Abstract: A superconducting current pump arranged to cause a DC electrical current to flow through a superconducting circuit accommodated within a cryogenic enclosure of a cryostat comprises a rotor external to the cryogenic enclosure and a stator within the cryogenic enclosure, the rotor and stator separated by a gap through which passes a thermally insulating wall of the cryogenic enclosure, the rotor and the stator comprising at least in part a ferromagnetic material to concentrate magnetic flux in a magnetic circuit across the gap between the rotor and the stator and through the wall, so that movement of the rotor external to the cryogenic enclosure relative to the stator within the cryogenic enclosure induces a DC transport current to flow around the superconducting circuit within the cryogenic enclosure.

Abstract: A superconducting current pump arranged to cause a DC electrical current to flow through a superconducting circuit accommodated within a cryogenic enclosure of a cryostat comprises a rotor external to the cryogenic enclosure and a stator within the cryogenic enclosure, the rotor and stator separated by a gap through which passes a thermally insulating wall of the cryogenic enclosure, the rotor and the stator comprising at least in part a ferromagnetic material to concentrate magnetic flux in a magnetic circuit across the gap between the rotor and the stator and through the wall, so that movement of the rotor external to the cryogenic enclosure relative to the stator within the cryogenic enclosure induces a DC transport current to flow around the superconducting circuit within the cryogenic enclosure.

Abstract: A magnet assembly for use in carrying out nuclear magnetic resonance experiments on a body or sample. The assembly comprises a set of superconducting coils within a cryostat, located about a bore, and arranged to generate a substantially uniform magnetic field in a primary working volume within the bore, and to generate a substantially uniform magnetic field in a secondary working volume within the coil structure and separate from the bore. At least part of a hyperpolarisation system intersects the at least one secondary working volume so as to hold a sample to be hyperpolarised in the secondary working volume.

Abstract: A method of operating a DNP system comprising: a cryostat (1); a magnetic field generator (2) located in the cryostat for generating a magnetic field in a working volume; a microwave cavity (8) within which the working volume is located; and a waveguide (18) for supplying microwave power to the microwave cavity; the method comprising: a) locating a sample in the working volume and subjecting the sample to a magnetic field generated by the magnetic field generator; b) supplying liquid coolant to the working volume to cool the sample; c) irradiating the sample with microwave power so as to hyperpolarize nuclear spins in the sample; and d) warming the sample following the irradiation step by expelling liquid coolant from the working volume while leaving the sample in the working volume.

Abstract: A coolant sub-assembly is provided for use in a DNP apparatus. The sub-assembly comprises a plurality of concentric jackets surrounding an inner bore tube having first and second opposed ends. The jackets are adapted to inhibit heat flow to the inner bore tube, a DNP working region being defined within the inner bore tube where a DNP process will be performed on a sample in the DNP working region. A coolant supply path extends adjacent an outer surface of the inner bore tube at the DNP working region in order to cool said outer surface, whereby a sample holder assembly can be inserted through the first end of the inner bore tube to bring a sample holder into the DNP working region and can be moved through the second end of the inner bore tube. An auxiliary coolant supply path supplies coolant to a sample, located in use in the sample holder at the DNP working region, through at least one aperture in the inner bore tube wall at the DNP working region.

Abstract: Apparatus for performing in-vitro DNP-NMR measurements on a sample comprises magnetic field generating apparatus (1a, 1b) located in a cryostat (2) and surrounding a bore defining respective NMR and DNP working regions (90, 92). A system for performing DNP on a suitably prepared sample in the DNP working region. A system for performing a NMR process on a sample in the NMR working region. A sample positioning mechanism (5) which can be inserted in the bore (3) to bring a sample in turn into each of the working regions. The magnetic field generating apparatus is suitably structured so that the magnetic field in the DNP working region has a homogeneity or profile suitable for performing DNP on the sample and the magnetic field in the NMR working region has a homogeneity or profile suitable for performing a NMR process on the sample.

Abstract: A method of providing magnetised particles at a location using particles which can be switched between magnetic and non-magnetic states by exposure to a suitable magnetic field. The method comprises conveying the particles in their non-magnetic state to the location; and then exposing the particles to the suitable magnetic field so that they switch to their magnetic state.

Abstract: A magnet assembly for use in carrying out nuclear magnetic resonance experiments on a body or sample. The assembly comprises a set of superconducting coils (12) within a cryostat, located about a bore, and arranged to generate a substantially uniform magnetic field in a primary working volume (101) within the bore, and to generate a substantially uniform magnetic field in a secondary working volume (100) within the coil structure and separate from the bore. At least part of a hyperpolarisation system intersects the at least one secondary working volume (101) so as to hold a sample to be hyperpolarised in the secondary working volume.

Abstract: An NMR inspection apparatus comprises a system for providing a dissolved, hyperpolarized sample and an NMR analysis system connected to the hyperpolarizing system are disclosed. The NMR analysis system includes a magnet for generating a substantially homogeneous magnetic field in a working volume suitable for carrying out NMR and a number of RF magnetic field generators located in the working volume. A non-electrically conducting conduit passes adjacent the RF magnetic field generators and is coupled to the hyperpolarizing system so as to convey a hyperpolarized sample past each RF magnetic field generator in sequence. A sample control system controls movement of a sample through the conduit. An NMR signal acquisition system controls the RF magnetic field generators to generate RF magnetic fields in accordance with a predetermined pulse sequence and detects the resulting NMR signals from the portions of the sample exposed to the RF magnetic fields.

