New High Tc SQUID System for the Detection of Corrosion in Fielded Environments

Recent research indicates that SQUID magnetic measurements have a unique capability for noninvasive detection of corrosion. To realize this potential in practical situations, a SQUID instrument based on high-temperature superconductors (HTS) is needed. Development of such a system poses a number of difficult technical problems. This proposal presents solutions to all of the key technical problems, drawing on a substantial body of work by the proposers in both the design and development of HTS systems and the use of SQUIDs for detecting corrosion. We first discuss in detail the key system features and requirements. We then describe solutions to specific problems, incorporating several recent proprietary advances in SQUID technology. In addition, we propose a new type of SQUID array which overcomes the practical problems of detecting the magnetic signal produced by corrosion. We propose an HTS corrosion detection system that is fully portable, cooled by a closed-cycle refrigerator, and capable of operation without magnetic shielding in practical environments. In Phase II, we will build an HTS SQUID system based on the design from Phase I. We will test the system at the Marine Corrosion Facility of the Naval Research Laboratory, and on aircraft in collaboration with a major aerospace manufacturer.