Abstract: A magnet arrangement comprising a superconducting magnet coil system (M) which has an ohmic resistance (R) of zero or more during operation, and a flux pump (P) which comprises at least one superconducting switch and at least two superconducting secondary coils (M1, M2), is characterized in that at least one superconducting current path is provided, wherein the superconducting magnet coil system (M) or parts thereof is/are connected in series with at least two secondary coils (M1, M2), and wherein at least one secondary coil (M2) can be superconductingly bridged through closing of a superconducting switch (S1), and at least two primary coils (C1, C2) are provided which can each be fed independently of each other with a current (I1, I2) and which are each inductively coupled with at least one of the secondary coils (M1, M2). The flux pump is suitable for the stabilization of the magnetic field of the magnet coil system (M) during long-term operation.

Abstract: A nuclear magnetic resonance (NMR) spectrometer for investigating a liquid sample in a sample tube, in particular a glass sample tube (12), has a sample bushing (1) surrounding the sample tube having a bore into which one end of the sample tube is inserted with tight fit. The sample bushing (1) is preferably substantially cylindrical and the bore extends along the cylindrical axis. The NMR spectrometer has a gripping device (13) for handling the sample bushing (1), the gripping device (13) having at least three gripping fingers (14a-14d), and the outer periphery of the sample bushing (1) has at least one groove (2) into which the gripping fingers (14a-14d) can engage to press onto the two outer edges of the groove (2) when the gripping device (13) is closed. The cooperation between the groove and the gripping device permits fully automated, precise handling of the samples.

Abstract: A device for centering an elongated sample tube (8), filled with a measuring substance, relative to a vertical axis of a nuclear magnetic resonance (NMR) receiver coil system (9) which is rigidly mounted in a support device is characterized in that at least two centering means are provided which are mutually separated in an axial direction of the receiver coil axis and act exclusively in a radial direction on the sample tube (8), one of which is disposed in the upper region (9a) and the other in the lower region (9b, 9b?) of the NMR receiver coil system (9a-k) and with at least one positioning means acting on the sample tube (8) in an exclusively axial direction which may be located either below (20a) or above (17) the NMR receiver coil system, wherein the exclusively radially acting centering means (9a, 9b, 9b?) are components of the NMR receiver coil system (9a-k).

Abstract: A cryohead (1) for nuclear magnetic resonance (NMR) measurements, comprising at least one detection channel for receiving NMR signals and at least one transmitting and decoupling channel, wherein different radio frequency (RF) coils or resonators (11, 12, 12b) are provided for the different channels, wherein the cryohead (1) comprises a heat exchanger which can be cooled by a passing fluid, in particular helium, and wherein the RF coils or resonators (11, 12, 12b) of at least one detection channel and also of at least one transmitting or decoupling channel can be cooled to cryogenic temperatures, is characterized in that at least two heat exchangers (14, 15) are provided.

Abstract: A nuclear magnetic resonance (NMR) spectrometer with a magnet arrangement (1) for generating a homogeneous static magnetic field B0 in the direction of a z axis and a radio frequency (RF) resonator (2) for receiving NMR signals from a measuring volume which has one or more superconducting components, is characterized in that a stabilization device is provided which keeps the magnetic field components BT, transverse to the homogeneous magnetic field B0, which acts on the superconducting components of the RF resonator (2), constant. The stabilization device can act actively or passively. It is thereby possible to completely suppress generation of disturbing transverse magnetization for RF resonator coils with superconducting components. Moreover, a demagnetised coil always remains demagnetised during the entire subsequent operation.

Abstract: A pulsed field gradient NMR (=nuclear magnetic resonance) method using stimulated echoes for determining the translational isotropic or anisotropic diffusion coefficient of a molecule or supra-molecular assembly or the flow rate and direction of fluids containing such molecules is characterized in that the molecule or supra-molecular assembly contains one or several isotopes (X) of non-zero nuclear spin other than protons having longitudinal relaxation times T1(X) that are longer than the longitudinal relaxation times T1(H) of the protons, and that the information about the localization of the molecule or supra-molecular assembly during the diffusion or flow interval is temporarily stored in the form of longitudinal magnetization of said isotope or isotopes. Thus, the determination of translational diffusion coefficients or flow rates of supra-molecular assemblies or molecules with short T1(H) values, in particular of supra-molecular assemblies or molecules with M≧50 kDa is accomplished.

