Abstract: A nuclear magnetic resonance (NMR) apparatus (10) comprises a superconducting main field magnet coil system (14) which generates a homogeneous magnetic field of at least 3T, and a gradient coil system (15) which generates a gradient strength of at least 10 mTm?1, with a slew rate of at least 100 Tm?1s?1, wherein the main field magnet coil system (14) is arranged in a cryostat (12) with liquid helium and a refrigerator (16) in the form of a pulse tube cooler or a Gifford-McMahon cooler, and wherein an evaporation line (17a, 27a, 37a) is provided for helium that might evaporate from the cryostat. In all states of operation of the NMR apparatus (10) without gradient switching, the refrigerator provides a cooling capacity which is at least 0.

Abstract: An analysis system (1) for the analysis of a sample, comprises a gel permeation chromatograph (14) that is coupled with a nuclear magnetic resonance (=NMR) spectrometer. The chromatograph (14) has a gel permeation chromatography (=GPC) separating column system (6a) that is filled with porous particles (21). The NMR spectrometer is configured as a low-field NMR spectrometer (8) with a permanent magnet system (9) for generating a B0 field of the NMR spectrometer. The low-field NMR spectrometer (8) comprises a shim system (10) with which homogeneity of the B0 field of at least 0.5 ppm can be achieved in a right circular cylindrical sample volume (27) having a diameter of at least 5 mm and a length of at least 15 mm. The system permits the quantitative and qualitative chemical analysis of samples containing substances of different molecular size using a less expensive apparatus.

Abstract: A method for sample preparation for magnetic resonance measurements using Hyperpolarization by Dissolution Dynamic Nuclear Polarization, involves preparation of frozen beads of a first kind containing paramagnetic substances in addition to the solute under investigation; insertion of the frozen beads into a polarizing magnet; creation of enhanced polarization of nuclei in a magnetic field; heating of the sample to room temperature; transfer of the sample to an MR magnet; and carrying out an MR measurement. In addition, frozen beads of a second kind containing a reducing agent are prepared and inserted into the polarization magnet together with the frozen beads of the first kind. By this method, longitudinal and transverse relaxation times in NMR are extended and free radicals in hyperpolarized solutions are eliminated.

Abstract: A multiple resonance sample coil for a magic angle spinning nuclear magnetic resonance probe is comprised of a solenoid coil that resonates at low frequencies and a resonator that resonates at high frequencies. The ends of the low frequency solenoid coil are electrically connected to the high frequency resonator to eliminate arcing and allow the solenoid coil to extend the full width of the resonator. In some embodiments, the high frequency resonator is constructed from the outermost turns of the solenoid coil in the form of a birdcage resonator. In another embodiment, the solenoid coil is electrically connected to one turn of the resonator and the other turn is used as part of a trap to shunt the resonator at low frequencies.

Abstract: An electronic interface (10) between a pure NMR receiver resonator (RO) and a preamplifier is characterized in that one or more control diodes (Dmatch1, Dtune1) are provided by means of which the current designed to flow through the switching diodes can be fed into these switching diodes, and the control diodes are connected to the switching diodes directly or via one or more additional series impedances. In this fashion, the impedance of the resonator is transformed to the required preamplifier or line impedance during the receiving process with little loss. In particular, during the receiving process, matching can be adjusted during the transmitting process, the current in the inductance of the resonator generated by the B1 field of the transmitting resonator is minimized and all components are protected against damage.

Abstract: In a coil arrangement for nuclear magnetic resonance comprising a main coil (13), a shielding coil (14), and at least one correction coil (41), the function of which consists in forming a magnetic field gradient with eddy current properties which are as good as possible, the main coil (13) and the shielding coil (14) are electrically connected in series with the correction coil (41). The deviations of the residual field from the desired design generated by production tolerances are thereby modified by the correction coil in such a fashion that the long-lasting eddy currents are suppressed. This either reduces the waiting time that must lapse after a gradient pulse before a predetermined field homogeneity is achieved or e.g. the deviations from the desired field are minimized in imaging applications.

