Quench detection of superconducting magnets using ultrasonic wave

An ultrasonic quench-detection method for superconducting magnets is presented. This nondestructive method monitors the change of the acoustic transfer function of a superconducting magnet induced by a local temperature rise or an epoxy crack. Experiments were carried out on a small epoxy-impregnated magnet. The experimental results show that a local temperature rise of about 2-3 K can be detected by this method. It is concluded that the technique can provide early quench warning by monitoring continuously the change of the acoustic transfer function of the magnet. >