The resistance element is of pure platinum, coiled and mounted in a strain-free construction. The former is of pure alumina material to avoid wire contamination.
Before final inspection and certification the sensor is pre-aged through temperature cycles to remove mechanical stress and therefore to improve long term stability.
Two models are available using respectively Inconel 600 (model 2180) and high purity allumina Ker710 (model 2182).
The thermocouple is made of two homogenous wires, in type S thermocouple are one in Platinum and the other one in Platinum 10% Rhodium alloy. Both are of the highest purity presently available.
Base metal thermocouples can be supplied, on request, to be used in applications requiring a lower accuracy and where a direct comparison with a sensor of the same composition of the actually used.