An NMR (=nuclear magnetic resonance) probe head comprising an RF (=radio
frequency) receiver coil system, which can be cooled down to cryogenic
temperatures, and a room temperature pipe (4), extending in a z direction,
for receiving a sample tube (6) containing sample substance (7) to be
examined by NMR measurements is characterized in that at least one,
preferably several radiation shields (9) extending in the z direction and
surrounding the room temperature pipe (4) in a radial direction are
disposed between the RF receiver coil system (1) and the room temperature
pipe (4) which are formed of one or several materials oriented in the z
direction and are almost completely transparent to RF fields, at least
have an absorption of <5%, preferably <1% for RF fields to thereby
provide simple and substantial reduction in the temperature gradient in
the z direction during operation without thereby impairing the NMR
measurement.