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: A cryostat configuration for keeping liquid helium comprises an outer jacket (1) surrounding a helium container (2) connected at at least two suspension tubes (3) to the outer jacket (1), and with a neck tube (4) whose upper warm end (5) is connected to the outer jacket (1) and whose lower cold end (6) is connected to the helium container (2) and into which a multi-stage cold head of a cryocooler (7) is installed, wherein the outer jacket (1), the helium container (2), the suspension tubes (3) and the neck tube (4) delimit an evacuated space, and the helium container (2) is surrounded by at least one radiation shield (8) which is connected in a heat-conducting fashion to the suspension tubes (3) and also to a contact surface (9) on the neck tube (4) of the helium container (2).

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 ? { ? 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: 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 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: Cryostat configuration for keeping cryogenic fluids in at least one cryocontainer (1) which is suspended on thermally insulating suspension tubes (2) and/or suspension devices which are connected to an outer jacket (3) of the cryostat configuration, wherein the at least one cryocontainer (1) is centered relative to a container disposed further outside, preferably the outer jacket (3), using at least three centering elements (4) which are distributed about the periphery of the cryocontainer (1), wherein one end (5) of each centering element (4) abuts or is connected to the container disposed further outside, characterized in that in at least one of the cryocontainers (1), each end (6) of the centering elements (4) facing away from the outer jacket (3) is connected to an actuator (7) which exerts a pressure or tensile force on the respective centering element (4), and which is mounted to the cryocontainer (1) at at least one contact point (A, A?, B, B?), wherein, through fixation of the actuator (7) to the cryo

Abstract: A method of projection spectroscopy for N-dimensional NMR experiments with the following steps. Data recording comprising: a) selection of N-dimensional NMR experiments out of a group of N-dimensional experiments, selection of the dimensionalities (Di) of the projections and unconstrained selection of j sets of projection angles, with j?2; b) recording of discrete sets of j projections from the N-dimensional NMR experiments at the selected projection angles; c) peak picking and creating a peak list for each of the j projection spectra is characterized by d) automated identification of peaks in the projection spectra that arise from the same resonance in the N-dimensional spectrum (N?3) using vector algebra to exploit geometrical properties of projections in the N-dimensional space, and computation of a N-dimensional peak list using vector algebra to exploit geometrical properties of projections in the N-dimensional space.

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 magnet configuration comprising a superconducting magnet coil system (M) which has a working volume and an ohmic resistance (R) of zero or more, and a current path (P) which comprises parts of the magnet coil system (M), with connecting points (AP1, AP2), a power supply (PS, PS?), and an electric network (D1, D1?, D2), wherein the connecting points (AP1, AP2) of the current path (P) are electrically connected to connections (AD1, AD2, AD1?, AD2?) of an electric network (D1, D1?, D2) facing away from the power supply, and the power supply (PS, PS?) is electrically connected to connections (AD3, AD4) on the power supply side of the electric network (D1), and wherein the network (D1, D1?) comprises a resistance (R1), is characterized in that the network (D1, D1?) comprises an inductance (L1), wherein the connections (AD1, AD2) are connected to each other via the resistance (R1), and the connections (AD3, AD4) are connected to each other via the resistance (R1) and the inductance (L1).

Abstract: A radio-frequency (RF) resonator system, in particular, for an NMR (nuclear magnetic resonance) probe head, with at least one RF resonator which comprises at least three non-interrupted conducting elements (21; 54, 56, 58; 75, 76; 91–94; 111a–111d; 131, 132a–132b; 169a–169f) which form at least one window (57; 77a; 124, 124a) in the RF resonator, wherein only part of the conducting elements delimits the at least one window, wherein the conducting elements are coupled through electromagnetic fields, wherein each conducting element has a limiting current density, is characterized in that the eigen-resonances of the individual conducting elements and/or the electromagnetic coupling between the conducting elements is/are selected such that upon excitation of the RF resonator system, the maxima of the quotient values along the individual conducting elements are substantially equal for all conducting elements, wherein these quotient values are defined as a quotient between an average current density which occurs in

Abstract: A method for operating a magnetic resonance spectrometer with a digital filter whose input is fed with an NMR signal of a time length TA, and whose output signal consists of a rising oscillation B1 of a length TB, a signal portion [F]? which consists of a filtered FID or echo signal of the length TA and a decaying oscillation B2 of a length TB, wherein this output signal is initially modified using a calculation process RV, and is subsequently transformed by Fourier transformation to a desired NMR spectrum, is characterized in that, during the calculation process RV, only the signal portion [F]? is initially selected, at least N copies of the rising oscillation B1 are subsequently generated in positive time shifts TA with respect to each other and are positioned on the signal portion [F?] in time such that the end of the first rising oscillation is positioned at the end of the signal portion, at least N copies of the decaying oscillation B2 are generated in negative shifts TA and are positioned on the signal

