Detection of 'hot spots' in HTS coils and test samples with acoustic emission signals

In this paper we report results of two series of experiments, one performed on a double-pancake coil wound with Bi2223/Ag tape and the other on coated YBCO samples to demonstrate that an acoustic emission (AE) technique is a promising diagnostic tool to detect the presence of a "hot spot" in HTS devices. The AE technique may be used as complement to standard voltage technique to facilitate early detection of the presence of a "hot spot" in HTS devices and thus help to protect the HTS devices from permanent damage.