Abstract: The invention relates to a composite (1), comprising a Cu—Sn bronze matrix (2) and filaments (3) surrounded by the bronze matrix (2), wherein the filaments (3) contain niobium (?Nb) or a Nb alloy, characterized in that the filaments (3) contain between 0.3% and 20% of volume of copper (?Cu) substructures (4), which are distributed within the Nb or the Nb alloy. The composite can be used to produce a superconducting element with the bronze route which has an improved critical current density.

Abstract: An apparatus for DNP-NMR measurement on a sample (P), with a magnet configuration (M) for producing a magnetic field in a first working volume (V1), wherein the magnet configuration (M) produces a stray field in a second working volume (V2) in the direction of an axis (z) with a magnetic field gradient (H1M, H2M, HnM) in the direction of the axis (z), wherein the axis (z) extends through the second working volume (V2), with a device (N) for measuring MR signals, with a DNP excitation device (D), and with a positioning mechanism (T) for transferring the sample (P), is characterized in that, near the second working volume (V2), a compensation configuration (m) made of magnetic material is mounted that, in the operating condition of the magnet configuration (M), produces a magnetic field gradient (H1m, H2m, Hnm) in the direction of the axis (z) in the second working volume (V2) that is between ?90% and ?110% of the magnetic field gradient of the same order (H1M, H2M, . . .

Abstract: A superconductive element containing Nb3Sn, in particular a multifilament wire, comprising at least one superconductive filament (8) which is obtained by a solid state diffusion reaction from a preliminary filament structure (1), said preliminary filament structure (1) containing an elongated hollow pipe (2) having an inner surface (3) and an outer surface (4), wherein said hollow pipe (2) consists of Nb or an Nb alloy, in particular NbTa, wherein the outer surface (4) is in close contact with a surrounding bronze matrix (5) containing Cu and Sn, and wherein the inner surface (3) is in close contact with an inner bronze matrix (5) also containing Cu and Sn, is characterized in that the inner bronze matrix (5) of the preliminary filament structure (1) encloses in its central region an elongated core (6) consisting of a metallic material, said metallic material having at room temperature (=RT) a thermal expansion coefficient ?core<17*10?6K?1, preferably ?core?8*10?6 K?1, said metallic material having at RT a

Abstract: A method for producing a superconductive element, in particular a multifilament wire, starting from a composite (1) comprising a bronze matrix containing Cu and Sn, in which at least one elongated structure containing Nb or an Nb alloy, in particular NbTa, is embedded, whereby in a first step the composite is extruded at a temperature between 300° C. and 750° C.

Abstract: An NMR apparatus comprising an NMR magnet system disposed in a first cryocontainer (2) of a cryostat (9), and an NMR probe head (1), wherein the first cryocontainer (2) is installed in an evacuated outer jacket and is surrounded by a radiation shield (24) and/or a further cryocontainer (3), wherein a cooling device is provided for cooling the NMR probe head (1) and a cryocontainer (2, 3), which comprises a cold head (4, 4a, 4b, 4c) with several cold stages (12a, 12b, 12c, 18a, 18b, 18c, 19a), wherein one cold stage (12a, 12b, 12c, 18a, 18b, 18c, 19a) is connected to a heat-transferring device, and wherein a cooling circuit is provided between the cooling device and the NMR probe head (1), is characterized in that the cooling device is disposed in a separate, evacuated housing (6) which is positioned directly above the cryostat (9), wherein the heat-transferring device is inserted directly into suspension tubes (29a, 29c) of the cryocontainer (2, 3) and/or is in contact with the radiation shield (24).

Abstract: A superconductive element containing Nb3Sn, in particular a multifilament wire, comprising at least one superconductive filament (8) which is obtained by a solid state diffusion reaction from a preliminary filament structure (1), said preliminary filament structure (1) containing an elongated hollow pipe (2) having an inner surface (3) and an outer surface (4), wherein said hollow pipe (2) consists of Nb or an Nb alloy, in particular NbTa, wherein the outer surface (4) is in close contact with a surrounding bronze matrix (5) containing Cu and Sn, and wherein the inner surface (3) is in close contact with an inner bronze matrix (5) also containing Cu and Sn, is characterized in that the inner bronze matrix (5) of the preliminary filament structure (1) encloses in its central region an elongated core (6) consisting of a metallic material, said metallic material having at room temperature (=RT) a thermal expansion coefficient ?core<17*10?6K?1, preferably ?core?8*10?6 K?1, said metallic material having at RT a

Abstract: A method for producing a superconductive element, in particular a multifilament wire, starting from a composite (1) comprising a bronze matrix containing Cu and Sn, in which at least one elongated structure containing Nb or an Nb alloy, in particular NbTa, is embedded, whereby in a first step the composite is extruded at a temperature between 300° C. and 750° C.

