Abstract: The invention relates to a sample cell for performing DNP-NMR measurements, for interchangeable use in an EPR microwave resonator, with the sample cell comprising a flat sample cavity for holding a liquid sample to be measured, wherein the flat sample cavity extends with a maximum length L and a maximum width W in a sample cavity plane, and extends with a maximum height H perpendicular to the sample cavity plane, with H? 1/15*L and H? 1/15*W, and an NMR coil wound around the flat sample cavity for generating an RF magnetic field B2, wherein a coil axis of the NMR coil about which the NMR coil is wound is oriented perpendicular to the sample cavity plane. The invention provides a sample cell which is easy to handle and improves the quality and the reproducibility of DNP-NMR measurements.

Abstract: An apparatus for detachably fastening an NMR probe head with a pedestal box to an NMR magnet system of an NMR spectrometer has a holding system rigidly connected to the magnet system. A base plate of the holding system fastens detachably to the probe head pedestal box. A receiving device on or in the base plate receives all electric, electronic, optical, pneumatic, and thermal feed lines and optionally discharge lines required for the operation of the probe head. A lower side of the base plate in contact with an upper side of the pedestal box comprises multiple connecting elements into which the feed lines and discharge lines merge. The upper side of the pedestal box comprises receiving elements into which the feed lines and discharge lines from the connecting elements merge in a predetermined relative assembled position.

Abstract: The invention relates to a sample cell for performing DNP-NMR measurements, for interchangeable use in an EPR microwave resonator, with the sample cell comprising a flat sample cavity for holding a liquid sample to be measured, wherein the flat sample cavity extends with a maximum length L and a maximum width W in a sample cavity plane, and extends with a maximum height H perpendicular to the sample cavity plane, with H? 1/15*L and H? 1/15*W, and an NMR coil wound around the flat sample cavity for generating an RF magnetic field B2, wherein a coil axis of the NMR coil about which the NMR coil is wound is oriented perpendicular to the sample cavity plane. The invention provides a sample cell which is easy to handle and improves the quality and the reproducibility of DNP-NMR measurements.

Abstract: An MAS probehead (1) positioned in a magnet bore (2) includes a sample chamber (3) with a stator (4) for receiving a rotor and an RF coil that radiates RF pulses into and/or receives RF signals from an NMR sample (5). A temperature-control apparatus guides gas at a first variable temperature T1 into the sample chamber and through the stator during an NMR measurement, and guides a pressurized gas stream at a second variable temperature T2 around the sample chamber. The sample chamber is surrounded by an encapsulation device (6), at least in the azimuthal direction around the axis of the magnet bore and counter to the flow direction of the pressurized gas, and is oriented to provide an air gap (7?) between the sample chamber and the magnet bore. This prevents dissipation of the gas temperature to outer parts of the probehead, and yields larger NMR measurement temperature ranges.

Abstract: An NMR probe head (1) having an RF coil arrangement (2a) in a coil region (2) and an RF shielding tube (3) for supply lines leading from a connection region (4) to the coil region. An elongated backbone (5) is arranged inside the shielding tube and has an inherently rigid, mechanically stiff structure having continuous bores and/or connecting channels (5a) which run parallel to the tube axis and accommodate the supply lines. The backbone has a continuously electrically conductive outer surface which leads from the connection region to the coil region and is electrically conductively connected to the conductive inner surface of the shielding tube via connecting elements (6). A continuous electrically conductive contour is formed thereby between the backbone and the shielding tube. This shields against externally incident RF fields and spatially separates the stable mechanical supporting construction and the supply lines from the electronic and RF components.

Abstract: An MAS probehead (1) positioned in a magnet bore (2) includes a sample chamber (3) with a stator (4) for receiving a rotor and an RF coil that radiates RF pulses into and/or receives RF signals from an NMR sample (5). A temperature-control apparatus guides gas at a first variable temperature T1 into the sample chamber and through the stator during an NMR measurement, and guides a pressurized gas stream at a second variable temperature T2 around the sample chamber. The sample chamber is surrounded by an encapsulation device (6), at least in the azimuthal direction around the axis of the magnet bore and counter to the flow direction of the pressurized gas, and is oriented to provide an air gap (7?) between the sample chamber and the magnet bore. This prevents dissipation of the gas temperature to outer parts of the probehead, and yields larger NMR measurement temperature ranges.

Abstract: A probe head (1) of an NMR-MAS assembly has a stator (2) with an opening (4) receiving a rotor (3) which, in a measuring position, rotates at the magic angle to the B0 field. The stator is pivotable between the measuring position and a loading position of the rotor. A detection device (5) permits external, contactless identification of whether the opening of the stator is fitted with a rotor. The detection device has a light source (5a), from which light is introduced into a lower end (6?) of a light guide (6). The stator has a first bore (2a), in which a first light guide stump (7a) is positioned such that, in the loading position of the stator, it produces an optical connection between a rotor inserted in the stator and an upper end (6?) of the light guide opposite the lower end.

Abstract: An NMR probe head (1) having an RF coil arrangement (2a) in a coil region (2) and an RF shielding tube (3) for supply lines leading from a connection region (4) to the coil region. An elongated backbone (5) is arranged inside the shielding tube and has an inherently rigid, mechanically stiff structure having continuous bores and/or connecting channels (5a) which run parallel to the tube axis and accommodate the supply lines. The backbone has a continuously electrically conductive outer surface which leads from the connection region to the coil region and is electrically conductively connected to the conductive inner surface of the shielding tube via connecting elements (6). A continuous electrically conductive contour is formed thereby between the backbone and the shielding tube. This shields against externally incident RF fields and spatially separates the stable mechanical supporting construction and the supply lines from the electronic and RF components.

