Abstract: RF electric fields produced by electric potential differences in NMR probe coil windings may penetrate the NMR sample and sample tube causing sensitivity loss and noise in NMR spectroscopy. Counter-wound spiral coils placed on the opposite surfaces of a planar substrate or on two adjacent planar substrates produce electric potentials that minimize the electric field over the sample region, thereby increasing the sensitivity of the NMR probe. Alternatively counter-wound spiral coils placed adjacent to each other on the outer surface of two concentric cylindrical surfaces that surround the NMR sample minimize the electric field over the sample region. The electric potential of the spiral coils is reduced by adjusting a length of at least one coil.

Abstract: RF electric fields produced by electric potential differences in NMR probe coil windings may penetrate the NMR sample and sample tube causing sensitivity loss and noise in NMR spectroscopy. Counter-wound spiral coils placed on the opposite surfaces of a planar substrate or on two adjacent planar substrates produce electric potentials that minimize the electric field over the sample region, thereby increasing the sensitivity of the NMR probe. Alternatively counter-wound spiral coils placed adjacent to each other on the outer surface of two concentric cylindrical surfaces that surround the NMR sample minimize the electric field over the sample region. The electric potential of the spiral coils is reduced by adjusting a length of at least one coil.

Abstract: Improved superconducting coils for a nuclear magnetic resonance probe use capacitive elements that are located in regions further from an active sample volume than magnetic field generating elements to which they are electrically connected. The sample volume is a substantially oblong shape, and the magnetic field generating elements run substantially parallel to the major axis of the shape, while the capacitor elements run perpendicular to the major axis. Gaps between the capacitor elements, and the width of the elements themselves, may increase toward the outside of the coil to minimize electrical discharge. The variation may be according to a monotonic, possibly linear, function. Discharge may also be minimized by using a dielectric cover that, together with a coil substrate, encloses the coil.

Abstract: Improved superconducting coils for a nuclear magnetic resonance probe use capacitive elements that are located in regions further from an active sample volume than magnetic field generating elements to which they are electrically connected. The sample volume is a substantially oblong shape, and the magnetic field generating elements run substantially parallel to the major axis of the shape, while the capacitor elements run perpendicular to the major axis. Gaps between the capacitor elements, and the width of the elements themselves, may increase toward the outside of the coil to minimize electrical discharge. The variation may be according to a monotonic, possibly linear, function. Discharge may also be minimized by using a dielectric cover that, together with a coil substrate, encloses the coil.

Abstract: An insulated dual-bayonet connector is provided. The connector provides simple alignment and connection for both fluid tubes of a fluid recirculation system. The connector is especially useful for closed-cycle systems, but is also useful for open-cycle gas systems where it is desired to vent a gas in a desired location remote from the item to be cooled or heated by the gas.