Author: Liu, Y.F.
Paper Title Page
WEPCAV013 Occurring Dependency between Adjustable Coupling and Q0 - Finding and Solving a Problem during Vertical Cavity Testing at DESY 619
 
  • Y.F. Liu, C. Luo
    SARI-CAS, Pudong, Shanghai, People’s Republic of China
  • D. Reschke, L. Steder, M. Wiencek
    DESY, Hamburg, Germany
 
  In the AMTF (Accelerator Module Test Facility) hall at DESY, various types of cavities have been tested for different accelerators and R&D projects during the last years. For R&D purposes, dedicated inserts with additional auxiliaries like a movable INPUT antenna can be used to perform accurate measurements at different temperatures between 1.4 K and 4 K. Since 2017 more than hundred vertical tests were conducted in these inserts without troubles besides rare expected occurrences of cold leaks or even rarer a loose antenna. However, in the last months, an unexpected dependency between the measured quality factor and the coupling coefficient ß has been observed. In order to understand the source of this measurement uncertainty, several different special checks have been performed. In a logical sequence of measurements with different cryostats, inserts and cavities the problem has been encircled and in the end was identified and solved. In this paper, the observed problem is described in detail as well as the entire path leading to its solution.  
poster icon Poster WEPCAV013 [1.073 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-WEPCAV013  
About • Received ※ 18 June 2021 — Revised ※ 18 October 2021 — Accepted ※ 18 October 2021 — Issue date ※ 22 November 2021
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