Abstract: A method of operating a DNP system comprising: a cryostat (1); a magnetic field generator (2) located in the cryostat for generating a magnetic field in a working volume; a microwave cavity (8) within which the working volume is located; and a waveguide (18) for supplying microwave power to the microwave cavity; the method comprising: a) locating a sample in the working volume and subjecting the sample to a magnetic field generated by the magnetic field generator; b) supplying liquid coolant to the working volume to cool the sample; c) irradiating the sample with microwave power so as to hyperpolarize nuclear spins in the sample; and d) warming the sample following the irradiation step by expelling liquid coolant from the working volume while leaving the sample in the working volume.

Abstract: A coolant sub-assembly is provided for use in a DNP apparatus. The sub-assembly comprises a plurality of concentric jackets surrounding an inner bore tube having first and second opposed ends. The jackets are adapted to inhibit heat flow to the inner bore tube, a DNP working region being defined within the inner bore tube where a DNP process will be performed on a sample in the DNP working region. A coolant supply path extends adjacent an outer surface of the inner bore tube at the DNP working region in order to cool said outer surface, whereby a sample holder assembly can be inserted through the first end of the inner bore tube to bring a sample holder into the DNP working region and can be moved through the second end of the inner bore tube. An auxiliary coolant supply path supplies coolant to a sample, located in use in the sample holder at the DNP working region, through at least one aperture in the inner bore tube wall at the DNP working region.

Abstract: A method of carrying out DNP on a sample with a molecular structure containing at least two J-coupled non-integer spin nuclear species, the method comprising hyperpolarizing the sample in a cooled, solid form while it is exposed to a homogeneous magnetic field of suitable strength; dissolving or melting the hyperpolarized sample; subjecting the sample to a polarization holding RF pulse sequence while the sample is exposed to a suitably homogeneous magnetic field of sufficient strength to ensure the spin's chemical shift is greater than the J-coupling, the pulse sequence causing the nuclear spin populations in the sample to be re-distributed between a plurality of energy levels in a non-equilibrium manner; and then, following a time less than the T1, relaxation time constant of the molecular species, causing the nuclear spin populations to transfer adiabatically to stable, equilibrium levels.

Abstract: A magnetic field generating assembly comprising a set (A1-A3;B1-B3;C1-C3) of, typically substantially coaxial, coils substantially symmetrically arranged about a plane orthogonal to the axis. At least some of the coils carry working currents in the opposite sense to the other coils The arrangement of turns and working currents carried by the coils is such that a first working volume (10) with a substantially homogeneous magnetic field is generated within the envelope defined by the assembly, and two second working volumes (11) each with a substantially homogeneous magnetic field are generated outside the envelope, the homogeneity of each of the first and second working volumes being sufficient to perform a NMR experiment on a sample in the working volume.

Abstract: A cryostat assembly includes a thermal shield, a cooling system including a cold member maintained in use at a temperature lower than that of the thermal shield, a first adsorption pump assembly located at least partly within the thermal shield, a first switch thermally connecting the adsorption pump to the thermal shield, a second switch selectively, thermally connecting the adsorption pump to the cold member, and a first thermal link. The first adsorption pump includes a pumping chamber containing a working fluid and an adsorption pump in fluid communication with the pumping chamber. The first thermal link couples the pumping chamber to the cold member. During adsorption of the working fluid by the adsorption pump, a portion of the working fluid evaporates so as to cause the temperature within the pumping chamber to fall below the temperature of the cold member.

Abstract: Apparatus for performing in-vitro DNP-NMR measurements on a sample comprises magnetic field generating apparatus (1a, 1b) located in a cryostat (2) and surrounding a bore defining respective NMR and DNP working regions (90, 92). A system for performing DNP on a suitably prepared sample in the DNP working region. A system for performing a NMR process on a sample in the NMR working region. A sample positioning mechanism (5) which can be inserted in the bore (3) to bring a sample in turn into each of the working regions. The magnetic field generating apparatus is suitably structured so that the magnetic field in the DNP working region has a homogeneity or profile suitable for performing DNP on the sample and the magnetic field in the NMR working region has a homogeneity or profile suitable for performing a NMR process on the sample.

Abstract: A magnet assembly comprising first and second sets of coils (1, 2) for generating respective magnetic fields, wherein the coils are constructed and arranged such that under working conditions, a first homogeneous region (3) can be generated within the envelope defined by the magnet 10 assembly and a second homogeneous region (4) can be generated outside the envelope, the resultant magnetic field in each region being sufficiently homogeneous to enable a NMR process to be performed on an object in the region.

Abstract: A magnetic field generating assembly comprises a magnetic field generation system (7, 8) for generating, in a first mode, a first, relatively strong static magnetic field in a working volume (71) located outside the assembly, and for generating, in a second mode, a second, static magnetic field in the working volume in a second mode. In the second mode the magnetic field in the working volume (71) is weaker but more uniform than the first relatively strong magnetic field.

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 a pulse train comprising a plurality of rf magnetic field pulses for use in an NMR investigation, the generator comprising(i) an amplifier (5) for generating an rf signal, the amplifier having an input for receiving a supply voltage;(ii) a transmitter coil (42) connected to an output of the amplifier, the transmitter coil being adapted to transmit the rf magnetic field pulses in response to the rf signal;(iii) a switched voltage regulator (4) for regulating the supply voltage by charging a local storage capacitor; and(iv) a controller (13) for causing the switched voltage regulator to charge the local storage capacitor only when a magnetic field pulse is not being transmitted.

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.