external magnetic flux sensitivity of SRF cavities is an important characteristic of SRF accelerator design. Previous studies have shown that n-doped elliptical cavities are very sensitive to external fields, resulting in stringent requirements for residual field and cavity cool-down speed. Few such studies have been done on HWRs and QWRs. The impact of applied field direction and cool-down speed of flux expulsion for these cavities is poorly understood. This study explores the effect of these cool-down characteristics on TRIUMF¿s QWR using COMSOL ® simulations and experimental results. This study seeks to maximize the flux expulsion that occurs when a cavity is cooled down through its superconducting temperature. Flux expulsion is affected by the cool-down speed, temperature gradient, and orientation of the cavity relative to an applied magnetic field. It was found that for a vertically applied magnetic field the cool-down speed and temperature gradient did not have a significant effect on flux expulsion. Contrarily, a horizontal magnetic field can be nearly completely expelled by a fast, high temperature gradient cool-down.  
poster icon Poster MOPMB023 [2.191 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB023  
About • Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 30 July 2023
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MOPMB024 Flux Expulsion Studies of Niobium Material of 650 MHz Cavities for PIP-II niobium, simulation, factory, radio-frequency 141
 
  • K.E. McGee
    FRIB, East Lansing, Michigan, USA
  • F. Furuta, M. Martinello, O.S. Melnychuk, A.V. Netepenko, G. Wu, Y. Xie
    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.
Two different vendors supplied the niobium sheet material for PIP-II 5-cell 650 MHz cavities, which was characterized by multiple different ASTM sizes. Cavities subsequently fabricated from these sheets were heat-treated at various temperatures, then the cavities’ flux-expulsion performance was measured. Where the initial measurements of vendor O materials showed that nearly all flux remained trapped despite a high thermal gradient, 900C heat treatment subsequently improved the flux expulsion to an acceptable rate. Understanding and characterizing vendor O materials in this way is key for upcoming and future projects planning to employ niobium sheet from this supplier. 		 
poster icon Poster MOPMB024 [4.064 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB024  
About • Received ※ 26 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 19 August 2023 — Issue date ※ 21 August 2023
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MOPMB026 Development of Transformative Cavity Processing - Superiority of Electropolishing on High Gradient Performance over Buffered Chemical Polishing at Low Frequency (322 MHz) SRF, operation, cryomodule, MMI 145
 
  • K. Saito, C. Compton, K. Elliott, W. Hartung, S.H. Kim, T.K. Konomi, E.S. Metzgar, S.J. Miller, L. Popielarski, A.T. Taylor, T. Xu
    FRIB, East Lansing, Michigan, USA
  
  Funding: The work is supported by DOE Awards DE-SC0022994.
A DOE grant R&D titled ¿Development of Transformative Preparation Technology to Push up High Q/G Performance of FRIB Spare HWR Cryomodule Cavities¿ is ongoing at FRIB. This R&D is for 2 years since September 2022. This project proposes four objectives: 1) Superiority on high gradient performance of electropolishing (EP) over buffered chemical polishing at low frequency (322 MHz), 2) High Qo performance by the local magnetic shield, 3) Development of HFQS-free BCP and, 4) Wet N-doping method. This paper will report the result of first object, and a local magnetic shield design and simulation to reduce the residual magnetic field < 0.1 mG in the vertical test Dewar, for the object 2. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB026  
About • Received ※ 14 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 08 July 2023
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MOPMB027 Successful Superheating Field Formulas from an Intuitive Model niobium, experiment, SRF, superconductivity 151
 
  • K. Saito, T. Konomi
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by the U.S. Department of Energy Office of Science DE-S0000661 and the National Science Foundation under Cooperative Agreement PHY-1102511
To date, many theoretical formulas for superheating field on SRF cavity are already proposed based rather complicated calculations. This paper proposes the formulas by a very intuitive simple model: energy balance between RF magnetic energy and superconducting condensed one, and a condition of vanishing the mirror vortex line image. The penetration of a single vortex determines the superheating field for a type II superconductor. On the other hand, for type I superconductors, the surface flux penetration determines it. The formula fits very well quantitatively the results of niobium cavity and Nb₃Sn one. In addition, it gives a nice guideline for new material beyond niobium.
male, senior 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB027  
About • Received ※ 23 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 15 July 2023
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MOPMB030 Medium Temperature Furnace Baking of Low-beta 650 MHz Five-cell Cavities niobium, radio-frequency, SRF, multipactoring 158
 
  • G. Wu, S.K. Chandrasekaran, V. Chouhan, G.V. Eremeev, F. Furuta, K.E. McGee, A.A. Murthy, A.V. Netepenko, J.P. Ozelis, H. Park, S. Posen
    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.
Medium Temperature baking of low beta 650 MHz cavities was conducted in a UHV furnace. A systematic study of cavity surface resistance components, residual and BCS, was conducted, including analyzing surface resistance due to trapped magnetic flux. Cavities showed an average 4.5 nano-ohm surface resistance at 17 MV/m under 2 K, which meets PIP-II specifications with a 40% margin. The results provided helpful information for the PIP-II project to optimize the cavity processing recipe for cryomodule application. The results were compared to the 1.3 GHz cavity that received a similar furnace baking. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB030  
About • Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 18 July 2023
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MOPMB032 The Collaborative Effects of Intrinsic and Extrinsic Impurities in Low RRR SRF Cavities SRF, niobium, radio-frequency, accelerating-gradient 162
 
  • K. Howard, Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  • D. Bafia, A. Grassellino
    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 SRF community has shown that introducing certain impurities into high-purity niobium can improve quality factors and accelerating gradients. We question why some impurities improve RF performance while others hinder it. The purpose of this study is to characterize the impurity profile of niobium coupons with a low residual resistance ratio (RRR) and correlate these impurities with the RF performance of low RRR cavities so that the mechanism of impurity-based improvements can be better understood and improved upon. The combination of RF testing and material analysis reveals a microscopic picture of why low RRR cavities experience low BCS resistance behavior more prominently than their high RRR counterparts. We performed surface treatments, low temperature baking and nitrogen-doping, on low RRR cavities to evaluate how the intentional addition of oxygen and nitrogen to the RF layer further improves performance through changes in the mean free path and impurity profile. The results of this study have the potential to unlock a new understanding on SRF materials and enable the next generation of high Q/high gradient surface treatments. 		 
poster icon Poster MOPMB032 [1.444 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB032  
About • Received ※ 21 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 23 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMB033 Efforts to Suppress Field Emission in SRF Cavities at KEK SRF, laser, acceleration, site 167
 
  • M. Omet, H. Araki, T. Dohmae, H. Ito, R. Katayama, K. Umemori, Y. Yamamoto
    KEK, Ibaraki, Japan
  
  Our main objective is to achieve as high as possible quality factors Q₀ and maximal accelerating voltages Eacc within 1.3 GHz superconducting radio frequency (SRF) cavities. Beside an adequate surface treatment, key to achieve good performance is a proper assembly in the clean room prior cavity testing or operation. In this contribution we present the methods and results of our efforts to get a better understanding of our clean room environment and the particulate generation caused during the assembly work. Furthermore, we present the measures taken to suppress filed emission, followed by an analysis of vertical test results of the last six years.  
poster icon Poster MOPMB033 [1.532 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB033  
About • Received ※ 14 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 02 September 2023 — Issue date ※ 02 September 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMB036 Magnetic Field Mapping of a Large-Grain 1.3 GHz Single-Cell Cavity radio-frequency, niobium, SRF, cryogenics 172
 
  • I.P. Parajuli, J.R. Delayen, A.V. Gurevich
    ODU, Norfolk, Virginia, USA
  • G. Ciovati
    JLab, Newport News, Virginia, USA
  
  Funding: This work was supported by the National Science Foundation under Grant No. PHY 100614-010. G.C. is supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A new magnetic field mapping system for 1.3 GHz single-cell cavities was developed in order to reveal the impact of ambient magnetic field and temperature gradients during cool-down on the flux trapping phenomenon. Measurements were done at 2 K for different cool-down conditions of a large-grain cavity before and after 120 °C bake. The fraction of applied magnetic field trapped in the cavity walls was ~ 50% after slow cool-down and ~20% after fast cool-down. The results showed a weak correlation between between trapped flux locations and hot-spots causing the high-field Q-slope. The results also showed an increase of the trapped flux at the quench location, after quenching, and a local redistribution of trapped flux with increasing RF field. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB036  
About • Received ※ 15 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 05 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMB037 Exploration of Parameters that Affect High Field Q-Slope niobium, accelerating-gradient, SRF, radio-frequency 178
 
  • K. Howard, Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  • D. Bafia, A. Grassellino
    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 onset of high field Q-slope (HFQS) around 25 MV/m prevents cavities in electropolished (EP) condition from reaching high quality factors at high gradients due to the precipitation of niobium hydrides during cooldown. These hydrides are non-superconducting at 2 K, and contribute to losses such as Q disease and HFQS. We are interested in exploring the parameters that affect the behavior of HFQS. We study a high RRR cavity that received an 800 C by 3 hour bake and EP treatment to observe HFQS. First, we explore the effect of trapped magnetic flux. The cavity is tested after cooling slowly through Tc while applying various levels of ambient field. We observe the onset of the HFQS and correlate this behavior with the amount of trapped flux. Next, we investigate the effect of the size/concentration of hydrides. The cavity is tested after holding the temperature at 100 K for 12 hours during the cooldown to promote the growth of hydrides. We can correlate the behavior of the HFQS with the increased hydride concentration. Our results will help further the understanding of the mechanism of HFQS. 		 
poster icon Poster MOPMB037 [1.648 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB037  
About • Received ※ 12 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 19 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMB038 Temperature Mapping for Coaxial Cavities at TRIUMF SRF, LabView, data-acquisition, ECR 183
 
  • P. Kolb, T. Junginger, J.J. Keir, R.E. Laxdal, B. Matheson, Z.Y. Yao
    TRIUMF, Vancouver, Canada
  • H. Al Hassini, T. Junginger
    UVIC, Victoria, Canada
  • L. Fearn
    UW/Physics, Waterloo, Ontario, Canada
  
  Temperature mapping (T-map) on superconducting radio-frequency (SRF) cavities has been shown as a useful tool to identify defects and other abnormal sources of losses. So far T-map systems have only been realized for elliptical cavities that have an easily accessible outer surface. TEM mode cavities such as quarterwave and halfwave resonators (QWR, HWR) dissipate most of their power on the inner conductor of the coaxial structure. The limited access and constrained space are a challenge for the design of a temperature mapping system. This paper describes the mechanical and electrical design including the data acquisition of a T-map system for the TRIUMF multi-mode coaxial cavities, and first results are shown.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB038  
About • Received ※ 20 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 30 June 2023
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MOPMB040 Comparing the Effectiveness of Low Temperature Bake in EP and BCP Cavities SRF, niobium, radio-frequency, factory 187
 
  • H. Hu, Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  • D. Bafia
    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.
Electropolishing (EP) and buffered chemical polishing (BCP) are conventional surface preparation techniques for superconducting radiofrequency (SRF) cavities. Both EP and BCP treated SRF cavities display high field Q-slope (HFQS) which degrades performance at high gradients. While high gradient performance in EP cavities can be improved by introducing oxygen via a low temperature bake (LTB) of 120°C by 48 hours, LTB does not consistently remove HFQS in BCP cavities. There is no consensus as to why LTB is not effective on BCP prepared cavities. We examine quench in EP, BCP, EP+LTB, and BCP+LTB treated 1.3 GHz single-cell Nb cavities by studying the heating behavior with field using a temperature mapping system. Cavity performance is correlated to characterizations of surface impurity profile obtained via time of flight secondary ion mass spectrometry studies. We observe a difference in near surface hydrogen concentration following BCP compared to EP that may suggest that the causes of quench in EP and BCP cavities are different. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB040  
About • Received ※ 14 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 03 July 2023
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MOPMB041 Microstructure Development in a Cold Worked SRF Niobium Sheet After Heat Treatments ECR, SRF, niobium, radio-frequency 191
 
  • S. Balachandran, P. Dhakal, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  • T.R. Bieler
    Michigan State University, East Lansing, Michigan, USA
  • S. Chetri, P.J. Lee
    NHMFL, Tallahassee, Florida, USA
  • Z.L. Thune
    MSU, East Lansing, USA
  
  Funding: Jefferson Science Associates, LLC under U.S. DOE Grant DEAC05-06OR23177, U.S. DOE, Office of HEP under Grant DE-SC0009960, and NHMFL through NSF Grant DMR-1644779 and the State of Florida.
Bulk Nb for TESLA shaped SRF cavities is a mature technology. Significant advances are in order to push Q0’s to 1010-11(T= 2K), and involve modifications to the sub-surface Nb layers by impurity doping. In order to achieve the lowest surface resistance any trapped flux needs to be expelled for cavities to reach high Q0’s. There is clear evidence that cavities fabricated from polycrystalline sheets meeting current specifications require higher temperatures beyond 800 °C leads to better flux expulsion, and hence improves Q0. Recently, cavities fabricated with a non-traditional Nb sheet with initial cold work due to cold rolling expelled flux better after 800 °C/3h heat treatment than cavities fabricated using fine-grain poly-crystalline Nb sheets. Here, we analyze the microstructure development in Nb from the vendor supplied cold work non- annealed sheet that was fabricated into an SRF cavity as a function of heat treatment building upon the methodology development to analyze microstructure being developed by the FSU-MSU-UT, Austin-JLAB collaboration. The results indicate correlation between full recrystallization and better flux expulsion. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB041  
About • Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 09 July 2023
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MOPMB042 Evaluation of Flux Expulsion and Flux Trapping Sensitivity of SRF Cavities Fabricated from Cold Work Nb Sheet with Successive Heat Treatment SRF, niobium, ECR, radio-frequency 197
 
  • B.D. Khanal
    ODU, Norfolk, Virginia, USA
  • P. Dhakal
    JLab, Newport News, Virginia, USA
  
  Funding: The work is partially supported by DOE HEP under Awards No. DE-SC 0009960. This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The main source of RF losses leading to lower quality factor of superconducting radio-frequency cavities is due to the residual magnetic flux trapped during cool-down. The loss due to flux trapping is more pronounced for cavities subjected to impurities doping. The flux trapping and its sensitivity to rf losses are related to several intrinsic and extrinsic phenomena. To elucidate the effect of re-crystallization by high temperature heat treatment on the flux trapping sensitivity, we have fabricated two 1.3 GHz single cell cavities from cold-worked Nb sheets and compared with cavities made from standard fine-grain Nb. Flux expulsion ratio and flux trapping sensitivity were measured after successive high temperature heat treatments. The cavity made from cold worked Nb showed better flux expulsion after 800 C/3h heat treatment and similar behavior when heat treated with additional 900 C/3h and 1000 C/3h. In this contribution, we present the summary of flux expulsion, trapping sensitivity, and RF results. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB042  
About • Received ※ 19 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 25 June 2023 — Issue date ※ 04 July 2023
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MOPMB043 Characterization of Dissipative Regions of an N-Doped SRF Cavity niobium, radio-frequency, electron, experiment 202
 
  • E.M. Lechner, G. Ciovati
    JLab, Newport News, Virginia, USA
  • G. Ciovati, A.V. Gurevich, J. Makita
    ODU, Norfolk, Virginia, USA
  • M. Iavarone, E.M. Lechner, B.D. Oli
    Temple University, Philadelphia, USA
  
  Funding: DE-AC05-06OR23177 NSF Award No. 1734075 W911NF-16-2-0189
We report scanning tunneling microscopy measurements on N-doped cavity hot and cold spot cutouts. Analysis of the electron tunneling spectra using a proximity effect theory shows that hot spots have a reduced superconducting gap and a wider distribution of the contact resistance. Alone, these degraded superconducting properties account for a much weaker excess dissipation as compared with the vortex contribution. Based on the correlation between the quasiparticle density of states and temperature mapping, we suggest that degraded superconducting properties may facilitate vortex nucleation or settling of trapped flux during cooling the cavity through the critical temperature. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB043  
About • Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 13 July 2023
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MOPMB044 Topographic Evolution of Nitrogen Doped Nb Subjected to Electropolishing SRF, niobium, vacuum, ECR 207
 
  • E.M. Lechner, C.G. Baxley, M.J. Kelley, C.E. Reece
    JLab, Newport News, Virginia, USA
  • J.W. Angle, M.J. Kelley
    Virginia Polytechnic Institute and State University, Blacksburg, USA
  
  Funding: DE-AC05-06OR23177 DE-SC-0014475
Surface quality is paramount in facilitating high perfor-mance SRF cavity operation. Here, we investigate the topographic evolution of samples subjected to N-doping and 600 °C vacuum anneal. We show that in N-doped Nb, niobium nitrides may grow continuously along grain boundaries. Upon electropolishing high slope angle grooves are revealed which sets up a condition that may facilitate a supression of the superheating field. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB044  
About • Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 17 July 2023
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MOPMB045 Quench Detection in a Superconducting Radio Frequency Cavity with Combined Temperature and Magnetic Field Mapping radio-frequency, niobium, SRF, ECR 211
 
  • B.D. Khanal, G. Ciovati
    ODU, Norfolk, Virginia, USA
  • G. Ciovati, P. Dhakal
    JLab, Newport News, Virginia, USA
  
  Funding: This is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
Local dissipation of rf power in SRF cavities create so called ’hot-spots’, primary precursors of cavity quench driven by either thermal or magnetic instability. These hot spots are may be detected by a temperature mapping system, and a large increase in temperature on the outer surface is detected during cavity quench events. Here, we have used combined magnetic and temperature mapping systems using anisotropic magneto-resistance sensors and carbon resisters to locate the hot spots and areas with high trapped flux on a 3 GHz single-cell Nb cavity during the rf tests at 2 K. The effect of global and localized flux trapping on the rf performance will be presented. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB045  
About • Received ※ 19 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 12 August 2023
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MOPMB047 Commissioning of Dedicated Furnace for Nb₃Sn Coatings of 2.6 GHz Single Cell Cavities niobium, SRF, MMI, factory 216
 
  • P.A. Kulyavtsev, G.V. Eremeev, S. Posen, B. Tennis
    Fermilab, Batavia, Illinois, USA
  • J. Zasadzinski
    IIT, Chicago, 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.
We present the results of commissioning a dedicated furnace for Nb₃Sn coatings of 2.6GHz single cell cavities. Nb₃Sn is a desired coating due to its high critical temperature and smaller surface resistance compared to bulk Nb. Usage of Nb₃Sn coated cavities will greatly reduce operating costs due to its higher operating temperature providing decreased cooling costs. Tin is deposited in the bulk Nb cavity by use of a tin chloride nucleation agent and tin vapor diffusion. Analysis of the resultant coating was performed using SEM/EDS to verify successful formation of desired Nb:Sn phase. Witness samples located in line of sight of the source were analyzed in order to understand the coating efficacy. The cavity’s performance was assessed in the Vertical Test Stand (VTS) at Fermilab. 		 
poster icon Poster MOPMB047 [4.858 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB047  
About • Received ※ 26 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 08 July 2023
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MOPMB049 Plasma Processing: Ignition Testing and Simulation Models for a 172 MHz HWR Cavity plasma, vacuum, simulation, SRF 219
 
  • M.E. McIntyre, B.R. Blomberg, M.P. Kelly, J.T. McLain, K.M. Villafania, G.P. Zinkann
    ANL, Lemont, Illinois, USA
  • Z. Wei
    GIT, Atlanta, Georgia, USA
  
  Maintenance and cleaning of superconducting RF cavities is labor intensive task that involves disassembling the cryostat holding the resonators and removing them to be cleaned. At the Argonne Tandem Linac Accelerating System (ATLAS) at Argonne National Laboratory, a project is underway to research cleaning the cavities in-situ by plasma processing. Previous plasma processing research by SNS, MSU, FNAL, and IJCLab has been successful in improving field emissions post processing. It is advantageous to pursue research in this method, allowing for possible use on modern ATLAS cryomodules, A-tank and G-tank quarter-wave resonators. The results presented show initial plasma ignition testing and plasma simulations for the coupled E and B fields, both done on a 172 MHz HWR cavity previously designed as early R&D for FRIB. Future plans are also included, laying out next steps to test plasma processing on the same HWR cavity and eventually a QWR.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB049  
About • Received ※ 05 July 2023 — Revised ※ 25 July 2023 — Accepted ※ 24 September 2023 — Issue date ※ 24 September 2023
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MOPMB050 Thermal Feedback in Coaxial SRF Cavities niobium, feedback, SRF, ECR 224
 
  • M.W. McMullin, P. Kolb, R.E. Laxdal, Z.Y. Yao
    TRIUMF, Vancouver, Canada
  • T. Junginger
    UVIC, Victoria, Canada
  
  Funding: Natural Sciences and Engineering Research Council of Canada
The phenomenon of Q-slope in SRF cavities is caused by a combination of thermal feedback and field-dependent surface resistance. There is currently no commonly accepted model of field-dependent surface resistance, and studies of Q-slope generally treat thermal feedback as a correction to whichever surface resistance model is being used. In the present study, we treat thermal feedback as a distinct physical effect whose effect on Q-slope is calculated using a novel finite-element code. We performed direct measurements of liquid helium pool boiling from niobium surfaces to obtain input parameters for the finite-element code. This code was used to analyze data from TRIUMF’s coaxial test cavity program, which has provided a rich dataset of Q-curves at temperatures between 1.7 K and 4.4 K at five different frequencies. Preliminary results show that thermal feedback makes only a small contribution to Q-slope at temperatures near 4.2 K, but has stronger effects as the bath temperature is lowered. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB050  
About • Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 09 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMB055 CEA Contribution to the PIP-II Linear Accelerator cryomodule, SRF, controls, linac 234
 
  • N. Bazin, S. Berry, J. Drant, M. Fontaine, P. Garin, H. Jenhani, A. Raut, P. Sahuquet, C. Simon
    CEA-DRF-IRFU, France
  • J. Belorgey, Q. Bertrand, P. Brédy, E. Cenni, C. Cloué, R. Cubizolles, S. Ladegaillerie, A. Le Baut, A. Moreau, O. Piquet, J. Plouin
    CEA-IRFU, Gif-sur-Yvette, France
  
  The Proton Improvement Plan II (PIP-II) that will be installed at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. CEA joined the international collaboration in 2018 and will deliver 10 low-beta cryomodules as In-Kind Contributions to the PIP-II project, with cavities supplied by LASA-INFN (Italy) and VECC-DAE (India), and power couplers and tuning systems supplied by Fermilab. An important milestone was reached in March 2023 with the Final Design Review of the cryomodule, launching the pre-production phase. This paper presents the status CEA activities on the design, manufacturing, assembly and tests of the cryomodules and the upgrade of the existing infrastructures to the PIP-II requirements.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB055  
About • Received ※ 25 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 03 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMB056 Saraf-Phase II: Test of the SRF Cavities with the First Cryomodule cryomodule, target, LLRF, MMI 238
 
  • G. Ferrand, S. Berry, D. Darde, G. Desmarchelier, F. Hassane, T.J. Joannem, S. Monnereau, N. Pichoff, O. Piquet, Th. Plaisant
    CEA-IRFU, Gif-sur-Yvette, France
  
  CEA is committed to delivering a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5 mA beam of either protons from 1.3 MeV to 35 MeV or deuterons from 2.6 MeV to 40 MeV. The SCL consists in four cryomodules. The first cryomodule hosts 6 half-wave resonator (HWR) low beta cavities (β = 0.09) at 176 MHz. The low-beta cavities were qualified in 2021, as well as the power couplers and frequency tuners. The Low-Level RF (LLRF) system was qualified in 2022 with a dedicated test stand. This contribution will present the results of the RF tests of the first SARAF cryomodule at Saclay.  
poster icon Poster MOPMB056 [1.437 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB056  
About • Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 14 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMB057 Implementation of the Test Bench for the PIP-II LB650 Cryomodules at CEA cryomodule, cryogenics, SRF, operation 243
 
  • H. Jenhani, N. Bazin, Q. Bertrand, P. Brédy, L. Maurice, O. Piquet, P. Sahuquet, C. Simon
    CEA-IRFU, Gif-sur-Yvette, France
  
  The Proton Improvement Plan II (PIP-II) at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. As a part of the French In-Kind Contributions to this project, CEA will provide ten 650 MHz low-beta cryomodules (LB650) equipped with LASA-INFN (Italy) and VECC-DAE (India) cavities and Fermilab power couplers and RF tuning systems. CEA is accordingly in charge of the design, manufacturing, assembly and testing of these cryomodules. This paper presents the future implementation of the test stand dedicated to the cryogenic and RF power testing of the LB650 cryomodules. The choice of the equipment and the current status will be detailed, as well.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB057  
About • Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 05 July 2023
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MOPMB058 Summary of the Superconducting Rf Measurements in AMTF Hall at DESY SRF, cryomodule, FEL, superconductivity 248
 
  • M. Wiencek, K. Kasprzak, D. Kostin, D. Reschke, L. Steder
    DESY, Hamburg, Germany
  
