Lake Shore germanium resistance temperature sensors are recognized as “Secondary Standard Thermometers” and have been employed in the measurement of temperature from 0.05 K to 30 K for nearly 40 years.
Germanium sensors have a useful temperature range of about two orders of magnitude. The exact range depends upon the doping of the germanium element. Cryogenic temperature sensors with ranges from below 0.05 K to 100 K are available. Between 100 K and 300 K, dR/dT changes sign and dR/dT above 100 K is very small for all models. Sensor resistance varies from several ohms at its upper useful temperature to several tens of kilohms at its lower temperature.
Because device sensitivity increases rapidly with decreasing temperature, a high degree of resolution is achieved at lower temperatures, making these resistors very useful for submillikelvin control at 4.2 K and below.
The sensors offer excellent stability, and ±0.5 mK reproducibility at 4.2 K. The germanium resistor is usually the best choice for high-accuracy work below 30 K. Use in a magnetic field is not recommended.