Abstract: A method for obtaining amplitude and phase dependencies of radio frequency pulses, which are irradiated within the scope of a main magnetic resonance experiment for generating a predetermined n-dimensional spatial distribution (n>=1) of transverse magnetization in an object by means of at least one radio frequency transmitting antenna of a magnetic resonance measuring system in combination with spatially and temporally varying additional magnetic fields which are superimposed on the static and homogeneous base field of the magnetic resonance measuring system and change the transverse magnetization phase in the object in dependence on location and time is characterized in that, prior to performance of the main experiment, a preparational measurement is performed in which the change with time of the transverse magnetization phase in the object under the action of the additional magnetic fields is measured in a position-resolved fashion and the amplitude and phase dependencies of the radio frequency pulses fo

Abstract: A method for position dependent change in the magnetization in an object, according to a requirement in a magnetic resonance measurement, wherein radio-frequency pulses are irradiated in conjunction with supplementary magnetic fields that vary in space and over time and are superposed on the static and homogeneous basic field of a magnetic resonance measurement apparatus along a z-direction, is characterized in that non-linear supplementary magnetic fields are used, whose spatial gradient of the z-component is not constant at least at one instant of the irradiation, and that the radio-frequency pulses to be irradiated are calculated in advance, wherein progressions over time of the field strengths of the supplementary magnetic fields in the region of the object that are calculated and/or measured position-dependently are included in this calculation.

Abstract: An imaging system for imaging an object. More specifically, an imaging system enabling depth sectioned fluorescence imaging in a turbid medium, such as human or animal tissue, to substantially minimize the excitation radiation from reaching the detection beam path. The imaging system includes an arrangement of the excitation radiation source wherein the optical axis of the source is inclined relative to the optical axis of the camera, the optical plane of the source and the optical plane of the object are subject to a Scheimpflug condition, and the angle of inclination of the source is selected such that the excitation radiation incident upon the object is reflected to minimize excitation radiation from reaching the detection beam path.

Abstract: A device used in performing imaging magnetic resonance measurements (=MRI) in a Region of Interest (ROI) (9) of a small animal (3) with an MRI magnet system (7), with a cradle (5) on which the small animal (3) is lying, and with a radio-frequency (=RF) antenna (6), wherein the RF antenna (6) and the small animal (3) can be positioned relative to each other, characterized in that the device comprises a slide (1) on which the cradle together with the small animal immobilized thereupon can be moved both outside and inside the MRI magnet system, and characterized in that the RF antenna is rigidly fixed on the slide. This results in a device for the relative positioning of the small animal with respect to the RF antenna for an MRI measurement, which is easy to retrofit on existing tomography equipment, with which this positioning can be implemented both inside and outside the MRI magnet by simple handling and without great additional technical effort.

Abstract: A method and apparatus for producing a hyperpolarized sample material for use in an NMR investigation provides for a cryogenic region having a target material containing a first hyperpolarizable nuclear species, a second hyperpolarizable nuclear species, and a nuclear spin polarizing agent, wherein the first nuclear species has a higher magnetic moment than the second nuclear species. Microwave energy is used to excite electron spin transitions in the polarizing agent in the presence of a magnetic field. The first hyperpolarizable nuclear species is thereby caused to interact with the electron spin system in the polarizing agent and generate hyperpolarization of at least the first nuclear species of the target material. The target material is then subjected to a lowered magnetic field, wherein the lowered magnetic field facilitates polarization transfer by nuclear thermal mixing between the species to thereby hyperpolarize the second nuclear species.

Abstract: A superconducting high-field magnet coil system comprising several radially nested main coil sections (1, 2, 3, 4, 5) which are connected to each other in series in such a fashion that currents of the same direction flow through them during operation, wherein a first main coil section (EHS) is disposed radially further inward than a second main coil section (ZHS) and at least one intermediate main coil section (ZW) is disposed radially between the first and the second main coil section (EHS, ZHS), and with a superconducting switch (11) via which all main coil sections (1, 2, 3, 4, 5) can be superconductingly short-circuited in series, is characterized in that the first main coil section (EHS) and the second main coil section (ZHS) are directly successively series-connected and the first main coil section (EHS) and the second main coil section (ZHS) are bridged by a common quench protection element, which does not bridge the at least one intermediate main coil section (ZW).

Abstract: A method for nuclear magnetic resonance (NMR) or magnetic resonance imaging (MRI) measurements, includes creation of enhanced polarization of nuclei of a first kind within a sample in a magnetic field at cryogenic temperatures and transfer of the polarized sample to room temperature. The enhanced polarization of nuclei of the first kind is thereby transformed into long-lived states (LLS) of nuclei of a second kind and these LLS are sustained. The LLS is at least partially converted into observable magnetization and an NMR or MRI measurement is carried out. The method allows one to extend the time needed between hyperpolarized magnetization and NMR detection.