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: A magnet system with a magnet arrangement (M), a working volume (V) and a pulse tube cooler (P) with magnetic regenerator material (r) is characterized in that a shielding (m) of magnetic material is provided which reduces the stray field of the magnet arrangement at the location of the magnetic regenerator material (r) and is characterized in that ?|{tilde over (m)}RegR|+|mMag?x|<?|mRegR|, wherein mMag is the dipole moment of the magnetic material of the shielding (m), ?? is the vibration amplitude of the magnetic material of the shielding (m), mReg is the amplitude of the dipole fluctuations of the magnetic regenerator material (r) in one cycle without magnetic shielding (m), {tilde over (m)}Reg is the amplitude of the dipole fluctuations of the magnetic regenerator material (r) in one cycle with magnetic shielding (m), and R is the average separation of the magnetic regenerator material (r) from the working volume (V).

Abstract: A cryostat configuration for keeping liquid helium comprising an outer jacket (3) surrounding a helium container (1) connected at at least two suspension tubes (2) to the outer jacket (3), wherein the helium container (1) also comprises a neck tube (5) whose upper warm end is connected to the outer jacket (3) and whose lower cold end is connected to the helium container (1) and into which a multi-stage cold head (6) of a cryocooler is installed, wherein the outer jacket (3), the helium container (1), the suspension tubes (2) and the neck tube (5) delimit an evacuated space (7), and the helium container (1) is surrounded by at least one radiation shield (4) which is connected in a heat-conducting fashion to the suspension tubes (2) and also to the neck tube (5) of the helium container (1) is characterized in that there is a direct connection (8) between the warm ends of the suspension tubes (2) and the neck tube (5) through which helium gas can flow.

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

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 magnet system with a magnet arrangement (M), a working volume (V) and a pulse tube cooler (P) with magnetic regenerator material (r) is characterized in that a shielding (m) of magnetic material is provided which reduces the stray field of the magnet arrangement at the location of the magnetic regenerator material (r) and is characterized in that 1 3 ? ? m ~ Reg ? R ? + ? m Mag ? ? ? ? ? x ? < 1 6 ? ? m Reg ? R ? , wherein mMag is the dipole moment of the magnetic material of the shielding (m), ?? is the vibration amplitude of the magnetic material of the shielding (m), mReg is the amplitude of the dipole fluctuations of the magnetic regenerator material (r) in one cycle without magnetic shielding (m), {tilde over (m)}Reg is the amplitude of the dipole fluctuations of the magnetic regenerator material (r) in one cycle with magnetic shielding (m), and R is the average separation of the magnetic regenerator material (r) from the working volume (V).

Abstract: A radio-frequency (RF) resonator system, in particular, for an NMR (nuclear magnetic resonance) probe head, with at least one RF resonator which comprises at least three non-interrupted conducting elements (21; 54, 56, 58; 75, 76; 91-94; 111a-111d; 131, 132a-132b; 169a-169f) which form at least one window (57; 77a; 124, 124a) in the RF resonator, wherein only part of the conducting elements delimits the at least one window, wherein the conducting elements are coupled through electromagnetic fields, wherein each conducting element has a limiting current density, is characterized in that the eigen-resonances of the individual conducting elements and/or the electromagnetic coupling between the conducting elements is/are selected such that upon excitation of the RF resonator system, the maxima of the quotient values along the individual conducting elements are substantially equal for all conducting elements, wherein these quotient values are defined as a quotient between an average current density which occurs in

Abstract: A method for operating a magnetic resonance spectrometer with a digital filter whose input is fed with an NMR signal of a time length TA, and whose output signal consists of a rising oscillation B1 of a length TB, a signal portion [F]? which consists of a filtered FID or echo signal of the length TA and a decaying oscillation B2 of a length TB, wherein this output signal is initially modified using a calculation process RV, and is subsequently transformed by Fourier transformation to a desired NMR spectrum, is characterized in that, during the calculation process RV, only the signal portion [F]? is initially selected, at least N copies of the rising oscillation B1 are subsequently generated in positive time shifts TA with respect to each other and are positioned on the signal portion [F?] in time such that the end of the first rising oscillation is positioned at the end of the signal portion, at least N copies of the decaying oscillation B2 are generated in negative shifts TA and are positioned on the signal

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.