  The AMTF (Accelerator Module Test Facility) in DESY was built for the tests of all superconducting cavities and cryomodules for the EuXFEL linac. After successful commissioning of the EuXFEL, the AMTF has been adapted in order to perform SRF (super conducting radio frequency) measurements of cavities and accelerating modules for different projects. Several SRF cavities related projects are still ongoing, while other were just finished. Some of those projects are dedicated to test components for the infrastructure of accelerators which are under construction, while the other ones are devoted to new R&D paths aiming for cavities and modules with high performance which are under investigation at DESY. This paper describes present activities performed at AMTF with special emphasis on performing SRF measurements for the ongoing cavities production. Most of the presented data is related to vertical cryostat cavity testing. However, some data about cryomodules and a new coupler test stand will be shown as well. Detailed statistics about the number of vertical tests performed within the last two years are also presented.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB058  
About • Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPMB062 Optimisation of Niobium Thin Film Deposition Parameters for SRF Cavities SRF, site, target, niobium 253
 
  • D.J. Seal, O.B. Malyshev, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G. Burt
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • J.A. Conlon, O.B. Malyshev, K.T. Morrow, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  In order to accelerate the progression of thin film (TF) development for future SRF cavities, it is desirable to optimise material properties on small flat samples. Most importantly, this requires the ability to measure their superconducting properties. At Daresbury Laboratory, it has been possible for many years to characterise these films under DC conditions; however, it is not yet fully understood whether this correlates with RF measurements. Recently, a high-throughput RF facility was commissioned that uses a novel 7.8 GHz choke cavity. The facility is able to evaluate the RF performance of planar-coated TF samples at low peak magnetic fields with a high throughput rate of 2-3 samples per week. Using this facility, an optimisation study of the deposition parameters of TF Nb samples deposited by HiPIMS has begun. The ultimate aim is to optimise TF Nb as a base layer for multilayer studies and replicate planar magnetron depositions on split 6 GHz cavities. The initial focus of this study was to investigate the effect of substrate temperature during deposition. A review of the RF facility used and results of this study will be presented.  
poster icon Poster MOPMB062 [2.395 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB062  
About • Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 24 July 2023
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MOPMB063 Multipacting Processing in Cryomodules for LCLS-II and LCLS-II-HE cryomodule, linac, radiation, multipactoring 259
 
  • A.T. Cravatta, T.T. Arkan, D. Bafia, J.A. Kaluzny, S. Posen
    Fermilab, Batavia, Illinois, USA
  • S. Aderhold, M. Checchin, D. Gonnella, J. Hogan, J.T. Maniscalco, J. Nelson, R.D. Porter, L.M. Zacarias
    SLAC, Menlo Park, California, USA
  • M.A. Drury, H. Vennekate
    JLab, Newport News, Virginia, 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.
Multipacting (MP) is a phenomenon which can affect stability in particle accelerators and limit performance in superconducting radio frequency cavities. In the TESLA shaped, 1.3 GHz, 9-cell cavities used in the LCLS-II (L2) and LCLS-II-HE (HE) projects, the MP-band (~17-24 MV/m) lies within the required accelerating gradients. For HE, the operating gradient of 20.8 MV/m lies well within the MP-band and cryomodule testing has confirmed that this is an issue. As such, MP processing for the HE cryomodule test program will be discussed. Early results on MP processing in cryomodules installed in the L2 linac will also be presented, demonstrating that the methods used in cryomodule acceptance testing are also successful at conditioning MP in the accelerator and that this processing is preserved in the mid-term. 		 
poster icon Poster MOPMB063 [1.066 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB063  
About • Received ※ 25 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 30 June 2023
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MOPMB065 Design Status of BCC Cryomodule for LCLS-II HE cryomodule, simulation, solenoid, cryogenics 263
 
  • C.S. Narug, T.T. Arkan, S. Cheban, M. Chen, B.D. Hartsell, J.A. Kaluzny, V.S. Kashikhin, Y.M. Orlov
    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.
A Buncher or Capture Cavity (BCC) Cryomodule is currently in development at Fermilab for use in a second injector for LCLS-II-HE. The BCC Cryomodule is designed to contain one 1.3 GHz cavity and one solenoid magnet as part of a 100MeV low emittance injector. The design considerations for the Cryomodule are similar to the LCLS-II cryomodule with additional requirements to account for additional vacuum loading at the end of this vessel due to the termination of the insulating vacuum. To accomplish this design, the cryomodule is being developed using the experience gained during the development of the LCLS-II cryomodule. The design, analysis, and status of the Cryomodule will be discussed. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB065  
About • Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023
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MOPMB068 Loading Test of Hom Dampers for Superconducting Cavities for High Current at Superkekb HOM, SRF, superconducting-cavity, operation 271
 
  • T. Okada, K. Akai, T. Furuya, S. Mitsunobu, Y. Morita, M. Nishiwaki
    KEK, Ibaraki, Japan
  
  SuperKEKB is an e⁻e⁺ collider, which is an upgraded accelerator of KEKB with the aim to increase the luminosity by more than one order. The superconducting cavities are used in the electron ring. The superconducting cavities were designed as a HOM-damped structure for KEKB and were operated up to 1.4 A in KEKB. However, the design storage current of the electron ring for SuperKEKB is 2.6 A, which is about twice the achievement current of KEKB. The HOM power is estimated to increase from 16 kW, which is the performance value in KEKB, to over 35 kW. This large load is unacceptable for the ferrite HOM dampers mounted on both sides of the cavity. As a countermeasure, duct type SiC HOM dampers are inserted between the cavities. The HOM damper load tests were performed during normal beam operation with a maximum current of 1.1 A. The load on the downstream ferrite HOM damper decreased due to the HOM power absorbed by the upstream SiC damper. In addition, the load was found to be dependent on the beam filling pattern. We will present the results and discussion of beam tests on the loading of HOM dampers and the dependence on the beam filling pattern in SuperKEKB.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB068  
About • Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 30 June 2023
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MOPMB072 LCLS-II-HE Cavity Qualification Testing cryomodule, radiation, SRF, accelerating-gradient 279
 
  • J.T. Maniscalco, S. Aderhold, M. Checchin, D. Gonnella, J. Hogan, R.D. Porter
    SLAC, Menlo Park, California, USA
  • T.T. Arkan, D. Bafia, A.T. Cravatta, J.A. Kaluzny, S. Posen
    Fermilab, Batavia, Illinois, USA
  • M.E. Bevins, A.J. Grabowski, C.E. Reece, H. Vennekate
    JLab, Newport News, Virginia, USA
  
  Acceptance testing of the LCLS-II-HE production cavities is approximately 65% complete. In this report, we present details of the test results, including summaries of the quench fields, intrinsic quality factors, and experience with field emission. We also offer an outlook on the remaining tests to be performed.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB072  
About • Received ※ 20 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 03 July 2023 — Issue date ※ 07 July 2023
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MOPMB074 Cryomodule Storage for LCLS-II HE cryomodule, vacuum, controls, cathode 282
 
  • D.A. White, M. Checchin, D. Gonnella, J. Hogan, J.T. Maniscalco, R.D. Porter
    SLAC, Menlo Park, California, USA
  
  Funding: U.S. Department of Energy
The Linac Coherent Light Source-II High Energy (LCLS-II HE) project will upgrade the superconducting LCLS-II with 23 additional cryomodules, increasing the beam energy from 4 GeV to 8 GeV. Due to the user schedule of the existing linac, Cryomodules arriving at SLAC cannot immediately be installed in the linac. They are scheduled to be stored for up to three years before the 12-month installation window. During this storage period, the risk of damage to Cryomodules prior to installation will be mitigated with procedures and best practices incorporating experience from LCLS-II. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB074  
About • Received ※ 25 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 03 July 2023 — Issue date ※ 10 July 2023
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MOPMB075 Provision of High Beta Cavities for European Spallation Source by UKRI-STFC Daresbury Laboratory radiation, ion-source, cryomodule, accelerating-gradient 286
 
  • A.E. Wheelhouse, A.E.T. Akintola, A.J. Blackett-May, M.J. Ellis, S. Hitchen, P.C. Hornickel, C.R. Jenkins, P.A. McIntosh, K.J. Middleman, S.M. Pattalwar, M.D. Pendleton, J.O.W. Poynton, I.M. Skachko, P.A. Smith, S. Wilde
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • M. Lowe, D.A. Mason, G. Miller, J. Mutch, A. Oates, N. Templeton, J.T.G. Wilson
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • D. Reschke, L. Steder, M. Wiencek
    DESY, Hamburg, Germany
  
  As part of the requirement for the European Spallation Source (ESS) facility in Lund, Sweden, a project has been undertaken by Accelerator Science and Technology Cen-tre (ASTeC) as part of a UK In Kind Contribution to pro-vide 84 704 MHz High-Beta superconducting RF cavities. The project has included the procurement of niobium and the testing of cavities at Daresbury Laboratory and Deutsches Elektronen-Synchrotron (DESY), in prepara-tion for integration into the cryomodules which is being performed at Commissariat à l¿Energie Atomique et aux Energies Alternatives (CEA) Saclay, France. To date all the cavities have been manufactured in industry apart from the final cavity and 3 cavities remain to be tested. An overview of the experiences for the provision of these cavities is described.  
poster icon Poster MOPMB075 [1.428 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB075  
About • Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 08 July 2023
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MOPMB076 Surface Characterization Studies of Gold-Plated Niobium niobium, controls, site, radio-frequency 290
 
  • S.G. Seddon-Stettler, M. Liepe, T.E. Oseroff, Z. Sun
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • N. Sitaraman
    Cornell University, Ithaca, New York, USA
  
  Funding: The National Science Foundation, Grant No. PHY-1549132
The native niobium oxide layer present on niobium has been shown to affect the performace of superconducting RF cavities. Extremely thin layers of gold on the surface of niobium have the potential to suppress surface oxidation and improve cavity performance. However, depositing uniform layers of gold at the desired thickness (sub-nm) is difficult, and different deposition methods may have different effects on the gold surface, on the niobium surface, and on the interface between the two. In particular, the question of whether gold deposition actually passivates the niobium oxide is extremely relevant for assessing the potential of gold deposition to improve RF performance. This work builds on previous research studying the RF performance of gold/niobium bilayers with different gold layer thicknesses. We here consider alternative methods to characterize the composition and chemical properties of gold/niobium bilayers to supplement the previous RF study. 		 
poster icon Poster MOPMB076 [1.536 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB076  
About • Received ※ 25 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 03 July 2023
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MOPMB078 Design and Prototyping of the Electron Ion Collider Electron Storage Ring SRF Cavity simulation, HOM, operation, electron 293
 
  • J. Guo, E.F. Daly, E. Drachuk, R.R. Fernandes, J. Henry, J. Matalevich, G.-T. Park, R.A. Rimmer, D. Savransky
    JLab, Newport News, Virginia, USA
  • D. Holmes, K.S. Smith, W. Xu, A. Zaltsman
    BNL, Upton, New York, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177
Among the EIC¿s numerous RF subsystems, the electron storage ring¿s (ESR) 591 MHz fundamental RF system is one of the most challenging. Each cavity in the system will handle up to 2.5 A of beam current and supply up to 600 kW beam power under a wide range of voltage. The EIC R&D plan includes the design, fabrication and testing of such a cavity. In this paper, we will report the latest status and findings of the ongoing design and prototyping of this cavity, including the RF and mechanical/thermal design, fabrication design, and the progress of fabrication. 		 
poster icon Poster MOPMB078 [1.489 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB078  
About • Received ※ 12 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 19 July 2023
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MOPMB081 Microphonics in the LCLS-II Superconducting Linac cryomodule, linac, operation, vacuum 302
 
  • R.D. Porter, S. Aderhold, L.E. Alsberg, D. Gonnella, J. Nelson, N.R. Neveu, L.M. Zacarias
    SLAC, Menlo Park, California, USA
  • A.T. Cravatta, J.P. Holzbauer, S. Posen
    Fermilab, Batavia, Illinois, USA
  • M.A. Drury, M.D. McCaughan, C.M. Wilson
    JLab, Newport News, Virginia, USA
  • G. Gaitan, N.A. Stilin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: Work supported by the LCLS-II project
The LCLS-II project has installed a new superconducting linac at SLAC that consists of 35 1.3 GHz cryomodules and 2 3.9 GHz cryomodules. The linac will provide a 4 GeV electron beam for generating soft and hard X-ray pulses. Cavity detuning induced by microphonics was a significant design challenge for the LCLS-II cryomodules. Cryomodules were produced that were within the detuning specification (10 Hz for 1.3 GHz cryomodules) on test stands. Here we present first measurements of the microphonics in the installed LCLS-II superconducting linac. Overall, the microphonics in the linac are manageable with 94% of cavities coming within the detune specification. Only two cavities are gradient limited due to microphonics. We identify a leaking cool down valve as the source of microphonics limiting those two cavities. 		 
poster icon Poster MOPMB081 [1.284 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB081  
About • Received ※ 18 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 01 July 2023
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MOPMB082 SRF Accelerating Modules Upgrade for Flash Linac at DESY SRF, FEL, linac, radiation 306
 
  • D. Kostin, S. Barbanotti, J. Eschke, K. Jensch, N. Krupka, A. Muhs, D. Reschke, S. Saegebarth, J. Schaffran, P. Schilling, M. Schmökel, L. Steder, N. Steinhau-Kühl, A. Sulimov, E. Vogel, H. Weise, M. Wiencek, B. van der Horst
    DESY, Hamburg, Germany
  
  SRF accelerating modules with 8 TESLA-type 1.3 GHz SRF cavities are the main part of the linear accelerators currently in user operation at DESY, FLASH [1, 2] and the European XFEL [3, 4]. For the FLASH upgrade in 2022 [5] two accelerating modules have been exchanged in order to enhance the beam energy to 1.3 GeV. The two modules have been prototype modules for the European XFEL. After reassembly both modules were successfully tested and installed in the FLASH linac. Data taken during the commissioning at the end of 2022 did confirm the test results. This paper presents described efforts and their conclusions since last two years and continues the presentation given at SRF 2021 [6].  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB082  
About • Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 27 June 2023
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MOPMB083 Investigation of the Multilayer Shielding Effect through NbTiN-AlN Coated Bulk Niobium site, SRF, niobium, shielding 311
 
  • I.H. Senevirathne, J.R. Delayen, A.V. Gurevich
    ODU, Norfolk, Virginia, USA
  • D.R. Beverstock, J.R. Delayen, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  • D.R. Beverstock
    The College of William and Mary, Williamsburg, Virginia, USA
  
  We report measurements of the dc field onset Bp of magnetic flux penetration through NbTiN-AlN coating on bulk niobium using the Hall probe experimental setup. The measurements of Bp reveal the multilayer shielding effect on bulk niobium under high magnetic fields at cryogenic temperatures. We observed a significant enhancement in Bp for the NbTiN-AlN coated Nb samples as compared to bare Nb samples. The observed dependence of Bp on the coating thickness is consistent with theoretical predictions.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB083  
About • Received ※ 18 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 12 August 2023
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MOPMB086 Development of Non-Destructive Beam Envelope Measurements in SRILAC with Low Beta Heavy Ion Beams Using BPMs simulation, quadrupole, operation, heavy-ion 319
 
  • T. Nishi, O. Kamigaito, N. Sakamoto, T. Watanabe, K. Yamada
    RIKEN Nishina Center, Wako, Japan
  • T. Adachi
    RIKEN, Saitama, Japan
  
  The RIKEN SRILAC* has been providing heavy ion beams of a few puA for the synthesis of new superheavy elements since June 2020, utilizing 10 superconducting quarter-wavelength resonators (SC-QWRs). Although the beam supply has been stable, it is crucial to measure and control the beam dynamics in the SRILAC to increase the beam intensity up to 10 puA. However, destructive monitors cannot be used to avoid the generation of dust particles and outgassing. Beam has been precisely tuned by monitoring the beam center using Beam Energy Position Monitors (BEPMs)** and the reactions of vacuum monitors. In our study, we are developing a method for estimating the beam envelope by combining the quadrupole moments from BEPMs, which consist of four cosine-shape electrodes, with calculations of the transfer matrix***. While this method has been applied to electron and proton beams, it has not been practically demonstrated for heavy ion beams in beta – 0.1 regions. By combining BEPM simulations, we are making the progress towards the reproduction of experimental results, overcoming specific issues associated with low beta. We will report on the current status of our developments.
* K. Yamada et al., in Proc. SRF’21, paper MOOFAV01(2021).
** T. Watanabe et al., in Proc. IBIC’20, paper FRAO04 (2020).
*** R. H. Miller et al., in Proc. HEAC’83, pp. 603–605 (1983). 		 
poster icon Poster MOPMB086 [10.338 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB086  
About • Received ※ 30 June 2023 — Revised ※ 01 July 2023 — Accepted ※ 19 August 2023 — Issue date ※ 22 August 2023
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MOPMB089 Installation of LCLS-II Cryomodules cryomodule, vacuum, hardware, MMI 324
 
  • D.A. White, S. Aderhold, R. Coy, D. Gonnella
    SLAC, Menlo Park, California, USA
  
  Funding: U.S. Department of Energy
The Linac Coherent Light Source II (LCLS-II) super-conducting accelerator is fully installed and operational. Cryomodules were designed and manufactured by Fermi National Accelerator Laboratory (FNAL) and Thomas Jefferson National Laboratory (JLab) during 2017-2020. From November 2018 through March 2021, SLAC Na-tional Accelerator Laboratory installed 37 Cryomodules. Full system cooldown was completed in March 2022. Installation processes were optimized at SLAC for best quality, especially during particle-free and UHV assem-bly. These processes and successful Cavity and Cry-omodule manufacturing resulted in installed gradient exceeding design requirements by more than 20%. No statistical variation in field emission onsets or magni-tudes were observed between manufacturing and site testing. This paper summarizes SLAC experience during installation, and relevant testing results. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB089  
About • Received ※ 20 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 July 2023
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MOPMB090 Measuring Q₀ in LCLS-II Cryomodules Using Helium Liquid Level cryomodule, linac, MMI, SRF 327
 
  • L.M. Zacarias, S. Aderhold, D. Gonnella, J.T. Maniscalco, J. Nelson, R.D. Porter
    SLAC, Menlo Park, California, USA
  • A.T. Cravatta, J.P. Holzbauer, S. Posen
    Fermilab, Batavia, Illinois, USA
  • M.A. Drury, M.D. McCaughan, C.M. Wilson
    JLab, Newport News, Virginia, USA
  
  The nitrogen-doped cavities used in the Linac Coherent Light Source II (LCLS-II) cryomodules have shown an unprecedented high Q₀ in vertical and cryomodule testing compared with cavities prepared with standard methods. While demonstration of high Q₀ in the test stand has been achieved, maintaining that performance in the linac is critical to the success of LCLS-II and future accelerator projects. The LCLS-II cryomodules required a novel method of measuring Q₀, due to hardware incompatibilities with existing procedures. Initially developed at Jefferson Lab during cryomodule acceptance testing before being used in the tunnel at SLAC, we use helium liquid level data to estimate the heat generated by cavities. We first establish the relationship between the rate of helium evaporation from known heat loads using electric heaters, and then use that relationship to determine heat from an RF load. Here we present the full procedure along with the development process, lessons learned, and reproducibility while demonstrating for the first time that world record Q₀ can be maintained within the real accelerator environment.  
poster icon Poster MOPMB090 [1.867 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB090  
About • Received ※ 20 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 13 July 2023
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MOPMB092 Performance of Contaminated Superconducting Linac after Vacuum Excursion cryomodule, vacuum, ISAC, linac 332
 
  • Z.Y. Yao, R.E. Laxdal
    TRIUMF, Vancouver, Canada
  
  ISAC-II superconducting heavy ion linac is the high energy section of TRIUMF ISAC facility to accelerate rare isotopes with A/q <= 6 from 1.5 MeV/u to above the Cou-lomb barrier for experiments. There was a vacuum excur-sion caused by an operational error and the failure of the fast protection system in summer 2022. The beamline downstream to the SC linac was vented with atmosphere air from the experimental hall resulting in pollution of the linac. This paper reports the RF performance of the con-taminated linac. The typical cavity performance changes, the average magnitude of degradation, the impact range in the SC linac, the observations in the recovery processes and the analyses on the most distinct cavity are discussed. The cavity refurbishment in the recent winter shutdown with the observations and outcomes is also reported. The ISAC-II event provided a unique data set for the SRF community.  
poster icon Poster MOPMB092 [6.186 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB092  
About • Received ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023  
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MOPMB093 Optimizing Growth of Niobium-3 Tin Through Pre-nucleation Chemical Treatments site, niobium, SRF, controls 337
 
  • S.G. Arnold, G. Gaitan, M. Liepe, L. Shpani, Z. Sun
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • T. Arias, N. Sitaraman
    Cornell University, Ithaca, New York, USA
  
  Funding: This work was supported by the U.S. National Science Foundation under award PHY-1549132, the Center for Bright Beams.
Nb₃Sn is a promising alternative material for SRF cavities that is close to reaching practical applications. To date, one of the most effective growth methods for this material is vapor diffusion, yet further improvement is needed for Nb₃Sn to reach its full potential. The major issues faced by vapor diffusion are tin depleted regions and surface roughness, both of which lead to impaired performance. Literature has shown that the niobium surface oxide plays an important role in the binding of tin to niobium. In this study, we performed various chemical treatments on niobium samples pre-nucleation to enhance tin nucleation. We quantify the effect that these various treatments had through scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). These methods reveal information on tin nucleation density and uniformity, and a thin tin film present on most samples, even in the absence of nucleation sites. We present our findings from these surface characterization methods and introduce a framework for quantitatively comparing the samples. We plan to apply the most effective treatment to a cavity and conduct an RF test soon. 		 
poster icon Poster MOPMB093 [1.118 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB093  
About • Received ※ 21 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 26 July 2023
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MOPMB094 Design of a 1.3 GHz High-Power RF Coupler for Conduction-Cooled Systems SRF, cryomodule, radio-frequency, operation 342
 
  • N.A. Stilin, A.T. Holic, M. Liepe, T.I. O’Connell, P. Quigley, J. Sears, V.D. Shemelin, J. Turco
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Cornell is designing a new standalone, compact SRF cryomodule which uses cryocoolers in place of liquid helium for cooling. One of the biggest challenges in implementing such a system is designing a high-power input coupler which is able to be cooled by the cryocoolers without any additional liquid cryogenics. Due to the limited heat load capacity of the cryocoolers at 4.2 K, this requires very careful thermal isolation of the 4.2 K portion of the coupler and thorough optimization of the RF behavior to minimize losses. This paper will present the various design considerations which enabled the creating of a conduction-cooled 1.3 GHz input coupler capable of delivering up to 100 kW CW RF power.  
poster icon Poster MOPMB094 [0.964 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB094  
About • Received ※ 16 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 23 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUIAA01 Twenty Years of Cryogenic Operation of the Flash Superconducting Linac cryomodule, linac, FEL, operation 347
 
  • S. Barbanotti, DESY. Abassi, Y. Bozhko, K. Honkavaara, K. Jensch, D. Kostin, S. Lederer, T. Schnautz, S. Schreiber, A. Wagner, H. Weise
    DESY, Hamburg, Germany
  • J. Roßbach
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • J. Zajac
    Linde Kryotechnik AG, Büro DESY Hamburg, Hamburg, Germany
  
  The FLASH superconducting linac is in operation at DESY since more than 20 years. Many changes and upgrades took place to transform a test stand for single cryomodules to a successful free electron laser. We summarize here the main steps of the FLASH history from the cryogenic point of view including the latest major upgrade that took place in 2022. We also give an overview of cryomodule performances like cavity gradient and heat load measurements and their evolution over the time.  
slides icon Slides TUIAA01 [6.861 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUIAA01  
About • Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 20 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUIBA01 A Three-Fluid Model of Dissipation at Surfaces in Superconducting Radiofrequency Cavities scattering, electron, niobium, SRF 361
 
  • M.M. Kelley, T. Arias, S. Deyo, D. Liarte, J.P. Sethna, N. Sitaraman
    Cornell University, Ithaca, New York, USA
  • M. Liepe, T.E. Oseroff
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: This work was supported by the U.S. National Science Foundation under Award PHY-1549132, the Center for Bright Beams.
Experiments on superconducting cavities have found that under large RF fields the quality factor can improve with increasing field amplitude, a so-called anti-Q slope. We numerically solve the Bogoliubov-de Gennes equations at a superconducting surface in a parallel magnetic field, finding at large fields there are surface quasiparticle states with energies below the bulk superconducting gap that emerge and disappear as the field cycles. Modifying the standard two-fluid model, we introduce a ‘‘three’’-fluid model where we partition the normal fluid to consider continuum and surface quasiparticle states separately. We compute dissipation in a semi-classical theory of conductivity, where we provide physical estimates of elastic scattering times of Bogoliubov quasiparticles with point-like impurities having potential strengths informed from complementary ab initio calculations of impurities in bulk niobium. We show, in this simple yet effective framework, how the relative scattering rates of surface and continuum quasiparticle states can play a role in producing an anti-Q slope while demonstrating how this model naturally includes a mechanism for turning the anti-Q slope on and off.
S. Deyo, M. Kelley et al. Phys. Rev. B 106, 104502 (2022) 		 
slides icon Slides TUIBA01 [2.019 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUIBA01  
About • Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 08 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUCBA01 Measurements of the Amplitude-Dependent Microwave Surface Resistance of a Proximity-Coupled Au/Nb Bilayer niobium, factory, SRF, extraction 369
 
