Abstract: A temperature-control system for an NMR magnet system. A permanent magnet arrangement (1) with a central air gap (2) generates a homogeneous static magnetic field inside the air gap. A probehead (3) transmits RF pulses and receives RF signals from a test sample (0). An H0 coil changes the amplitude of the static magnetic field. A shim system (4) in the air gap further homogenizes the magnetic field. A first insulation chamber (5) surrounds and thermally shields the permanent magnet arrangement and includes an arrangement (6) controlling a temperature T1 of the first insulation chamber. The shim system, the H0 coil and the NMR probehead are arranged outside the first insulation chamber in the air gap. A heat-conducting body (7) is arranged between the shim system and the H0 coil on one side and the permanent magnet arrangement on the other, thereby enhancing field stability and suppressing drift.

Abstract: A temperature-control system for an NMR magnet system. A permanent magnet arrangement (1) with a central air gap (2) generates a homogeneous static magnetic field inside the air gap. A probehead (3) transmits RF pulses and receives RF signals from a test sample (0). An H0 coil changes the amplitude of the static magnetic field. A shim system (4) in the air gap further homogenizes the magnetic field. A first insulation chamber (5) surrounds and thermally shields the permanent magnet arrangement and includes an arrangement (6) controlling a temperature Ti of the first insulation chamber. The shim system, the H0 coil and the NMR probehead are arranged outside the first insulation chamber in the air gap. A heat-conducting body (7) is arranged between the shim system and the H0 coil on one side and the permanent magnet arrangement on the other, thereby enhancing field stability and suppressing drift.

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 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.