Improvement of the signalhyphen;tohyphen;noise (Ssol;N) ratio of cw NMR spectrometers by cooling circuit components to liquid helium temperature is discussed. Criteria for design of a low temperature circuit using a twinhyphen;T bridge and MOSFET amplifier are presented. A liquid helium temperature spectrometer for operation at 16 MHz which improves Ssol;N ratio by a factor of 5 over conventional techniques is described.
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