  • T.E. Oseroff, M. Liepe, Z. Sun
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  A sample host cavity is used to measure the surface resistance of a niobium substrate with a gold film deposited in place of its surface oxide. This talk will report about this measurement result. The film thickness of the gold layer was increased from 0.1 nm to 2.0 nm in five steps to study the impact of the normal layer thickness. The 0.1 nm film was found to reduce the surface resistance below its value with the surface oxide present and to enhance the quench field. The magnitude of the surface resistance increased substantially with gold film thickness. The surface resistance field-dependence appeared to be independent from the normal layer thickness. The observations reported in this work have profound implications for both low-field and high-field S.C. microwave devices. By controlling or eliminating the niobium oxide using a gold layer to passivate the niobium surface, it may be possible to improve the performance of SRF cavities used for particle acceleration. This method to reduce surface oxidation while maintaining low surface resistance could also be relevant for minimizing dissipation due to two-level systems observed in low-field low-temperature devices.  
slides icon Slides TUCBA01 [2.292 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUCBA01  
About • Received ※ 19 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 26 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUCXA01 Study of the Dynamics of Flux Trapping in Different SRF Materials experiment, ECR, niobium, controls 380
 
  • F. Kramer, S. Keckert, J. Knobloch, O. Kugeler
    HZB, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
  • T. Kubo
    KEK, Ibaraki, Japan
  
  A dedicated experimental setup to measure magnetic flux dynamics and trapped flux in samples is used to precisely map out how trapped flux is influenced by different parameters. The setup allows for rapid thermal cycling of the sample so that effects of cooldown parameters can be investigated in detail. We show how temperature gradient, cooldown rate, and the magnitude of external field influence trapped flux in large grain, fine grain and coated niobium samples. The detailed measurements show unexpected results, namely that too fast cooldowns increase trapped flux, large grain material traps flux only when the external field is larger than a temperature gradient dependent threshold field, and the measured dependence of trapped flux on temperature gradient does not agree with an existing model. Therefore, a new model is presented which agrees better with the measured results.  
slides icon Slides TUCXA01 [3.180 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUCXA01  
About • Received ※ 17 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 26 June 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB001 Demonstration of Niobium Tin in 218 MHz Low-Beta Quarter Wave Accelerator Cavity niobium, multipactoring, SRF, vacuum 388
 
  • T.B. Petersen, G. Chen, B.M. Guilfoyle, M. Kedzie, M.P. Kelly, T. Reid
    ANL, Lemont, Illinois, USA
  • G.V. Eremeev, S. Posen, B. Tennis
    Fermilab, Batavia, Illinois, USA
  
  A 218 MHz quarter wave niobium cavity has been fabricated for the purpose of demonstrating Nb₃Sn technology on a low-beta accelerator cavity. Niobium-tin has been established as a promising next generation SRF material, but development has focused primarily in high-beta elliptical cell cavities. This material has a significantly higher TC than niobium, allowing for design of higher frequency quarter wave cavities (that are subsequently smaller) as well as for significantly lowered cooling requirements (possibly leading to cryocooler based de-signs). The fabrication, initial cold testing, and Nb₃Sn coating are discussed as well as test plans and details of future applications.  
poster icon Poster TUPTB001 [0.653 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB001  
About • Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 08 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB002 Modelling Trapped Flux in Niobium ECR, experiment, niobium, controls 393
 
  • F. Kramer, S. Keckert, J. Knobloch, O. Kugeler
    HZB, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
  • T. Kubo
    KEK, Ibaraki, Japan
  
  Detailed measurements of magnetic flux dynamics and trapped magnetic flux in niobium samples were conducted with a new experimental setup that permits precise control of the cooldown parameters. With this setup the dependency of trapped flux on the temperature gradient, external magnetic field, and cooldown rate can be mapped out in more detail compared to cavity measurements. We have obtained unexpected results, and an existing model describing trapped flux in dependence of temperature gradient does not agree with the measured data. Therefore, a new model is developed which describes the magnitude of trapped flux in dependence of the temperature gradient across the sample during cooldown. The model describes the amount of trapped flux lines with help of a density distribution function of the pinning forces of pinning centers and the thermal force which can de-pin flux lines from pinning centers. The model shows good agreement with the measured data and correctly predicts trapped flux at different external flux densities.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB002  
About • Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB006 Materials Design for Superconducting RF Cavities: Electroplating Sn, Zr, and Au onto Nb and and Chemical Vapor Deposition SRF, plasma, controls, niobium 401
 
  • Z. Sun, M. Liepe, T.E. Oseroff
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • Z. Baraissov, D.A. Muller, M.O. Thompson
    Cornell University, Ithaca, New York, USA
  
  Funding: This work was supported by the U.S. National Science Foundation under Award PHY-1549132, the Center for Bright Beams.
Materials scientists seek to contribute to the development of next-generation superconducting radio-frequency (SRF) accelerating cavities. Here, we summarize our achievements and learnings in designing advanced SRF materials and surfaces, including Nb₃Sn [1¿3], ZrNb(CO) [4, 5], and Au/Nb surface design [6,7]. Our efforts involve electrochemical synthesis, phase transformation, and surface chemistry, which are closely coupled with superconducting properties, SRF performance, and engineering considerations. We develop electrochemical processes for Sn, Zr, and Au on the Nb surface, an essential step in our investigation for producing high-quality Nb₃Sn, ZrNb(CO), and Au/Nb structures. Additionally, we design a custom chemical vapor deposition system to offer additional growth options. Notably, we find the second-phase NbC formation in ZrNb(CO) and in ultra-high-vacuum baked or nitrogen-processed Nb. We also identify low-dielectric-loss ZrO2 on Nb and NbZr(CO) surfaces. These advancements provide materials science approaches dealing with fundamental and technical challenges to build high-performance, multi-scale, robust SRF cavities for particle accelerators and quantum applications. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB006  
About • Received ※ 30 June 2023 — Revised ※ 11 August 2023 — Accepted ※ 20 August 2023 — Issue date ※ 21 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB010 Preservation of the High Quality Factor and Accelerating Gradient of Nb₃Sn-Coated Cavity During Pair Assembly SRF, accelerating-gradient, cryomodule, niobium 405
 
  • G.V. Eremeev, S. Cheban, S. Posen, B. Tennis
    Fermilab, Batavia, Illinois, USA
  • J.F. Fischer, D. Forehand, U. Pudasaini, A.V. Reilly, R.A. Rimmer
    JLab, Newport News, Virginia, 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.
Two CEBAF 5-cell accelerator cavities have been coated with Nb₃Sn film using the vapor diffusion technique. One cavity was coated in the Jefferson Lab Nb₃Sn cavity coating system, and the other in the Fermilab Nb₃Sn coating system. Both cavities were measured at 4 K and 2 K in the vertical dewar test in each lab and then assembled into a cavity pair at Jefferson Lab. Previous attempts to assemble Nb₃Sn cavities into a cavity pair degraded the superconducting properties of Nb₃Sn-coated cavities. This contribution discusses the efforts to identify and mitigate the pair assembly challenges and will present the results of the vertical tests before and after pair assembly. Notably, one of the cavities reached the highest gradient above 80 mT in the vertical test after the pair assembly. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB010  
About • Received ※ 23 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 02 July 2023 — Issue date ※ 09 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB013 Commissioning of a New Sample Test Cavity for Rapid RF Characterization of SRF Materials niobium, MMI, SRF, operation 410
 
  • S. Keckert, J. Knobloch, F. Kramer, O. Kugeler
    HZB, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
  
  RaSTA, the Rapid Superconductor Test Apparatus, is a new sample test cavity that is currently being commissioned at HZB. It uses the established QPR sample geometry but with a much smaller cylindrical cavity operating in the TM020 mode at 4.8 GHz. Its compact design allows for smaller cryogenic test stands and reduced turnaround time, enabling iterative measurement campaigns for thin film R&D. Using the same calorimetric measurement technique as known from the QPR allows direct measurements of the residual resistance. We report first prototype results obtained from a niobium sample that demonstrate the capabilities of the system.  
poster icon Poster TUPTB013 [0.464 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB013  
About • Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 28 June 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB014 Development of Nb₃Sn Coating System and RF Measurement Results at KEK SRF, radio-frequency, accelerating-gradient, controls 414
 
  • H. Ito, H. Sakai, K. Umemori, T. Yamada
    KEK, Ibaraki, Japan
  • K. Takahashi
    Sokendai, Ibaraki, Japan
  
  We have constructed an Nb₃Sn cavity coating system based on the Sn vapor diffusion method. After the construction, improvement of our coating system and environment has been conducted through sample and cavity coating research. Our cavity achieves a Q-value above 1E10 at 4 K after improvement. We will report on the detail of improvement on our coating system and RF measurement results of single-cell Nb₃Sn cavity.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB014  
About • Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 28 June 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB016 Summary of the FRIB Electropolishing Facility Design and Commissioning, Cavity Processing, and Cavity Test Results cathode, MMI, power-supply, controls 419
 
  • E.S. Metzgar, B.W. Barker, K. Elliott, J.D. Hulbert, C. Knowles, L. Nguyen, A.R. Nunham, L. Popielarski, A.T. Taylor, T. Xu
    FRIB, East Lansing, Michigan, USA
  
  Funding: U.S. Department of Energy, Office of Science, Office of Nuclear Physics and used resources of the FRIB, which is a DOE Office of Science User Facility, under Award Number DE-SC0000661.
Recently, a new Electropolishing (EP) facility was con-structed and commissioned at the Facility for Rare Isotope Beam (FRIB) with the purpose of supporting advanced surface processing techniques for SRF R&D activities. The FRIB production cavities opted for a Buffered Chemical Polish (BCP) method due to its cost effectiveness and was supported by successful outcomes in other facilities with low beta cavities in a similar frequency range. All 324 cavities used in FRIB Linac were processed in-house at MSU using BCP and exhibited satisfactory performance during testing. As part of the FRIB energy upgrade R&D, 5-cell 644 MHz elliptical resonators will be employed, desiring the use of EP and advanced techniques such as nitrogen doping and medium-T baking. The EP facility is designed to accommodate all types of cavities used in FRIB and possesses the capability for performing EP at low temperatures. Here we report the details of design and commissioning of the EP facility, highlights of encountered issues and subsequent improvements, and preliminary results from vertical tests conducted on the cavities. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB016  
About • Received ※ 15 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 14 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB018 MgB₂ Coating Parameter Optimization Using a 1.3-GHz 1-Cell Cavity SRF, controls, experiment, vacuum 425
 
  • T. Tajima, T.P. Grumstrup, J.D. Thompson
    LANL, Los Alamos, New Mexico, USA
  • H. Ito, E. Kako, T. Okada, H. Sakai, K. Umemori
    KEK, Ibaraki, Japan
  
  Funding: DOE Office of Science, Office of High Energy Physics
We have started parameter optimization for the coating of MgB₂ using a 1-cell 1.3-GHz elliptical cavity with holes for small samples. Our coating method is based on a 2-step technique, i.e., coat a B layer by flowing diborane gas in the first step and react it with Mg vapor in the 2nd step. Three 6 mm x 6 mm B-coated flat samples are attached at inlet, outlet beam pipes, and at a cell equator and reacted with Mg vapor with different parameters and conditions. We started to see the superconducting transitions on samples but Tc is still lower than our goal of >35 K. We will present our current status of B-Mg reaction tests and construction of B coating system. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB018  
About • Received ※ 06 July 2023 — Revised ※ 26 July 2023 — Accepted ※ 02 September 2023 — Issue date ※ 03 September 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB019 First Results from Nb₃Sn Coatings of 2.6 GHz Nb SRF Cavities Using DC Cylindrical Magnetron Sputtering System SRF, site, vacuum, MMI 429
 
  • M.S. Shakel, H. Elsayed-Ali
    ODU, Norfolk, Virginia, USA
  • G.V. Eremeev
    Fermilab, Batavia, Illinois, USA
  • U. Pudasaini, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  
  Funding: Supported by DOE, Office of Accelerator R&D and Production, Contact No. DE-SC0022284, with partial support by DOE, Office of Nuclear Physics DE-AC05-06OR23177, Early Career Award to G. Eremeev.
A DC cylindrical magnetron sputtering system has been commissioned and operated to deposit Nb₃Sn onto 2.6 GHz Nb SRF cavities. After optimizing the deposition conditions in a mock-up cavity, Nb-Sn films are deposited first on flat samples by multilayer sequential sputtering of Nb and Sn, and later annealed at 950 °C for 3 hours. X-ray diffraction of the films showed multiple peaks for the Nb₃Sn phase and Nb (substrate). No peaks from any Nb-Sn compound other than Nb₃Sn were detected. Later three 2.6 GHz Nb SRF cavities are coated with ~1 µm thick Nb₃Sn. The first Nb₃Sn coated cavity reached close to Eacc = 8 MV/m, demonstrating a quality factor Q₀ of 3.2 × 108 at Tbath = 4.4 K and Eacc = 5 MV/m, about a factor of three higher than that of Nb at this temperature. Q₀ was close to 1.1 × 109, dominated by the residual resistance, at 2 K and Eacc = 5 MV/m. The Nb₃Sn coated cavities demonstrated Tc in the range of 17.9 ¿ 18 K. Here we present the commissioning experience, system optimization, and the first results from the Nb₃Sn fabrication on flat samples and SRF cavities. 		 
poster icon Poster TUPTB019 [1.216 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB019  
About • Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 10 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB020 Surface Properties and RF Performance of Vapor Diffused Nb₃Sn on Nb after Sequential Anneals below 1000 °C SRF, ECR, electron, experiment 433
 
  • J.K. Tiskumara, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • G.V. Eremeev
    Fermilab, Batavia, Illinois, USA
  • U. Pudasaini
    JLab, Newport News, Virginia, USA
  
  Nb₃Sn is a next-generation superconducting material that can be used for future superconducting radiofrequency (SRF) accelerator cavities, promising better performance, cost reduction, and higher operating temperature than Nb. The Sn vapor diffusion method is currently the most preferred and successful technique to coat niobium cavities with Nb₃Sn. Among post-coating treatments to optimize the coating quality, higher temperature annealing without Sn is known to degrade Nb₃Sn because of Sn loss. We have investigated Nb₃Sn/Nb samples briefly annealed at 800-1000 °C, for 10 and 20 minutes to potentially improve the surface to enhance the performance of Nb₃Sn-coated cavities. Following the sample studies, a coated single-cell cavity was sequentially annealed at 900 °C and tested its performance each time, improving the cavity’s quality factor relatively. This paper summarizes the sample studies and discusses the RF test results from sequentially annealed SRF Nb₃Sn/Nb cavity.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB020  
About • Received ※ 19 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 01 July 2023 — Issue date ※ 07 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB024 Cobotisation of ESS Cryomodule Assembly at CEA operation, cryomodule, MMI, SRF 438
 
  • S. Berry, A. Bouygues, J. Drant, C. Madec
    CEA-DRF-IRFU, France
  • A. Gonzalez-Moreau, C. Servouin
    CEA-IRFU, Gif-sur-Yvette, France
  
  The assembly of cavity string in the clean room is a tedious work that has noisy and painful steps such as cleaning the taped holes of a part. CEA together with the company INGELIANCE has developed a cobot: a collaborative robot operated by an technician one time and repeating the action without the operator. The cobot can work anytime without any operators : therefore it is working at night reducing the assembly duration by some hours. The cobot consists of a FANUC CRX10 a 6-axis arm on an Arvis cart. At CEA, the cobot is used to blow the flange holes of the cavities and bellows. This allows to reduce the noisy steps that the technicians are exposed to. The process is also more reproducible since the cobot does always the same steps. The cobot is used on ESS cavity string to clean the coupler and cavity flanges. Our activities and results will be presented in this poster.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB024  
About • Received ※ 18 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 03 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB025 Preparation of the Assembly of the 650 MHz Low Beta Cryomodules for the PIP-II Linear Accelerator cryomodule, alignment, vacuum, feedback 442
 
  • J. Drant, N. Bazin, S. Berry, A. Raut
    CEA-DRF-IRFU, France
  • R. Cubizolles, A. Moreau
    CEA-IRFU, Gif-sur-Yvette, France
  
  The Proton Improvement Plan II (PIP-II) that will be installed at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. CEA¿s scope covers the supply of the 650 MHz low-beta cryomodule sections with the cavities provided by LASA-INFN (Italy) and VECC-DAE (India) as well as the power couplers supplied by Fermilab. This scope includes the assembly of the 650 MHz low-beta cryomodules. Assembly studies have been conducted based on CEA experience acquired on previous projects as well as on the feedback of Fermilab on the assembly of the HB650 prototype cryomodule. This paper presents the organization of assembly phases from the cavity string in the clean room and the assembly of the cryostat to the preparation of the cryomodule before its shipment to Fermilab.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB025  
About • Received ※ 16 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 07 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB026 Measurements of High Values of Dielectric Permittivity Using Transmission Lines GUI, resonance, simulation, higher-order-mode 447
 
  • V.D. Shemelin, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Funding: DOE
Usage of lossy materials is necessary for absorption of higher order modes excited in the RF cavities. Presently, measurements of lossy materials with usage of transmission lines give errors rapidly increasing with increase of the dielectric permittivity. A method is presented for measurements of high values of dielectric permittivity epsilon in a waveguide at high frequencies with lower errors. This method supplements the method of measurements evolved for low values of epsilon and is close to resonant methods, when a sample is placed into a cavity and the measurement is done at one only frequency. The new approach with use of Microwave Studio simulations makes possible to measure this value in several frequency points at one measurement. 		 
poster icon Poster TUPTB026 [0.872 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB026  
About • Received ※ 20 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB027 Cleanroom Assembly of the LIPAc Cryomodule solenoid, SRF, cryomodule, pick-up 452
 
  • J.K. Chambrillon, P. Cara, Y. Carin, G. Duglue, H. Dzitko, D. Gex, G. Phillips, F. Scantamburlo
    Fusion for Energy, Garching, Germany
  • N. Bazin, N. Chauvin
    CEA-DRF-IRFU, France
  • Y. Carin, D. Gex, K. Masuda, F. Scantamburlo, M. Sugimoto
    IFMIF/EVEDA, Rokkasho, Japan
  • T. Ebisawa, K. Hasegawa, K. Kondo, K. Masuda, M. Sugimoto, T.Y. Yanagimachi
    QST Rokkasho, Aomori, Japan
  • D. Jimenez-Rey, J. Mollá, I. Podadera
    CIEMAT, Madrid, Spain
  • E. Kako, H. Sakai
    KEK, Ibaraki, Japan
  • W.-D. Möller
    Private Address, Hamburg, Germany
  
  In complement to the development activities for fusion reactors (JT-60SA & ITER), Fusion for Energy contributes to the R&D for material characterisation facilities. LIPAc is the technical demonstrator for the production and acceleration of a D+ beam that will be used for neutron production by nuclear stripping reaction on a liquid Li target. Since its first beam in 2014, the LIPAc construction and commissioning continues and will be concluded with the cryomodule installation, aiming for beam validation at nominal power. The cryomodule assembly, started in March 2019, was paused due to welding issues on the solenoid bellows. The slow pumping group used for the cleanroom assembly also needed improvement to overcome helium contamination. Two and half years were devoted to the pumping improvement and, repair, cold tests and high pressure rinsing of the solenoids. In August 2022, the cleanroom assembly resumed with the mounting of all power couplers to the SRF cavities. Despite good progress, the assembly had to be paused again to fix leaks on different vacuum components and a solenoid BPM port. This paper presents the issues faced and their solutions along the cold mass assembly.  
poster icon Poster TUPTB027 [2.384 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB027  
About • Received ※ 15 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 16 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB029 Measurement of Particulates under Slow Pumping after High Pressure Rinsing of Superconducting Cavity by Using Modified Slow Pumping System vacuum, controls, cryomodule, SRF 458
 
  • H. Sakai, E. Kako, R. Katayama, K. Umemori
    KEK, Ibaraki, Japan
  
  Funding: This research was partially supported by the research fund from Ministry of Education, Culture, Sports, Science and Technology (MEXT).
Slow pumping system was used for particle free vacuum pumping in Superconducting rf accelerator. In KEK, recently slow pumping system was developed for the cryomodule assembly work for STF 9-cell cavities and worked well to reduce the particulates movements under pumping. However, this slow pumping system want to be used for preparation of vertical test. Before assembly work in clean room for vertical test, we normally apply high pressure rinsing. There were many waters in the cavity. Therefore, we kept one night to dry inside cavity in clean room. Unfortunately, there were some waters in the cavity even though we kept drying in clean room for one night. This water might make some icing under pumping and stop pumping in mass flow meter, which used for slow pumping to control the mass flow. Therefore, we modify the slow pumping system to be robust under slow pumping even when water exists in the cavity. In this paper, we present the modified slow pumping system in KEK and the results of the vacuum trend through slow pumping of 9-cell superconducting cavity. Under slow pumping, we measure the particulates after high pressure rinsing by using vacuum particle monitor. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB029  
About • Received ※ 16 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 21 August 2023 — Issue date ※ 22 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB030 Development of Automatic Cleaning and Assembly Systems in Clean Room at KEK gun, operation, monitoring, controls 463
 
  • Y. Yamamoto, T. Dohmae, M.H. Hiraki, H. Sakai, K. Umemori, T. Yamada
    KEK, Ibaraki, Japan
  
  At KEK, new clean work systems including vertical auto cleaning system, replacement system between blank flange and bellows, and robot arm have been developed and installed since 2020 under the collaboration between Japan and France. The main purpose is unmanned and dust-free operation in clean room to avoid performance degradation with field emission in vertical test and cryomodule test. The vertical auto cleaning system and the replacement system between blank flange and bellows have been operated successfully in 2021-2022. Currently, clean work studies related to auto cleaning and assembly is under progress by combining the blank-bellows replacement system and a robot arm. In this report, the recent status of clean works at KEK will be presented.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB030  
About • Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 30 June 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB033 On the Way to a 10 MeV, Conduction-Cooled, Compact SRF Accelerator SRF, electron, cryogenics, simulation 471
 
  • H. Vennekate, G. Cheng, G. Ciovati, J. Guo, K.A. Harding, J. Henry, U. Pudasaini, R.A. Rimmer
    JLab, Newport News, VA, USA
  • A. Castilla
    JLAB, Newport News, USA
  • F.E. Hannon
    Phase Space Tech, Bjärred, Sweden
  • D.A. Packard
    GA, San Diego, California, USA
  • J. Rathke
    TechSource, Los Alamos, New Mexico, USA
  • T. Schultheiss
    TJS Technologies, Commack, New York, USA
  
  Funding: The presentation has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
After the success of designing a compact 1 MeV, 1 MW accelerator based on conduction-cooled SRF, Jefferson Lab is now pursuing a concept to provide a tenfold increase of the beam energy. The higher energy significantly extends the range of applications for environmental remediation and industry in general. The obvious challenge for SRF is to move from a single-cell to a multicell cavity while maintaining high efficiency and the ability to operate the machine without a complex cryogenic plant. The contribution presents the latest results of this design study with respect to its centerpiece, a Nb₃Sn coated 915 MHz five-cell cavity and its corresponding RF components, i.e. FPC and HOM absorber, as well as the conduction-cooling concept based on commercially available cryocoolers. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB033  
About • Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 18 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB035 Design, Fabrication, and Test of a 175 MHz, β = 0.18, Half Wave Resonator for the IFMIF-DONES SRF-Linac SRF, linac, multipactoring, target 477
 
  • J. Plouin, M. Baudrier, S. Chel, G. Devanz, A. Madur, L. Maurice, C. Servouin
    CEA-DRF-IRFU, France
  • N. Bazin, G. Jullien
    CEA-IRFU, Gif-sur-Yvette, France
  
  The IFMIF-DONES facility will serve as a fusion-like neutron source for the assessment of materials damage in future fusion reactors. The neutron flux will be generated by the interaction between the lithium curtain and the deuteron beam from an RF linear accelerator at 40 MeV and nominal CW current of 125 mA. The last accelerating stage is a superconducting (SRF) Linac hosting five cryomodules. This SRF-Linac is equipped of two types of 175 MHz half wave superconducting cavities (HWRs). The first type of cavities (cryomodules 1 and 2), characterized by beta equal to 0.11, have been studied and qualified in the frame of IFMIF/EVEDA project. The development of the second type of cavities (cryomodules 3, 4 and 5), with higher beta of 0.18 is presented in this paper. A prototype has been designed, fabricated and tested in a vertical cryostat at CEA. The measured quality factor at nominal accelerating field (4.5 MV/m) is 2.3 109 and keeps higher than 109 up to 10 MV/m, which gives confidence in the cavity design and preparation to reach the expected performances after integration in the SRF linac.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB035  
About • Received ※ 20 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB036 Equidistant Optimization of Elliptical SRF Standing Wave Cavities SRF, ECR, linac, acceleration 480
 
