Abstract: An NMR apparatus having a magnet coil system for generating a homogeneous magnetic field comprises a superconducting magnet arranged within a vacuum vessel in the cold region of a cryostat, and a shim system containing shim elements arranged outside the vacuum vessel. The superconducting magnet has a first mechanical connection point to the vacuum vessel via a magnet suspension, and the shim system has a second mechanical connection point to the vacuum vessel via a positioning element. On at least one portion of a path along the vacuum vessel from the first connection point to the second connection point and/or on at least one portion of a path along the positioning element from the second connection point to the shim system, a regulating element for regulating thermally caused changes in length is arranged on the relevant path. Magnetic field homogeneity can thus be kept largely stable.

Abstract: An NMR apparatus having a magnet coil system for generating a homogeneous magnetic field comprises a superconducting magnet arranged within a vacuum vessel in the cold region of a cryostat, and a shim system containing shim elements arranged outside the vacuum vessel. The superconducting magnet has a first mechanical connection point to the vacuum vessel via a magnet suspension, and the shim system has a second mechanical connection point to the vacuum vessel via a positioning element. On at least one portion of a path along the vacuum vessel from the first connection point to the second connection point and/or on at least one portion of a path along the positioning element from the second connection point to the shim system, a regulating element for regulating thermally caused changes in length is arranged on the relevant path. Magnetic field homogeneity can thus be kept largely stable.

Abstract: An NMR apparatus having a magnet coil system for generating a homogeneous magnetic field comprises a superconducting magnet arranged within a vacuum vessel in the cold region of a cryostat, and a shim system containing shim elements arranged outside the vacuum vessel. The superconducting magnet has a first mechanical connection point to the vacuum vessel via a magnet suspension, and the shim system has a second mechanical connection point to the vacuum vessel via a positioning element. On at least one portion of a path along the vacuum vessel from the first connection point to the second connection point and/or on at least one portion of a path along the positioning element from the second connection point to the shim system, a regulating element for regulating thermally caused changes in length is arranged on the relevant path. Magnetic field homogeneity can thus be kept largely stable.

Abstract: A cryostat assembly comprises an outer container that houses a coil tank with a superconducting magnet coil system and a first cryogenic fluid, and a storage tank with a second cryogenic fluid. The coil tank is secured to the outer container by a first suspension element and the storage tank is secured to the outer container by a second suspension element. The storage tank is thermally connected to a cover element having a mechanical and thermally-conductive connection to a tube element and to the first suspension element. The cover element connects to the storage tank via a resilient, heat-conducting connection that is in thermal contact with the cover element and the storage tank. This allows thermal coupling between the storage tank and cover element, and independent relative movements between the storage tank and cover element, while suppressing relative movements between the tube element and the superconducting magnet coil system.

Abstract: A superconducting magnet assembly with a reinforced coil region (3) having a layered conductor coil assembly (10) forming cylindrical conductor layers (11, . . . ), each having plural circular conductor turns (12) centered around and aligned along the axis of cylindrical symmetry (z). The reinforced coil region further includes a layered corset coil assembly (20) having an inner radius bigger than an outer radius of the layered conductor coil assembly (10), and a corset sheet assembly (30) including a foil element forming a corset sheet (31, . . . ). A cross section of the corset sheet with any plane perpendicular to the z-axis forms a segmented circle centered around the z-axis, the radius of which is bigger than that of one of the conductor layers and smaller than that of another of the conductor layers. In addition, the segmented circle covers at least 90% of a full circle but has at most four segments. The assembly provides mechanical reinforcement against radial magnetic forces.

Abstract: A method for charging an HTS shim device in a cryostat having a room temperature bore using a charging device. A shim switch temporarily interrupts the superconducting state in a section of an HTS shim conductor path. The charging device includes a primary circuit with a normal-conducting charging coil and the conductor path forms a secondary circuit. A current change in the secondary circuit results from a change in magnetic flux generated by the charging coil through the secondary circuit. In a first phase the shim switch is opened to interrupt the superconducting state in a section of the conductor path, the charging coil is positioned in the bore, and the current in the primary circuit is changed; in a second phase, the conductor path is superconductingly closed; in a third phase, the current in the primary circuit is changed and/or the charging coil is removed from the bore.

Abstract: A shim device having an HTS shim conductor track (C) and a shim switch (Sw1) The track (C) is curved around an axis (z) and the shim switch is arranged in a first conductor track portion (S1), to interrupt its superconducting state. The track (C) extends around at least a first opening (O1) and a second opening (O2) such that the track (C) has a first circumferential current path (L1), a second circumferential current path (L2) and a third circumferential current path (L3). Two of the three paths (L1, L2, L3) each surround only one of the two openings and one of the three paths (L1, L2, L3) surrounds both openings. The first portion (S1) is part of only the first path (L1) and the second path (L2). This produces a persistent HTS shim for field homogenization, allowing both a complex field distribution and a large degree of design freedom.

