Abstract: An NMR apparatus having a magnet coil system for generating a homogeneous magnetic field comprises a superconducting magnet within a vacuum vessel in the cold region of a cryostat and a shim system containing shim elements outside the vacuum vessel, wherein the 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 mechanical connection point to the second mechanical connection point and/or on at least one portion of a path along the positioning element from the second mechanical connection point to the shim system, only materials whose thermal expansion coefficient at operating temperature is less than 5 ppm/K are used. Magnetic field homogeneity can thus be kept largely stable and constant.

Abstract: An NMR apparatus includes a superconducting magnet coil system configured to generate a homogeneous magnetic field, and a helium (He) tank having an inner tube mechanically rigidly connected to the He tank and in which the magnet coil system is positioned. The He tank is configured to contain liquid helium to cool the magnet coils. A radiation shield has a radiation shield inner tube encompassing the He tank and spaced from the He inner tube to create a space between the He inner tube and the radiation shield inner tube to reduce an evaporation rate of the liquid helium. The NMR apparatus additionally includes a field shaping device with a magnetic material arranged in the space, in order to shim the homogeneous magnetic field. The field shaping device is fixed in the space so as to be in rigid mechanical contact with the He tank but without contacting the radiation shield.

Abstract: An NMR apparatus includes a superconducting magnet coil system configured to generate a homogeneous magnetic field, and a helium (He) tank having an inner tube mechanically rigidly connected to the He tank and in which the magnet coil system is positioned. The He tank is configured to contain liquid helium to cool the magnet coils. A radiation shield has a radiation shield inner tube encompassing the He tank and spaced from the He inner tube to create a space between the He inner tube and the radiation shield inner tube to reduce an evaporation rate of the liquid helium. The NMR apparatus additionally includes a field shaping device with a magnetic material arranged in the space, in order to shim the homogeneous magnetic field. The field shaping device is fixed in the space so as to be in rigid mechanical contact with the He tank but without contacting the radiation shield.

Abstract: An NMR apparatus includes a superconducting magnet coil system configured to generate a homogeneous magnetic field, and a helium (He) tank having an inner tube mechanically rigidly connected to the He tank and in which the magnet coil system is positioned. The He tank is configured to contain liquid helium to cool the magnet coils. A radiation shield has a radiation shield inner tube encompassing the He tank and spaced from the He inner tube to create a space between the He inner tube and the radiation shield inner tube to reduce an evaporation rate of the liquid helium. The NMR apparatus additionally includes a field shaping device with a magnetic material arranged in the space, in order to shim the homogeneous magnetic field. The field shaping device is fixed in the space so as to be in rigid mechanical contact with the He tank but without contacting the radiation shield.

Abstract: Temperature control device (20) for an NMR sample tube (22), wherein multiple interleaved, concentric flow channels (28, 31; 40, 41, 42; 50, 51) for temperature control fluid extending coaxially with respect to a cylindrical interior space (21) for holding the NMR sample tube are constituted around said interior space (21), wherein said temperature control device is constituted such that it is closed toward the interior space in an axial end region (26) and, an axial end region (23) at the opposite end thereto, open to the interior space for inserting the NMR sample tube into said interior space (21), wherein, in a counter flow region (GB), adjacent flow channels (28, 31; 40, 41, 42; 51) are interconnected through a fluid passage (34, 43, 44) at one axial end in such a way that the direction of a fluid flow in the flow channels of the counter flow region is reversed with respect to the corresponding adjacent flow channel in the counter flow region, wherein the outermost flow channel (28; 51) of the counter fl

Abstract: A sample frame (30; 81) for preparing a plurality of sample vessels (41, 42), in particular sample tubes, having a plurality of retainers, in each of which a sample vessel (41, 42) is situated, is characterized in that the sample vessels (41, 42) each have a cap (43, 44), which is put over the open end of the sample vessel (41, 42), the cap (41, 42) having a drilled hole (53, 54), through which the interior of the sample vessel (41, 42) is accessible, the sample frame (30; 81) has a removable cover plate (8), whose bottom side faces toward the caps (43, 44) of the sample vessels (41, 42) in the put-on state of the cover plate (8), and the cover plate (8) has an approximately funnel-shaped depression (11, 71) on the top side for each retainer, in whose center a through opening (57) through the cover plate (8) is provided, the through opening (57) aligning with the drilled hole (53, 54) of a cap (43, 44) of a sample vessel (41, 42) retained underneath when the cover plate (8) is put on.