  • V.D. Shemelin
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  A record accelerating rate was achieved earlier in standing wave (SW) SRF cavities when their shape was optimized for lower peak surface magnetic field. In view of new materials with higher limiting magnetic fields, expected for SRF cavities, in the first line Nb₃Sn, the approach to optimization of cavity shape should be revised. A method of equidistant optimization, offered earlier for traveling wave cavities is applied to SW cavities. It is shown here that without limitation by magnetic field, the maximal accelerating rate is defined to a significant degree by the cavity shape. For example, for a cavity with the aperture radius Ra = 35 mm the minimal ratio of the peak surface electric field to the accelerating rate is about Epk/Eacc = 1.54. So, with the maximal surface field experimentally achieved Epk ¿ 125 MV/m, the maximal achievable accelerating rate is about 80 MeV/m even if there are no restrictions by the magnetic field. Another opportunity ¿ optimization for a low magnetic field, is opening for the same material, Nb₃Sn, with the purpose to have a high quality factor and increased accelerating rate that can be used for industrial linacs.  
poster icon Poster TUPTB036 [0.787 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB036  
About • Received ※ 15 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 08 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB037 Refurbishment and Reactivation of a Niobium Retort Furnace at DESY vacuum, controls, niobium, target 485
 
  • L. Trelle, C. Bate, H. Remde, D. Reschke, J. Schaffran, L. Steder, H. Weise
    DESY, Hamburg, Germany
  
  Funding: This work was supported by the Helmholtz Association within the topic Accelerator Research and Development (ARD) of the Matter and Technologies (MT) Program.
For research in the field of heat treatments of supercon-ducting cavities, a niobium ultra-high vacuum furnace built in 1992 - originally used for the titanization of 1.3 GHz nine-cell cavities - and later shut down was recently refurbished and reactivated. A significant upgrade is the ability to run the furnace in partial pressure mode with nitrogen. The furnace is connected directly to the ISO4 area of the clean room for cavity handling. At room temperature vacuum values of around 3×10-8 mbar are achieved. The revision included the replacement of the complete control system and a partial renewal of the pump technology. The internal mounting structures are optimized for single-cell operation including tandem operation (two single-cell cavities at once) and corresponding accessories such as witness-samples and caps for the cavities. The installation of additional thermocouples for a detailed monitoring of the temperature curves is also possible at the mounting structure. Due to the furnace design, its location and the strict routines in handling, very high purity levels are achieved in comparison to similar setups and hence provide a mighty tool for SRF cavity R&D at DESY. 		 
poster icon Poster TUPTB037 [0.404 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB037  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 01 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB038 Novel Approaches in Characterization and Modelling of Fabrication Processes for SRF Components SRF, simulation, FEM, experiment 490
 
  • J.S. Swieszek, A. Gallifa Terricabras, M. Garlasché, D. Smakulska
    CERN, Meyrin, Switzerland
  • J.S. Swieszek
    Kraftanlagen Nukleartechnik GmbH, Heidelberg, Germany
  
  In the past years, Finite Element Methods have been increasingly applied at CERN, with the aim of modelling fabrication processes for SRF components. Currently, many large deformation processes such as deep drawing, forging, hydroforming, and spinning, are being simulat-ed. Taking the initial trials out of the workshop via simu-lation has proven very efficient for steering fabrication strategy, avoiding unnecessary trials, and helping to re-duce time and costs. This contribution will present a novel approach for studying fabrication process feasibil-ity and failure prediction using numerical tools, based on the Forming Limit Diagram method, developed for OFE copper sheets. This contribution will show the applica-tion of the mentioned method on the study of tubular hydroforming, as an alternative way to produce seamless elliptical RF cavities. Analysis of past hydroforming trials is also discussed, together with the comparison of different fabrication strategies.  
poster icon Poster TUPTB038 [1.674 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB038  
About • Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 17 July 2023
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TUPTB039 Simulation of High Pressure Rinse in Superconducting Radio Frequency Cavities simulation, SRF, radio-frequency, site 496
 
  • B.E. Gower, K. Elliott, E.S. Metzgar, T. Xu
    FRIB, East Lansing, Michigan, USA
  
  Funding: U.S. Department of Energy, Office of Science, Office of Nuclear Physics. Resources of the Facility for Rare Isotope Beams, a DOE Office of Science User Facility, under Award Number DE-SC0000661.
The finish of radio frequency (RF) surfaces inside superconducting RF (SRF) cavities is of utmost importance as it dictates ultimate cavity performance. After the cavity surfaces have undergone chemical etching, polishing, and hydrogen degassing, the final step in surface preparation involves cleaning using a high pressure rinse (HPR) with ultra-high purity water (UPW) to remove any residue from the previous chemical processes. The complex surface geometry of cavities poses difficulties in achieving effective and thorough HPR cleaning. This study introduces a versatile simulation tool created in MATLAB, which has the potential to be applied to various SRF cavities. The detail of the algorithm used and nozzle and motion setup will be described using an FRIB 0.53 half wave resonator (HWR) cavity as an example. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB039  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 07 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB040 Mechanical Design and Analysis of SRF Gun Cavity Using ASME BPVC Section Viii, Division-2, Design by Analysis Requirement SRF, gun, niobium, vacuum 501
 
  • M.S. Patil, C. Compton, S.H. Kim, S.J. Miller, T. Xu
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by the Department of Energy Contract DE-AC02- 76SF00515
A prototype SRF gun is currently being designed at FRIB, MSU for the Low Emittance Injector of the Linac Coherent Light Source high energy upgrade at SLAC. This employs a 185.7 MHz superconducting quarter-wave resonator (QWR). The mechanical design of this cavity has been optimized for performance and to comply with ASME Section VIII, Div 2, Design by analysis requirements. This paper presents the various design by analysis procedures and how they have been adopted for the SRF gun cavity design. 		 
poster icon Poster TUPTB040 [1.235 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB040  
About • Received ※ 15 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 18 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB041 Visual, Optical and Replica Inspections: Surface Preparation of 650 MHz Nb Cavity for PIP-II Linac SRF, linac, niobium, embedded 507
 
  • V. Chouhan, D.J. Bice, D.A. Burk, M.K. Ng, G. Wu
    Fermilab, Batavia, Illinois, USA
  
  Surface preparation of niobium superconducting RF cavities is a critical step for achieving good RF performance under the superconducting state. Surface defect, roughness, and contamination affect the accelerating gradient and quality factor of the cavities. We report surface inspection methods used to control the surface processing of 650 MHz cavities that will be used in the pre-production cryomodule for PIP-II linac. The cavity surface was routinely inspected visually, with an optical camera, and by microscopic scanning of surface replicas. This article covers details on the surface inspection methods and surface polishing process used to repair the surface.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB041  
About • Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 12 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB042 Latest Development of Electropolishing Optimization for 650 MHz Cavity cathode, SRF, niobium, polarization 512
 
  • V. Chouhan, D.J. Bice, D.A. Burk, S.K. Chandrasekaran, A.T. Cravatta, P.F. Dubiel, G.V. Eremeev, F. Furuta, O.S. Melnychuk, A.V. Netepenko, M.K. Ng, J.P. Ozelis, H. Park, T.J. Ring, G. Wu
    Fermilab, Batavia, Illinois, USA
  • B.M. Guilfoyle, M.P. Kelly, T. Reid
    ANL, Lemont, Illinois, USA
  
  Electropolishing (EP) of 1.3 GHz niobium (Nb) superconducting RF cavities is conducted to achieve a desired smooth and contaminant-free surface that yields good RF performance. Achieving a smooth surface of a large-sized elliptical cavity with the standard EP conditions was found to be challenging. This work aimed to conduct a systematic parametric EP study to understand the effects of various EP parameters on the surface of 650 MHz cavities used in PIP-II linac. Parameters optimized in this study provided a smooth surface of the cavities. The electropolished cavities met the baseline requirement of field gradient and qualified for further surface treatment to improve the cavity quality factor.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB042  
About • Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 06 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB043 Development of 3-Cell Traveling Wave SRF Cavity resonance, SRF, cryogenics, GUI 517
 
  • F. Furuta, T.N. Khabiboulline, K.E. McGee, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • P.V. Avrakhov, R.A. Kostin
    Euclid TechLabs, Solon, Ohio, 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
Traveling wave SRF cavity is a new technology and requires a multi-stage process for development. Concep-tual designs have been proposed to adopt TW resonance in an SRF cavity The early stages of developments have been funded by several SBIR grants to Euclid Techlabs which were completed in collaboration with Fermilab. A 3-cell proof-of-principle TW cavity was fabricated as part of that and demonstrated the TW resonance excita-tion at room temperature. A TW resonance control tuner for the 3-cell was also fabricated and the preliminary tests were performed. Now, the 3-cell cavity is being processed and prepared for the first cryogenic testing. 		 
poster icon Poster TUPTB043 [1.743 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB043  
About • Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB044 Compact Multicell Superconducting Crab Cavity for ILC HOM, impedance, dipole, SRF 521
 
  • A. Lunin, S.A. Belomestnykh, I.V. Gonin, T.N. Khabiboulline, Y.M. Orlov, V. Poloubotko, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by the Fermi National Accelerator Laboratory; managed by Fermi Research Alliance, LLC under Contract No. DEAC02-07CH11359 with the U.S. Department of Energy
We propose a novel design of a deflecting cavity for the ILC project with low parasitic HOM losses and preserving the beam emittance, which is critical for operation with high beam current intensity. Multiple electrodes immersed in the hollow waveguide form a trapped-mode resonator. The transverse components of the electromagnetic field of the trapped dipole mode induce a transverse kick and efficiently deflect charged particles passing through the cavity. We present a scalable design of a superconducting Quasi-waveguide Multicell Resonator (QMiR) seamlessly connected with a beam vacuum chamber. The cavity is completely open at both ends, which significantly reduces the maximum loaded quality factor of the higher order modes (HOM), avoids complex HOM couplers and thus simplifies the mechanical design of the cavity. The same port is used to feed RF power to the operating mode and to extract the same order modes (SOM). Finally, we estimate the expected cryogenic losses, HOM impedance limits, RF input power required, and frequency tuning for a QMiR cavity designed to operate at 2.6 GHz. 		 
poster icon Poster TUPTB044 [6.975 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB044  
About • Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 16 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB045 PIP-II SSR2 Cavities Fabrication and Processing Experience SRF, niobium, linac, target 526
 
  • M. Parise, P. Berrutti, D. Passarelli
    Fermilab, Batavia, Illinois, USA
  • P. Duchesne, D. Longuevergne
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  
  The Proton Improvement Plan-II (PIP-II) linac will include 35 Single Spoke Resonators type 2 (SSR2). A pre-production SSR2 cryomodule will contain 5 jacketed cavities. Several units are already manufactured and prepared for cold testing. In this work, data collected from the fabrication, processing and preparation of the cavities will be presented and the improvements implemented after the completion of the first unit will be highlighted.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB045  
About • Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 08 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB046 Development and Performance of RFD Crab Cavity Prototypes for HL-LHC AUP HOM, impedance, niobium, higher-order-mode 531
 
  • L. Ristori, P. Berrutti, M. Narduzzi
    Fermilab, Batavia, Illinois, USA
  • A. Castilla
    JLAB, Newport News, USA
  • S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • N.A. Huque
    JLab, Newport News, Virginia, USA
  • Z. Li, A. Ratti
    SLAC, Menlo Park, California, USA
  
  Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
The US will be contributing to the HL-LHC upgrade at CERN with the fabrication and qualification of RFD crabbing cavities in the framework of the HL-LHC Accelerator Upgrade Project (AUP) managed by Fermilab. AUP received Critical Decision 3 (CD-3) approval by DOE in December 2020 launching the project into the production phase. The electro-magnetic design of the cavity was inherited from the LHC Accelerator Research Program (LARP) but needed to be revised to meet new project requirements and to prevent issues encountered during beam tests performed at CERN in the R&D phase. Two prototype cavities were manufactured in industry and cold tested. Challenges specific to the RFD cavity were the stringent interface tolerances, the pole symmetry and the higher-order-mode impedance spectrum. Chemical processing and heat treatments were performed initially at FNAL/ANL and are now being transferred to industry for the production phase. HOM dampers are manufactured and validated by JLAB. A summary of cold test results with and without HOM dampers is presented. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB046  
About • Received ※ 20 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 11 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB047 The Evaluation of Mechanical Properties of LB650 Cavities controls, cryomodule, niobium, SRF 536
 
  • G. Wu, S.D. Adams, D.J. Bice, S.K. Chandrasekaran, I.V. Gonin, C.J. Grimm, J.P. Holzbauer, T.N. Khabiboulline, C.S. Narug, J.P. Ozelis, H. Park, G.V. Romanov, R. Thiede, R. Treece, A.D. Wixson
    Fermilab, Batavia, Illinois, USA
  • K.E. McGee
    FRIB, East Lansing, Michigan, 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 650 MHz cavities have a stronger requirement of niobium mechanical properties because of the geometric shape of the cavity due to reduced beta. The mechanical property of the niobium half-cell was measured following various heat treatments. The 5-cell cavities were tested in a controlled drop test fashion and the real-world road test. The result showed that the 900C heat treatment was compatible with cavity handling and transportation during production. The test provides the bases of the transportation specification and shipping container design guidelines. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB047  
About • Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 14 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB049 Horizontal Test Results of 1.3 GHz Superconducting RF Gun #2 at KEK gun, cathode, SRF, laser 540
 
  • T. Konomi, K. Hara, Y. Honda, K. Hosoyama, H. Inoue, E. Kako, Y. Kondo, M. Masuzawa, M. Omet, T. Takatomi, A. Terashima, K. Tsuchiya, R. Ueki, K. Umemori, X. Wang
    KEK, Ibaraki, Japan
  
  Superconducting radio-frequency (SRF) electron guns are attractive for delivery of beams at a high bunch repetition rate with a high accelerating field. KEK has been developing the SRF gun to demonstrate basic performance. The SRF gun consists of 1.3 GHz and 1.5 cell SRF gun cavity and K2CsSb photocathode coated on 2K cathode plug. In the vertical test, the surface peak electric field and the surface peak magnetic field reached to 75 MV/m and 170 mT respectively. The SRF gun was installed to horizontal multipurpose cryostat equipped with a superconducting solenoid, photocathode preparation chamber and beam diagnostic line. The results showed the peak surface electric field degraded to 42 MV/m. We suspect that cavity was contaminated during assembly. In this presentation, we will present the high gradient performance in vertical and horizontal test and individual test for each beam line components.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB049  
About • Received ※ 24 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB052 A Novel Manufacture of Niobium SRF Cavities by Cold Spray SRF, niobium, radio-frequency, experiment 545
 
  • M. Yamanaka
    KEK, Ibaraki, Japan
  • K. Shimada
    Nihon University, College of Engineering, Koriyama, Japan
  
  Cold spray is a lower-temperature solid-state thermal spray process that deposits metal powder using a heated inert gas through a supersonic nozzle. When the material hits at supersonic speed and reaches the critical speed, the particles themselves are plastically deformed to form a film. The material of the superconducting cavity is niobium, a very expensive rare metal. To reduce the amount of niobium and the cost, we propose a novel manufacturing method of forming a thick niobium film on the surface of a mandrel by cold spray using niobium powder and removing the mandrel to finish a hollow shape. We confirmed the feasibility of the proposed method using a model similar to a 3.9 GHz one-cell cavity. Also, the RRR measurement of the niobium specimen made by cold spray was carried out and the measured value of 11 was obtained. We report on these results.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB052  
About • Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 10 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB059 INFN LASA Experimental Activities for the PIP-II Project SRF, experiment, diagnostics, controls 549
 
  • M. Bertucci, M. Bonezzi, A. Bosotti, D. Cardelli, E. Del Core, F. Fiorina, A.T. Grimaldi, L. Monaco, C. Pagani, R. Paparella, D. Sertore, G.M. Zaggia
    INFN/LASA, Segrate (MI), Italy
  
  INFN LASA is upgrading its vertical test facility to allow high-Q measurements of the PIP-II LB650 SRF cavities. Such facility is equipped with a wide set of diagnostics for quench, field emission and magnetic flux expulsion studies and will offer a better understanding of cavity performance. At the same time, R&D on LB650 cavity prototypes is ongoing, in order to optimize the overall processing as well as the cavity Jacketing in view of the forthcoming series production with industry. This paper reports on the overall status of these experimental activities.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB059  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 18 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB060 Reconstruction of Field Emission Pattern for PIP-II LB650 Cavity electron, radiation, experiment, site 554
 
  • E. Del Core, M. Bertucci, A. Bosotti, A.T. Grimaldi, L. Monaco, C. Pagani, R. Paparella, D. Sertore
    INFN/LASA, Segrate (MI), Italy
  • C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
  
  Field emission (FE) is a key limiting phenomenon in SRF cavities. An algorithm exploiting a self-consistent model of cavity FE has been developed. This method exploits experimental observables (such as Q value , X-ray endpoint, and dose rate) to reconstruct emitter position and size as well as the field enhancement factor. To demonstrate the model effectiveness, the algorithm has been applied to a data set of the PIP-II LB650 prototype cavity.  
poster icon Poster TUPTB060 [0.956 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB060  
About • Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 28 June 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB061 Status of the ESS Medium Beta Cavities at INFN LASA cryomodule, linac, simulation, SRF 559
 
  • D. Sertore, M. Bertucci, M. Bonezzi, A. Bosotti, D. Cardelli, A. D’Ambros, E. Del Core, F. Fiorina, A.T. Grimaldi, L. Monaco, C. Pagani, R. Paparella, G.M. Zaggia
    INFN/LASA, Segrate (MI), Italy
  
  The INFN LASA’s contribution to the ESS Medium Beta Superconducting Linac consists of 36 cavities that raise the proton beam energy from 216 MeV to 571 MeV. Out of the 36 cavities, 28 have been successfully qualified and delivered for assembly into a cryomodule at CEA Saclay. The remaining cavities have been reprocessed in order to bring them up to ESS specifications. To mitigate further delays in the delivery of the cavities, four new ones are currently under construction. We are reporting on the current status of both the recovery actions we have developed so far and the performance of the newly produced resonators.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB061  
About • Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 14 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB062 RF Measurements of the 3rd Harmonic Superconducting Cavity for a Bunch Lengthening niobium, target, superconducting-cavity, MMI 565
 
  • J.Y. Yoon, J.H. Han, H.S. Park, Y.D. Yoon
    Kiswire Advanced Technology Ltd., Daejeon, Republic of Korea
  • E. Kako
    KEK, Ibaraki, Japan
  • E.-S. Kim
    Korea University Sejong Campus, Sejong, Republic of Korea
  
  The brightness can be increased by minimizing the emittance in the light source, but the reduced emittance also increases the number of collisions of electrons in the beam bunch. Therefore, the bunch lengthening by using the 3rd harmonic cavity reduces the collisions of electrons and increases the Touschek lifetime. Since the resonant frequency of the main RF cavity is 500 MHz, the resonant frequency of 3rd harmonic cavity is selected as 1500 MHz. The prototype cavity is a passive type in which a power coupler is not used, and power is supplied from the beam. The operating temperature is 4.5 K, which is a superconducting cavity. The elliptical double-cell geometry was selected to increase the accelerating voltage of the cavity and reduce power losses. Based on this design, three niobium cavities are fabricated and tested. In this paper, we present the RF measurement results of the 3rd harmonic cavity at room temperature.
*3rd harmonic cavity
*4th generation storage ring 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB062  
About • Received ※ 12 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB063 Fabrication Efforts Toward a Superconducting Rf Photo-Infector Quarter-Wave Cavity for Use in Low Emittance Injector Applications niobium, SRF, cryomodule, gun 568
 
  • C. Compton
    NSCL, East Lansing, Michigan, USA
  • K. Elliott, W. Hartung, J.D. Hulbert, S.H. Kim, T. Konomi, S.J. Miller, M.S. Patil, J.T. Popielarski, L. Popielarski, K. Saito, K. Witgen, T. Xu
    FRIB, East Lansing, Michigan, USA
  • M. Kedzie, M.P. Kelly, T.B. Petersen
    ANL, Lemont, Illinois, USA
  • J.W. Lewellen, J. Smedley
    SLAC, Menlo Park, California, USA
  
  Funding: * Work supported by the Department of Energy Contract DE-AC02- 76SF00515
The Facility for Rare Isotope Beams (FRIB), in collaboration with Argonne National Laboratory (ANL) and Helmholtz-Zentrum Dresden-Rossendorf (HDZR), is working on the design and fabrication of a photo-injector cryomodule; suitable for operation as part of accelerator systems at SLAC National Accelerator Laboratory. Project scope requires the fabrication of two 185.7 MHz superconducting, quarter-wave resonators (QWR) based, injector cavities. Cavity fabrication will be completed at FRIB with contracted vendors supporting subcomponent fabrication and electron-beam welding. Fabrication will use poly-crystalline and large grain RRR niobium materials. The current status of cavity fabrication will be presented including material procurement, prototype forming, and electron-beam welding development. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB063  
About • Received ※ 17 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 21 August 2023 — Issue date ※ 21 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB066 Fabrication and Testing of a Prototype RF-Dipole Crabbing Cavity dipole, collider, electron, multipactoring 573
 
  • S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • H. Park
    Fermilab, Batavia, Illinois, USA
  
  Crabbing cavities are essential in particle colliders to compensate the luminosity degradation due to beam collision at a crossing angle. The 952.6 MHz 2-cell rf-dipole crabbing cavity system was proposed for the Jef-ferson Lab Electron-Ion Collider to restore the head-on collisions of electron and proton bunches at the interac-tion point. A prototype cavity was designed and devel-oped to demonstrate the performance of multi-cell rf-dipole structures. This paper presents the fabrication pro-cess and cold test results of the first 2-cell rf-dipole proto-type cavity.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB066  
About • Received ※ 18 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 21 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB067 Fabrication and Surface Treatment of Superconducting Rf Single Spoke Cavities for the Myrrha Project niobium, simulation, MMI, linac 578
 
  • M. Moretti, Y.N. Hoerstensmeyer, A. Navitski
    RI Research Instruments GmbH, Bergisch Gladbach, Germany
  • F. Marhauser
    SCK•CEN, Mol, Belgium
  
  The MYRRHA project, based at SCK•CEN (Belgium), aims at coupling a 600 MeV proton accelerator to a subcritical fission core with a maximal output of 100 MWth. The first phase of the project, MINERVA, includes the design, construction, and commissioning of a 100 MeV superconducting RF linac in order to demonstrate the machine requirements in terms of reliability and fault tolerance. The MINERVA linac comprises several cryomodules, each containing two Single Spoke 352.2 MHz cavities made out of high RRR niobium and operating at 2K. The fabrication and surface treatment of the Single Spoke RF Cavities is currently ongoing and completely carried out by RI Research Instruments GmbH (Germany); the first pre-series cavities were completed and delivered for cold testing. Main highlights of the fabrication include the deep-drawing of complex shapes, such as central spokes and outer caps of the cavity, which was successfully accomplished. As for the surface treatment, RI has commissioned, tested, and effectively started utilizing a new rotational buffered chemical polishing facility; this is required to polish the cavity inner surface, while ensuring an almost uniform material removal.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB067  
About • Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 09 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTB068 EIC 197 MHz Crab Cavity RF Optimization HOM, multipactoring, GUI, impedance 584
 
  • Z. Li
    SLAC, Menlo Park, California, USA
  • S.U. De Silva, J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • R.A. Rimmer
    JLab, Newport News, Virginia, USA
  • Q. Wu, B.P. Xiao, W. Xu
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under U.S. DOE K No. DE-SC0012704, by Jefferson Science Associates, LLC under U.S. DOE K No. DE-SC0002769, and by DOE K No. DE-AC02-76SF00515.
Crab cavities, operating at 197 MHz and 394 MHz respectively, will be used to compensate the loss of luminosity due to a 25 mrad crossing angle at the interaction point in the Electron Ion Collider (EIC). Both crab cavities are of the RF Dipole (RFD) shape. To meet the machine design requirements, there are a few important cavity design considerations that need to be addressed. First, to achieve stable cavity operation at the design voltages, cavity geometry details must be optimized to suppress potential multipacting. Incorporating strong HOM damping in the cavity design is required for the beam stability and quality. Furthermore, due to the finite pole width, the multipole fields, especially the sextupole and the decapole terms, need to be minimized to maintain an acceptable beam dynamic aperture. This paper will present the RF optimization details of the 197 MHz cavity. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB068  
About • Received ※ 16 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 03 July 2023 — Issue date ※ 08 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEIAA03 Surface Roughness Reduction and Performance of Vapor-Diffusion Coating of Nb3Sn Film for SRF Application SRF, site, accelerating-gradient, factory 593
 
  • U. Pudasaini, M.J. Kelley, E.M. Lechner, C.E. Reece, O. Trofimova, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  
  Funding: This work is authored by Jefferson Science Associates LLC under U.S. DOE Contract No. DE-AC05- 06OR23177.
Nb₃Sn offers the prospect of better RF performance (Q and Eacc) than niobium at any given temperature because of its superior superconducting properties. Nb₃Sn-coated SRF cavities are routinely produced by growing a few microns thick Nb₃Sn film on Nb cavities via tin vapor diffusion. It has been observed that a clean and smooth surface can enhance the performance of the Nb₃Sn-coated cavity, typically, the attainable acceleration gradient. The reduction of surface roughness is often linked with a correlative reduction in average coating thickness and grain size. Besides Sn supply’s careful tuning, the temperature profiles were varied to reduce the surface roughness as low as ~40 nm in 20 µm × 20 µm AFM scans, one-third that of the typical coating. Samples were systematically coated inside a mock single-cell cavity and examined using different material characterization techniques. A few sets of coating parameters were used to coat 1.3 GHz single-cell cavities to understand the effects of roughness variation on the RF performance. This presentation will discuss ways to reduce surface roughness with results from a systematic analysis of the samples and Nb₃Sn-coated single-cell cavities. 		 
slides icon Slides WEIAA03 [7.231 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIAA03  
About • Received ※ 19 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 19 August 2023 — Issue date ※ 21 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEIAA04 Development of High-performance Niobium-3 Tin Cavities at Cornell University niobium, SRF, site, accelerating-gradient 600
 
