The long-term goal of this project is to create a robust, commercially available imaging probe for high-resolution (25-micromole isotropic voxel) high-field (7 to 14 T) nuclear magnetic resonance microscopy (NMRM) in reasonable (equal to or less than 60 min) imaging times. These probes will utilize thin-film receive coils of YBCO (Y1-Ba2-Cu3-O7), a high- temperature superconductor (HTS), which are expected to provide an improvement in signal-to-noise ratio (SNR) of a factor of 10 or more over conventional probes. During Phase 1, a 400-MHz HTS coil was used in an existing quartz dewar to image rat kidney in a 9.4T magnet. This coil has an unloaded quality factor (Qu) of 20,000 at a temperature of 12 K in the 9.4-T magnet, about 50 times that of normal-metal coils, and demonstrated an SNR improvement of approximately 10. The existing quartz probe uses open-cycle flowing liquid helium and is not reliable. The proposed project will create a continuously operating, closed-cycle, user-friendly probe containing similar coils coupled to a cold preamplifier. The end goal is to construct a viable system with 90-day maintenance-free operation for initial marketing to the NMRM research community. Experiments to demonstrate the instrument's utility for clinical pathology will be conducted in the second half of the effort. PROPOSED COMMERCIAL APPLICATION: The initial NMRM research market for complete systems with HTS probes is estimated to be $5,000,000 to $10,000,000 per year. If applications in histopathology are developed, a market for clinical instruments of over $90,000,000 per year exists.