Abstract: An NMR probe head with an MAS stator (1) supplied with microwave radiation from a microwave guide (9) through an opening in a coil block (2) has a microwave lens (6) and a microwave mirror (8a) on an inner side of the MAS stator. The MAS rotor (3) is surrounded by a solenoid RF coil (5) and the microwave lens is arranged and embodied in the opening of the coil block on the side facing a sample volume (4) such that the cylinder axis of the MAS rotor lies in the focus of the microwave lens. The microwave mirror is arranged on, or in, the inner wall of the MAS stator that lies opposite the microwave guide and has a cylindrical and concave structure, such that the microwave mirror focuses the microwave radiation incident from the sample volume onto the central axis of the MAS rotor.

Abstract: An NMR probe head with an MAS stator (1) supplied with microwave radiation from a microwave guide (9) through an opening in a coil block (2) has a microwave lens (6) and a microwave mirror (8a) on an inner side of the MAS stator. The MAS rotor (3) is surrounded by a solenoid RF coil (5) and the microwave lens is arranged and embodied in the opening of the coil block on the side facing a sample volume (4) such that the cylinder axis of the MAS rotor lies in the focus of the microwave lens. The microwave mirror is arranged on, or in, the inner wall of the MAS stator that lies opposite the microwave guide and has a cylindrical and concave structure, such that the microwave mirror focuses the microwave radiation incident from the sample volume onto the central axis of the MAS rotor.