  • L. Shpani, S.G. Arnold, G. Gaitan, M. Liepe, T.E. Oseroff, R.D. Porter, N.A. Stilin, Z. Sun, N.M. Verboncoeur
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • N. Sitaraman
    Cornell University, Ithaca, New York, USA
  
  Funding: Work supported by the National Science Foundation under Grant No. PHY-1549132, the Center for Bright Beam and U.S. DOE grant No. DE-SC0008431.
Niobium-3 tin is a promising material for next-generation superconducting RF cavities due to its high critical temperature and high theoretical field limit. There is currently significant worldwide effort aiming to improve Nb₃Sn growth to push this material to its ultimate performance limits. This talk will present an overview of Nb₃Sn cavity development at Cornell University. One approach we are pursuing is to further advance the vapor diffusion process through optimized nucleation and film thickness. Additionally, we are exploring alternative Nb₃Sn growth methods, such as the development of a plasma-enhanced chemical vapor deposition (CVD) system, as well as Nb₃Sn growth via electrochemical synthesis. 		 
slides icon Slides WEIAA04 [5.260 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIAA04  
About • Received ※ 29 June 2023 — Revised ※ 11 August 2023 — Accepted ※ 21 August 2023 — Issue date ※ 22 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WECAA01 Progress in European Thin Film Activities SRF, target, niobium, laser 607
 
  • C. Pira, O. Azzolini, R. Caforio, E. Chyhyrynets, D. Fonnesu, D. Ford, V.A. Garcia, G. Keppel, G. Marconato, A. Salmaso, F. Stivanello
    INFN/LNL, Legnaro (PD), Italy
  • C.Z. Antoine, Y. Kalboussi, Th. Proslier
    CEA-IRFU, Gif-sur-Yvette, France
  • C. Benjamin, O.B. Malyshev, N. Marks, B.S. Sian, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • C. Benjamin, J.W. Bradley, G. Burt, O.B. Malyshev, N. Marks, D.J. Seal, B.S. Sian, S. Simon, D.A. Turner, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • S. Berry
    CEA-DRF-IRFU, France
  • R. Berton, D. Piccoli, F. Piccoli, G. Squizzato, F. Telatin
    Piccoli, Noale (VE), Italy
  • M. Bertucci, R. Paparella
    INFN/LASA, Segrate (MI), Italy
  • M. Bonesso, S. Candela, V. Candela, R. Dima, G. Favero, A. Pepato, P. Rebesan, M. Romanato
    INFN- Sez. di Padova, Padova, Italy
  • J.W. Bradley, S. Simon
    The University of Liverpool, Liverpool, United Kingdom
  • G. Burt, D.J. Seal, D.A. Turner
    Lancaster University, Lancaster, United Kingdom
  • O. Hryhorenko, D. Longuevergne
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • X. Jiang, T. Staedler, A.O. Zubtsovskii
    University Siegen, Siegen, Germany
  • S. Keckert, J. Knobloch, O. Kugeler
    HZB, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
  • N.L. Leicester
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • A. Medvids, A. Mychko, P. Onufrijevs
    Riga Technical University, Riga, Latvia
  • S. Prucnal, S. Zhou
    HZDR, Dresden, Germany
  • R. Ries
    Slovak Academy of Sciences, Institute of Electrical Engineering, Bratislava, Slovak Republic
  • E. Seiler
    IEE, Bratislava, Slovak Republic
  • L.G.P. Smith
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  
  Funding: This project has received funding from the European Union s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730.
Thin-film cavities with higher Tc superconductors (SC) than Nb promise to move the operating temperature from 2 to 4.5 K with savings 3 orders of magnitude in cryogenic power consumption. Several European labs are coordinating their efforts to obtain a first 1.3 GHz cavity prototype through the I.FAST collaboration and other informal collaborations with CERN and DESY. R&D covers the entire production chain. In particular, new production techniques of seamless Copper and Niobium elliptical cavities via additive manufacturing are studied and evaluated. New acid-free polishing techniques to reduce surface roughness in a more sustainable way such as plasma electropolishing and metallographic polishing have been tested. Optimization of coating parameters of higher Tc SC than Nb (Nb₃Sn, V₃Si, NbTiN) via PVD and multilayer via ALD are on the way. Finally, rapid heat treatments such as Flash Lamp Annealing and Laser Annealing are used to avoid or reduce Cu diffusion in the SC film. The development and characterization of SC coatings is done on planar samples, 6 GHz cavities, choke cavities, QPR and 1.3 GHz cavities. This work presents the progress status of these coordinated efforts. 		 
slides icon Slides WECAA01 [15.846 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WECAA01  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 02 September 2023 — Issue date ※ 02 September 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEIBA01 Surface Engineering by ALD for Superconducting RF Cavities niobium, vacuum, SRF, site 615
 
  • Y. Kalboussi, C.Z. Antoine, M. Baudrier, Q. Bertrand, C. Boulch, B. Delatte, G. Jullien, L. Maurice, Th. Proslier, P. Sahuquet, T.V. Vacher
    CEA-IRFU, Gif-sur-Yvette, France
  • M. Asaduzzaman, T. Junginger
    UVIC, Victoria, Canada
  • M. Asaduzzaman
    TRIUMF, Vancouver, Canada
  • D. Dragoe
    ICMMO, Orsay, France
  • F. Éozénou
    CEA-DRF-IRFU, France
  • N. Lochet
    CEA, DES, Université Paris-Saclay, Gif-sur-Yvette, France
  • D. Longuevergne, T. Pépin-Donat
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • F. Miserque
    CEA, LECA, Université Paris-Saclay, Gif-sur-Yvette, France
  
  Atomic Layer Deposition is a synthesis method that enable a unique control of thin films chemical composition and thickness over complex shape objects such as SRF cavities. This level of control opens the way to new surface treatments and to study their effect on RF cavity performances. We will present coupon and, in some cases, preliminary cavity results, from various surface engineering routes based on the deposition of thin oxides and nitrides films combined with post annealing treatments and study their interactions with the niobium. Three main research directions will be presented: 1/ replacing the niobium oxides by other surface layers (Al₂O₃, Y2O3, MgO) and probe their effect on the low and high field performances, 2/ doping with N and combine approaches 1/ and 2/ and finally 3/ optimize the superconducting properties of NbTiN multilayers on Nb and Sapphire.  
slides icon Slides WEIBA01 [13.613 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIBA01  
About • Received ※ 06 July 2023 — Revised ※ 12 August 2023 — Accepted ※ 19 August 2023 — Issue date ※ 19 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEIXA02 Results of the R&D RF Testing Campaign of 1.3 GHz Nb/Cu Cavities SRF, niobium, operation, cryogenics 621
 
  • L. Vega Cid, S. Atieh, G. Bellini, A. Bianchi, L.M.A. Ferreira, C. Pereira Carlos, G.J. Rosaz, W. Venturini Delsolaro
    CERN, Meyrin, Switzerland
  • S.B. Leith
    European Organization for Nuclear Research (CERN), Geneva, Switzerland
  
  In the context of the R&D program on Nb/Cu carried out at CERN, a total of 25 tests have been performed since 2021. This talk will present these results. Three different manufacturing techniques have been used to produce the copper substrates, in order to investigate which is the most suitable in terms of quality and economy of scale. On one hand, the focus has been on optimizing the surface resistance at 4.2K, as this will be the operating temperature of FCC. The results at this temperature are encouraging, showing repeatable and optimized RF performance. On the other hand, RF tests have been done at 1.85 K too aiming at deepening the knowledge of the mechanisms behind the Q slope. This is key to work on the mitigation of this phenomenon and ultimately to extend the application of this technology to high energy, high gradient accelerators. The influence of the thermal cycles has been thoroughly investigated. A systematic improvement has been observed of both the Q slope and the residual resistance with slow thermal cycles.  
slides icon Slides WEIXA02 [5.385 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA02  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 02 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEIXA03 Optimizing the Manufacture of High-Purity Niobium SRF Cavities Using the Forming Limit Diagram: A Case Study of the HL-LHC Crab Cavities RFD Pole simulation, niobium, SRF, luminosity 627
 
  • A. Gallifa Terricabras, I. Aviles Santillana, S. Barrière, M. Garlasché, L. Prever-Loiri, J.S. Swieszek
    CERN, Meyrin, Switzerland
  • E. Cano-Pleite
    UC3M, Leganes, Spain
  • M. Narduzzi
    Fermilab, Batavia, Illinois, USA
  • S. Pfeiffer
    European Organization for Nuclear Research (CERN), Geneva, Switzerland
  
  Funding: CERN HL-LHC
The Crab Cavities are key components of the High Luminosity Large Hadron Collider (HL-LHC) project at CERN, which aims to increase the integrated luminosity of the LHC, the world’s largest particle accelerator, by a factor of ten. This paper explores the application of the Forming Limit Diagram (FLD) to enhance the manufacturing process of complex-shape Nb-based cavities, with a focus on the formability challenges experienced with the pole of the Radio Frequency Dipole (RFD) Crab Cavities. The study includes the material characterization of ultra-high-purity niobium (Nb RRR300) sheets, namely mechanical tests and microstructural analysis; it also contains large-deformation Finite Element simulations of the pole deep drawing process, and the translation of the resulting strains in a FLD diagram, together with several suggestions on how to improve the manufacturing process of such deep drawn parts. The results of this study can provide valuable insights into improving the design and fabrication of complex-shaped superconducting radio-frequency cavities made by large-deformation metal-sheet forming processes. 		 
slides icon Slides WEIXA03 [15.991 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA03  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 27 June 2023
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WEIXA04 Development of the Directly-Sliced Niobium Material for High Performance SRF Cavities SRF, niobium, collider, linear-collider 634
 
  • A. Kumar, H. Araki, T. Dohmae, H. Ito, T. Saeki, K. Umemori, A. Yamamoto, M. Yamanaka
    KEK, Ibaraki, Japan
  • A. Yamamoto
    CERN, Meyrin, Switzerland
  
  For the purpose of cost reduction for the ILC, KEK has been conducting R&D on direct sliced Nb materials such as large grain and medium grain Nb. Single-cell, 3-cell, and 9-cell cavities have been manufactured, and each has demonstrated a high-performance accelerating gradient exceeding 35 MV/m. The results of applying high-Q/high-G recipes, such as two-step baking and furnace baking to these cavities are also shown. Moreover, mechanical tests have been carried out for the beforementioned materials to evaluate their strength for application to the High-Pressure Gas Safety Law. The status of development of these large grain and Medium grain Nb will be presented.  
slides icon Slides WEIXA04 [3.773 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA04  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 12 July 2023
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WEIXA05 Electropolishing Study on Nitrogen-Doped Niobium Surface niobium, SRF, cathode, radio-frequency 641
 
  • V. Chouhan, T.J. Ring, G. Wu
    Fermilab, Batavia, Illinois, USA
  • E.A.S. Viklund
    NU, Evanston, Illinois, USA
  
  The nitrogen doping (N-doping) process is applied to niobium (Nb) superconducting cavities to enhance their quality factors. The N-doping is followed by an electropolishing process that provides the final surface of the cavities. A controlled EP process is necessary to get the benefit of N-doping and achieve a high accelerating gradient. We have performed electropolishing of N-doped Nb surface under various conditions to understand their impact on the surface. A modified EP process was developed to obtain a smooth pit-free surface.  
slides icon Slides WEIXA05 [17.622 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA05  
About • Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 03 July 2023
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WEIXA06 Recent Advances in Metallographic Polishing for SRF Application SRF, niobium, laser, framework 646
 
  • O. Hryhorenko
    JLab, Newport News, Virginia, USA
  • C.Z. Antoine, F. Éozénou, Th. Proslier
    Université Paris-Saclay, CEA, Gif-sur-Yvette, France
  • T. Dohmae
    KEK, Ibaraki, Japan
  • S. Keckert, J. Knobloch, O. Kugeler
    HZB, Berlin, Germany
  • D. Longuevergne
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  
  Funding: ENSAR-2 under grant agreement N° 654002. IFAST under Grant Agreement No 101004730. The U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
This talk is an overview of the metallographic polishing R&D program covering Niobium and Copper substrates treatment for thin film coating as an alternative fabrication pathway for 1.3 GHz elliptical cavities. The presented research is the result of a collaborative effort between IJCLab, CEA/Irfu, HZB, and KEK in order to develop innovative surface processing and cavity fabrication protocols capable of meeting stringent requirements for SRF surfaces, including the reduction of safety risks and ecological footprint, enhancing reliability, improving the surface roughness, and potentially allowing cost reduction. The research findings will be disclosed. 		 
slides icon Slides WEIXA06 [7.469 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA06  
About • Received ※ 16 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 14 July 2023
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WEPWB001 Preparation and Characterization of Nb Films Deposited in SRF Cavity via HiPIMS SRF, niobium, site, lattice 651
 
  • P. He, J. Dai, H.C. Duan, J.W. Kan, Y. Ma, T. Xin, Y.C. Yang, P. Zhang
    IHEP, Beijing, People’s Republic of China
  
  The RF performance of the niobium superconducting cavity has been continuously improved in recent 50 years. Since the maximum acceleration field (Eacc) has approached its theoretical limit, developing a more efficient and low-cost SRF cavity is one of the key challenges of the next generation particle accelerators. Niobium coated copper cavities are promising solutions because the SRF phenomenon occurrs within several hundred nanometers under the cavity surface. In literatures, the Nb coated Cu cavity prepared by direct current magnetron sputtering (DCMS) has serious Q-slope problem, which may be related to the low energy deposition. High power impulse magnetron sputtering (HiPIMS) can produce a high peak power and high ionization rate which may improve the thin film quality. Therefore, we prepared Nb coated Cu samples via HiPIMS on the 1.3 GHz dummy cavity at IHEP.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB001  
About • Received ※ 15 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 19 August 2023 — Issue date ※ 20 August 2023
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WEPWB043 Nb3Sn Vapor Diffusion Coating System at SARI: Design, Construction, and Commissioning vacuum, niobium, MMI, superconducting-cavity 655
 
  • Q.X. Chen, Y. Zong
    SINAP, Shanghai, People’s Republic of China
  • J.F. Chen, S. Xing
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
  • J. Rong
    SSRF, Shanghai, People’s Republic of China
  
  This paper describes the design of a coating system for the preparation of a superconducting radio-frequency cavity with Nb3Sn thin films. The device consists of a coating chamber made of pure niobium, a vacuum furnace for heating the coating chamber, a superconducting cavity bracket and two crucible heaters. The chamber is vacuum isolated from the furnace body to protect the superconducting cavity from contamination during the coating process. The device has been built and commissioned, which could be used for Nb₃Sn coating of a 1.3 GHz single-cell superconducting cavity in future.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB043  
About • Received ※ 19 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 08 July 2023
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WEPWB044 Realization of Accelerating Gradient Larger than 25 MV/m on High-Q 1.3 GHz 9-Cell Cavities for SHINE accelerating-gradient, SRF, experiment, FEL 658
 
  • Y. Zong, Q.X. Chen, X. Huang, Z. Wang
    SINAP, Shanghai, People’s Republic of China
  • J.F. Chen, P.C. Dong, H.T. Hou, X.Y. Pu, J. Shi, S. Sun, D. Wang, J.N. Wu, S. Xing, S.J. Zhao, Y.L. Zhao
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
  • Y.W. Huang
    ShanghaiTech University, Shanghai, People’s Republic of China
  • X.W. Wu
    Zhangjiang Lab, Shanghai, People’s Republic of China
  
  Funding: This work was supported by Shanghai Municipal Science and Technology Major Project (No. 2017SHZDZX02).
We present our studies on the optimized nitrogen-doping and medium-temperature baking recipes applied on 1.3GHz SRF cavities, aiming at meeting the requirements of the SHINE project. The optimized nitrogen-doping process resulted in achieving a Q₀ of over 4.0×1010 at medium field and a maximum accelerating gradient exceeding 35 MV/m on single cell cavities, and a Q₀ of over 2.8×1010 at medium field and a maximum accelerating gradient exceeding 26 MV/m in 9-cell cavities. For 1.3 GHz 9-cell cavities subjected to medium-temperature baking, Q₀ values exceeding 3.5×1010 at 16 MV/m and maximum accelerating gradients surpassing 25 MV/m were achieved. These studies provide two options of high-Q recipes for SHINE cavities. The treatment processes of cavities and their vertical test results are described in this paper.
*chenjinfang@sari.ac.cn
 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB044  
About • Received ※ 19 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 26 June 2023
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WEPWB045 The Oxidizing Responses of Baked Niobium Exposed to Various Gases via In-situ NAXPS niobium, experiment, SRF, vacuum 662
 
  • Z.T. Yang, J.K. Hao, K.X. Liu, S.W. Quan
    PKU, Beijing, People’s Republic of China
  
  We carried out in-situ NAXPS (Near-atmospheric X-ray Photoelectron Spectroscopy) on SRF-cavity class niobium to observe its oxidizing responses when exposed to various gases. The niobium samples were baked at 800°C until the peaks of niobium oxides disappeared in the spectrum. Then the revealed pure niobium samples were exposed to the air-proportion mixture of nitrogen and oxygen, pure oxygen, and pure water vapor respectively. And for the pure oxygen and water vapor group, we also carried out TOF-SIMS (Time-of-Flight Secondary Ion Mass Spectroscopy) measurements before and after the baking and oxidation experiments. We found that pure oxygen and water vapor could oxidize niobium at similar rate which was faster than the N2/O2 mixture. After re-oxidized by pure oxygen and water vapor, the niobium sample presented a significant increase of interstitial carbon and a moderate increase of interstitial oxygen in the magnetic penetration depth, while it showed a mild decrease of interstitial hydrogen.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB045  
About • Received ※ 15 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 25 June 2023 — Issue date ※ 31 July 2023
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WEPWB047 Higher Order Mode Analysis of a 915 MHz 2-Cell Cavity for a Prototype Industrial Accelerator impedance, HOM, SRF, higher-order-mode 667
 
  • A. Castilla
    JLAB, Newport News, USA
  • G. Ciovati, J. Guo, G.-T. Park, R.A. Rimmer, H. Vennekate
    JLab, Newport News, Virginia, USA
  
  A possible solution to reduce the complexity posed by the cryogenic systems in a superconducting RF accelerator for industrial applications, is to capitalize on the advances achieved by the Nb₃Sn superconducting RF technology, as well as the feasibility of a reliable 4 K cooling system, based on commercial cryocoolers. Following this philosophy, the conceptual design for a prototype, conduction-cooled, 4 MeV, 20 kW SRF electron linac, is being developed at Jefferson Lab. Such design is based on a 915 MHz two-cell Nb₃Sn cavity. In this contribution, we present the proposed cavity design, including the fundamental power coupler, and the preliminary analysis of the Higher Order Modes, using numerical simulations to estimate the potentially dangerous modes as a starting point to evaluate the requirements for damping for reliable operations with a cryocooler. Finally, different methods to calculate the Higher Order Modes’ Impedances are briefly discussed.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB047  
About • Received ※ 25 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 04 July 2023 — Issue date ※ 16 July 2023
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WEPWB048 Geometry Optimization for a Quadrupole Resonator at Jefferson Lab quadrupole, SRF, simulation, ECR 670
 
  • S. Bira, M. Ge, A-M. Valente-Feliciano
    JLab, Newport News, Virginia, USA
  • L. Vega Cid, W. Venturini Delsolaro
    CERN, Meyrin, Switzerland
  
  Funding: This manuscript is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-6OR23177 with Jefferson Science Associates
The quadrupole resonator (QPR) is a sample characterization tool to measure the RF properties of superconducting materials using the calorimetry method at different temperatures, magnetic fields, and frequencies. Such resonators are currently operating at CERN and HZB but suffer from Lorentz force detuning and modes overlapping, resulting in higher uncertainties in surface resistance measurement. Using the two CERN’s QPR model iterations, the geometry was optimized via electromagnetic and mechanical simulations to eliminate these issues. The new QPR version was modeled for an increasing range of magnetic fields. The magnetic field is concentrated at the center of the sample to reduce the uncertainty in surface resistance measurements significantly. This paper will discuss the QPR geometry optimization for the new version of QPR, which is now progressing towards fabrication. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB048  
About • Received ※ 19 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 19 August 2023 — Issue date ※ 21 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB049 Multipacting in C75 Cavities electron, simulation, SRF, multipactoring 674
 
  • G. Ciovati, P. Dhakal, R.A. Rimmer, H. Wang, S. Wang
    JLab, Newport News, Virginia, USA
  
  Funding: This work was supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Cavities for the C75 cryomodule refurbishment program are currently being built, processed, tested and installed in the CEBAF accelerator at Jefferson Lab. They consist of 5-cell, 1497 MHz cavities with waveguide-type power coupler and for higher-order modes. Most of the cavities rf tests in a vertical cryostat at 2.07 K were limited by strong multipacting at accelerating gradients in the range 18 - 23 MV/m. A softer multipacting barrier was sometimes found at 13 - 15 MV/m. An unusual feature of the multipacting was that the barrier often shifted to a lower gradient ~17 MV/m, after multiple quenches at ~20 MV/m. This phenomenon was reproduced in a single-cell cavity of the same shape. The cavity was tested after different amounts of mechanical tuning and residual magnetic field, with no significant impact to the multipacting behavior. This contribution summarizes the experimental results from cavity rf tests, some of which were complemented by additional diagnostic instrumentation. Results from 2D and 3D simulations are also presented, indicating favorable conditions for multipacting at the equator in the range 20 - 29 MV/m. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB049  
About • Received ※ 15 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 01 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB050 Exploring Innovative Pathway for SRF Cavity Fabrication SRF, niobium, laser, electron 680
 
  • O. Hryhorenko
    JLab, Newport News, Virginia, USA
  • C.Z. Antoine
    Université Paris-Saclay, CEA, Gif-sur-Yvette, France
  • T. Dohmae
    KEK, Ibaraki, Japan
  • D. Longuevergne
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  
  Funding: ENSAR-2 under grant agreement N° 654002. The U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
This article shows a study on an alternative pathway for the fabrication of a complete 1.3 GHz SRF cavity, aiming at improving production reliability, reducing the use of chemical polishing (EP or BCP) which is a costly and safety-critical step, and preserving surface quality after forming. Unlike the conventional pathway, the fabrication process is performed after polishing. This point is crucial as the used polishing technology could be applied only to flat geometries. The performed investigation demonstrates that damages during the fabrication process are considered minor, localized, and limited to the near-surface. Moreover, these studies confirm that the damaged layer (100-200 µm) is mainly caused by the rolling process, and not by the subsequent fabrication steps. A laser confocal microscope and SEM-EBSD technique were used to compare samples before and after forming. The preliminary results are discussed and presented in this paper. 		 
poster icon Poster WEPWB050 [2.263 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB050  
About • Received ※ 20 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 01 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB051 Development of a Prototype 197 MHz Crab Cavity for the Electron-Ion Collider at JLab GUI, niobium, HOM, electron 685
 
  • N.A. Huque, E.F. Daly, E. Drachuk, J. Henry, M. Marchlik
    JLab, Newport News, Virginia, USA
  • A. Castilla
    JLAB, Newport News, USA
  • S.U. De Silva
    ODU, Norfolk, Virginia, USA
  • B.P. Xiao
    BNL, Upton, New York, USA
  
  Thomas Jefferson National Accelerator Facility (JLab) is currently developing a prototype 197 MHz Radio-Frequency Dipole (RFD) crab cavity as part of the Electron-Ion Collider (EIC) to be built at Brookhaven National Laboratory (BNL). Cryomodules containing these cavities will be part of Hadron Storage Ring (HSR) of the EIC. The prototype cavity is constructed primarily of formed niobium sheets of thickness 4.17 mm, with machined niobium parts used as interfaces where tight tolerancing is required. The cavity¿s large size and complex features present a number of challenges in fabrication, tuning, and RF testing. Structural and forming analyses have been carried out to optimize the design and fabricated processes. An overview of the design phase and the current state of fabrication are presented in this paper.
Work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB051  
About • Received ※ 17 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 16 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB052 Temperature, RF Field, and Frequency Dependence Performance Evaluation of Superconducting Niobium Half-Wave Coaxial Cavity niobium, SRF, radio-frequency, experiment 691
 
  • N.K. Raut, G. Ciovati, P. Dhakal
    JLab, Newport News, Virginia, USA
  • S.U. De Silva, J.R. Delayen, B.D. Khanal, J.K. Tiskumara
    ODU, Norfolk, Virginia, USA
  
