Abstract: An electrical current limiting device comprises an electrical superconductor for attachment in an electrical circuit. The superconductor achieves a superconducting condition at relatively high temperatures. A cooling system includes a motor for flowing a cooled gas past the superconductor so that heat can be removed from the superconductor by a heat transfer process with the cooled gas.

Abstract: An NMR sensor including a magnetic field generating assembly, an RF antenna, and a plurality of ferrite members which couple with RF magnetic fields transmitted or received by the RF antenna. The sensor is typically used in apparatus for performing borehole measurements.

Abstract: An rf magnetic field pulse generator for generating an rf magnetic field pulse for use in an NMR investigation. The generator includes two arms connected in parallel between a pair of input terminals, each arm having two serially connected solid-state switches, a transmitter coil connected between output terminals defined between each pair of serially connected solid-state switches respectively, the transmitter coil being adapted to transmit the magnetic field pulse in response to an alternating rf signal at the output terminals, a power source connected to one or both input terminals, and a controller adapted to alternatively operate a respective switch in each arm at a required radio frequency in use whereby the power source is connected with alternating polarity across the transmitter coil and generates an alternating rf signal at the output terminals.

Abstract: A magnet assembly having a pair of substantially aligned, spaced apart first magnets having like poles facing each other; and one or more auxiliary magnets axially aligned with the first magnets such that all magnets in the assembly are axially aligned. A magnetic field of sufficient homogeneity to perform a nuclear magnetic resonance (NMR) process is generated in a working region laterally offset form the first and second magnets. An oscillating magnetic field generating assembly is provided for performing an NMR experiment and includes a set of electrical coils connected to an oscillating electrical source. The coils are arranged between the first magnets such that the magnetic field generated by the oscillating magnet field generating assembly is also sufficiently uniform within the working region to perform an NMR experiment.

Abstract: An energy storage device comprising an array of electrical coils formed from relatively high temperature superconducting material, the coils being arranged around a common axis and carrying working currents in the same sense.