"An MAS probe is disclosed for obtaining a substantial improvement in
signal to noise (S/N) in triple-resonance high-resolution (HR)
magic-angle-spinning (MAS) NMR of samples near room temperature (RT) in
high-field magnets where the magnet's RT shim bore is greater than 60 mm.
All critical circuit components, including the sample coils, are located
along with the spinner assembly in a thermally insulated cold zone
pressurized with helium gas. The spinner assembly attaches to a sealed,
curved, rotor-loading tube to permit automatic sample change, and it is
surrounded by a partially insulated jacket cooled with a cryogenic fluid,
generally nitrogen gas. The MAS probe is also compatible with magic angle
gradients, variable temperature operation, field locking, and commonly
available closed-cycle cold fingers."