Abstract: A magnet assembly for generating a magnetic field (H) in the direction of a z axis in a working volume (AV) comprises an actively shielded superconducting magnet coil system (M) and at least one current path (P1, . . . , Pn) which is superconductingly closed in the operating state. The actively shielded superconducting magnet coil system (M) has a radially inner partial coil system (C1) and a radially outer partial coil system (C2) disposed coaxially with respect to each other. An external device supplies current to the current paths (P1, . . . , Pn) to charge each path to a respective current (IP1, . . . , IPn) in the operating state. When optimizing the fringe field behavior outside of the magnet system, the overall magnitude of magnetic dipole moments of the current paths (P1, . . . , Pn), charged to their respective operating currents (IP1, . . . , IPn), is at least 0.1% of the magnitude of the magnetic dipole moment of the charged partial coil system (C2). When charging the current paths (P1, . . .

Abstract: An NMR resonator with RF resonator for receiving RF signals at a resonance frequency from a measuring sample in a volume under investigation of an NMR apparatus with a means for producing a homogeneous magnetic field B0 in the direction of a z axis, wherein normally conducting conductor structures of the RF resonator which act inductively and partially also capacitively are disposed between z=−|z1| and z=+|z2| on a surface which is translation-invariant (=z-invariant) in the z direction at a radial (x, y) separation from the measuring sample, is characterized in that a compensation arrangement is additionally provided on the z-invariant surface, which extends to values of at least z<−|z1|−0.5|r| and z>+|z2|+0.

Abstract: An RF receiver coil arrangement for the reception of measuring signals from a measuring sample in the measuring volume of an NMR spectrometer comprising an RF resonator having superconducting, inductively and capacitively acting conducting structures, which form resonant circuits, on planar substrate elements and which are disposed about the measuring sample, is characterized in that each individual current-carrying resonant circuit on the planar substrate element produces a magnetic field in the center of the measuring volume, which is parallel to the plane of the planar substrate element, on which the individual resonant circuit is located, wherein the deviation from parallelism, does not exceed 40 degrees. This introduces a new class of superconducting NMR resonators which better meet the technical requirements than those of prior art.

Abstract: A magnet assembly for generating a magnetic field (H) in the direction of a z axis in a working volume (AV) disposed on the z axis about z=0 with an actively shielded superconducting magnet coil system (M) and at least one current path (P1, . . . , Pn) which is superconductingly closed in the operating state, wherein the actively shielded superconducting magnet coil system (M) comprises a radially inner partial coil system (C1) and a radially outer partial coil system (C2) disposed coaxially with respect to each other and whose magnetic dipole moments have opposite signs in the operating state and differ by an amount &Dgr;m, with |&Dgr;m|<2.5% of the magnitude of the magnetic dipole moment of the radially inner partial coil system (C1), is characterized in that the current paths (P1, . . . ,Pn) are at least temporally superconductingly short-circuited during charging of the actively shielded superconducting magnet coil system (M) and that the current paths (P1, . . .

Abstract: A device for transporting an elongated sample tube (8) into the measuring chamber (22) of an NMR magnet system comprising a spinner which has an axial through-bore through which the sample tube can be inserted, transported together with the spinner on an air cushion into the measuring chamber, and positioned therein relative to the vertical axis of the NMR receiver coil system (9) is characterized by a mounting sleeve (17) which is disposed in a collar-like manner radially around the sample tube such that it cannot slip and which, in the operating position of the sample tube, flatly abuts with one end face thereof on a horizontal stop surface (18) in the bottom region inside a two-stage axial bore (20) of the spinner (7b), wherein the inner diameter of the bore (20), in a first stage in the upper region, is larger than the outer diameter of the mounting sleeve, and the inner diameter of a second stage, in the bottom region of the spinner, is smaller than the outer diameter of the mounting sleeve but larger th

Abstract: An NMR measuring system comprising an NMR probe head (34) with a cooled NMR receiver resonator (35) is connected via a transfer line (19) to a cooling device for supplying two coolant loops with coolant at two different cryogenic temperature levels, wherein the transfer line (19) contains one coolant feed line and/or one coolant return line for each of the two coolant loops for cooling the NMR probe head (34), and where these feed lines and return lines terminate on one side in four preferably standardized connection points (7,11,12,16) of the cooling device and on the other side, facing the probe head, in a standardized cryo-coupling device (28) which in its turn can be connected to a matching also standardized cryo-coupling device (29) attached to the probe head.

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 assembly for generating a magnetic field (H) in the direction of a z axis in a working volume (AV) comprises an actively shielded superconducting magnet coil system (M) and at least one current path (P1, . . . , Pn) which is superconductingly closed in the operating state. The actively shielded superconducting magnet coil system (M) has a radially inner partial coil system (C1) and a radially outer partial coil system (C2) disposed coaxially with respect to each other. An external device supplies current to the current paths (P1, . . . , Pn) to charge each path to a respective current (IP1, . . . , IPn) in the operating state. When optimizing the fringe field behavior outside of the magnet system, the overall magnitude of magnetic dipole moments of the current paths (P1, . . . , Pn), charged to their respective operating currents (IP1, . . . , IPn), is at least 0.1% of the magnitude of the magnetic dipole moment of the charged partial coil system (C2). When charging the current paths (P1, . . .

