Abstract: A method of 2-dimensional nuclear magnetic resonance (2D-NMR) correlation spectroscopy, comprises a pulse sequence with the following steps: excitation of double quantum coherence; immediate reconversion to single transition single quantum coherence; evolution of the set of single transitions; mixing with zero quantum mixing Hamiltonian; and signal detection. The method can achieve an improved sensitivity, has a transition selectivity and suppresses diagonal peaks.

Abstract: A cryostat configuration comprising an outer shell and a cryocontainer (2) for cryogenic fluid installed therein, wherein the cryocontainer (2) is connected to the outer shell via at least two suspension tubes (16), and with a neck tube (1) whose upper warm end is connected to the outer shell and whose lower cold end is connected to the cryocontainer (2) and into which a cold head (3) of a multi-stage cryocooler is installed, wherein the outer shell, the cryocontainer (2), the suspension tubes (16) and the neck tube (1) delimit an evacuated space, and wherein the cryocontainer (2) is moreover surrounded by at least one radiation shield which is connected to the suspension tubes (16) and optionally to the neck tube (1) of the cryocontainer (2) in a thermally conducting fashion, is characterized by a seal which can be manually and/or automatically actuated to separate the cold end of the neck tube (1) from the cryocontainer (2) in such a manner that fluid flow between the cryocontainer (2) and the neck tube (1)

Abstract: A method for homogenizing a static magnetic field with a magnetic field distribution B0(r) for nuclear magnetic resonance spectroscopy by adjusting the currents Ci through the shim coils, thus creating spatial field distributions Ci·Si(r), where r stands for one, two, or three of the spatial dimensions x, y, and z, and said magnetic field distribution B0(r) has only a field component along z, in a working volume of a magnetic resonance apparatus with one or more radio frequency (=RF) coils (5) for inducing RF pulses and receiving RF signals within a working volume, said RF coils having a spatial sensitivity distribution of magnitudes B1k(r), and with shim coils (6) for homogenizing the magnetic field within the working volume, said shim coils (6) being characterized by their magnetic field distributions per unit current Si(r) and having components only along z, includes the following steps: (a) Mapping the magnetic field distribution B0(r) of the main magnetic field, (b) calculating a simulated spectrum IS

Abstract: A matrix shim system for generating magnetic field components superimposed on a main static magnetic field, comprising a plurality of annular coils, is characterized in that it comprises g groups G1 . . . Gg of coils, with g being a natural number ?1, wherein each group Gi consists of at least two single annular coils connected in series, wherein each group Gi is designed to generate, in use, a magnetic field B z ? ( G i ) = ? n = 0 ? ? A n ? ? 0 ? ( G i ) · T n ? ? 0 . For each group Gi, there are at least two values of n for which ? A n ? ? 0 ? ( G i ) · R n ? max ? { ? A 20 ? ( G i ) · R 2 ? , … ? , ? A N ? ? 0 ? ( G i ) · R N ? } ? 0.5 ? ? and ? ? N ? n ? 2 , with N: the total number of current supplies of the matrix shim system, and R: smallest inside radius of any of the annular coils of the matrix shim system.

Abstract: A cryostat configuration has at least three centering elements (4) which are distributed about the periphery of a cryocontainer (1). Each end (6) of the centering elements (4) facing away from an outer jacket (3) of the cryostat configuration is connected to an actuator (7) which exerts a pressure or tensile force on the respective centering element (4) to generate a mechanical tension in a corresponding centering element (4) which loads the centering elements (4) with a nearly constant pressure or tension, irrespective of the temperature changes within the cryostat configuration. This yields a cryostat configuration which permits pressure centering without overloading the centering elements.

Abstract: A magnetic resonance (MR) probe head comprises a detecting device (3) with at least one antenna system which is cryogenically cooled by a cooling device, and a cooled preamplifier (16) in a preamplifier housing (15a) which is spatially separated from the detecting device (3), and a thermally insulating connecting means via which the detecting device (3) and the preamplifier housing are connected, wherein the connecting means (15c) comprises at least one cooling line (9, 9a, 9b) for supplying and/or returning a cooling fluid, and with at least one RF line (10) for transmitting the electric signals. The connecting means is implemented as a mechanically flexible connecting line (8) with mechanically flexible RF lines (10) and cooling lines (9, 9a, 9b) disposed therein. The MR probe head is easy to handle and can be highly sensitive, wherein the detecting device can be quickly installed, removed and put into operation.