  Funding: This is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05- 06OR23177
Recent advancement in superconducting radio frequency cavity processing techniques, with diffusion of impurities within the RF penetration depth, resulted in high quality factor with increase in quality factor with increasing accelerating gradient. The increase in quality factor is the result of a decrease in the surface resistance as a result of nonmagnetic impurities doping and change in electronic density of states. The fundamental understanding of the dependence of surface resistance on frequency and surface preparation is still an active area of research. Here, we present the result of RF measurements of the TEM modes in a coaxial half-wave niobium cavity resonating at frequencies between 0.3 - 1.3 GHz. The temperature dependence of the surface resistance was measured between 4.2 K and 1.6 K. The field dependence of the surface resistance was measured at 2.0 K. The baseline measurements were made after standard surface preparation by buffered chemical polishing. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB052  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 20 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB053 Simulation of the Dynamics of Gas Mixtures during Plasma Processing in the C75 Cavity plasma, electron, simulation, SRF 696
 
  • N.K. Raut, P. Dhakal, T.D. Ganey, T. Powers
    JLab, Newport News, Virginia, USA
  
  Funding: The work is supported by SC Nuclear Physics Program through DOE SC Lab funding announcement DE-FOA-0002670 & is authored by JSA, LLC under U.S. DOE Contract No. DE-AC05- 06OR23177
Plasma processing using a mixture of noble gas and oxygen is a technique that is currently being used to reduce field emission and multipacting in accelerating cavities. Plasma is created inside the cavity when the gas mixture is exposed to an electromagnetic field that is generated by applying RF power through the fundamental power or higher-order mode couplers. Oxygen ions and atomic oxygen are created in the plasma which breaks down the hydrocarbons on the surface of the cavity and the residuals from this process are removed as part of the process gas flow. Removal of hydrocarbons from the surface increases the work function and reduces the secondary emission coefficient. This work describes the initial results of plasma simulation, which provides insight into the ignition process, distribution of different species, and interactions of free oxygen and oxygen ions with the cavity surfaces. The simulations have been done with an Ar/¿2 plasma using COMSOL® multiphysics. These simulations help in understanding the dynamics and control of plasma inside the cavity and the exploration of different gas mixtures. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB053  
About • Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 29 June 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB054 In Situ Plasma Processing of Superconducting Cavities at JLab, 2023 Update plasma, cryomodule, HOM, radiation 701
 
  • T. Powers, N.C. Brock, T.D. Ganey
    JLab, Newport News, Virginia, USA
  
  Jefferson Lab has an ongoing R&D program in plasma processing which just completed a round of production processing in the CEBAF accelerator. Plasma processing is a common technique for removing hydrocarbons from surfaces, which increases the work function and reduces the secondary emission coefficient. Unlike helium processing which relies on ion bombardment of the field emitters, plasma processing uses free oxygen produced in the plasma to break down the hydrocarbons on the surface of the cavity. The initial focus of the effort was processing C100 cavities by injecting RF power into the HOM coupler ports. Results from processing cryomodules in the CEBAF accelerator as well as vertical test results will be presented. The goal will be to improve the operational gradients and the energy margin of the linacs. This work will describe the systems and methods used at JLAB for processing cavities using an argon-oxygen gas mixture as well as a helium-oxygen gas mixture. Before and after plasma processing results will also be presented.
Funding provided by SC Nuclear Physics Program through DOE SC Lab funding announcement DE-FOA-0002670. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB054  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 01 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB055 First Experience with Liquid Nitrogen Cleaning SRF, cryomodule, operation, booster 706
 
  • R.J.M.Y. Ruber, A.B. Eslinger, R.L. Geng
    JLab, Newport News, Virginia, USA
  
  Field emission caused by microscopic particulate contamination is a limiting factor for the performance of superconducting RF (SRF) cavities. In an SRF accelerator, particulates may be transported over the surface of an operational SRF cavity, becoming field emitters and consequentially degrading the performance of the SRF cavity. The most commonly used method for removing particulates from cavity surfaces is high-pressure ultra-pure water rinsing. We are developing a novel high-pressure liquid nitrogen cleaning technique that may possibly enable superior cleaning power and particulate removal from cavities in a cryomodule without taking apart the cryomodule components. This technique provides cleaning mechanisms beyond what are accessible by its high-pressure water counterpart and leaves no residues on the cleaned surface. We present the test setup and first experience.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB055  
About • Received ※ 15 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 27 June 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB057 Refurbishment of an Elbe-Type Cryomodule for Coated HOM-Antenna Tests for MESA HOM, cryomodule, electron, niobium 709
 
  • P.S. Plattner, F. Hug, T. Stengler
    KPH, Mainz, Germany
  
  Funding: The work received funding by BMBF through 05H21UMRB1.
The Mainz Energy-Recovering Superconducting Accelerator (MESA), an energy-recovering (ER) LINAC, is currently under construction at the university Mainz. In the ER mode a continues wave (CW) beam is accelerated from 5 MeV up to 105 MeV with a beam current of up to 1 mA. This current is accelerated and decelerated twice within a cavity. For future experiments, the beam current limit has to be pushed up to 10 mA. An analysis of the MESA cavities has shown that the HOM antennas quench at such high beam currents due to the extensive power deposition and the resulting heating of the HOM coupler. To avoid quenching it is necessary to use superconducting materials with higher critical temperature. For this purpose, the HOM antennas will be coated with NbTiN and Nb3SN and their properties will be investigated. For use in the accelerator, the HOM antennas will be installed in the cavities of a former ALICE cryomodule, kindly provided by STFC Daresburry. This paper will show both the status of the refurbishment of the ALICE module to suit MESA, and the coating of the HOM antennas.
The authors would like to express their sincere gratitude to STFC Daresbury for the donation of the ALICE module, which strongly supports SRF research in Mainz. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB057  
About • Received ※ 18 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 09 July 2023
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WEPWB058 Contribution of IN2P3 to PIP-II Project: Plans and Progress SRF, linac, vacuum, status 714
 
  • D. Longuevergne, N. Bippus, P. Duchesne, N. Gandolfo, D. Le Dréan, G. Mavilla, T. Pépin-Donat, S. Roset, L.M. Vogt, S. Wallon
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • P. Berrutti, J. Helsper, S. Kazakov, M. Parise, D. Passarelli, N. Solyak, A.I. Sukhanov
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by IN2P3. 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.
IJCLab is one of the labs of IN2P3 (National institute of nuclear and particle physics), one of the ten research institutes composing the French National Center for Scientific Research (CNRS). Since 2018, IJCLab has been involved in the PIP-II project, assisting with the design, development, and qualification of accelerator components for the SSR2 (Single Spoke Resonator type 2) section of the superconducting linac. The first pre-production components (cavity, coupler, and tuner) have been fabricated, and some of the first qualification tests have been performed at IJCLab. This paper will summarize the complete scope of IJCLab¿s contributions to PIP-II and give updates on the performances of the first pre-production components. 		 
poster icon Poster WEPWB058 [1.727 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB058  
About • Received ※ 24 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 05 July 2023 — Issue date ※ 10 July 2023
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WEPWB061 Pre-Installation Performance of the RHIC 56 MHz Superconducting System cryomodule, operation, coupling, HOM 718
 
  • Z.A. Conway, R. Anderson, J.C. Brutus, K. Hernandez, D. Holmes, K. Mernick, G. Narayan, S. Polizzo, S.K. Seberg, F. Severino, M. Sowinski, R. Than, Q. Wu, B.P. Xiao, W. Xu, A. Zaltsman
    BNL, Upton, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under contract No. DE-SC0012704 with the U.S. Department of Energy.
Pre-installation test results for the RHIC 56 MHz superconducting RF system are presented here. The 56 MHz quarter-wave resonator achieved a stable accelerating potential of 1.1 MV with 13 W of RF loss at 4.5 K demonstrating its viability for increasing the luminosity of sPHENIX collisions. The new 120 kW travelling wave fundamental mode damper and dual 6 kW combined-function fundamental power couplers perform as expected at 3 kW but remain to be operated with the expected ~40 times greater power achievable with the RHIC sPHENIX beams. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB061  
About • Received ※ 15 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 02 July 2023 — Issue date ※ 17 July 2023
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WEPWB063 Final Design of the LB650 Cryomodule for the PIP-II Linear Accelerator cryomodule, vacuum, interface, simulation 721
 
  • R. Cubizolles, S. Ladegaillerie, A. Moreau
    CEA-IRFU, Gif-sur-Yvette, France
  • N. Bazin, S. Berry, J. Drant, P. Garin, A. Raut, C. Simon
    CEA-DRF-IRFU, France
  • S.K. Chandrasekaran, O. Napoly, V. Roger
    Fermilab, Batavia, Illinois, USA
  
  The Proton Improvement Plan II (PIP-II) that will be installed at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. CEA joined the international collaboration in 2018, and its scope covers the supply of the 650 MHz low-beta cryomodule section, with the design of the cryostat (i.e the cryomodule without the cavities, the power couplers and the frequency tuning systems) and the manufacturing of its components, the assembly and tests of the pre-production cryomodule and 9 production modules. An important milestone was reached in April 2023 with the Final Design Review. This paper presents the detailed design of the 650 MHz low-beta cryomodules.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB063  
About • Received ※ 21 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 04 July 2023 — Issue date ※ 20 July 2023
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WEPWB064 Performance Analysis from ESS Cryomodule Testing at CEA cryomodule, controls, electron, cryogenics 727
 
  • O. Piquet, C. Arcambal, Q. Bertrand, P. Bosland, E. Cenni, G. Devanz, T. Hamelin
    CEA-IRFU, Gif-sur-Yvette, France
  • P. Sahuquet
    CEA-DRF-IRFU, France
  
  CEA Saclay is in charge of the production of 30 elliptical cavities cryomodule as part of the in Kind contribution to the ESS superconducting. The two medium and high beta prototypes and the three first of each type of the series cryomodules have been tested at CEA in slightly different conditions than at ESS (both in terms of cryogenic operation as well as RF conditions). The goal of these tests was to validate the assembly procedure before the delivery of the series to ESS where the final acceptance tests are performed. This paper summarizes the main results obtained during the tests at CEA with a particular attention to the field emission behaviour.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB064  
About • Received ※ 20 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 07 July 2023
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WEPWB065 Impact of Medium Temperature Heat Treatments on the Magnetic Flux Expulsion Behavior of SRF Cavities SRF, controls, niobium, experiment 731
 
  • J.C. Wolff, J. Eschke, A. Gössel, K. Kasprzak, D. Reschke, L. Steder, L. Trelle, M. Wiencek
    DESY, Hamburg, Germany
  • W. Hillert
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  
  Funding: This work was supported by the Helmholtz Association within the topic Accelerator Research and Development (ARD) of the Matter and Technologies (MT) Program.
Medium temperature (mid-T) heat treatments at 300 °C are used to enhance the intrinsic quality factor of superconducting radio frequency (SRF) cavities. Unfortunately, such treatments potentially increase the sensitivity to trapped magnetic flux and consequently the surface resistance of the cavity. For this reason, it is crucial to maximize the expulsion of magnetic flux during the cool down. The flux expulsion behavior is next to the heat treatment mainly determined by the geometry, the niobium grain size and the grain orientation. However, it is also affected by parameters of the cavity performance tests like the cool down velocity, the spatial temperature gradient along the cavity surface and the magnetic flux density during the transition of the critical temperature. To improve the flux expulsion behavior and hence the efficiency of future accelerator facilities, the impact of these adjustable parameters as well as the mid-T heat treatment on 1.3 GHz TESLA-Type single-cell cavities is investigated by a new approach of a magnetometric mapping system. In this contribution first performance test results of cavities before- and after mid-T heat treatment are presented. 		 
poster icon Poster WEPWB065 [3.077 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB065  
About • Received ※ 21 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 13 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB066 Final Design of the Production SSR1 Cryomodule for PIP-II Project at Fermilab vacuum, cryomodule, alignment, solenoid 736
 
  • J. Bernardini, M. Chen, J. Helsper, M. Kramp, F.L. Lewis, T.H. Nicol, M. Parise, D. Passarelli, V. Roger, G.V. Romanov, B. Squires
    Fermilab, Batavia, Illinois, USA
  • P. Neri
    University of Pisa, Pisa, Italy
  
  Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DEAC02- 07CH11359 with the United States Department of Energy, Office of Science, Office of High Energy Physics.
This contribution reports the design of the production Single Spoke Resonator Type 1 Cryomodule (SSR1 CM) for the PIP-II project at Fermilab. The innovative design is based on a structure, the strongback, which supports the coldmass from the bottom, stays at room temperature during operations, and can slide longitudinally with respect to the vacuum vessel. The Fermilab style cryomodule developed for the prototype Single Spoke Resonator Type 1 (pSSR1), the prototype High Beta 650 MHz (pHB650), and preproduction Single Spoke Resonator Type 2 (ppSSR2) cryomodules is the baseline of the present design. The focus of this contribution is on the results of calculations and finite element analyses performed to optimize the critical components of the cryomodule: vacuum vessel, strongback, thermal shield, and magnetic shield. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB066  
About • Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 15 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB067 HB650 Cryomodule Design: From Prototype to Production cryomodule, radiation, SRF, vacuum 741
 
  • V. Roger, S.K. Chandrasekaran, C.J. Grimm, J.P. Holzbauer, O. Napoly, J.P. Ozelis, 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.
In early 2023 the assembly of the prototype HB650 cryomodule (pHB650 CM) was completed and cold tests started to evaluate its performance. The lessons learned from the design, assembly and preliminary cold tests of this cryomodule, and from the design of the SSR2 pre-production cryomodule played a fundamental role during the design optimization process of the production HB650 cryomodule (HB650 CM). Several workshops have been organized to share experiences and solve problems. This paper presents the main design changes from pHB650 to the HB650 production cryomodules and their impact on the heat loads. 		 
poster icon Poster WEPWB067 [2.178 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB067  
About • Received ※ 18 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 01 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB068 Characterization of Additive Manufacturing Materials for String Assembly in Cleanroom cryomodule, SRF, linac, detector 746
 
  • J. Bernardini, M. Parise, D. Passarelli
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DEAC02- 07CH11359 with the United States Department of Energy, Office of Science, Office of High Energy Physics.
Beamline components, such as superconducting radio frequency cavities and focusing lenses, need to be assembled together in a string while in a cleanroom environment. The present contribution identifies and characterizes materials for additive manufacturing that can be used in a cleanroom. The well known advantages of additive manufacturing processes would highly benefit the design and development of tooling needed for the mechanical support and alignment of string components. Cleanliness, mechanical properties, and leak tightness of the chosen materials are the main focus of this contribution, which also paves the way for the integration of such materials in cryomodule assemblies. Results reported here were obtained in the framework of the PIP-II project at Fermilab. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB068  
About • Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 04 July 2023
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WEPWB073 Prototype HB650 Cryomodule Heat Loads Simulations cryomodule, SRF, experiment, cryogenics 755
 
  • G. Coladonato
    University of Illinois at Chicago, Chicago, USA
  • D. Passarelli, V. Roger
    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.
During the design stages of the PIP-II cryomodules, many analytical calculations and FEA have been performed on simpler geometry in order to estimate the heat loads and also to optimize the design. To better analyze the cryomodule cold tests, simulations have been performed with MATLAB to determine the temperature of the main components during cool down and to determine the heat loads of the cryomodule. These simulations have been applied to the High Beta 650 MHz prototype cryomodule design and compared to the cold tests performed on it. 		 
poster icon Poster WEPWB073 [1.981 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB073  
About • Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 28 June 2023
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WEPWB075 Impact of Solenoid Induced Residual Magnetic Fields on the Prototype SSR1 CM Performance cryomodule, focusing, SRF, solenoid 760
 
  • D. Passarelli, J. Bernardini, C. Boffo, S.K. Chandrasekaran, A.H. Hogberg, T.N. Khabiboulline, J.P. Ozelis, M. Parise, V. Roger, G.V. Romanov, A.I. Sukhanov, G. Wu, Y. Xie, V.P. Yakovlev
    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.
A prototype cryomodule containing eight Single Spoke Resonators type-1 (SSR1) operating at 325 MHz and four superconducting focusing lenses was successfully assembled, cold tested, and accelerated beam in the framework of the PIP-II project at Fermilab. The impact of induced residual magnetic fields from the solenoids on performance of cavities is presented in this contribution. In addition, design optimizations for the production cryomodules as a result of this impact are highlighted. 		 
poster icon Poster WEPWB075 [2.429 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB075  
About • Received ※ 26 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 11 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB076 Low Particulates Nitrogen Purge and Backfill during Prototype HB650 Cryomodule String Assembly controls, vacuum, SRF, cryomodule 765
 
  • T.J. Ring, M.B. Quinlan, G. Wu
    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.
A low particulate vacuum and purging system was developed to support PIP-II cryomodule string assembly. The overpressure can be controlled at a precision of 1 mbar above the atmospheric pressure regardless of the cavity or string assembly air volume. The system minimized the risk of uncontrolled nitrogen flow during the string assembly. Design features will be presented. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB076  
About • Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 09 July 2023
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WEPWB082 Operational Experience with Turn-Key SRF Systems for Small Accelerators Like MESA SRF, cryomodule, operation, cryogenics 768
 
  • T. Stengler, K. Aulenbacher, F. Hug, P.S. Plattner
    KPH, Mainz, Germany
  
  Funding: The work is funded by the German Research Foundation (DFG) under the Cluster of Excellence "PRISMA+" EXC 2118/2019 and the Federal Ministry of Education and Research (BMBF) through project 05H21UMRB1
New SRF-based accelerator development at sites without long-term experience in SRF development is a major challenge. Especially in-house development of cryomodules is an almost impossible obstacle to overcome for small projects. To minimize such obstacles, turn-key SRF systems provided by industry can be of great importance. For the multiturn ERL MESA, which is currently under construction at Johannes Gutenberg-Universität Mainz, two turnkey cryomodules have been purchased from industry and successfully tested. The specifications of a design gradient of 12.5 MV/m in CW operation with an unloaded Q of 1.25*1010 at 1.8 K had to be met. Since the design of the modules had to be modified for high current CW operation, a close cooperation with the manufacturer was of great importance. By purchasing such a turn-key SRF system, the MESA project successfully established the SRF accelerator technology at the site within six years. This was achieved through close monitoring of the manufacturing process and close cooperation with the manufacturer. An overview of the experience with the successful technology transfer of a complete turn-key SRF system for small accelerators will be given. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB082  
About • Received ※ 25 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 03 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB083 Basic Design and Consideration of Li-Vapor Contamination for A-FNS SRF SRF, solenoid, linac, operation 773
 
  • T. Ebisawa, K. Hasegawa, A. Kasugai, M. Oyaidzu, S. Sato
    QST Rokkasho, Aomori, Japan
  • E. Kako, H. Sakai, K. Umemori
    KEK, Ibaraki, Japan
  
  The Advanced Fusion Neutron Source (A-FNS) project is in progressing in Japan, QST Rokkasho institute. A-FNS will demonstrate a performance of the DEMO DT fusion reactor material. In order to perform the test, a high intensity deuteron beam accelerator will be used to produce a high flux neutron field which is similar to the 14 MeV DT neutron. The Superconducting Radio-Frequency linear accelerator (SRF) is one component of the A-FNS accelerator system. Although the A-FNS accelerator system design is based on the IFMIF design, the improvement of some subsystem has been considering by taking into account the lessons learnt from the LIPAc project. In order to keep a high stability and availability of the SRF performance, we plan to increase the number of SRF cavities and cryomodules considering the trouble or degradation of the cavity performance and modify the engineering design of some components. In addition, changing of the beam transport line design and Li vapor contamination study of SRF cavity are conducting. In this presentation, the progress of the SRF design and related activities for A-FNS in QST will be presented.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB083  
About • Received ※ 28 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 17 August 2023
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WEPWB084 The Interaction among Interstitial C/N/O/H and Vacancy in Niobium via First-Principles Calculation niobium, lattice, electron, site 778
 
  • H. Liu, J.K. Hao, Z.T. Yang
    PKU, Beijing, People’s Republic of China
  
  We calculate the interaction among zero dimensional defects in niobium lattice through first-principles calculation. And we compare the trapping effect of hydrogen among carbon, nitrogen, and oxygen as well as the trapping effect of interstitial atoms by vacancy. We find that the interstitial C/N/O have similar effect of trapping interstitial hydrogen in niobium lattice, and the vacancy can trap interstitial C/N/O/H in adjacent protocells and strengthen their chemical bond with Nb. These calculations give some explanation for improving superconducting performance of niobium cavities through medium temperature baking.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB084  
About • Received ※ 15 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 03 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB085 Degradation and Recovery of Cavity Performance in SRILAC Cryomodules at RIBF operation, vacuum, SRF, acceleration 784
 
  • N. Sakamoto, O. Kamigaito, K. Ozeki, K. Suda, K. Yamada
    RIKEN Nishina Center, Wako, Japan
  
  The RIKEN superconducting (SC) heavy-ion linear accelerator (SRILAC) has been providing beam supply for super-heavy elements synthesis experiments since its commissioning in January 2020. However, the long-term operation of SC radio-frequency (RF) cavities leads an increase in the X-ray levels caused by field emissions resulting from changes in the inner surface conditions. More than half of the ten SC 1/4 wavelength resonators (SC-QWRs) of SRILAC, operating at a frequency of 73 MHz, have experienced an increase in X-ray levels, thus, requiring adjustments to the acceleration voltage for continuous operation. While several conditioning methods have been employed for SC cavities, a fully established technique is yet to be determined. To address this situation, a relatively simple conditioning method was implemented at RIKEN. The proposed method uses high-voltage pulsed power and imposes a low load on the cavities.  
poster icon Poster WEPWB085 [12.789 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB085  
About • Received ※ 13 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 01 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB087 Copper Plating Qualification Process for the Fundamental Power Coupler Waveguides for CEBAF Cryomodules GUI, cryomodule, SRF, operation 790
 
  • L. Zhao, G. Cheng, G. Ciovati, K.M. Wilson
    JLab, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC, supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
To provide sufficient energy for CEBAF operation, cryomodules and components are being refurbished yearly as necessary. Copper plated fundamental power coupler waveguides are important components of the cryomodules. The integrity and quality of copper plating is critical to reduce the heat load from the waveguides into the He bath at 2.07 K. A search of copper plating resources is underway for plating or re-plating CEBAF-style waveguides. This effort ensures a continuous capability of copper plating on cryomodule components, especially on waveguides. To qualify plating vendors, the waveguide copper plating specifications were revisited, and a thorough plating evaluation process is being developed. The evaluation process ranges from coupon testing to sample waveguide qualification. Recent results are summarized and future work is planned. 		 
poster icon Poster WEPWB087 [1.582 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB087  
About • Received ※ 15 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 11 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB089 Theoretical Model of External Q Tuning for an SRF Cavity with Waveguide Tuner GUI, SRF, operation, electron 794
 
  • W. Xu, Z.A. Conway, K.S. Smith, A. Zaltsman
    BNL, Upton, New York, USA
  • E.F. Daly, J. Guo, R.A. Rimmer
    JLab, Newport News, Virginia, USA
  
  Funding: The work is supported by by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
A wide range of electron beam energies (5 ¿ 18 GeV) and beam currents (0.2 ¿ 2.5 A) in EIC Electron Storage Ring (ESR) operating scenarios requires a capability of adjusting coupling factor up to a factor of 20 for the 591 MHz Superconducting Radio Frequency (SRF) cavities, which contains two fundamental power couplers (FPC) delivering continuous wave (CW) 800 kW RF power to the beam. Currently, adjusting external Q of a SRF cavity is done by varying protrusion of FPC¿s inner conductor in beam pipe or using three stub tuner to adjust external Q value, which either has limit on tuning range or limit on operating power. This paper presents a method of tuning the FPC external Q by a multiple-waveguide tuner, which allows for high power, wide tuning range operations. The theoretical model of matching beam impedance with waveguide tuner and detailed matching conditions and limits will be presented. Follow the theoretical model, a preliminary design of a 3D waveguide tuner will be presented.
The work is supported by by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
 		 
poster icon Poster WEPWB089 [1.269 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB089  
About • Received ※ 26 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 19 August 2023 — Issue date ※ 22 August 2023
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WEPWB092 Test-Stand for Conditioning of Fundamental Power Couplers at DESY FEL, vacuum, GUI, MMI 797
 
  • K. Kasprzak, Th. Buettner, A. Gössel, D. Klinke, D. Kostin, C. Müller, E. Vogel, M. Wiencek
    DESY, Hamburg, Germany
  
  During the construction of the European-XFEL, activities related to Fundamental Power Couplers (FPCs) were outsourced to external partners and the former FPC test-stand area at DESY was given up due to infrastructure rearrangements. For the study of various XFEL upgrade scenarios a new test-stand for conditioning of FPCs at DESY is required. It will be used for evaluation of new coupler preparation methods with particular emphasis on Continuous Wave (CW) and long RF pulse operation. The new test-stand has been recently commissioned. Four FPCs have been prepared and tested. RF pulses were applied to the couplers, starting with the shortest possible pulse and increasing it’s power until maximum power was reached. The process was repeated with several pulse lengths until the maximum RF pulse length was reached. A review of the commissioning and first operation experience of the RF system are presented here.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB092  
About • Received ※ 15 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 16 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB094 Design, Manufacturing, Assembly, and Lessons Learned of the Pre-Production 325 MHz Couplers for the PIP-II Project at Fermilab vacuum, SRF, interface, cryomodule 806
 