Abstract: A magnet assembly for generating a magnetic field (H) in the direction of a z axis in a working volume (AV) disposed on the z axis about z=0 with an actively shielded superconducting magnet coil system (M) and at least one current path (P1, . . . , Pn) which is superconductingly closed in the operating state, wherein the actively shielded superconducting magnet coil system (M) comprises a radially inner partial coil system (C1) and a radially outer partial coil system (C2) disposed coaxially with respect to each other and whose magnetic dipole moments have opposite signs in the operating state and differ by an amount &Dgr;m, with |&Dgr;m|<2.5% of the magnitude of the magnetic dipole moment of the radially inner partial coil system (C1), is characterized in that the current paths (P1, . . . , Pn) are at least temporally superconductingly short-circuited during charging of the actively shielded superconducting magnet coil system (M) and that the current paths (P1, . . .

Abstract: A device for centering an elongated sample tube (8), filled with a measuring substance, relative to a vertical axis of a nuclear magnetic resonance (NMR) receiver coil system (9) which is rigidly mounted in a support device is characterized in that at least two centering means are provided which are mutually separated in an axial direction of the receiver coil axis and act exclusively in a radial direction on the sample tube (8), one of which is disposed in the upper region (9a) and the other in the lower region (9b, 9b′) of the NMR receiver coil system (9a-k) and with at least one positioning means acting on the sample tube (8) in an exclusively axial direction which may be located either below (20a) or above (17) the NMR receiver coil system, wherein the exclusively radially acting centering means (9a, 9b, 9b′) are components of the NMR receiver coil system (9a-k).

Abstract: A pulsed field gradient NMR (=nuclear magnetic resonance) method using stimulated echoes for determining the translational isotropic or anisotropic diffusion coefficient of a molecule or supra-molecular assembly or the flow rate and direction of fluids containing such molecules is characterized in that the molecule or supra-molecular assembly contains one or several isotopes (X) of non-zero nuclear spin other than protons having longitudinal relaxation times T1(X) that are longer than the longitudinal relaxation times T1(H) of the protons, and that the information about the localization of the molecule or supra-molecular assembly during the diffusion or flow interval is temporarily stored in the form of longitudinal magnetization of said isotope or isotopes. Thus, the determination of translational diffusion coefficients or flow rates of supra-molecular assemblies or molecules with short T1(H) values, in particular of supra-molecular assemblies or molecules with M≧50 kDa is accomplished.

Abstract: A magnet arrangement comprising a superconducting magnet coil system (C) for generating 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 field of the magnet coil system (C) in the working volume (AV) comprises at least one inhomogeneous contribution Hn·zn with n≧2 whose contribution to the total field strength on the z axis about z=0 varies with the nth power of z, and wherein a field shaping device (P) of magnetic material is provided, which is substantially cylindrically symmetrical with respect to the z axis, is characterized in that the magnet coil system (C) is provided for use in an apparatus for high-resolution magnetic resonance spectroscopy and the field shaping device (P) has, at least partially, a radial separation from the z axis of less than 80 mm and compensates for at least one of the inhomogeneous field contributions Hn·zn of the magnet coil system (C) by at least 50%, wherein at least one additi

Abstract: An NMR resonator for receiving RF signals at desired resonance frequencies from a measuring sample in a volume under investigation disposed about a coordinate origin (x,y,z=0), with a means for producing a homogeneous magnetic field B0 in the direction of a z axis, wherein superconducting conductor structures are disposed between z=−|z1| and z=+|z2| on a surface which is translation-invariant (=z-invariant) in the z direction at a radial separation from the measuring sample, is characterized in that a compensation arrangement is additionally provided on the z-invariant surface, which extends to values of at least +|z2|+0.5|r|>z>−|z1|−0.

Abstract: A magnet arrangement comprising an actively shielded superconducting magnet coil system (M) and a plurality of protective elements (R1, . . . , Rl) for protection in case of a quench, wherein the superconducting magnet coil system (M) comprises a radially inner partial coil system (C1) and a radially outer partial coil system (C2) which are electrically connected in series and arranged coaxially with respect to one another and which each produce a magnetic field of opposite direction, wherein the superconducting current path of the magnet coil system (M) is subdivided into several sections (A1, . . . , An) each of which is electrically connected in parallel with at least one of the protective elements (R1, . . . , Rl), and wherein at least one of these sections (A1, . . .