SQUID NMR Imaging for Ultrahigh Fidelity Inspection of Advance Composite Materials

This project will exploit the properties of a SQUID in developing a single-sided NMR imaging system for advanced composite materials nondestructive inspection (NDI). Unlike conventional NMR detectors, SQUIDs offer a combination of high sensitivity and broad bandwidth at low and relatively inhomogeneous fields. Since the geometry of many test objects may require single-sided imaging, where one is constrained to use low and relatively inhomogeneous fields, a SQUID NMR imaging system will be much superior to a conventional NMR imaging system in providing the required high level of imaging sensitivity and fidelity. In Phase I we propose to demonstrate the feasibility of using a high temperature (HTS) SQUID to detect NMR signals and to do NMR imaging on a small sample. We will also address, through a detailed analysis, issues important to single-sided NMR imaging. In Phase II we will design and construct a prototype NDI system which will be capable of evaluating practical samples. Since the imaging will be done at low fields, the system is expected to be much less expensive than present day medical NMR imagers.