Abstract: An MAS NMR probe head arrangement has a stator (2) aligned along an axis of rotation (RA) to support a rotor (1), a stator mount (32), and a RF coil arrangement (21) to emit/receive RF pulses into/from the measurement substance (40) in the rotor. The stator mount has a stator bearing (41) into which the stator can be axially inserted and extracted. The stator, when inserted, passes through the RF coil arrangement (21), and can be fed through the RF coil arrangement (21). A mechanism fixes the stator axially in the stator bearing (41) when inserted. This arrangement enhances both ease of assembly and maintenance of the arrangement.

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: An MAS NMR probe head arrangement has a stator (2) aligned along an axis of rotation (RA) to support a rotor (1), a stator mount (32), and a RF coil arrangement (21) to emit/receive RF pulses into/from the measurement substance (40) in the rotor. The stator mount has a stator bearing (41) into which the stator can be axially inserted and extracted. The stator, when inserted, passes through the RF coil arrangement (21), and can be fed through the RF coil arrangement (21). A mechanism fixes the stator axially in the stator bearing (41) when inserted. This arrangement enhances both ease of assembly and maintenance of the arrangement.

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 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 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 a support frame with 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.