  • J. Helsper, S. Kazakov, D. Passarelli, N. Solyak
    Fermilab, Batavia, Illinois, USA
  • D. Longuevergne, S. Wallon
    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.
Five 325 MHz high-power couplers will be integrated into the pre-production Single Spoke Resonator Type-II (ppSSR2) cryomodule for the PIP-II project at Fermilab. Couplers were procured by both Fermilab and IJCLAB for this effort. The design of the coupler is described, including design optimizations from the previous generation. This paper then describes the coupler life cycle, including design, manufacturing, and assembly, along with the lessons learned at each stage. 		 
poster icon Poster WEPWB094 [3.561 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB094  
About • Received ※ 19 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 29 June 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB096 Testing of PIP-II Pre-production 650 MHz Couplers in Warm Test Stand and Cryomodule vacuum, cryomodule, resonance, coupling 812
 
  • N. Solyak, S.K. Chandrasekaran, B.M. Hanna, J. Helsper, J.P. Holzbauer, S. Kazakov, A.I. Sukhanov
    Fermilab, Batavia, Illinois, USA
  
  650 MHz fundamental power couplers were developed for PIP-II project to deliver RF power for low-beta and high-beta elliptical cavities. Few prototypes were built and tested and after some modification we built 8 pre-production couplers (with three spares for vacuum side) for ppHB650 cryomodule. All couplers were successfully tested in pulse mode (up to 100kW) and in CW mode (up to 50kW) in test stand at full reflection at 8 phases. In baseline configuration with DC bias we do not see any multipactoring activity after short processing. We also tested power processing without bias for uncoated and TiN coated ceramic window. Results of these studies presented in this paper. One of the coupler was assembled on LB650 cavity and tested at cryogenic environment in STC cryostat at ~30kW power with full reflection at different reflection phase. We also demonstrated good result from power processing without bias for warm and cold cavity. Six couplers were assembled on HB650 cavities in pre-production cryomodule. Test results from cryomodule qualification is discussing in this paper.  
poster icon Poster WEPWB096 [2.748 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB096  
About • Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 17 July 2023
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WEPWB097 Testing and Processing of Pre-production 325 MHz Single Spoke Resonator Power Couplers for PIP-II Project vacuum, coupling, SRF, pick-up 816
 
  • N. Solyak, B.M. Hanna, J. Helsper, S. Kazakov, D. Passarelli
    Fermilab, Batavia, Illinois, USA
  • S. Wallon
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  
  Fundamental 325 MHz power couplers are designed, built and tested for SSR cavities in PIP-II project [1]. Couplers should work in CW mode at power level 7.5kW w/o beam and ~15 kW with the 2 mA beam. At pre-production stage we built and tested 6 couplers, produced by CPI (FNAL) and PMB (IJCLab) and 4 more couplers will be tested soon. Two of tested cou-plers had TiN coated ceramic window. In warm test stand two couplers were mounted on the coupling chamber and tested in SW regime at full reflection with phase controlled by position of short and reflection insert. Couplers were tested at pulse mode (up to 25kW) and cw mode (12kW) with HV bias or without bias. Test results demonstrated that 3.5 kV DC bias completely suppresses multipactor in coupler. Vacuum activity in coupler was controlled by e-pickups and build-in vacuum gauges, located near the vacuum side of window. Power processing without DC bias was done for several couplers with and without TiN coating on ceramic window. Test results are presented and discussing in paper.  
poster icon Poster WEPWB097 [2.439 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB097  
About • Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 29 June 2023
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WEPWB098 Development and Evaluation of STF-Type Power Coupler for Cost Reduction at the High Energy Accelerator Research Organization vacuum, SRF, GUI, cryomodule 820
 
  • Y. Yamamoto, T. Matsumoto, S. Michizono
    KEK, Ibaraki, Japan
  
  At KEK, cost reduction study for STF-type input power coupler used in the STF-2 accelerator has been attempted since FY2015. In FY2019, one coupler was fabricated by some cost-effective and non-conventional methods including different alumina-ceramic material, copper plating and TiN coating. In high power RF test at room temperature, this coupler achieved 1 MW at 900 µsec/5Hz, and 935 kW @1.65 msec/5Hz. After that, this coupler experienced 10 thermal cycle tests from room temperature to liquid nitrogen temperature without vacuum leakage. In this report, the detailed results will be presented.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB098  
About • Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023
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WEPWB102 Recent Progress of Fundamental Power Couplers for the SHINE Project FEL, vacuum, cryomodule, electron 827
 
  • Z.Y. Ma, J.F. Chen, H.T. Hou, B. Liu, Y. Liu, S. Sun, D. Wang, L. Yin, M. Zhang, S.J. Zhao, Y.B. Zhao, Z.T. Zhao, X. Zheng
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
  
  Funding: Project supported by Shanghai Municipal Science and Technology Major Project (Grant No.2017SHZDZX02).
The superconducting radio-frequency electron linear accelerator of the Shanghai HIgh repetition rate XFEL aNd Extreme light facility (SHINE) contains 610 1.3 GHz fundamental power couplers which are assembled in 77 superconducting cryomodules used for beam acceleration, and 16 3.9 GHz fundamental power couplers, which are assembled in two third harmonic superconducting cryomodules used for linearizing the longitudinal phase space. The first batch of 26 1.3 GHz coupler prototypes and two 3.9 GHz coupler prototypes have been fabricated from three domestic manufacturers for basic research. Several key manufacturing processes have been developed and qualified, including high residual resistivity ratio (RRR) copper plating, vacuum brazing of ceramic windows, electron beam welding and titanium nitride coating. All the 1.3 GHz coupler prototypes have been power conditioned with 14 kW travelling wave (TW) and 7 kW standing wave (SW) RF in continuous-wave (CW) mode. Even higher power levels have been demonstrated with 20 kW TW and 10 kW SW RF, which indicates their robustness. Both 3.9 GHz coupler prototypes have been power conditioned with 2.2 kW TW and 2 kW SW RF in CW mode. 		 
poster icon Poster WEPWB102 [2.361 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB102  
About • Received ※ 16 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 05 July 2023
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WEPWB103 Simulations and First RF Measurements of Coaxial HOM Coupler Prototypes for PERLE SRF Cavities HOM, damping, coupling, simulation 831
 
  • C. Barbagallo, P. Duchesne, W. Kaabi, G. Olivier, G. Olry, S. Roset, Z.F. Zomer
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • B.S. Barriere, C.S. Clement, R.L.A. Gerard, F. Gerigk, P.M. Maurin
    CERN, Meyrin, Switzerland
  • J. Henry, S.A. Overstreet, G.-T. Park, R.A. Rimmer, H. Wang
    JLab, Newport News, Virginia, USA
  
  Superconducting Radio-Frequency (SRF) linac cryomodules are foreseen for the high-current multi-turn energy recovery linac PERLE (Powerful Energy Recovery Linac for Experiments). Coaxial higher order mode (HOM) couplers are the primary design choice to absorb beam-induced power and avoid beam instabilities. We have used 3D-printed and copper-coated HOM couplers for the prototyping and bench RF measurements on the copper PERLE cavities. We have started a collaboration with JLab and CERN on this effort. This paper presents electromagnetic simulations of the cavity HOM-damping performance on those couplers. Bench RF measurements of the HOMs on an 801.58 MHz 2-cell copper cavity performed at JLab are detailed. The results are compared to eigenmode simulations in CST to confirm the design. RF-thermal simulations are conducted to investigate if the studied HOM couplers undergo quenching.  
poster icon Poster WEPWB103 [1.533 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB103  
About • Received ※ 18 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 02 July 2023
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WEPWB104 RF Conditioning of MYRRHA Couplers at IJCLab vacuum, electron, FEL, multipactoring 835
 
  • N. ElKamchi, S. Berthelot, P. Duchesne, C. Joly, W. Kaabi, C. Magueur
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • Y. Gómez Martínez
    LPSC, Grenoble Cedex, France
  • C. Lhomme
    IJCLab, ORSAY, France
  
  Multi-purpose hYbrid Research Reactor for High-tech Applications (MYRRHA) is an experimental accelerator-driven system in development at SCK•CEN. It will allow fuel developments, material developments for GEN IV systems, material developments for fusion reactors and radioisotope production for medical and industrial applications1. The IJCLab has in charge the industrial monitoring, the quality control and the RF conditioning of the power couplers up to 80KW at 352Mhz. This paper presents the conditioning bench adapted from the successful experience of IJCLab in the conditioning of the XFEL couplers2. The results of the conditioning of prototype couplers are described and discussed.
1. Abderrahim, P. MYRRHA a multi-purpose hybrid research reactor for high-tech applications. United States: N. p., 2012. Web
2. H. Guler, Proceedings of IPAC2016, Busan, Korea
 		 
poster icon Poster WEPWB104 [0.875 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB104  
About • Received ※ 26 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 08 August 2023
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WEPWB105 Improved Study of the Multipactor Phenomenon for the MYRRHA 80 kW CW RF Couplers multipactoring, electron, coupling, linac 838
 
  • Y. Gómez Martínez, P.-O. Dumont
    LPSC, Grenoble Cedex, France
  • P. Duchesne, N. ElKamchi, C. Joly, W. Kaabi
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • C. Lhomme
    IJCLab, ORSAY, France
  • C. Lhomme
    ACS, Orsay, France
  
  MYRRHA (Multi Purpose Hybrid Reactor for High Tech Applications) is an Accelerator Driven System (ADS) project. Its superconducting linac will provide a 600 MeV - 4 mA proton beam. The first project phase based on a 100 MeV linac is launched. The Radio-Frequency (RF) couplers have been designed to handle 80 kW CW (Continuous Wave) at 352.2 MHz. This paper describes the multipactor studies on the coupler when it does not work in the nominal configuration without reflected power.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB105  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 12 July 2023
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WEPWB108 Update on Cornell High Pulsed Power Sample Host Cavity SRF, coupling, pulsed-power, simulation 841
 
  • N.M. Verboncoeur, A.T. Holic, M. Liepe, T.E. Oseroff, R.D. Porter, J. Sears, L. Shpani
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • R.D. Porter
    SLAC, Menlo Park, California, USA
  
  The Cornell High Pulsed Power Sample Host Cavity (CHPPSHC) is designed to measure the temperature-dependent superheating fields of future SRF materials and thereby gain insights into the ultimate limits of their performance. Theoretical estimation of the superheating fields of SRF materials is challenging and mostly has been done for temperatures near the critical temperature or in the infinite kappa limit. Experimental data currently available is incomplete, and often impacted by material defects and their resulting thermal heating, preventing finding the fundamental limits of theses materials. The CHPPSHC system allows reaching RF fields in excess of half a Tesla within microseconds on material samples by utilizing high pulsed power, thereby outrunning thermal effects. We are principally interested in the superheating field of Nb₃Sn, a material of interest for the SRF community, and present here the current fabrication and assembly status of the CHPPSHC as well as early results.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB108  
About • Received ※ 27 June 2023 — Revised ※ 20 July 2023 — Accepted ※ 20 August 2023 — Issue date ※ 22 August 2023
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WEPWB109 PI Loop Resonance Control for the Dark Photon Experiment at 2 K using a 2.6 GHz SRF cavity photon, simulation, experiment, SRF 847
 
  • C. Contreras-Martinez, B. Giaccone, O.S. Melnychuk, A.V. Netepenko, Y.M. Pischalnikov, S. Posen, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  
  Two 2.6 GHz cavities are being used for dark photon search at VTS in FNAL. During testing at 2 K the cavities experience frequency detuning caused by microphonics and slow frequency drifts. The experiment requires that the two cavities have the same frequency within 5 Hz. These two cavities are equipped with frequency tuners consisting of three piezo actuators. The piezo actuators are used for fine-fast frequency tuning. A PI loop utilizing the piezos was used to maintain both cavities at the same frequency, and the results are presented.  
poster icon Poster WEPWB109 [1.151 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB109  
About • Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 18 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB110 Prevention of Dual-Mode Excitation in 9-Cell Cavities for LCLSII-HE resonance, controls, feedback, SRF 852
 
  • P.D. Owen
    JLab, Newport News, Virginia, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Dual-Mode Excitation, also referred to as mode-mixing, is a superposition of two pi modes in an SRF cavity. In 9-cell TESLA cavities used for the LCLSII-HE project, the two modes that are commonly excited are the pi mode (1300.2 MHz), and the 7/9 pi mode (1297.8 MHz). During vertical cavity qualification testing, it is regularly observed that emitted power at the frequency of the 7/9 pi mode grows, despite the RF system only driving the pi mode. When this happens, the RF power measurement system is unable to differentiate between the superimposed modes which invalidates any data taken. A new RF control solution prevents the 7/9 pi mode from being excited. A second RF control system is connected to drive the 7/9 pi mode. The loop phase for driving this mode is determined, then shifted by 180 degrees, thus providing a negative feedback to the undesired mode. Because this off-resonance power can be very small, it does not interfere with the high-power measurements of the fundamental pi mode. At Jefferson Lab, we are now able to test a cavity for the LCLSII-HE project with no complications from mode-mixing, which allows for CW processing of high-gradient multipacting. 		 
poster icon Poster WEPWB110 [1.818 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB110  
About • Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023
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WEPWB111 A New Ultra-High Vacuum Furnace for SRF R&D vacuum, niobium, operation, SRF 855
 
  • M. Wenskat, C. Bate
    DESY, Hamburg, Germany
  • C. Bate, C. Martens
    University of Hamburg, Hamburg, Germany
  • R. Ghanbari, W. Hillert
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  
  Funding: This work was supported by the BMBF under the research grants 05K19GUB and 05H2021.
A new vacuum furnace has been designed and purchased by the University of Hamburg and is operating in an ISO5 cleanroom. This furnace can anneal single-cell TESLA cavities at temperatures up to 1000°C and with a pressure of less than 10-7mbar or in a nitrogen atmosphere of up to 10-2mbar. We will lay out the underlying design ideas, based on the gained experience from our previous annealing research, and present the commissioning of the furnace itself. Additionally, we will show for the first time the results of sample and cavity tests after annealing in the furnace. This will be accompanied by an overview of the intended R&D process and scientific questions to be addressed. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB111  
About • Received ※ 21 June 2023 — Revised ※ 15 July 2023 — Accepted ※ 20 August 2023 — Issue date ※ 21 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB116 The Influence of Sample Preparation, Soak Time, and Heating Rate on Measured Recrystallization of Deformed Polycrystalline Niobium ECR, niobium, SRF, electron 863
 
  • Z.L. Thune
    MSU, East Lansing, USA
  • T.R. Bieler
    Michigan State University, East Lansing, Michigan, USA
  
  Funding: DOE/OHEP (Grant Number: DE-SC0009960)
Improving accelerator performance relies on consistent production of high-purity niobium superconducting radiofrequency (SRF) cavities. Current production uses an 800 °C 3 hr heat treatment, but 900-1000 °C can improve cavity performance via recrystallization (Rx) and grain growth. As Rx is thermally activated, increasing the temperature and/or the heating rate could facilitate a reduction in geometrically necessary dislocation (GND) density that is associated with the degradation of cavity performance via trapped magnetic flux. Recent work shows that increasing the annealing temperature increased the Rx fraction in cold-rolled polycrystalline niobium. However, the influence of heating rate on the extent of Rx was minimal with a 3 hr soak time. To further assess the influence of heating rate on measured Rx, as well as the effects of sample preparation, electron backscatter diffraction (EBSD) was used to quantify the extent of Rx on samples annealed at a single temperature with different soak times. Comparing samples with different surface preparation shows that pinned grain boundaries on the free surface reveal a much smaller grain size than below the surface.
* Z.L. Thune et al., "The Influence of Strain Path and Heat Treatment Variations on Recrystallization in Cold-Rolled High-Purity Niobium Polycrystals," doi: 10.1109/TASC.2023.3248533. 		 
poster icon Poster WEPWB116 [1.312 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB116  
About • Received ※ 23 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 20 August 2023 — Issue date ※ 21 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB118 Study and Improvements of Liquid Tin Diffusion Process to Synthesize Nb₃Sn Cylindrical Targets target, niobium, simulation, experiment 868
 
  • D. Ford, E. Chyhyrynets, D. Fonnesu, G. Keppel, G. Marconato, C. Pira, A. Salmaso
    INFN/LNL, Legnaro (PD), Italy
  
  Funding: This project has received funding from the European Union¿s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730. Work supported by the INFN CSNV experiment SAMARA.
Nb₃Sn thin films on bulk Nb cavities exhibit comparable performance to bulk Nb at lower temperatures, and using Cu as a substrate material can further improve performance and reduce costs. However, coating substrates with curved geometries like elliptical cavities can be challenging due to the brittleness of Nb₃Sn targets produced by a classical sintering technique. This work explores the use of the Liquid Tin Diffusion (LTD) technique to produce sputtering targets for 6 GHz elliptical cavities, which allows for the deposition of thick and uniform coatings on Nb substrate, even for complex geometries. The study includes improvements in the LTD process and the production of a single-use LTD target, as well as the characterization of Nb₃Sn films coated by DC magnetron sputtering using these innovative targets. 		 
poster icon Poster WEPWB118 [5.462 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB118  
About • Received ※ 17 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 01 August 2023
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WEPWB119 Additive Manufacturing of Pure Niobium and Copper Using Laser Powder Bed Fusion for Particle Accelerator Applications niobium, laser, SRF, plasma 872
 
  • D. Ford, R. Caforio, E. Chyhyrynets, G. Keppel, C. Pira
    INFN/LNL, Legnaro (PD), Italy
  • M. Bonesso, S. Candela, V. Candela, R. Dima, G. Favero, A. Pepato, P. Rebesan, M. Romanato
    INFN- Sez. di Padova, Padova, Italy
  • M. Pozzi
    Rösler Italiana s.r.l., Concorezzo, Italy
  
  Funding: This project has received funding from the European Union¿s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730. Work supported by the INFN CSNV experiment SAMARA.
In this study, Metal Additive Manufacturing (MAM) was evaluated as a viable method for producing seamless 6 GHz pure copper and niobium prototypes without the use of internal supports. Preliminary tests were performed to evaluate printability, leading to further investigations into surface treatments to reduce surface roughness from 35 µm to less than 1 µm. Additional prototypes were printed using different powders and machines, exploring various printing parameters and innovative contactless supporting structures to improve the quality of downward-facing surfaces with small inclination angles. These structures enabled the fabrication of seamless SRF cavities with a relative density greater than 99.8%. Quality testing was conducted using techniques such as tomography, leak testing, resonant frequency assessment, and internal inspection. The results of this study are presented herein. 		 
poster icon Poster WEPWB119 [9.235 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB119  
About • Received ※ 18 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 18 July 2023
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WEPWB120 Flux Expulsion Testing for LCLS-II-HE Cavity Production cryomodule, niobium, SRF, ECR 876
 
  • J.T. Maniscalco, S. Aderhold, M. Checchin, D. Gonnella, R.D. Porter
    SLAC, Menlo Park, California, USA
  • T.T. Arkan, D. Bafia, J.A. Kaluzny, S. Posen
    Fermilab, Batavia, Illinois, USA
  • M.E. Bevins, A.J. Grabowski, J. Hogan, C.E. Reece, D. Savransky, H. Vennekate
    JLab, Newport News, Virginia, USA
  
  Nitrogen-doped niobium SRF cavities are sensitive to trapped magnetic flux, which decreases the cavity intrinsic Q₀. Prior experimental results have shown that heat treatments to 900°C and higher can result in stronger flux expulsion during cooldown; the precise temperature required tends to vary by vendor lot/ingot of the niobium material used in the cavity cells. For LCLS-II-HE, to ensure sufficient flux expulsion in all cavities, we built and tested single-cell cavities to determine this required temperature for each vendor lot of niobium material to be used in cavity cells. In this report, we present the results of the single-cell flux expulsion testing and the Q₀ of the nine-cell cavities built using the characterized vendor lots. We discuss mixing material from different vendor lots, examine the lessons learned, and finally present an outlook on possible refinements to the single-cell technique.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB120  
About • Received ※ 15 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 03 July 2023 — Issue date ※ 13 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB121 Niobium Chronicles: Surface Quality Investigation and Recovery During Material Procurement for the PIP-II High Beta 650 MHz Cavities niobium, controls, factory, synchrotron 880
 
  • A.D. Shabalina
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  
  The surface quality of high-purity niobium for superconducting radiofrequency cavities experienced a sudden and significant decline in 2021. The recovery process and root cause analysis were challenging due to a variety of factors such as COVID-19 travel restrictions, cultural differences, and bureaucratic processes. Effective open communication was crucial to resolving the issue, especially with direct vendor oversight being impossible.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB121  
About • Received ※ 28 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 20 August 2023 — Issue date ※ 20 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB125 Thermodynamic Properties of Srf Niobium SRF, niobium, radio-frequency, cryogenics 884
 
  • P. Dhakal
    JLab, Newport News, Virginia, USA
  
  Funding: This is authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05- 06OR23177.
Bulk and thin films of niobium are the materials of choice in fabricating superconducting radio frequency (SRF) cavities for modern particle accelerators and quantum computing applications. The thermodynamic properties of Nb are of particular interest in heat management in cryogenic environments. Here, we report the results of measurements of the thermodynamic properties of niobium used in the fabrication of superconducting radio frequency (SRF) cavities. The temperature and magnetic field dependence of thermal conductivity, Seebeck coefficient, and specific heat capacity was measured on bulk niobium samples. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB125  
About • Received ※ 11 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 04 July 2023
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WEPWB126 First Results from Nanoindentation of Vapor Diffused Nb₃Sn Films on Nb SRF, linac, experiment, accelerating-gradient 888
 
  • U. Pudasaini
    JLab, Newport News, Virginia, USA
  • S. Cheban, G.V. Eremeev
    Fermilab, Batavia, Illinois, USA
  
  Funding: U.S. Department of Energy, Office of Science, Office of Nuclear Physics & Office of High Energy Physics.
The mechanical vulnerability of the Nb₃Sn-coated cavities is identified as one of the significant technical hurdles toward deploying them in practical accelerator applications in the not-so-distant future. It is crucial to characterize the material’s mechanical properties in ways to address such vulnerability. Nanoindentation is a widely used technique for measuring the mechanical properties of thin films that involves indenting the film with a small diamond tip and measuring the force-displacement response to calculate the film’s elastic modulus, hardness, and other mechanical properties. The nanoindentation analysis was performed on multiple vapor-diffused Nb₃Sn samples coated at Jefferson Lab and Fermilab coating facilities for the first time. This contribution will discuss the first results obtained from the nanoindentation of Nb₃Sn-coated Nb samples prepared via the Sn vapor diffusion technique. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB126  
About • Received ※ 19 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 16 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB127 Investigation of Coupler Breakdown Thresholds for Plasma Processing of FRIB Quarter-Wave Resonators with Fundamental and Higher-Order Modes plasma, electron, HOM, simulation 893
 
  • P.R. Tutt, W. Hartung, S.H. Kim, T. Xu
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics and used resources of the Facility for Rare Isotope Beams (FRIB) under Award Number DE-SC0000661.
FRIB is developing plasma processing techniques for in-situ recovery of cavity performance in linac cryomodules during long-term user operation. While plasma processing has been shown to be effective for high-frequency (0.8 - 1.5 GHz) elliptical cavities, one of the challenges for FRIB is to avoid plasma breakdown in the fundamental input coupler (FPC), which has relatively weak coupling strength (Qext ranging from 2E6 to 1E7). FRIB cavities are not equipped with higher-order-mode (HOM) couplers; however, in preliminary tests, we found that HOMs are suitable for plasma processing of FRIB Quarter-Wave Resonators (QWRs) driven via the FPC. In this study, we investigated plasma breakdown thresholds in the fundamental and the first 2 HOMs for the FRIB β = 0.085 QWRs. Electric field distributions in the FPC region and cavity region were calculated for the room-temperature case using CST Microwave Studio’s frequency domain solver (FDS). Simulation results will be presented, with comparison of breakdown thresholds inferred from the RF modeling to the experimental results. 		 
poster icon Poster WEPWB127 [5.068 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB127  
About • Received ※ 19 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 11 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB128 Experimental Study of Mechanical Dampers for the FRIB β=0.041 Quarter-Wave Resonators damping, operation, linac, ECR 898
 
  • J. Brown, W. Chang, W. Hartung, S.H. Kim, T. Xu
    FRIB, East Lansing, Michigan, USA
  
  Funding: Work supported by the US Department of Energy, Office of Science, High Energy Physics under Cooperative Agreement award numbers DE-SC0018362 and DE-SC0000661 and Michigan State University.
The ’pendulum’ mechanical mode of quarter-wave resonators (QWR) often causes an issue with microphonics and/or ponderomotive instability unless otherwise the inner conductors are properly stiffened and/or damped. FRIB QWRs are equipped with a Legnaro-style frictional damper installed inside of the inner conductor such that it counteracts the oscillations of the inner conductor. In cryomodule tests and linac operation, we observed that the damping efficiency is different for a few β=0.041 QWRs. This study aimed to experimentally characterize the damping efficacy as a function of damper mass and surface roughness. We present damping measurements at room temperature and at two different masses and surface roughness as well as discuss future studies for damper re-optimization based on this follow-on study. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB128  
About • Received ※ 20 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 04 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB131 Demonstration of Magnetron as an Alternative RF Source for SRF Accelerators injection, controls, power-supply, klystron 902
 