Abstract: A device has a first control loop (28) with which a frequency RF of an RF generator is synchronized with a resonance frequency F0 of an NMR line. A phase shifter (22) is provided to rotate the radio frequency phase of the NMR receiver system in the first control loop. The phase shifter is controlled by a second control loop (27) whose input signal comes from a signal extraction stage.

Abstract: A method for cooling a cryostat configuration (1, 1?) during transport, wherein the cryostat configuration (1) comprises a superconducting magnet coil (2) in a helium tank (8) containing liquid helium (9), which is surrounded by at least one radiation shield (10), wherein the cooling inside the cryostat configuration (1, 1?) in stationary operation is performed entirely without liquid nitrogen by means of a refrigerator, characterized in that during transport, the refrigerator is switched off and instead, liquid nitrogen (6) is conducted from an external nitrogen vessel (4) via a supply tube (7) from the nitrogen vessel (4) to the cryostat configuration (1, 1?) and brought into thermal contact with the radiation shield (10) by means of a thermal contact element (11) in the cryostat configuration (1, 1?). In this way, the consumption of liquid helium during transport can be greatly reduced and the possible transport time of a charged superconducting magnet configuration increased.

Abstract: An imaging target, suited for use in multi-modal imaging systems, includes test patterns for testing quality of focus and co-registration for multiple magnifications and multiple modalities of operation of a multimodal imaging system.

Abstract: A method for magnetic resonance spectroscopy (=MRS) or magnetic resonance imaging (=MRI) in which an NMR time-domain signal is generated by an excited transverse nuclear magnetization precessing about the applied magnetic field, whereby the RF excitation pulse is adapted to cover a whole range of NMR frequencies of interest present in the object, and time-domain signal acquisition takes place during, or during and after the application of the RF excitation pulse, is characterized in that spectral or image data are reconstructed by a matrix product of a reconstruction matrix and a vector of time-domain signal points, the reconstruction matrix being an inversion of an encoding matrix. An improved method for reconstructing spectral or image data from a time-domain signal is thereby provided which is more versatile than conventional Fourier transform.

Abstract: A device for supplying cold gases to an NMR installation or analytical apparatus equipped with a measuring probe, with cold gases ensuring the cooling of the sample contained in the probe, but also its lift and rotation, the device including an insulated tank containing liquid gas at boiling point and in which are arranged exchangers through which gas streams to be cooled pass, these exchangers being connected to transfer lines channeling the cooled gases to the probe. The device also includes at least one additional exchanger that ensures a pre-cooling of the gas stream before it is channeled to the corresponding exchanger, with the or each additional exchanger coming in the form of a double-flow exchanger that is supplied either by the gaseous vapor produced by the boiling of the liquid gas in the tank or by the cold gas that is evacuated or that escapes at the probe.

Abstract: A cryostat (1) with a magnet coil system including superconductors for the production of a magnet field B0 in a measuring volume (3) has a plurality of radically nested solenoid-shaped coil sections (4, 5, 6) and which are electrically connected in series, at least one of which being an LTS section (5, 6) with a conventional low temperature superconductor (LTS) and at least one of which being an HTS section (4) including a high temperature superconductor (HTS), wherein the magnet coil system is located in a helium tank (9) of the cryostat (1) along with liquid helium at a helium temperature TL<4 K. The apparatus is characterized in that heating means are provided which always keep the HTS at an increased temperature TH>TL and TH>2.2 K. The cryostat in accordance with the invention can maintain the HTS section over a long period of time in a reliable manner.

Abstract: A method for producing a superconductive wire, whereby an elongated intermediate element is formed out of an initial element in a deformation step and whereby the superconductive filaments are formed by a final reaction heat treatment, is characterized in that prior to the final reaction heat treatment the filaments in the intermediate element are densified in one or more high pressure densification steps following up the deformation step, said densification steps comprising a simultaneous action of at least four hard surfaces perpendicular to the axis of the elongated intermediate element, building up high pressure P?100 MPa on a part of the intermediate element having an axial length L. This leads to a substantial increase of the critical current density Jc, whereby the anisotropy factor ? is be almost not affected thus enabling production of almost isotropic wires or tapes.