The use of thermocouples for measuring temperatures below 70 K. A new type of low temperature thermocouple

The use of thermocouples such as copper-constantan to measure low temperatures (e.g. approximately equal to10° K) may result in considerable uncertainty in the measured temperature. These uncertainties are discussed and a method described for reducing them to ±0.5°. It is shown that thermocouples composed of pure copper against certain dilute copper alloys (e.g. copper + approximately equal to0.005 wt% tin) have particular advantages for measuring temperatures in the range 2-30° K.