Abstract. A new type of high-temperature platinum resistance thermometer has been developed and tested. The thermometer with a strip-shaped support was designed in such a special way that the curvature of the platinum wire in a sensor is kept almost uniform, and thus the strain in the wire can be reduced to a minimum. The experiments, which have lasted for over 3 years, show that the stability of the thermometers is excellent. The average change in resistance of the thermometer at 0 °C was equivalent to about 1 mK for every 100 h of exposure to temperatures from 1070 °C to 1100 °C. The anneal time at 1100 °C required to achieve this stability was only 150 h. The changes of R₀ are usually less than 1.0 mK equivalent after rapidly cooling from 1064 °C to ambient temperatures, followed by annealing at 650 °C for half an hour. The leakage resistance of these thermometers at 1064 °C is greater than 27 MΩ. It seems that the problem of fused silica devitrification can be solved.

Print publication: Issue 4 (October 1982)
Received 31 March 1982