Abstract: A high-frequency interface circuit to direct transmitted signals to a connector (PR) for a HF arrangement in a transmit mode via an input (TX) of the high-frequency interface circuit and received signals from the connector (PR) to a receiver system in a receive mode via an output (RX) of the high-frequency interface circuit is presented. The circuit includes a transmit path (SP) linking the input (TX) to the connector (PR) and a receive path (EP) linking the connector (PR) to the output (RX). The receive path (EP) includes a first circuit (K1), with at least a first switching element (S1) that is electro-conductive in transmit mode and is electrically insulating in receive mode, connected to the connector (PR). In transmit mode, the first circuit (K1) forms two parallel resonance circuits connected in series, while in receive mode, the first circuit (K1) includes two series resonance circuits connected in parallel.

Abstract: A method to generate an attenuation correction map to compensate imaging errors in emission tomography resulting from the presence of hardware parts inside the imaging volume of an emission tomograph. Components of 3-dimensional CAD models of the hardware parts to be compensated are converted into voxels on a predetermined grid and assigned a filling factor per voxel. Image data sets of each component are multiplied with respective attenuation coefficients and thereafter superimposed to form an attenuation correction map. Thereby, in a simple and automatable way a profoundly exact, mostly noise-free and exactly reproducible attenuation correction map for attenuation correction in an emission tomography device may be generated.

Abstract: A method for operating an NMR probehead (10) with an MAS stator (11) receiving a circular-cylindrical hollow MAS rotor (13) with an outer jacket. The MAS rotor is mounted on pressurized gas in a measuring position within the MAS stator via a gas supply device with a bearing nozzle (12?) and rotates about the cylinder axis of the MAS rotor at a rotation frequency f?30 kHz. During a measurement, a temperature control gas is blown by a temperature control nozzle (12) onto the outer jacket of the rotor at an angle ?<90° with respect to the longitudinal axis of the cylinder-symmetrical rotor. The flow speed of the temperature control gas corresponds in the nozzle cross section to at least half the circumferential speed of the outer jacket of the rotating rotor and to at most the speed of sound in the temperature control gas.

Abstract: A magnetic resonance (MR) device, having a gradient arrangement that includes a gradient coil (G) with an internal resistance (Rg), as well as an electric circuit for generating variable pulse-shaped currents through the gradient arrangement. The electric circuit has at least one low-voltage voltage source (V) for generating a voltage U?100V, and a first circuit section in the electric circuit for current in the gradient coil in one direction and a second circuit section in the electric circuit for current in the gradient coil in a reverse direction to the first circuit section. This permits the generation of accurate square-wave current pulses, with a simultaneously short charging time of the auxiliary inductance.

Abstract: A carrier for a sample of highly polarized material includes a shell having a radially exterior surface and a radially interior surface, and a sample of highly polarized material interiorly adjacent to the radially interior surface. The shell may be substantially cylindrical, and may be constructed from a magnetic or non-magnetic material. The sample of highly polarized material may comprise a methyl rotor group material. The sample of highly polarized material may comprise pyruvic acid or an acetic acid. The sample of highly polarized material may be co-axial with the cylindrical shell. The sample of highly polarized material may be bonded or frozen to the radially interior surface of the shell. The carrier may further comprise a wad of material that forms a volume and contacts an axially proximate end of at least one of the shell or the sample.

Abstract: A cooling device (1) has a cryostat (2) and a cold head (3) of a cooling system (52), and additionally includes a pivot bearing (35), with which the cold head (3) is mounted on the cryostat (2) so as to be rotatable about a rotation axis (A). A connecting line (15) for a working gas of the cooling system (52) is connected to the cold head so that forces caused by the cooling system (52) act on the cold head (3) via the connecting line (15) at a force application point (EP) in a force application direction (ER). The force application direction (ER) is inclined by no more than 40° with respect to the normal (N) of a lever plane (HE) which contains the rotation axis (A) and the force application point (EP).

Abstract: Correlation information between captured characteristics and chemical shift values of captured NMR spin systems is provided by a model appliance for a fluid class. An NMR spectrum of a sample of the fluid class is recorded. Peaks in the recorded NMR spectrum which belong to defined reference NMR spin systems are identified, and experimental chemical shift values of the peaks from the recorded NMR spectrum are determined. A chemical shift value of at least one of the captured NMR spin systems not belonging to the reference NMR spin systems is predicted by applying the model appliance onto the experimental chemical shift values of the reference NMR spin systems. Peaks in an NMR spectrum of a sample of a fluid class are attributed more quickly and reliably to NMR spins systems of compounds contained in the sample.