Abstract: An NMR apparatus comprising an NMR magnet system disposed in a first cryocontainer (2) of a cryostat (9), and an NMR probe head (1), wherein the first cryocontainer (2) is installed in an evacuated outer jacket and is surrounded by a radiation shield (24) and/or a further cryocontainer (3), wherein a cooling device is provided for cooling the NMR probe head (1) and a cryocontainer (2, 3), which comprises a cold head (4, 4a, 4b, 4c) with several cold stages (12a, 12b, 12c, 18a, 18b, 18c, 19a), wherein one cold stage (12a, 12b, 12c, 18a, 18b, 18c, 19a) is connected to a heat-transferring device, and wherein a cooling circuit is provided between the cooling device and the NMR probe head (1), is characterized in that the cooling device is disposed in a separate, evacuated housing (6) which is positioned directly above the cryostat (9), wherein the heat-transferring device is inserted directly into suspension tubes (29a, 29c) of the cryocontainer (2, 3) and/or is in contact with the radiation shield (24).

Abstract: A cooling device (7) for re-liquefying cryogenic gases, comprising an outer jacket (8) which delimits a vacuum chamber (9), and a cryocooler cold head (10) installed therein, which has at least two cold stages (11, 12) and is at least partially surrounded by a radiation shield (13) is characterized in that at least two cold stages (11, 12) of the cold head (10) are separately individually connected in a heat-conducting manner to a heat-transferring device (14a, 14b) which can be inserted into the neck or suspension tubes (3a, 3b) of a cryostat (1) for keeping at least two different cryogenic liquids (18a, 18b). The cooling device can be easily retrofitted into existing cryostat configurations, in particular, those containing superconducting magnets and without (or with minimum) adjustment to permit operation with no or little cryogen loss, even if several cryogens are used.

Abstract: The invention relates to a composite (1), comprising a Cu—Sn bronze matrix (2) and filaments (3) surrounded by the bronze matrix (2), wherein the filaments (3) contain niobium (?Nb) or a Nb alloy, characterized in that the filaments (3) contain between 0.3% and 20% of volume of copper (?Cu) substructures (4), which are distributed within the Nb or the Nb alloy. The composite can be used to produce a superconducting element with the bronze route which has an improved critical current density.

Abstract: A magnet arrangement comprising a superconducting magnet coil system (M) for producing a magnetic field in the direction of a z axis in a working volume (AV) disposed on the z axis about z=0, wherein the superconducting magnet coil system (M) comprises a radially inner partial coil system (C1) and a radially outer partial coil system (C2) which is coaxial thereto, and with a field forming device (P) of magnetic material disposed in a preferably cylindrically symmetrical fashion about the z axis, located radially between the radially inner and the radially outer partial coil system (C1, C2), and being coaxial with respect to the two partial coil systems (C1, C2), wherein the radially inner partial coil system (C1) produces a homogeneous field in the working volume (AV) and the radially outer partial coil system (C2) produces an inhomogeneous field in the working volume (AV) is characterized in that the radially outer partial coil system (C2) produces, together with the magnetic field forming device (P),

Abstract: A magnet arrangement comprising a superconducting magnet coil system (M) for producing a magnetic field in the direction of a z axis in a working volume (AV) disposed on the z axis about z=0, wherein the superconducting magnet coil system (M) comprises a radially inner partial coil system (C1) and a radially outer partial coil system (C2) which is coaxial thereto, and with a field forming device (P) of magnetic material disposed in a preferably cylindrically symmetrical fashion about the z axis, located radially between the radially inner and the radially outer partial coil system (C1, C2), and being coaxial with respect to the two partial coil systems (C1, C2), wherein the radially inner partial coil system (C1) produces a homogeneous field in the working volume (AV) and the radially outer partial coil system (C2) produces an inhomogeneous field in the working volume (AV) is characterized in that the radially outer partial coil system (C2) produces, together with the magnetic field forming device (P),

Abstract: A magnet system for magnetic resonance spectrometers comprising an actively shielded superconducting magnet with a radially inner and a radially outer coil system (M1, M2), wherein the two coil systems carry the same current and have identical opposite dipole moments, and comprising a shim coil system for correcting magnetic field inhomogeneities in the working volume, whose z component varies in proportion to z2, is characterized in that the shim coil system comprises a radially inner shim coil set (Si) which is inductively decoupled from the magnet system and generates a magnetic field in the working volume, whose z component varies like &Dgr;H0 +c2·z2 with c2=const., and a radially outer shim coil set (Sa) which is also inductively decoupled from the magnet system and generates a homogeneous magnetic field −&Dgr;H0 in the working volume.