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 probe head (1) of an NMR-MAS assembly has a stator (2) with an opening (4) receiving a rotor (3) which, in a measuring position, rotates at the magic angle to the B0 field. The stator is pivotable between the measuring position and a loading position of the rotor. A detection device (5) permits external, contactless identification of whether the opening of the stator is fitted with a rotor. The detection device has a light source (5a), from which light is introduced into a lower end (6?) of a light guide (6). The stator has a first bore (2a), in which a first light guide stump (7a) is positioned such that, in the loading position of the stator, it produces an optical connection between a rotor inserted in the stator and an upper end (6?) of the light guide opposite the lower end.

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: An NMR DNP-MAS probe head (10) has an MAS stator (2) for receiving an MAS rotor (3) having a sample substance in a sample volume (4), and a hollow microwave waveguide (5)? for feeding microwave radiation through an opening (5a) of the microwave waveguide into the sample volume, an axially expanded rod-shaped microwave coupler (6) located in the opening made of dielectric material, characterized in that the microwave waveguide has a conically tapered hollow transition piece for coupling in an HE 11 mode, into which the microwave coupler projects at an all-round radial distance to the opening of the microwave waveguide. It is thus possible, in a surprisingly simple manner and by means of readily available technical means, to irradiate a considerably higher microwave energy in the HE 11 mode into the NMR measuring sample than by means of the known arrangements.

Abstract: An NMR (nuclear magnetic resonance) probe head has a microwave resonator with at least two elements which are reflective in the microwave range, at least one of which is focusing. The reflective elements at least partly delimit a resonance volume of the microwave resonator. At least one of the reflective elements is a DBR (“Distributed Bragg Reflector”), and the NMR probe head has at least one NMR coil integrated into the DBR. The NMR detection coil can thereby be positioned particularly near to the sample and the distortions of the static field by resonator components are reduced, such that the detection sensitivity and the spectral resolution of the experiment are significantly improved.

Abstract: An NMR DNP-MAS probe head (10) has an MAS stator (2) for receiving an MAS rotor (3) having a sample substance in a sample volume (4), and a hollow microwave waveguide (5)? for feeding microwave radiation through an opening (5a) of the microwave waveguide into the sample volume, an axially expanded rod-shaped microwave coupler (6) located in the opening made of dielectric material, characterized in that the microwave waveguide has a conically tapered hollow transition piece for coupling in an HE 11 mode, into which the microwave coupler projects at an all-round radial distance to the opening of the microwave waveguide. It is thus possible, in a surprisingly simple manner and by means of readily available technical means, to irradiate a considerably higher microwave energy in the HE 11 mode into the NMR measuring sample than by means of the known arrangements.

Abstract: An NMR (nuclear magnetic resonance) probe head has a microwave resonator with at least two elements which are reflective in the microwave range, at least one of which is focusing. The reflective elements at least partly delimit a resonance volume of the microwave resonator. At least one of the reflective elements is a DBR (“Distributed Bragg Reflector”), and the NMR probe head has at least one NMR coil integrated into the DBR. The NMR detection coil can thereby be positioned particularly near to the sample and the distortions of the static field by resonator components are reduced, such that the detection sensitivity and the spectral resolution of the experiment are significantly improved.

Abstract: A resonator assembly for executing measurements on a sample within a constant magnetic field B0 by means of magnetic resonance is disclosed. It comprises a resonator portion defining a longitudinal axis and an axial direction. The resonator portion has, along the axial direction, a hollow cavity for exciting electron resonance within the sample. A coupling portion is provided adjacent the resonator portion and has, along the longitudinal axis, a stepped through being electrically conductive at its inner surface. A first, middle section of the stepped through configures the hollow cavity. A second and a third, lateral section adjacent axially opposed sides of the hollow cavity are each dimensioned such that a basic mode being resonant within the hollow cavity is unable to propagate within the second and the third section. A coil is wound around the resonator portion for additionally exciting a nuclear resonance within the sample.

Abstract: A resonator assembly for executing measurements on a sample within a constant magnetic field B0 by means of magnetic resonance is disclosed. It comprises a resonator portion defining a longitudinal axis and an axial direction. The resonator portion has, along the axial direction, a hollow cavity for exciting electron resonance within the sample. A coupling portion is provided adjacent the resonator portion and has, along the longitudinal axis, a stepped through being electrically conductive at its inner surface. A first, middle section of the stepped through configures the hollow cavity. A second and a third, lateral section adjacent axially opposed sides of the hollow cavity are each dimensioned such that a basic mode being resonant within the hollow cavity is unable to propagate within the second and the third section. A coil is wound around the resonator portion for additionally exciting a nuclear resonance within the sample.

Abstract: A probe head for nuclear magnetic resonance measurements comprises a sample holder having a stator and a rotor. The rotor is journalled for rotation about an axis of rotation within the stator. It is adapted for receiving a sample substance. The axis of rotation is inclined by an angle with respect to a longitudinal axis of the probe head. The stator is configured as a dielectric resonator.

Abstract: A probe head for nuclear magnetic resonance measurements comprises a sample holder having a stator and a rotor. The rotor is journalled for rotation about an axis of rotation within the stator. It is adapted for receiving a sample substance. The axis of rotation is inclined by an angle with respect to a longitudinal axis of the probe head. The stator is configured as a dielectric resonator.