Abstract: A superconducting magnet coil arrangement has a high-temperature superconductor (HTS) coil section (1a,1b,1c) in the form of a solenoid that is wound with an HTS tape conductor, and also has a field-shaping device comprising at least two field-shaping elements (2a,2b,2c). At least one respective field-shaping element is arranged adjoining each of the two axial ends of the HTS coil section, the field-shaping elements being configured in such a way that they reduce the field angle of the magnetic field generated by the magnet coil arrangement with respect to the axial direction in the region of the HTS coil section by at least 1.5°.

Abstract: A fastening system for attaching an NMR probe to an NMR magnet includes a discoid insert and a retention system that is rigidly connected to the magnet and on which the insert can be mounted. A form-fitting, variable-force connection is established between the NMR probe and the retention system using a spring element. The probe attaches to the insert by a plurality of integral, rigid retaining elements that are of an invariable fixed length. The spring element and the retaining elements are designed geometrically such that in a first, opened state the connection between the insert and the retaining elements has a mechanical backlash between 0.5 mm and 5 mm when the spring element is relaxed. In a second, closed state the connection between the insert and the retaining elements has no mechanical backlash when the spring element is under mechanical tension.

Abstract: A microwave resonator for an EPR probe head has a metal cavity body (1) supporting an electromagnetic microwave resonance mode. The metal cavity body (1) has an opening for inserting a sample tube (2) to a center position of the resonator. The center of the opening and the center position of the resonator define an x-axis. The cavity body also has an opening for transmitting microwave radiation into the resonator. Two dielectric elements (4a, 4b) are located symmetrically to the E-field nodal plane containing the x-axis and a z-axis perpendicular to the x-axis. Each dielectric element is geometrically formed and positioned such that it provides an equal overlap with a local maximum of the microwave electric field energy. The microwave resonant cavity has a thin planar shape and the resonator is loaded with two dielectric elements, placed symmetrically relative to the central EPR sample.

Abstract: A layer wound magnet coil includes a central coil region and end coil regions adjoining the central coil region along an axial line of symmetry. The central coil region includes layers of coil windings of an anisotropic material. The end coil regions include layers of coil windings of the anisotropic superconducting material interspersed with layers of non-superconducting material.

Abstract: A spectroscopic method for calculating a limit of quantification and a relative error includes: 1. selecting an error function F(C); 2. providing a blank spectrum; 3. recording a reference spectrum with a signal content of the substance being investigated; 4. determining start concentrations; 5.a. multiplying the reference spectrum with the signal content of the substance by a factor; 5.b. adding the resulting spectrum to the blank spectrum and determining the corresponding concentration of the substance and calculating the corresponding relative error; 6. iteratively adapting parameters of the selected error function F(C): recording a measurement spectrum of the test sample and determining the concentration of the substance being investigated using 5.b. and comparing with the calculated limit of quantification and calculating the relative error by applying the error function from step 6.

Abstract: A nuclear magnetic resonance coil configuration having at least one flat or cylindrical coil (18), through which current flows in operation, which coil generates a high-frequency magnetic B1 field at the location of a sample (16) which is oriented parallel to an x-axis, and which for the purpose of connection to a tuning network is connected to at least two electrical feed lines (11), through which in-phase currents flow in operation, and which generate a high-frequency magnetic B2 field in the sample (16), the orientation of which encloses an angle ? with the direction of the B1 field, is characterized in that the following applies for the angle ?: ?=180°±??, where ??<90°. In this way, a B1 field profile, which is as rectangular as possible and is particularly steep on both sides, can be generated.

Abstract: An HF resonator assembly generates at least two independent alternating magnetic fields in a test volume of a magnetic resonance apparatus. The HF resonator assembly includes a first pair of flat coils that form a first HF resonator and comprise electrical conductor portions that surround a planar surface portion. The flat coils are arranged on opposing sides of the test volume, on coil support plates that are mutually parallel and in parallel with the longitudinal axis. A second pair of flat coils forms a second HF resonator on second coil support plates. The projections of the planar surface portions of the flat coils in each of the first pair of flat coils and the second pair of flat coils overlap in part, but not completely, when viewed in a direction perpendicular to the respective planar surface portions.