  • H. Wang, K. Jordan, R.A. Rimmer
    JLab, Newport News, Virginia, USA
  • J.P. Anderson, C.P. Moeller, K.A. Thackston
    GA, San Diego, California, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177, and DOE OS/ARDAP Accelerator Stewardship award 2019-2023.
Magnetron has been considered as alternate high-efficiency, low-cost RF sources for linacs and storage rings [1] for national labs and industrial applications. After the demonstration of magnetrons power to drive and combine for a radio frequency cavity at 2450 MHz in CW mode, we have used trim coils adding to a water-cooled magnetron and amplitude modulation feedback to further suppress the side-band noise to -46.7 dBc level. We also demonstrated the phase-locking to an industrial grade cooking magnetron transmitter at 915 MHz with a 75 kW CW power delivered to a water load by using a -26.6 dBc injection signal [2]. The sideband noise from the 3-Phase SCRs DC power supply can be reduced to -16.2 dBc level. Further noise reduction and their power combining scheme using magic-tee and cavity type combiners for higher power application (2x75kW) are to be presented. We intent to use one power station to drive the normal conducting and superconducting RF cavities for the inductrial linac. We also going to demonstarte a vertical SRF cavity test with a high input coupling Q using a 2.45GHz magnetron and comparing with a baseline test result using a solid state amplifier.
[1]. doi:10.18429/JACoW-IPAC2015-WEPWI028.
[2]. doi:10.18429/JACoW-NAPAC2022-WEZD3.
 		 
poster icon Poster WEPWB131 [2.445 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB131  
About • Received ※ 16 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 30 June 2023 — Issue date ※ 19 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB133 Testing of the 2.6 GHz SRF Cavity Tuner for the Dark Photon Experiment at 2 K photon, SRF, experiment, ECR 907
 
  • C. Contreras-Martinez, B. Giaccone, I.V. Gonin, T.N. Khabiboulline, O.S. Melnychuk, Y.M. Pischalnikov, S. Posen, O.V. Pronitchev, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  
  At FNAL two 2.6 GHz SRF cavities are being used to search for dark photons, the experiment can be conducted at 2 K or in a dilution refrigerator. Precise frequency tuning is required for these two cavities so they can be matched in frequency. A cooling capacity constraint on the dilution refrigerator only allows piezo actuators to be part of the design of the 2.6 GHz cavity tuner. The tuner is equipped with three encapsulated piezo that deliver the long- and short-range frequency tuning. Modifications were implemented on the first tuner design due to the low forces on the piezos due to the cavity. Three brass rods with Belleville washers were added to the design to increase the overall force on the piezos. The results at 2 K of testing this tuner with and without the modification will be presented.  
poster icon Poster WEPWB133 [0.829 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB133  
About • Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 04 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB134 Study of Different Piezoelectric Material Stroke Displacement at Different Temperatures Using an SRF Cavity SRF, experiment, controls, resonance 911
 
  • C. Contreras-Martinez, Y.M. Pischalnikov, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  
  Piezoelectric actuators are used for resonance control in superconducting linacs. The level of frequency compensation depends on the piezoelectric stroke displacement. In this study, the stroke displacement will be measured with a 1.3 GHz SRF cavity by measuring the frequency shift with respect to the voltage applied. The entire system was submerged in liquid helium. This study characterizes the PZT piezoelectric actuator (P-844K093) and a lithium niobate (P-844B0005) piezoelectric actuator. All these actuators were developed at Physik Instrumente (PI). The piezo-electric displacement was measured at different temperatures.  
poster icon Poster WEPWB134 [0.776 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB134  
About • Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 13 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB135 A Novel Twin Drive Tuner Mechanism for 1.3 GHz ILC Cavity SRF, FEL, operation, site 914
 
  • M. Yamanaka
    KEK, Ibaraki, Japan
  
  A tuner is a device that adjusts the resonant frequency of a cavity. Here we propose a new tuner mechanism for the 1.3 GHz ILC cavity. A bellow is provided in the central portion of the helium tank in the longitudinal direction, and flanges are provided on both sides of the bellows. A linear motion actuator is fixed to the flange on one side, and the frequency is changed by pushing and pulling the flange on the opposite side. Significantly, two linear motion actuators are placed in circumference and working simultaneously. It is named a twin-drive tuner. According to the ILC specification, the cavity has a spring constant of 3 KN/mm, requiring a stroke of 2 mm to adjust the 600 kHz range. A loading force of 6 kN is required. This is shared by two linear motion actuators. We developed a prototype actuator with a loading force of 4 kN per unit. It consists of a stepping motor and a sliding screw with a plastic nut. An experimental device was constructed using this actuator and a 1.3 GHz cavity with a helium tank, and the frequency tuning was evaluated. The displacement between the flanges and the frequency are proportional, both have good linearity, and the slope is 296 kHz/mm.  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB135  
About • Received ※ 17 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 17 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPWB137 Prototype SSR2 Tuner Procurement and Testing at IJCLab for PIP-II Project vacuum, insertion, SRF, cryomodule 917
 
  • N. Gandolfo, P. Duchesne, D. Le Dréan, D. Longuevergne, G. Mavilla, T. Pépin-Donat
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • M. Parise, D. Passarelli, Y.M. Pischalnikov
    Fermilab, Batavia, Illinois, USA
  
  Funding: Work supported by IN2P3. 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.
IJCLab is involved in the PIP-II project on the design and development of accelerator components for the SSR2 (Single Spoke Resonator type 2) section of the superconducting linac. Five prototype tuners have been built and are being tested at IJCLab. After a short description of the tuner, this paper reports on the procurement strategy and the performance observed at both room and low temperatures in vertical cryostat test with SSR2 prototype cavities. This paper will also share results on accelerated lifetime tests performed in a dedicated nitrogen-cooled cryostat. 		 
poster icon Poster WEPWB137 [1.395 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB137  
About • Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 16 July 2023
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THIAA01 Development of 3.9 GHz 9-Cell Cavities at SHINE electron, linac, FEL, laser 921
 
  • X.W. Wu
    Zhangjiang Lab, Shanghai, People’s Republic of China
  • J.F. Chen, P.C. Dong, Y.F. Liu, X.H. Ouyang, S. Sun, J.N. Wu, S. Xing, Y.X. Zhang, S.J. Zhao, Y.L. Zhao
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
  • X. Huang, Z. Wang, Y. Zong
    SINAP, Shanghai, People’s Republic of China
  • Y.W. Huang, R.Z. Xia
    ShanghaiTech University, Shanghai, People’s Republic of China
  
  The Shanghai high-repetition-rate XFEL and extreme light facility (SHINE) Linac requires two 3.9~GHz crymodules to linearize energy distribution before the bunch compressor. As a key component to the project, studies of 3.9~GHz cavities were conducted in the past few years. The first 3.9~GHz 9-cell prototype cavity has been fabricated, tested, and qualified. It reached Q0=3.5×109 at 13.1~MV/m and a maximum accelerating gradient of 25.0~MV/m during the vertical test of the bare cavity. The prototype has been helium tank integrated and reached Q0=2.9×109 at 13.1~MV/m in the vertical test, with a large margin with respect to the SHINE specification. The second prototype has been fabricated and is planned to be tested in 2023. This paper will cover the fabrication, surface treatment, and RF test of the 3.9~GHz cavities.  
slides icon Slides THIAA01 [7.573 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-THIAA01  
About • Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 18 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THIAA02 RF Performance Results of RF Double Quarter Wave Resonators for LHC High Luminosity Project HOM, luminosity, vacuum, radiation 925
 
  • K. Turaj, J. Bastard, R. Calaga, S.J. Calvo, O. Capatina, A. Castilla, M. Chiodini, C. Duval, A.V. Edwards, L.M.A. Ferreira, M. Gourragne, P. Kohler, E. Montesinos, C. Pasquino, G. Pechaud, N. Stapley, N. Valverde Alonso, J.D. Walker
    CERN, Meyrin, Switzerland
  • A. Castilla
    JLAB, Newport News, USA
  • A.V. Edwards
    Lancaster University, Lancaster, United Kingdom
  
  The LHC High Luminosity (HL-LHC) project includes, among other key items, the installation of superconducting crab cavities in the LHC machine. The Double Quarter Wave (DQW) crab cavity will be utilised to compensate for the effects of the vertical crossing angle. Two bare DQW series cavities were manufactured in Germany by RI Research Instruments and validated successfully at CERN through a cold test at 2K. Two DQW series cavities were produced in-house at CERN, integrated into a titanium helium tank, and equipped with RF ancillaries. This paper addresses the cavities preparation processes and summarizes the results of cryogenic tests of DQW cavities at CERN  
slides icon Slides THIAA02 [10.840 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-THIAA02  
About • Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 01 July 2023
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THIAA03 Completion of Testing Series Double-spoke Cavity Cryomodules for ESS cryomodule, vacuum, operation, SRF 932
 
  • R. Santiago Kern, K. Fransson, K.J. Gajewski, L. Hermansson, H. Li, T. Lofnes, A. Miyazaki, M. Olvegård, I.P. Profatilova, R.J.M.Y. Ruber, C.D.I. Svanberg, M. Zhovner
    Uppsala University, Uppsala, Sweden
  
  The FREIA Laboratory at Uppsala University, Sweden, has completed the evaluation of 13 double-spoke cavity cryomodules for ESS. This is the first time double-spoke cavities will be deployed in a real machine. This paper summarizes testing procedures and statistics of the results and lessons learned.  
slides icon Slides THIAA03 [4.687 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-THIAA03  
About • Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 29 June 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THIAA04 Performance Analysis of Spoke Resonators, Statistics from Cavity Fabrication to Cryomodule Testing SRF, operation, cryomodule, proton 940
 
  • A. Miyazaki, P. Duchesne, D. Le Dréan, D. Longuevergne, G. Olry
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  
  Irène Joliot-Curie Laboratory (IJCLab) has been leading the development of spoke resonators in multiple interna- tional SRF projects, from fundamental R&D, prototyping, to series production. The European Spallation Source (ESS) superconducting linac is the first of its kind to put into op- eration the spoke resonators. After three prototype cavities, 29 ESS production cavities have been processed, tested, as- sembled into cryomodules at IJCLab, and then shipped to Uppsala for the site acceptance test. Seven prototypes for two other major projects, Multi-purpose hYbrid Research Reactor for High-tech Application (MYRRHA) and Proton Improvement Plan II (PIP-II), designed in collaboration with external institutions, have as well been processed and tested at IJCLab. A new challenge is to fully process series cavi- ties in industry, following the successful implementation of 1.3 GHz elliptical cavities in the other projects. This paper summarises main results obtained from fabrication to final testing, including frequency tuning strategy, performance, limitation in vertical cryostat, and identifies future direction of projects and R&D in the field of spoke cavities.  
slides icon Slides THIAA04 [4.623 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-THIAA04  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 19 July 2023
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THCAA01 Development of Single-spoke Cavities for ADS at JAEA linac, SRF, emittance, proton 947
 
  • Y. Kondo
    JAEA, Ibaraki-ken, Japan
  • T. Dohmae, E. Kako, H. Sakai, K. Umemori
    KEK, Ibaraki, Japan
  • F. Maekawa, S.I. Meigo, J. Tamura, B. Yee-Rendón
    JAEA/J-PARC, Tokai-mura, Japan
  
  Japan Atomic Energy Agency (JAEA) has been proposing an accelerator-driven system (ADS) as a future nuclear system to efficiently reduce the high-level radioactive waste generated at nuclear power plants. As the first step toward the full-scale CW proton linac for the JAEA-ADS, we are now prototyping a low-beta (around 0.2) single-spoke cavity. Because there is no experience in manufacturing superconducting spoke cavities in Japan, prototyping and performance testing of the cavity are essential to ensure the feasibility of the JAEA-ADS. The dimensional parameters of the prototype spoke cavity were optimized to obtain higher cavity performance. The actual cavity fabrication started in 2020. Most of the cavity parts were fabricated in fiscal year 2020 by press-forming and machining. In 2021, we started welding the cavity parts together. After investigating the optimum welding conditions using mock-up test pieces, each cavity part was joined with smooth welding beads. Currently, the cavity’s body section and the beam port sections have been assembled. This paper presents the current status of the JAEA-ADS and it’s cavity prototyping.  
slides icon Slides THCAA01 [8.433 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-THCAA01  
About • Received ※ 18 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 10 July 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THCAA02 Commissioning of the UHH Quadrupole Resonator at DESY quadrupole, SRF, dipole, operation 952
 
  • R. Monroy-Villa, W. Hillert, M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • A. Gössel, D. Reschke, M. Röhling, M. Schmökel, J.H. Thie, M. Wiencek
    DESY, Hamburg, Germany
  • C. Martens
    University of Hamburg, Hamburg, Germany
  
  Funding: This work was supported by the BMBF under the research grants 05H18GURB1, 05K19GUB and 05H2021.
Pushing the limits of the accelerating field or quality factor of SRF cavities beyond pure Nb requires the implementation of specific inner surface treatments, which are yet to be studied and optimized. One of the fundamental challenges in exploring alternative materials is that only samples or cavity cuts can be fully characterized from a material point of view. On the other hand, complete cavities allow for the SRF characterization of the inner surface, while samples can usually only be analyzed using DC methods. To address this problem, a test resonator for samples, called "Quadrupole Resonator", was designed and operated at CERN and later at HZB. It allows for a full RF characterization of samples at frequencies of 0.42 GHz, 0.86 GHz, and 1.3 GHz, within a temperature range of 2-20 K and at magnetic fields up to 120 mT. This work presents the design process, which incorporated improvements motivated by mechanical and RF studies and experience, and the results from both warm and cold commissioning are discussed. More important, the results for the RF tests of a Nb sample after undergoing a series of heat treatments and an outlook of the further usage of the QPR is presented. 		 
slides icon Slides THCAA02 [6.677 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-THCAA02  
About • Received ※ 25 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 19 August 2023 — Issue date ※ 19 August 2023
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THIXA01 Investigation of Plasma Processing for Coaxial Resonators plasma, SRF, HOM, coupling 960
 
  • W. Hartung, W. Chang, K. Elliott, S.H. Kim, T. Konomi, K. Saito, P.R. Tutt, T. Xu
    FRIB, East Lansing, Michigan, USA
  
  Plasma processing has been investigated by several facilities as a method to mitigate degradation of SRF cavity performance. It provides an alternative to removal and disassembly of cryomodules for refurbishment of each cavity via repeat etching and rinsing. Promising results have been obtained by several groups. Studies of plasma processing for quarter-wave resonators (QWRs) and half-wave resonators (HWRs) were undertaken at FRIB, where a total of 324 such resonators are presently in operation. Plasma ignition and optimization measurements were done with room-temperature-matched input couplers. Plasma cleaning tests were done on several QWRs using the fundamental power coupler (FPC) to drive the plasma. We investigated the usefulness of higher-order modes (HOMs) to drive the plasma. HOMs allow for less mismatch at the FPC and hence lower field in the coupler relative to the cavity. Before-and-after cold tests showed a significant reduction in field emission X-rays with judicious application of plasma processing.  
slides icon Slides THIXA01 [2.060 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-THIXA01  
About • Received ※ 01 September 2023 — Accepted ※ 02 September 2023 — Issue date ※ 02 September 2023  
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THIXA03 Cryocooler Application for Accelerator and Development Status of Powerful Cryocooler at SHI Ltd. controls, SRF, interface, operation 968
 
  • T. Ikeda, S. Sasazaki
    SHI, Tokyo, Japan
  
  Advances in recent Nb₃Sn cavity development makes possible to operate the cavities with Qo ~ 1xE10 at 4.3 K and to design SRF accelerator in which the cavities are cooled directly with small mechanical cryocoolers instead of using liquid helium. Conduction-cooling with cryocoolers greatly simplify the overall design and also contribute for cost saving of an SRF accelerator, making the SRF technology feasible for industrial accelerators. However, in the case of using current cryocooler systems (like Gifford-McMahon cryocooler, Pulse-Tube cryocooler, etc.) for the conduction-cooling, since the cooling capacity per unit is small, multiple units will be used in combination depending on the required cooling capacity, it will cause problems in terms of power consumption (efficiency), footprint, and maintenance costs. Therefore, SHI have been developing a large-capacity and high-efficiency 4KGM-JT (Gifford-McMahon-Joule-Thomson) cryocooler system in the 10 W class at 4.2 K. This contribution will report the overview of this cryocooler system and its status of development.  
slides icon Slides THIXA03 [1.638 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-THIXA03  
About • Received ※ 20 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 04 July 2023
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THIXA05 Conduction-Cooled SRF Cavities: Opportunities and Challenges SRF, operation, cryomodule, radio-frequency 973
 
  • N.A. Stilin, H. Conklin, T. Gruber, A.T. Holic, M. Liepe, T.I. O’Connell, P. Quigley, J. Sears, V.D. Shemelin, J. Turco
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Thanks to improvements in the performance of both commercial cryocoolers and Nb₃Sn-coated superconducting radio-frequency (SRF) cavities, it is now possible to design and build compact, SRF cryomodules without the need for liquid cryogenics. In addition, these systems offer robust, non-expert, turn-key operation, making SRF technology significantly more accessible for smaller-scale applications in fields such as industry, national security, medicine, environmental sustainability, etc. To fully realize these systems, many technical and operational challenges must be overcome. These include properly cooling the SRF cavity via thermal conduction and designing high-power (~ 100 kW continuous) RF couplers which dissipate minimal heat (~ 1 W) at 4.2 K. This presentation will discuss these challenges and the solutions which have been developed at Cornell University and elsewhere.  
slides icon Slides THIXA05 [7.219 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-THIXA05  
About • Received ※ 27 June 2023 — Revised ※ 29 June 2023 — Accepted ※ 04 July 2023 — Issue date ※ 08 July 2023
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FRIBA02 Instrumentation for High Performance Cavities and Cryomodule Field Emission Analysis radiation, electron, neutron, simulation 978
 
  • G. Devanz
    CEA-IRFU, Gif-sur-Yvette, France
  • M. Baudrier, E. Cenni, L. Maurice, O. Piquet
    CEA-DRF-IRFU, France
  
  Field emission (FE) is one of the main reasons for the degradation of accelerator cryomodules, as field emitted current tends to become more severe during the beam operation. It is essential to better understand how this phenomenon is generated and evolves from the SRF cavity preparation in the clean room, through their assembly in the cryomodule until their final test and operation. Due to the shielding environment of a cavity in its vertical test stand, or the architecture of a cryomodule, the more faint radiation occurring at the FE onset remains undetected. More precise diagnostic and analysis tools are required to gain more information. We present the developpement of dedicated time-resolved detectors for the FE radiation which aim at improving its coverage in terms of solid angle and lower energy threshold sensitivity. We approach this topic through detailed simulation based on the Geant4 toolkit in order to analyse the interaction of FE radiation with the cavity environement and optimize the detectors with respect to their application in cryomodule or vertical test stands. We illustrate by analysing recent cryomodule experimental test data.  
slides icon Slides FRIBA02 [9.606 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA02  
About • Received ※ 27 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 05 July 2023 — Issue date ※ 09 July 2023
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FRIBA03 Heavily Damped Crab Cavities for High Luminosity Collisions GUI, HOM, impedance, collider 986
 
  • B.P. Xiao
    BNL, Upton, New York, USA
  • S.U. De Silva
    ODU, Norfolk, Virginia, USA
  
  Funding: Work supported by BSA under U.S. DOE contract No. DE-SC0012704, by JSA under U.S. DOE Contract No. DE-SC0002769, and by DOE Contract No. DE-AC02-76SF00515.
Next generation colliders require crab cavities to mitigate parasitic collisions caused by finite crossing angle for luminosity leveling and detector data pile up reduction. The Electron Ion Collider (EIC) crab cavity designs will be introduced as an example to fulfill the geometrical constraints, crabbing voltages, multipole components, Higher Order Mode (HOM) power and impedance budgets. Operational challenges such as tuning, high gain low delay control loop, amplitude and phase noises control will be discussed. 		 
slides icon Slides FRIBA03 [3.666 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA03  
About • Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 06 July 2023
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FRIBA04 Crab Cavities for ILC HOM, SRF, operation, impedance 990
 
  • P.A. McIntosh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • S.A. Belomestnykh, I.V. Gonin, T.N. Khabiboulline, A. Lunin, Y.M. Orlov, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
  • G. Burt
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • R. Calaga
    CERN, Meyrin, Switzerland
  • S.U. De Silva
    JLab, Newport News, Virginia, USA
  • J.R. Delayen
    ODU, Norfolk, Virginia, USA
  • T. Okugi, A. Yamamoto
    KEK, Ibaraki, Japan
  • S. Verdú-Andrés, B.P. Xiao
    BNL, Upton, New York, USA
  
  For the 14 mrad crossing angle proposed, crab cavity systems are fundamentally anticipated for the viable operation of the International Linear Collider (ILC), in order to maximise its luminosity performance. Since 2021, a specialist development team have been defining optimum crab cavity technologies which can fulfil the operational requirements for ILC, both for its baseline centre-of-mass energy of 250 GeV, but also extending those requirements out to higher beam collision intensities. Five design teams have established crab cavity technology solutions, which have the capability to also operate up to 1 TeV centre-of-mass. This presentation showcases the key performance capabilities of these designs and their associated benefits for both manufacture and integration into the ILC Interaction Region. The recommended outcome of the recently conducted crab cavity technology down-selection, will also be highlighted.  
slides icon Slides FRIBA04 [2.526 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA04  
About • Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 20 July 2023
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FRIBA05 Automation of FRIB SRF Cavities and SC Solenoids Turn-on/off cryomodule, solenoid, SRF, linac 999
 
  • W. Chang, Y. Choi, X.J. Du, W. Hartung, S.H. Kim, T. Konomi, S.R. Kunjir, H. Nguyen, K. Saito, T. Xu, S. Zhao
    FRIB, East Lansing, Michigan, USA
  • A. Facco
    INFN/LNL, Legnaro (PD), Italy
  
  The superconducting driver Linac for the Facility for Rare Isotope Beams (FRIB) is a heavy ion accelerator that accelerate ions to 200 MeV per nucleon. The Linac has 46 cryomodules that contain 324 superconducting radio frequency (SRF) cavities and 69 superconducting (SC) solenoid packages. For operation of all cryomodules with high efficiency and reliability, automation for SRF cavity and SC solenoid fast turn-on/off is essentially. Based on cryomodule commissioning results and expert experience, all manual cavity and solenoid turn-on/off procedures and steps have been replaced by automatic programs for FRIB linac operation. This allows the operators to turn the systems on and off without expert-level training. Automation reduces the risk of human error, speeds up beam recovery after user access to experimental areas, and increases beam availability. The cavity turn-on procedure makes sure that the cavity can operate at low field with expected read backs, ramps up the field, and makes sure that the RF amplitude and phase are stable. The design, implementation, and operating experience with automation will be presented.  
slides icon Slides FRIBA05 [3.503 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA05  
About • Received ※ 29 June 2023 — Revised ※ 16 August 2023 — Accepted ※ 21 August 2023 — Issue date ※ 21 August 2023
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FRIBA07 Status of the SLAC/MSU SRF Gun Development Project cryomodule, SRF, cathode, alignment 1003
 
  • S.J. Miller, Y. Al-Mahmoud, W. Chang, Y. Choi, C. Compton, X.J. Du, K. Elliott, W. Hartung, J.D. Hulbert, S.H. Kim, T. Konomi, D.G. Morris, M.S. Patil, L. Popielarski, K. Saito, A. Taylor, B.P. Tousignant, J. Wei, J.D. Wenstrom, K. Witgen, T. Xu
    FRIB, East Lansing, Michigan, USA
  • C. Adolphsen, R. Coy, F. Ji, M.J. Murphy, J. Smedley, L. Xiao
    SLAC, Menlo Park, California, USA
  • A. Arnold, S. Gatzmaga, P. Murcek, J. Teichert, R. Xiang
    HZDR, Dresden, Germany
  • M.P. Kelly, T.B. Petersen, P. Piot
    ANL, Lemont, Illinois, USA
  • J.W. Lewellen
    LANL, Los Alamos, New Mexico, USA
  
  Funding: Work supported by the Department of Energy under Contract DE-AC02-76SF00515
The Linac Coherent Light Source II High Energy (LCLS-II-HE) Project at SLAC includes the construction of a low-emittance injector (LEI) and a superconducting quarter-wave resonator (QWR) at 185.7 MHz. Several alternatives to a superconducting radio frequency (SRF) QWR gun were considered for the LEI, including nor-mal-conducting RF guns evolved from the LCLS-II gun design. Compared to normal-conducting designs, the combination of an intrinsically outstanding vacuum environment (for cathode lifetime), and the potential for a larger ultimate performance envelope, led to the deci-sion to pursue development of the QWR-SRF gun. A prototype gun is currently being designed and fabricated at the Facility for Rare Isotope Beams (FRIB) at Michi-gan State University (MSU). This paper presents perfor-mance goals for the new gun design, an overview of the prototype development effort, status, and future plans including fabrication. 		 
slides icon Slides FRIBA07 [9.655 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA07  
About • Received ※ 15 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 11 July 2023
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