Abstract: Temperature control device (20) for an NMR sample tube (22), wherein multiple interleaved, concentric flow channels (28, 31; 40, 41, 42; 50, 51) for temperature control fluid extending coaxially with respect to a cylindrical interior space (21) for holding the NMR sample tube are constituted around said interior space (21), wherein said temperature control device is constituted such that it is closed toward the interior space in an axial end region (26) and, an axial end region (23) at the opposite end thereto, open to the interior space for inserting the NMR sample tube into said interior space (21), wherein, in a counter flow region (GB), adjacent flow channels (28, 31; 40, 41, 42; 51) are interconnected through a fluid passage (34, 43, 44) at one axial end in such a way that the direction of a fluid flow in the flow channels of the counter flow region is reversed with respect to the corresponding adjacent flow channel in the counter flow region, wherein the outermost flow channel (28; 51) of the counter fl

Abstract: A sample frame (30; 81) for preparing a plurality of sample vessels (41, 42), in particular sample tubes, having a plurality of retainers, in each of which a sample vessel (41, 42) is situated, is characterized in that the sample vessels (41, 42) each have a cap (43, 44), which is put over the open end of the sample vessel (41, 42), the cap (41, 42) having a drilled hole (53, 54), through which the interior of the sample vessel (41, 42) is accessible, the sample frame (30; 81) has a removable cover plate (8), whose bottom side faces toward the caps (43, 44) of the sample vessels (41, 42) in the put-on state of the cover plate (8), and the cover plate (8) has an approximately funnel-shaped depression (11, 71) on the top side for each retainer, in whose center a through opening (57) through the cover plate (8) is provided, the through opening (57) aligning with the drilled hole (53, 54) of a cap (43, 44) of a sample vessel (41, 42) retained underneath when the cover plate (8) is put on.

Abstract: A cap (1; 51) for an NMR sample tube (52) having an inner bore (3) for receiving an open end (54) of an NMR sample tube (52), wherein the inner bore (3) has a narrowing for sealing a received NMR sample tube (52) against the cap (1; 51) along the outer periphery of the NMR sample tube (52), is characterized in that the narrowing is designed as an inner sealing lip (4). The cap provides good sealing between the cap and the NMR tube, and the cap can be produced from a plurality of materials, in particular, materials with good chemical resistance to NMR solvents.

Abstract: A tubular capacitor with variable capacitance, including a cylindrical tube (3) of dielectric material, a metallic outer electrode (1) which surrounds the cylindrical tube (3), and an inner electrode which can axially move in the inner bore (41) of the cylindrical tube (3) and which abuts the inner bore (41), wherein the inner electrode includes a metallic rod (2; 2a; 2b; 2c), is characterized in that the metallic rod (2; 2a; 2b; 2c) is axially extended at its end (5?), located in the inner bore (41) of the cylindrical tube (3), using a rod (9; 9a; 9b; 9c) of dielectric material. The inventive tubular capacitor has an increased dielectric strength and improves the resolution of NMR spectrometers.

Abstract: A tubular capacitor with variable capacitance, comprising a cylindrical tube (3) of dielectric material, a metallic outer electrode (1) which surrounds the cylindrical tube (3), and an inner electrode which can axially move in the inner bore (41) of the cylindrical tube (3) and which abuts the inner bore (41), wherein the inner electrode comprises a metallic rod (2; 2a; 2b; 2c), is characterized in that the metallic rod (2; 2a; 2b; 2c) is axially extended at its end (5?), located in the inner bore (41) of the cylindrical tube (3), using a rod (9; 9a; 9b; 9c) of dielectric material. The inventive tubular capacitor has an increased dielectric strength and improves the resolution of NMR spectrometers.