Acoustic Emission Behavior in the 0.5 MJ Pulsed Magnet at Osaka University

Abstract

Recently, some investigations on the application of acoustic emission (AE) techniques to the diagnosis of superconducting magnets have been performed. Sinclair et al.1 suggested that quenches in magnets could be predicted by AE signals. Nomura et al.4–6 reported that the particular AE wave form was noticed just before the quench. Tsukamoto et al.2,3 claimed that AE and a voltage spike occur simultaneously when a quench is induced by conductor motion. As shown in these reports the information on AE from magnets has been gradually accumulating. Before practical use of the AE technique to the monitoring of superconducting magnets, however, there some problems remain to be clarified; the exact correlation between the AE and the dynamic properties of the magnets and quench behavior, and identification of the AE sources. Almost no AE data have been reported from pulsed magnets of MJ size.