An NMR
spectrometer comprising an
NMR magnet system (27) disposed in a
helium tank of a
cryostat and an NMR probe head (11) disposed in a
room temperature bore of the
cryostat, which contains a cooled RF
resonator (9) for receiving NMR signals from a sample to be investigated, and a cooled pre-
amplifier (10), wherein the NMR probe head (11) is cooled by a common multi-stage compressor-operated refrigerator (2), wherein the refrigerator (2) comprises a cold head and several heat exchangers (5, 6) at different temperature levels, wherein the refrigerator (2) is disposed at a spatial separation from the
cryostat in a separate, evacuated and thermally insulated housing (1) and wherein at least one cooling circuit with cooling lines, which are thermally insulated by a
transfer line (13, 14) is disposed between the housing (1) containing the heat exchangers (5, 6) and the NMR probe head (11), is characterized in that additional cooling lines to an LN2 tank (18) or
radiation shield (21) disposed in the cryostat and surrounding the
helium tank are provided, and the refrigerator (2) also cools the LN2 tank (18) or the
radiation shield (21). The inventive NMR
spectrometer comprises a simple and inexpensive device for matching the
holding time of LN2 to that of LHe through cooling the LN2 tank using the refrigerator provided for cooling the NMR probe head and without great expense.