Magnet Quench Detection and Protection
A superconducting magnet that loses superconductivity can destroy itself in seconds; detecting the onset fast is a hard real-time task.
What a quench is
A superconducting magnet carries large current with no resistance. If a small region warms above its critical temperature it becomes resistive, heats further, and the normal zone spreads. This is a quench. Unmanaged, the stored magnetic energy dumps into that region and can damage the coil. Detection must be fast and protection immediate.
Detecting the onset
- Voltage taps sense the resistive signal as it appears.
- Temperature and quench-detection wires provide corroborating signals.
- Models distinguish a true quench from electrical noise and normal transients.
- The decision must be made in milliseconds.
The false-alarm trade-off
Triggering protection unnecessarily interrupts operation and stresses the magnet, but missing a real quench risks the coil. Detection algorithms are tuned to balance sensitivity against false alarms, a trade-off shared with disruption prediction and quantified honestly.
Protection response
Once a quench is confirmed, the stored energy must be extracted safely, spreading the heat rather than concentrating it. The protection system is designed and verified in simulation so its response is known before it is ever needed.
High fields at Kronos
The Hyperion breeder runs a peak field of 16.84 T, and the burner reaches 26.49 T at its plug. High fields store large energy, so quench detection and protection are among the more consequential real-time systems on both machines.
Verification
Detection thresholds are validated against modeled quench signatures, part of verification and validation, and every trip is logged for safety review.