Abstract: A superconducting magnet assembly with a reinforced coil region (3) having a layered conductor coil assembly (10) forming cylindrical conductor layers (11, . . . ), each having plural circular conductor turns (12) centered around and aligned along the axis of cylindrical symmetry (z). The reinforced coil region further includes a layered corset coil assembly (20) having an inner radius bigger than an outer radius of the layered conductor coil assembly (10), and a corset sheet assembly (30) including a foil element forming a corset sheet (31, . . . ). A cross section of the corset sheet with any plane perpendicular to the z-axis forms a segmented circle centered around the z-axis, the radius of which is bigger than that of one of the conductor layers and smaller than that of another of the conductor layers. In addition, the segmented circle covers at least 90% of a full circle but has at most four segments. The assembly provides mechanical reinforcement against radial magnetic forces.

Abstract: A magnet assembly in a magnetic resonance apparatus includes a cryostat and a superconducting main field magnet coil system arranged therein for generating a magnetic field in the direction of a z-axis in a working volume. The magnet assembly includes a shim device arranged inside the cryostat for adjusting the spatial variation or homogeneity of the magnetic field generated in the working volume by the magnet coil system. The shim device comprises at least one closed superconducting shim conductor path having an HTS layer. The HTS layer forms a surface that is geometrically developable such that unwrapping onto a plane changes the geodesic distance between any two points on the surface formed by the HTS layer by no more than 10%. The inner and/or outer contour of the geometrical development of the HTS layer describes a non-convex curve.

Abstract: A shim device having an HTS shim conductor track (C) and a shim switch (Sw1) The track (C) is curved around an axis (z) and the shim switch is arranged in a first conductor track portion (S1), to interrupt its superconducting state. The track (C) extends around at least a first opening (O1) and a second opening (O2) such that the track (C) has a first circumferential current path (L1), a second circumferential current path (L2) and a third circumferential current path (L3). Two of the three paths (L1, L2, L3) each surround only one of the two openings and one of the three paths (L1, L2, L3) surrounds both openings. The first portion (S1) is part of only the first path (L1) and the second path (L2). This produces a persistent HTS shim for field homogenization, allowing both a complex field distribution and a large degree of design freedom.

Abstract: An NMR rotor comprises a receptacle for inserting a sample container into a homogeneous region of an NMR magnetic field with flux density B, the field vector of which in the homogeneous region extends in the vertical direction along a z-axis. The rotor passes through regions with inhomogeneous magnetic field components and a flux density gradient dB/dz when the sample container is introduced. The rotor includes at least two different materials, one with diamagnetic properties and another with non-diamagnetic properties. The different materials are arranged to be geometrically distributed in the rotor so that the magnetic force on the rotor under the effect of a product t of magnetic flux density B and flux density gradient dB/dz, the magnitude of which exceeds 1400 T2/m, either acts in the same direction as the weight force of the rotor or is smaller in magnitude than the weight force of the rotor.

Abstract: A superconductor magnet apparatus (2) includes a superconductor bulk magnet (9), a cryostat (7) and a ferromagnetic shielding body (11). The bulk magnet has a superconductor bore (10), an axis (z) of rotational symmetry, and a maximum outer diameter ODbm in a plane perpendicular to the z axis. The superconductor bore has a minimum cross-sectional area Sbo in a plane perpendicular to the z axis. The cryostat has a room temperature bore (8), the bulk magnet is arranged within the cryostat and the room temperature bore is arranged within the superconductor bore. The shielding body has a shielding bore (12), the bulk magnet is arranged within the shielding bore and the shielding body extends beyond the bulk magnet at each axial end by at least ODbm/3. For an average cross-sectional area Sfb of the shielding body, Sfb?2.5*Sbo, and the shielding body is arranged within the cryostat.

Abstract: A cryostat assembly comprises an outer container that houses a coil tank with a superconducting magnet coil system and a first cryogenic fluid, and a storage tank with a second cryogenic fluid. The coil tank is secured to the outer container by a first suspension element and the storage tank is secured to the outer container by a second suspension element. The storage tank is thermally connected to a cover element having a mechanical and thermally-conductive connection to a tube element and to the first suspension element. The cover element connects to the storage tank via a resilient, heat-conducting connection that is in thermal contact with the cover element and the storage tank. This allows thermal coupling between the storage tank and cover element, and independent relative movements between the storage tank and cover element, while suppressing relative movements between the tube element and the superconducting magnet coil system.

