Speakers
Description
Accelerator magnets based on high-temperature superconductors will be fundamental to producing a field in excess of 16 T for future HEP machines. One of the known challenges of practical conductors made with HTS materials is a slow normal zone propagation resulting from a large superconducting temperature margin in combination with a higher heat capacity compared to conventional low-temperature superconductors. As a result, traditional voltage-based schemes may be ineffective for detecting normal zone formation in superconducting coil windings. Non-voltage techniques designed to measure local temperature rise along the HTS conductor are therefore being developed as a viable alternative to voltage detection and redundancy. We will review non-voltage quench detection and localization techniques based on optical fibers, ultrasonic waveguides, and radio-frequency time-domain reflectometry and compare these techniques' capabilities, advantages, and drawbacks. The most recent results on strain and temperature sensing and localization will be presented using all three techniques. Directions for future improvement of these methods to fully address the HTS magnet protection challenges will be discussed.
