Monitoring of a superconducting magnet using an ultrasonic technique

Abstract

A new method to detect the quench of a superconducting magnet is presented. This method detects a change of the acoustic transfer function of a magnet caused by the local temperature rise, wire movement, etc. This time, we have tried to improve the detection sensitivity to a temperature rise of 2–3 K. Some experiments have been carried out using a small epoxy impregnated superconducting magnet and a plain GFRP rod. Experimental results show that although the gain characteristics of the transfer function do not change clearly, the phase characteristics show a clear change through the local temperature rise. We have also considered the optimal frequency of the acoustic wave for the detection of the local temperature rise.