Abstract: In a method and apparatus for detecting and locating a quench zone in a superconducting coil, a sensor is positioned adjacent to and in heat transfer communication with the entire length of the superconducting coil. When a portion of the superconducting coil becomes normal, the adjacent portion of the sensor becomes resistive. A series of electrical pulses sent along the sensor are reflected back by the discontinuity in impedance which occurs at such a normal zone. The reflected pulses and echo pulses produced by various terminations on the sensor are detected by an associated receiver and processor which calculates the location of the resistive zone along the sensor and the corresponding quench zone along the superconducting coil using information derived from the pulses. A second embodiment provides two sensors which are adjacent to and in heat transfer communication with the coil which are pulsed from opposite ends.