Abstract: A superconductor magnet apparatus (2) includes a superconductor bulk magnet (9), a cryostat (7) and a ferromagnetic shielding body (11). The bulk magnet has a superconductor bore (10), an axis (z) of rotational symmetry, and a maximum outer diameter ODbm in a plane perpendicular to the z axis. The superconductor bore has a minimum cross-sectional area Sbo in a plane perpendicular to the z axis. The cryostat has a room temperature bore (8), the bulk magnet is arranged within the cryostat and the room temperature bore is arranged within the superconductor bore. The shielding body has a shielding bore (12), the bulk magnet is arranged within the shielding bore and the shielding body extends beyond the bulk magnet at each axial end by at least ODbm/3. For an average cross-sectional area Sfb of the shielding body, Sfb?2.5*Sbo, and the shielding body is arranged within the cryostat.

Abstract: A method for charging an HTS shim device in a cryostat having a room temperature bore using a charging device. A shim switch temporarily interrupts the superconducting state in a section of an HTS shim conductor path. The charging device includes a primary circuit with a normal-conducting charging coil and the conductor path forms a secondary circuit. A current change in the secondary circuit results from a change in magnetic flux generated by the charging coil through the secondary circuit. In a first phase the shim switch is opened to interrupt the superconducting state in a section of the conductor path, the charging coil is positioned in the bore, and the current in the primary circuit is changed; in a second phase, the conductor path is superconductingly closed; in a third phase, the current in the primary circuit is changed and/or the charging coil is removed from the bore.

Abstract: A superconductive magnet coil assembly includes a layer-wound coil that is cylindrically symmetric, wherein the rectangular coil cross section of the coil has a first rectangular portion (1; 1?; 1?; 1??) within the coil cross section, and at least one second rectangular portion (2; 2?; 2?; 2??) and third rectangular portion (3; 3?; 3?; 3??) within the first portion which spans the first portion completely in the radial direction and in part in the axial direction, the second portion being completely wound with the first strip-like superconductor, and the third portion being completely wound with the second strip-like superconductor, and the strip-like superconductors being guided into a region outside the coil cross section and being electrically connected there, and wherein the second and the third rectangular portions are disjunct.

Abstract: A layer wound magnet coil includes a central coil region and end coil regions adjoining the central coil region along an axial line of symmetry. The central coil region includes layers of coil windings of an anisotropic material. The end coil regions include layers of coil windings of the anisotropic superconducting material interspersed with layers of non-superconducting material.

Abstract: A superconducting magnet assembly includes a cryostat, a vacuum vessel and a refrigeration stage. An NMR probe using the assembly includes comprises cooled probe components, a two-stage cryocooler, and a counter flow heat exchanger. A cooling circuit guides coolant from one outlet of the counter flow heat exchanger back to an inlet of the counter flow heat exchanger via the second cooling stage, a cooled probe component, and a heat exchanger in the cryostat or a heat exchanger in a helium suspension tube. Both the intake temperature of the coolant flowing into the heat exchanger in the cryostat or in the suspension tube and the return flow temperature of the emerging coolant are at least 5 K lower than the operating temperature of the first cooling stage. Excess cooling capacity of the cryocooler reduces the evaporation rate of liquid helium or cools a superconducting magnet in a cryogen-free cryostat.

Abstract: A superconductive magnet coil assembly includes a layer-wound coil that is cylindrically symmetric, wherein the rectangular coil cross section of the coil has a first rectangular portion (1; 1?; 1?; 1??) within the coil cross section, and at least one second rectangular portion (2; 2?; 2?; 2??) and third rectangular portion (3; 3?; 3?; 3??) within the first portion which spans the first portion completely in the radial direction and in part in the axial direction, the second portion being completely wound with the first strip-like superconductor, and the third portion being completely wound with the second strip-like superconductor, and the strip-like superconductors being guided into a region outside the coil cross section and being electrically connected there, and wherein the second and the third rectangular portions are disjunct.

Abstract: A magnet assembly in a magnetic resonance apparatus includes a cryostat and a superconducting main field magnet coil system arranged therein for generating a magnetic field in the direction of a z-axis in a working volume. The magnet assembly includes a shim device arranged inside the cryostat for adjusting the spatial variation or homogeneity of the magnetic field generated in the working volume by the magnet coil system. The shim device comprises at least one closed superconducting shim conductor path having an HTS layer. The HTS layer forms a surface that is geometrically developable such that unwrapping onto a plane changes the geodesic distance between any two points on the surface formed by the HTS layer by no more than 10%. The inner and/or outer contour of the geometrical development of the HTS layer describes a non-convex curve.