Probe

The probe consists of the transmit/receive coils for inductive coupling of the sample to the transmitter/receiver subsystems of the the RF electronics. The geometry of the probe dictates the volume over which a constant magnitude RF field will be generated.

The signal-to-noise ratio for a given probe increases with decrease in temperature. This is due to the decrease in thermal noise with decrease in temperature. Cryogenic probes take advantage of this observation and keep the probe at a much lower temperature than the sample. Therefore, cryogenic probes usually have much higher signal-to-noise ratios than comparable probes operating at room temperature.