Abstract: In a magnet arrangement (M, D, P1, . . . , Pn) having a magnet coil system (M) with at least one current-carrying superconducting magnet coil, with an additional current-carrying coil system (D) which can be fed by an external current source to produce a magnetic field in the working volume which differs substantially from zero, and optionally with additional superconductingly closed current paths (P1, . . . , Pn), wherein the magnetic fields in the z direction, generated by the additional current paths (P1, . . . , Pn) due to currents induced during operation and the field of the additional current-carrying coil system (D) do not exceed 0.1 Tesla in the working volume, the additional coil system (D) is designed such that its field contribution to the working volume is determined taking into account the diamagnetism of the superconductor in the main coil system. This permits as large as possible an effective field efficiency of the additional coil system (D).

Abstract: In a magnet arrangement (M, D, P1, . . . , Pn) having a magnet coil system (M) with at least one current-carrying superconducting magnet coil, with an additional current-carrying coil system (D) which can be fed by an external current source to produce a magnetic field in the working volume which differs substantially from zero, and optionally with additional superconductingly closed current paths (P1, . . . , Pn), wherein the magnetic fields in the z direction, generated by the additional current paths (P1, . . . , Pn) due to currents induced during operation and the field of the additional current-carrying coil system (D) do not exceed 0.1 Tesla in the working volume, the additional coil system (D) is designed such that its field contribution to the working volume is determined taking into account the diamagnetism of the superconductor in the main coil system. This permits as large as possible an effective field efficiency of the additional coil system (D).

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: 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 superconducting magnet arrangement (M, S, P1, . . . , Pn) for generating a magnetic field in the direction of a z axis in a working volume, disposed about z=0, comprising a magnet coil system (M) with at least one current-carrying superconducting magnet coil, a shim device (S) with at least one superconducting shim coil and additional superconductingly closed current paths (P1, . . . , Pn), wherein the magnetic fields generated in the z direction and in the working volume by the additional current paths due to induced currents during operation, do not exceed a magnitude of 0.1 Tesla, and wherein the shim device generates a field which varies along the z axis with a kth power of z for an even power of k>0, is characterized in that the shim device is designed such that the effective field efficiency gSeff of the shim device is substantially zero taking into consideration the diamagnetism of the superconductor in the magnet coil system.

Abstract: A superconducting magnet system for generating a magnetic field in the direction of a z axis in a working volume disposed about z=0 with at least one current-carrying magnet coil (M) and with at least one additional, superconductingly closed current path (P1, . . . , Pn), which can react inductively to the changes of the magnetic flux through the area enclosed by it, wherein the magnetic fields in the z direction in the working volume which are produced by these additional current paths during operation and due to induced currents, do not exceed a magnitude of 0.1 Tesla, is characterized in that, when an additional disturbance coil (D) produces a substantially homogeneous disturbance field in the magnet volume, the diamagnetic expulsion of the disturbance field from the main magnet coil is taken into consideration when designing the magnet coil(s) and the current paths.

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: 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, . . .

Abstract: A method for performing polarization transfer in NMR experiments with coupled spin ½ nuclei I and S being irradiated by a sequence of rf pulses comprising a first 90° pulse exciting the spins of the nuclei I and after a delay time a further 90° pulse exciting the spins of the nuclei S is characterized in that there is no inversion pulse acting on the spins of the nuclei S during a time period T between the first 90° pulse exciting the spins of the nuclei I and either the further 90° pulse exciting the spins of the nuclei S or a second 90° pulse acting on the spins of the nuclei I, and that the length of the time period T is chosen such that d/dT[{square root over (sinh+L (RCT+L )2+L +sin(&pgr;JIST+L )2+L )} exp(−RIT)] is minimized, where RC is the transverse cross-correlation-relaxation rate of nuclei I, RI is the total transverse relaxation rate of nuclei I and JIS is the scalar coupling constant between nuclei I and S.

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 superconducting magnet arrangement (M, S, P1, . . . , Pn) for generating a magnetic field in the direction of a z axis in a working volume, disposed about z=0, comprising a magnet coil system (M) with at least one current-carrying superconducting magnet coil, a shim device (S) with at least one superconducting shim coil and additional superconductingly closed current paths (P1, . . . , Pn), wherein the magnetic fields generated in the z direction and in the working volume by the additional current paths due to induced currents during operation, do not exceed a magnitude of 0.1 Tesla, and wherein the shim device generates a field which varies along the z axis with a kth power of z for an even power of k>0. is characterized in that the shim device is designed such that the effective field efficiency gSeff of the shim device is substantially zero taking into consideration the diamagnetism of the superconductor in the magnet coil system.

Abstract: A superconducting magnet system for generating a magnetic field in the direction of a z axis in a working volume disposed about z=0 with at least one current-carrying magnet coil (M) and with at least one additional, superconductingly closed current path (P1, . . . , Pn), which can react inductively to the changes of the magnetic flux through the area enclosed by it, wherein the magnetic fields in the z direction in the working volume which are produced by these additional current paths during operation and due to induced currents, do not exceed a magnitude of 0.1 Tesla, is characterized in that, when an additional disturbance coil (D) produces a substantially homogeneous disturbance field in the magnet volume, the diamagnetic expulsion of the disturbance field from the main magnet coil is taken into consideration when designing the magnet coil(s) and the current paths.

