Document Type

Article

Publication Date

2021

DOI

10.1103/PhysRevAccelBeams.24.092001

Publication Title

Physical Review Accelerators and Beams

Volume

24

Issue

9

Pages

092001 (1-14)

Abstract

High radio-frequency (rf) losses measured for cavities in original Continuous Electron Beam Accelerator Facility (CEBAF) cryomodules, compared to the losses measured in single-cavity tests, have been a long-standing issue related to their performance. We summarize experimental evidence of increased rf losses in CEBAF cavities arising from the fundamental power coupler cold window and waveguide, respectively. Cryogenic rf tests were done on cavities tested in vertical cryostats as well as inside cryomodules in the accelerator tunnel. The cold window metallization losses were assessed by combining numerical results with measured data obtained with an existing cryogenic waveguide resonator setup. The results showed that the cold window metallization losses can increase the cavity rf heat load at 2.07 K by up to 86%, depending on the standing-wave pattern in the fundamental power coupler waveguide, and that such losses are reduced if the distance between the waveguide and the cavity cells is increased.

Comments

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Original Publication Citation

Marhauser, F., & Ciovati, G. (2021). Evidence of increased radio-frequency losses in cavities from the fundamental power coupler cold window. Physical Review Accelerators and Beams, 24(9), 1-14, Article 092001. https://doi.org/10.1103/PhysRevAccelBeams.24.092001

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