Tamashevich, Y.: Advanced OST System for the Second-sound Test of Fully Dressed Cavities. In: Volker RW Schaa ... [Ed.] : SRF2017 : Proceedings of the 18th International Conference on RF Superconductivity, Lanzhou China, July 2017.Geneve: JaCoW, 2018. - ISBN 978-3-95450-191-5, p. THX06/703-707
Open Access Version
Abstract:
Cavities which exhibit a low field quench are normally discarded from usage in accelerator projects. However, they can be repaired if the exact location of the quench is known. Optical inspection alone cannot reliably locate the source of a quench. Methods that directly measure the quench, such as thermometry or second sound detection, could so far only be performed at undressed cavities. A new, specially designed, second-sound system for the first time allows the localization of the quench in multicell cavities equipped with a helium vessel. It can be easily installed in the helium pipe of the cavity. Information on the quench location can be acquired during a standard rf test. A new algorithm localizes the quench based on the real path of the second-sound wave around the cavity surface, rather than using simple triangulation. The implemented pathfinding method leads to a high precision and high accuracy of the quench location. This was verified by testing standard dressed 9-cell XFEL cavities. The system can be easily applied to other cavity shapes and sizes.