MAS NMR probe head arrangement with replaceable stator

A magic angle spinning (MAS) nuclear magnetic resonance (NMR) probe head arrangement, comprising:

• a stator aligned along an axis of rotation and configured to support a rotor holding a measurement substance,
• a stator mount,
• a radio frequency (RF) coil arrangement configured to emit RF pulses into the measurement substance held in the rotor and/or to receive RF signals from the measurement substance held in the rotor, and
• a mechanism,
• wherein the stator comprises a first bearing base, a sleeve element, and a second bearing base, wherein the sleeve element connects the first bearing base and the second bearing base to each other axially as a unit, wherein the first bearing base is configured as a first pneumatic bearing and the second bearing base is configured as a second pneumatic bearing,
• wherein the second bearing base has a greatest external diameter AD2,
• wherein the sleeve element has a frontal section which adjoins the second bearing base axially and has a greatest external diameter ADV,
• wherein the RF coil arrangement has a least inner diameter IDS,
• wherein:
• AD2<IDS and ADV<IDS,
• wherein the stator mount is formed with a stator bearing configured for axial insertion and axial extraction of the stator as the unit into and from the stator mount,
• wherein the stator is configured to pass through the RF coil arrangement for axial insertion into and axial extraction from the stator mount, and
• wherein the mechanism is configured to fix the stator axially in the stator bearing when the stator is inserted into the stator mount.