Author: Stilin, N.A.
Paper Title Page
MOPMB081 Microphonics in the LCLS-II Superconducting Linac 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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MOPMB094 Design of a 1.3 GHz High-Power RF Coupler for Conduction-Cooled Systems 342
SUSPB027   use link to see paper's listing under its alternate paper code  
 
  • 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
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WEIAA04 Development of High-performance Niobium-3 Tin Cavities at Cornell University 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
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THIXA05 Conduction-Cooled SRF Cavities: Opportunities and Challenges 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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