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Title: High Power RF Testing of A 3-Cell Superconducting Traveling Wave Accelerating Structure

Abstract

Euclid Techlabs has completed the Phase II SBIR project, entitled “High Power RF Testing of a 3-Cell Superconducting Traveling Wave Accelerating Structure” under Grant #DE-SC0006300. In this final technical report, we summarize the major achievements of Phase I of the project and review the details of Phase II of the project. The accelerating gradient in a superconducting structure is limited mainly by quenching, i.e., by the maximum surface RF magnetic field. Various techniques have been developed to increase the gradient. A traveling wave accelerating SC structure with a feedback waveguide was suggested to allow an increased transit time factor and ultimately, a maximum gradient that is 22%-24% higher than in the best of the time standing wave SRF cavity solution. The proposed structure has an additional benefit in that it can be fabricated much longer than the standing wave ones that are limited by the field flatness factor. Taken together, all of these factors will result in a significant overall length and, correspondingly cost reduction of the SRF based linear collider ILC or SRF technology based FELs. In Phase I of this project, a 3-cell L-band SC traveling wave cavity was designed. Cavity shape, surface field ratios, inter-cell coupling coefficients,more » accelerating field flatness have been reviewed with the analysis of tuning issues. Moreover, the technological aspects of SC traveling wave accelerating structure fabrication have been studied. As the next step in the project, the Phase II experimental program included engineering design, manufacturing, surface processing and high gradient testing. Euclid Techlabs, LLC contracted AES, Inc. to manufacture two niobium cavities. Euclid Techlabs cold tested traveling wave regime in the cavity, and the results showed very good agreement with mathematical model specially developed for superconducting traveling wave cavity performance analysis. Traveling wave regime was adjusted by amplitude and phase variation of input signals due to application of developed power feeding scheme. Traveling wave excitation, adjustment and detection were successfully tested. Auxiliary equipment required for high power test such as the tuner, power and measure couplers, holding plates for VTS at Fermilab were developed and successfully tested. Both TW SRF cavities were fabricated by AES, Inc. without stiffening ribs before this company closed their production facility. Currently Roark EB welding company is finishing now welding process of the cavity for the high power testing at Fermilab VTS. Successful demonstration of high gradients in the 3-cell cavity along with studies of traveling wave excitation and tuning issues is leading to successful development of superconducting traveling wave technology for ILC applications and other future high energy SC accelerators.« less

Authors:
 [1];  [1];  [1];  [2];  [2];  [2]
  1. Euclid Techlabs, LLC, Solon, OH (United States)
  2. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States). Technical Division
Publication Date:
Research Org.:
Euclid Techlabs, LLC, Solon, OH (United States)
Sponsoring Org.:
USDOE
Contributing Org.:
Fermi National Accelerator Laboratory, Technical Division
OSTI Identifier:
1406245
Report Number(s):
DOE-EuclidTechlabs-06300
6300
DOE Contract Number:
SC0006300
Type / Phase:
SBIR (Phase II)
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; Superconducting traveling wave accelerator; International Linear Collider; Cost reduction

Citation Formats

Kanareykin, Alex, Kostin, Romna, Avrakhov, Pavel, Yakovlev, V., Solyak, N., and Khabiboulline, T. High Power RF Testing of A 3-Cell Superconducting Traveling Wave Accelerating Structure. United States: N. p., 2017. Web.
Kanareykin, Alex, Kostin, Romna, Avrakhov, Pavel, Yakovlev, V., Solyak, N., & Khabiboulline, T. High Power RF Testing of A 3-Cell Superconducting Traveling Wave Accelerating Structure. United States.
Kanareykin, Alex, Kostin, Romna, Avrakhov, Pavel, Yakovlev, V., Solyak, N., and Khabiboulline, T. Wed . "High Power RF Testing of A 3-Cell Superconducting Traveling Wave Accelerating Structure". United States. doi:.
@article{osti_1406245,
title = {High Power RF Testing of A 3-Cell Superconducting Traveling Wave Accelerating Structure},
author = {Kanareykin, Alex and Kostin, Romna and Avrakhov, Pavel and Yakovlev, V. and Solyak, N. and Khabiboulline, T.},
abstractNote = {Euclid Techlabs has completed the Phase II SBIR project, entitled “High Power RF Testing of a 3-Cell Superconducting Traveling Wave Accelerating Structure” under Grant #DE-SC0006300. In this final technical report, we summarize the major achievements of Phase I of the project and review the details of Phase II of the project. The accelerating gradient in a superconducting structure is limited mainly by quenching, i.e., by the maximum surface RF magnetic field. Various techniques have been developed to increase the gradient. A traveling wave accelerating SC structure with a feedback waveguide was suggested to allow an increased transit time factor and ultimately, a maximum gradient that is 22%-24% higher than in the best of the time standing wave SRF cavity solution. The proposed structure has an additional benefit in that it can be fabricated much longer than the standing wave ones that are limited by the field flatness factor. Taken together, all of these factors will result in a significant overall length and, correspondingly cost reduction of the SRF based linear collider ILC or SRF technology based FELs. In Phase I of this project, a 3-cell L-band SC traveling wave cavity was designed. Cavity shape, surface field ratios, inter-cell coupling coefficients, accelerating field flatness have been reviewed with the analysis of tuning issues. Moreover, the technological aspects of SC traveling wave accelerating structure fabrication have been studied. As the next step in the project, the Phase II experimental program included engineering design, manufacturing, surface processing and high gradient testing. Euclid Techlabs, LLC contracted AES, Inc. to manufacture two niobium cavities. Euclid Techlabs cold tested traveling wave regime in the cavity, and the results showed very good agreement with mathematical model specially developed for superconducting traveling wave cavity performance analysis. Traveling wave regime was adjusted by amplitude and phase variation of input signals due to application of developed power feeding scheme. Traveling wave excitation, adjustment and detection were successfully tested. Auxiliary equipment required for high power test such as the tuner, power and measure couplers, holding plates for VTS at Fermilab were developed and successfully tested. Both TW SRF cavities were fabricated by AES, Inc. without stiffening ribs before this company closed their production facility. Currently Roark EB welding company is finishing now welding process of the cavity for the high power testing at Fermilab VTS. Successful demonstration of high gradients in the 3-cell cavity along with studies of traveling wave excitation and tuning issues is leading to successful development of superconducting traveling wave technology for ILC applications and other future high energy SC accelerators.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jun 07 00:00:00 EDT 2017},
month = {Wed Jun 07 00:00:00 EDT 2017}
}

Technical Report:
This technical report may be released as soon as November 1, 2021
Other availability
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