Abstract: A probehead of an NMR-MAS apparatus includes a sample which has a rotation axis tilted by an angle ?>0 with respect to the z-axis. The angle ? can be adjusted about a target angle ?target by tilting around a tilt axis. The rotation axis has a fixed angle with respect to the probehead, and the NMR-MAS apparatus tilts at least part of the probehead to adjust the angle ?. The probehead has an outer contour K between an upper end and a lower end. For all z between the upper end and the lower end, a cross-section S(z) of the contour K exists parallel to the xy-plane with a width Q(z) in the x-direction. The width Q(z) is smaller at points away from z=0, such that Q(z1)<Q(0) and Q(z2)<Q(0) for z1<0 and z2>0.

Abstract: A magnet coil system (1) has a first end section (19a) of an HTSL-tape conductor (4) located ahead of a first end (19) of an HTSL-tape conductor (4) and a first end section (20a) of an LTS wire (7) located prior to a first end (20) of the LTS wire (7) which are connected electrically but not in a superconducting way in a connecting section (17) along the length of the connecting section. The LTS wire (7) has a flat shape at least within the connecting section (17) and one side of the flat LTS wire (7) abutting the HTSL-tape conductor (4) and the connecting section (17) has a length of at least 5 m. The magnet coil system has an acceptably small residual ohmic resistance which is achieved by simple means.

Abstract: A method for the transmission/reception of RF signals for NMR measurements uses a heat exchanger (1) for cooling heat sources (5), the heat exchanger having a contact element (4.2) for thermal connection between a cryogenic fluid and the heat source, is characterized in that the heat exchanger comprises a container having an interior volume VB into which a first cryogenic fluid F1 that has a liquid component F1L and a gaseous component F1G flows through an inflow conduit (8) and from which a second cryogenic fluid F2 that has liquid component F2L and a gaseous component F2G flows out through an outflow conduit (9). The inflow conduit has a flow cross-section QZ and a circumference UZ from which an associated parameter VZ=4·Q2Z/UZ results, wherein VB>10·VZ, and the outflow conduit has a flow diameter QA wherein QA?QZ. The contact element is in close thermal contact with both the liquid volume component VL of the cryogenic fluid and with the heat source.

Abstract: This disclosure describes an imaging radiation detection module with novel configuration of the scintillator sensor allowing for simultaneous optimization of the two key parameters: detection efficiency and spatial resolution, that typically cannot be achieved. The disclosed device is also improving response uniformity across the whole detector module, and especially in the edge regions. This is achieved by constructing the scintillation modules as hybrid structures with continuous (also referred to as monolithic) scintillator plate(s) and pixelated scintillator array(s) that are optically coupled to each other and to the photodetector.

Abstract: An MPI-apparatus comprising a magnet system for generating a time-varying and position-dependent magnetic field and a detection system detecting signals from MPI contrast agents exposed to said magnetic field within a detection volume, said signals being suitable for reconstructing an image of the spatial and temporal distribution of said MPI contrast agents, is characterized in that the magnet system comprises an array with a plurality of permanent magnetic elements geometrically arranged in such a way that at least a part of the plurality of permanent magnetic elements are moved with sufficient speed in the vicinity of the detection volume to create the spatial and temporal magnetic field variations for inducing within the contrast agent the MPI signals recorded by the detection system. This avoids the high power requirements of current MPI scanners, while opening the way for higher spatial resolutions and variable scanning frequencies.

Abstract: A cryostat has a cooling arm with a first thermal contact surface which can be brought into thermal contact with a second thermal contact surface on an object to be cooled. A hollow volume (2) between the inner side of the neck tube, the cooling arm, and the object is filled with gas and the cooling arm is pressurized by the inner pressure of the gas and also by atmospheric pressure. A contact device brings the first and the second contact surfaces into thermal contact below a threshold gas pressure and moves them away from each other when the threshold pressure has been exceeded such that a gap (13) filled with gas thermally separates the first and second contact surfaces. Operationally safe and fully automatic reduction of the thermal load acting on the object to be cooled is thereby obtained in case the cooling machine fails.