Abstract: An actively shielded, superconducting magnet arrangement for the generation of a magnetic field in the direction of a z axis in a working volume arranged about z=0, having a radially inner and a radially outer coaxial coil system, wherein the two coil systems carry the same current and have dipole moments of the same magnitude, but of opposite directions, wherein parts of the radially outer coil system (C2′) are electrically connected in series with the radially inner coil system (C1) and wherein a first superconducting switch (S1) is provided via which during operation a superconducting short circuit of a first current path of the magnet arrangement can be effected, is characterized in that a section (A′) of the radially outer coil system (C2′), which can be superconductingly short-circuited during operation via a further superconducting switch (S2) is arranged symmetrically to the plane z=0 and that the further superconducting current path formed by the superconductingly shor

Abstract: A superconducting magnet arrangement with at least two current paths, short-circuited via switches in the operational state, which may carry different currents, wherein the magnet arrangement comprises at least one actively shielded superconducting magnet with a radially inner and a radially outer coil system which carry approximately the same current and have dipole moments of approximately the same magnitude, but opposite in direction, such that an outer magnetic field disturbance in a working volume of the magnet arrangement in the long-term behavior is suppressed to a remaining value of less than 20% of the external magnetic field disturbance, is characterized in that sections of the superconducting current paths are disturbance, is characterized in that sections of the superconducting current paths are bridged by ohmic resistors and that said sections and the ohmic resistors are chosen such that the magnetic field disturbance in the working volume is reduced already directly after its occurrence with res

Abstract: An NMR (=nuclear magnetic resonance) probe head comprising an RF (=radio frequency) receiver coil system, which can be cooled down to cryogenic temperatures, and a room temperature pipe (5), extending in a z direction, for receiving a sample tube (6) containing sample substance to be examined by NMR measurements is characterized by a centering device (10) for centering the sample tube (6) in its measuring position about the axis of the room temperature pipe (5) to thereby provide simple and substantial reduction in the temperature gradient in the z direction during operation without thereby impairing the NMR measurement.

Abstract: An NMR (=nuclear magnetic resonance) probe head comprising an RF (=radio frequency) receiver coil system, which can be cooled down to cryogenic temperatures, and a room temperature pipe (5), extending in a z direction, for receiving a sample tube containing sample substance to be examined by NMR measurements is characterized in that a tempering means (11) is disposed between the RF receiver coil system and the sample tube which surrounds the sample tube in a radial direction and extends in the z direction and is almost completely transparent to RF fields, or at least has an absorption of <5%, preferably <1% for RF fields to thereby provide simple and substantial reduction in the temperature gradient in the z direction during operation without thereby impairing the NMR measurement.

Abstract: A method of operating a high-resolution NMR spectrometer comprising a DDS generator containing an NCOL for generating an LO frequency, wherein the frequency of the NCOL is defined by inputting a numerical value Z, is characterized in that this numerical value Z may assume only values which satisfy the equation Z=n·N/m, wherein Z, n, N, and m are integer and positive numbers, N is a power of 2 with a positive integer exponent, wherein said exponent represents the maximum number of bits during the calculation process, m is approximately 2·fs/&Dgr;B, n approximately m·fout/fs and m additionally a common integer divisor of n·N and fs is the clock frequency of the NCOL, &Dgr;B is the desired bandwidth with high spectral purity and fout is the output frequency of the NCOL.

Abstract: An NMR (=nuclear magnetic resonance) probe head comprising an RF (=radio frequency) receiver coil system, which can be cooled down to cryogenic temperatures, and a room temperature pipe (4), extending in a z direction, for receiving a sample tube (6) containing sample substance (7) to be examined by NMR measurements is characterized in that at least one, preferably several radiation shields (9) extending in the z direction and surrounding the room temperature pipe (4) in a radial direction are disposed between the RF receiver coil system (1) and the room temperature pipe (4) which are formed of one or several materials oriented in the z direction and are almost completely transparent to RF fields, at least have an absorption of <5%, preferably <1% for RF fields to thereby provide simple and substantial reduction in the temperature gradient in the z direction during operation without thereby impairing the NMR measurement.

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.

Abstract: A nuclear magnetic resonance (NMR) spectrometer probe head having one or more drive units, one or more transmission units and one or more drive shafts which are coupled to adjustment rods and a means for directly mounting and fastening the drive unit, transmission unit, and drive shaft to the lower portion of the probe head during operation of the NMR spectrometer, which increases user comfort and freedom of motion below the magnet. The probe head also having an actuator for remote control adjustment of electrical and/or mechanical units, e.g. trimmer capacitors, variable resistors, and adjustable inductors within the probe head. The probe head is characterized in that the amount of space needed for the actuator is minimized, access to the region below the magnet is optimized, and installation of the actuator is simplified because the actuator is an integral part of the NMR-probe head within an NMR-spectrometer.