JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
TY - CONF AU - Liu, Y.F. AU - Luo, C. AU - Reschke, D. AU - Steder, L. AU - Wiencek, M. ED - Saito, Kenji ED - Xu, Ting ED - Sakamoto, Naruhiko ED - Lesage, Ana ED - Schaa, Volker R.W. TI - Occurring Dependency between Adjustable Coupling and Q₀ - Finding and Solving a Problem during Vertical Cavity Testing at DESY J2 - Proc. of SRF2021, East Lansing, MI, USA, 28 June-02 July 2021 CY - East Lansing, MI, USA T2 - International Conference on RF Superconductivity T3 - 20 LA - english AB - 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. PB - JACoW Publishing CP - Geneva, Switzerland SP - 619 EP - 623 KW - cavity KW - coupling KW - SRF KW - vacuum KW - resonance DA - 2022/10 PY - 2022 SN - 2673-5504 SN - 978-3-95450-233-2 DO - doi:10.18429/JACoW-SRF2021-WEPCAV013 UR - https://jacow.org/srf2021/papers/wepcav013.pdf ER -