Speaker
Description
Proper detection and localization of quench events is essential to protect superconducting magnets for particle accelerators. Voltage taps are widely adopted for low-temperature superconductors (LTS), but they do not ensure reliable quench detection for high temperature superconducting (HTS) magnets. Indeed, the propagation velocity of the normal conducting zone is in the order of m s−1 for LTS, compared to cm s-1 for HTS, leading to a higher risk of irreversible conductor degradation before any voltage can be detected. As an alternative solution, non-leaky ultrasonic waveguides have been proposed [1] as a diagnostic option to monitor hot spots by tracking thermally induced sound velocity variations. A first practical implementation of this concept has been developed and tested for a Uni-layer [2] magnet at Lawrence Berkeley National Laboratory (LBNL).
In this work, we present the practical design of a non-leaky acoustic waveguide tailored for this magnet. We also show the results of an experimental campaign conducted to assess hot-spot detection and localization for the ultrasonic waveguide sensor both in a straight and a geometric configuration representing the magnet working condition. Finally, the application of this technique is presented over a Uni-Layer magnet copper mock-up. The results of the tests at room temperature and liquid nitrogen temperature are discussed.
References
[1] Marchevsky, M., and S. Prestemon. "Distributed thermometry for superconducting magnets using non-leaky acoustic waveguides." Superconductor Science and Technology 36.4 (2023): 045005.
[2] Fernández, José Luis Rudeiros, and Paolo Ferracin. "Uni-layer magnets: a new concept for LTS and HTS based superconducting magnets." Superconductor Science and Technology 36.5 (2023): 055003.