Abstract: A magnetic resonance (MR) probe head comprises a detecting device (3) with at least one antenna system which is cryogenically cooled by a cooling device, a cooled preamplifier (16) in a preamplifier housing (15a, 15b) which is spatially separated from the detecting device (3), and a thermally insulating connecting means via which the detecting device (3) and the preamplifier housing (15a, 15b) are connected, wherein the connecting means (15c) comprises at least one cooling line (9a, 9b, 53a, 53b) for supplying and/or returning a cooling fluid, and at least one RF line (10, 52) for transmitting electric signals. The connecting means (15c), including its RF and cooling lines (10, 52, 9a, 9b, 53a, 53b), can be separated from the preamplifier housing (15a, 15b) by a coupling. The MR probe head is an open system which can be used in a universal fashion through use of different measuring inserts.

Abstract: A nuclear magnetic resonance apparatus for generating a homogeneous static magnetic field in the z-direction, comprising a coil/resonator system, a gradient system, and a shielding configuration which is positioned radially between the coil/resonator system and the gradient system, wherein the shielding configuration comprises an electrically conducting layer with a slot, wherein the electrically conducting layer is disposed about the center of the shielding configuration to be axially symmetrical with respect to the z-axis, is characterized in that, in an axial section z1<z<z2 with z2?z1>L, containing at least 90% of the magnetic field energy of the coil/resonator system, the shielding configuration comprises at least one pair of regions which have a cylinder envelope shape, wherein the regions of each pair are each defined by two respectively closed limiting lines circulating about the z-axis, and wherein the two limiting lines of each region have a mutual axial separation a ? z ? ? 2 -

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: 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: A sample holder for fixing and transporting a sample vial (1) within an NMR configuration comprising an outer shell (4) and a continuous hollow space disposed inside the outer shell (4) and extending along its axis for receiving the sample vial, is characterized in that a clamping device that can be switched on and off and a switching element (6) are provided inside the hollow space, wherein, in the activated state, the clamping device fixes a sample vial (1) that is introduced into the sample holder, the switching element (6) can be operated from the outside, and the clamping device can be deactivated using the switching element (6) such that, in the deactivated state, the sample vial (1) inserted into- or removed from the sample holder is not fixed. Such a sample holder may be used to realize an automatic supply device for changing NMR sample vials which has a very compact structure and can be mounted using little space.

Abstract: A device for transporting heat from a cold reservoir to a warm reservoir, in which at least two cyclic processes are employed for transporting heat thereby absorbing work, of which at least one is a regenerative cyclic process, and at least one is a magnetocaloric cyclic process, wherein the regenerative cyclic process has a working fluid and a heat storage medium, is characterized in that the heat storage medium of the regenerative cyclic process comprises a magnetocaloric material for the magnetocaloric cyclic process, wherein the magnetocaloric material is in a regenerator area with a cold end and a warm end, the working fluid of the regenerative cyclic process additionally serving as a heat transfer fluid for the magnetocaloric cyclic process. This produces a compact device with low apparative expense, wherein the power density and also the efficiency of the device are increased. The device may advantageously be used for cooling a superconducting magnet configuration.

Abstract: A nuclear magnetic resonance probe head comprising at least two coil/resonator configurations A1 and A2, wherein at least one of the coil/resonator configurations A1 has two saddle-shaped coils S1 and S2 (1, 2; 21; 41, 42; 53), wherein each coil (1, 2; 21; 41, 42; 53) has a window (9) about which N windings (3, 4; 26, 28, 30) are disposed which are connected in series, wherein N?2, wherein the coil/resonator configurations A1 and A2 are aligned perpendicularly to each other, and wherein the coil/resonator configurations A1 and A2 have different resonance frequencies is characterized in that each coil S1 and S2 (1, 2; 21; 41, 42; 53) is formed mirror-symmetrically relative to a central plane (5) of the respective coil (1, 2; 21; 41, 42; 53), which is perpendicular to the window (9) of the respective coil, and wherein the central planes (5) of the coils S1 and S2 are identical to minimize the electromagnetic coupling between the two coil/resonator configurations A1 and A2 at the resonance frequency of A2.

