Abstract
Results are reported of an investigation of the triple point of succinonitrile as a temperature-fixed point and of its use in the calibration of thermistor thermometers. The average value of the triple point of several samples of this material was determined to be 58.0805 °C, with an estimated uncertainty of ±0.0015 °C relative to the International Practical Temperature Scale of 1968. Three-point calibrations of thermistor thermometers, using temperature-fixed points provided by succinonitrile, gallium, and water were compared with 15-point comparison calibrations performed with a standard platinum resistance thermometer (SPRT). Equations, solved by simultaneous solution using data obtained at the three calibration points, yield values of temperatures in the range from 0° to 70 °C which agree to within about ±1 mK with those obtained by calibration with a SPRT in a bath.
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