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: Magnet apparatus (2) is provided comprising a magnet chamber (20), a magnet (2) positioned within the magnet chamber (20) and a quantity of superfluid coolant (30) which partially fills the magnet chamber (20) such that at least part of the magnet (2) is cooled by a superfluids film (31) of the coolant.

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: Cooling apparatus comprises a vacuum chamber, an inner chamber positioned within the vacuum chamber adapted to contain a coolant for cooling target apparatus, and a mechanical refrigerator for refrigerating the coolant and having at least one cooled part in contact with the coolant. The mechanical refrigerator is coupled to one or each of the vacuum chamber and inner chamber through vibration-reducing couplings, so as to reduce the effect upon the target apparatus of vibrations from the mechanical refrigerator.

Abstract: A magnetic field generating assembly comprises a superconducting magnet located in a cryostat defining a bore accessible from outside the cryostat, and a mechanical refrigerator having at least two cooling stages for at least partly cooling the cryostat. A coolant path extends from the refrigerator into the magnet bore. The coolant path is coupled for heat exchange with a cooling stage of the refrigerator other than the coldest cooling stage, so that the refrigerator is adapted also to cool coolant in the coolant path.

Abstract: A particle detector assembly includes a substrate on which are mounted at least two superconducting quasiparticle detectors. A processing system is connected to the detectors and distinguishes between events detected simultaneously in each detector and non-simultaneous events.

Abstract: A particle detector assembly includes a superconducting absorber to which is coupled superconducting tunnel junction detectors for detecting particles incident on the absorber. Each superconducting tunnel junction detector includes superconducting tunnel junction devices connected in parallel.

Abstract: A magnetic field generating assembly comprises a superconducting magnet located in a cryostat defining a bore accessible from outside the cryostat, and a mechanical refrigerator having at least two cooling stages for at least partly cooling the cryostat. A coolant path extends from the refrigerator into the magnet bore. The coolant path is coupled for heat exchange with a cooling stage of the refrigerator other than the coldest cooling stage, so that the refrigerator is adapted also to cool coolant in the coolant path.

Abstract: Cooling apparatus comprises a vacuum chamber, an inner chamber positioned within the vacuum chamber adapted to contain a coolant for cooling target apparatus, and a mechanical refrigerator for refrigerating the coolant and having at least one cooled part in contact with the coolant. The mechanical refrigerator is coupled to one or each of the vacuum chamber and inner chamber through vibration-reducing couplings, so as to reduce the effect upon the target apparatus of vibrations from the mechanical refrigerator.

Abstract: Cooling apparatus comprises a cooling system defining a closed path around which a coolant flows. The system includes a pump for causing coolant flow, a supply line extending from the pump to a cold location, positioned in a cryostat, in order to cool that location, and a return line extending from the cold location to the pump. The pump is located externally of the cryostat. A first heat exchanger is positioned within the cryostat and links the supply and return lines to allow heat exchange therebetween such that coolant flowing in the supply line is cooled by coolant flowing in the return line. A refrigerator is provided having a cooling stage within the cryostat and coupled to the supply line downstream of the first heat exchanger such that coolant reaching the first cooling stage has been precooled by the first heat exchanger.

Abstract: A particle detector assembly comprises a substrate on which are mounted at least two superconducting quasiparticle detectors. A processing system is connected to the detectors and adapted to distinguish between events detected substantially simultaneously in each detector and non-simultaneous events.

Abstract: A particle detector assembly comprises a superconducting absorber to which is coupled at least two superconducting tunnel junction detectors for detecting particles incident on the absorber. Each superconducting tunnel junction detector comprises at least two superconducting tunnel junction devices connected in parallel.

Abstract: A superconducting magnet assembly comprises a superconducting magnet (1) which, under working conditions, generates a magnetic field in a working volume, the superconducting magnet being connected in parallel with a superconducting switch (3), the switch and magnet being adapted to be connected in parallel to a power source (4) whereby under working conditions with the switch (3) open, the magnet (1) can be energised by the power source to generate a desired magnetic field in the working volume following which the switch (3) is closed, characterised in that the assembly further comprises a resistor (5) connected in series with the switch (3), the resistor (5) and switch (3) being connected in parallel to each of the magnet (1) and the power source (4).

Abstract: A pulsed NMR tool has a magnet arrangement that is used to generate a static magnetic field having a substantially uniform field strength in a region of the formation surrounding the borehole. An RF coil is used to produce pulsed RF fields orthogonal to the static field in the region of examination. The nuclear spins in the formation align themselves along the externally applied static magnetic field. A pulsed RF field is applied to tip the spins by 90°, resulting in a precession of the spins. The tipping pulse is followed by a series of refocusing pulses and the resulting series of pulse echoes is detected. Motion sensors on the tool produce signals indicative of the motion of the tool and a processor on the tool controls the timing of the tipping pulse to coincide with substantially zero motion of the tool in an axial direction or one perpendicular to the axial direction. A Kalman filter or other predictive filter is used to predict the desirable pulse triggering times.

Abstract: A method and apparatus for determining a characteristic of an earth formation surrounding a borehole in which a pulsed nuclear magnetic resonance (NMR) tool is received. A static magnetic field is produced in the borehole using at least two spaced-apart magnets in the NMR tool. The static magnetic field has a first region of substantially uniform magnetic intensity at a first location in the borehole, the first location in the borehole having a first temperature. The NMR tool is moved to a second location in the borehole having a second temperature, and a static magnetic field having a second region of substantially uniform magnetic is produced. The at least two spaced-apart magnets are controllably moved relative to each other wherein the first region of substantially uniform magnetic intensity and the second region of substantially uniform magnetic intensity are substantially equal in size and distance from the NMR tool.