Abstract: A magnet configuration comprising a superconducting magnet coil system (M) and a current path (P) which comprises parts of the magnet coil system (M), wherein at least two electric connecting points (A1, A2, A3, A4) are disposed on the current path (P), which define a section (PA1-A2, PA2-A3, PA3-A4) within the current path (P), wherein the section (PA1-A2, PA2-A3, PA3-A4) does not comprise all parts of the magnet coil system (M) contained in the current path (P), and comprising a resistive element (WA1-A2, WA2-A3, WA3-A4) having an electric resistance value ?0, and at least two contacts (K1, K2, K3, K4), wherein the contacts (K1, K2, K3, K4) are disposed between the resistive element (WA1-A2, WA2-A3, WA3-A4) and one connecting point (A1, A2, A3, A4), is characterized in that in the superconducting state of the magnet coil system (M), an electric contact (K1, K2, K3, K4) between an electric connecting point (A1, A2, A3, A4) and a resistive element (WA1-A2, WA2-A3, WA3-A4) can be closed and opened.

Abstract: A sample tube for an NMR probe head, which extends along a z axis and has an internal cavity that extends in an axial direction of the z axis, is open to the outside at the axially upper end, is closed at the axially lower end and contains a liquid NMR sample substance during operation, wherein the cross-sectional surface of this cavity extending perpendicularly to the z axis and parallel to the xy coordinate plane has an elongated shape in the direction of the x axis with maximum dimensions a in the y direction and b in the x direction, wherein a<b, is characterized in that the cross-sectional surface of the sample tube, which extends perpendicularly to the z axis and is parallel to the xy coordinate plane has a circular outer shape. Sample tubes of this type provide a particularly large signal-to-noise ratio, can be easily inserted into a conventional cryogenic probe head and be axially and radially positioned therein by existing precision centering devices.

Abstract: An NMR spectrometer comprising an NMR magnet system (27) disposed in a helium tank of a cryostat and an NMR probe head (11) disposed in a room temperature bore of the cryostat, which contains a cooled RF resonator (9) for receiving NMR signals from a sample to be investigated, and a cooled pre-amplifier (10), wherein the NMR probe head (11) is cooled by a common multi-stage compressor-operated refrigerator (2), wherein the refrigerator (2) comprises a cold head and several heat exchangers (5, 6) at different temperature levels, wherein the refrigerator (2) is disposed at a spatial separation from the cryostat in a separate, evacuated and thermally insulated housing (1) and wherein at least one cooling circuit with cooling lines, which are thermally insulated by a transfer line (13, 14) is disposed between the housing (1) containing the heat exchangers (5, 6) and the NMR probe head (11), is characterized in that additional cooling lines to an LN2 tank (18) or radiation shield (21) disposed in the cryostat and

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 cryostat configuration for keeping cryogenic fluids in at least one cryocontainer, comprising an outer shell and a neck tube containing a cold head of a cryocooler, wherein the coldest cold stage of the cold head is disposed in a contact-free manner relative to the neck tube and the cryocontainer, and wherein a cryogenic fluid is located in the neck tube, is characterized in that the neck tube is disposed between the outer shell and a cryocontainer and/or the radiation shield, the neck tube is closed in a gas-tight manner at the end facing the cryocontainer and/or the radiation shield, the neck tube is coupled to the cryocontainer and/or a radiation shield disposed between the cryocontainers or a cryocontainer and the outer shell, via a connection having a good thermal conductivity, the neck tube comprising a fill-in device at an end located at ambient temperature.

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.

Abstract: A resonator system for generating a radio frequency (RF) magnetic field in a volume under investigation of a magnetic resonance (MR) arrangement, comprises a number N of individual resonators (2) which surround the volume under investigation and which are each disposed on a flat dielectric substrate (1) around a z-axis, wherein the individual resonators (2) have windows (8) through each of which one individual RF field is generated in the volume under investigation in single operation of the individual resonators (2) and, through cooperation among the individual resonators (2), a useful RF field (7) is generated in the volume under investigation, wherein a remote RF field (6) is asymptotically generated far outside of the resonator system, and the spatial distribution of the useful RF field (7) is substantially mirror-symmetrical relative to a first plane A which contains the z-axis, and that of the asymptotic remote RF field (6) is substantially mirror-symmetrical relative to a second plane B which contains