[16p-C43-1~12] 1.5 Instrumentation, measurement and Metrology

1:45 PM - 2:00 PM JST(4:45 AM - 5:00 AM UTC)

[16p-C43-4] A Study on Uncertainty Analysis for Calibration of Air Thermometer in Test Chamber

〇Naoya Ishiwata¹, Hisashi Abe¹ (1.AIST)

Keywords:

temperature,uncertainty,calibration

The accuracy of relative humidity measurement has recently become necessary in various applications. Since relative humidity depends on air temperature, air thermometers used in these applications should be calibrated with a small uncertainty, less than 25 mK, in order to meet this requirement. To calibrate a thermometer with such small uncertainty, which is easy in liquid, is difficult in gas even for national metrology institutes. This is because due to low heat capacity and thermal conductivity of air, temperature uniformity in a climatic chamber is generally lower than that in a liquid bath, and contribution of several uncertainty components such as thermal radiation and stem conduction is not negligible in the gas phase. In this study, we conducted an uncertainty analysis for the calibration of an air thermometer with a test chamber of the NMIJ’s high humidity generator to understand dominant uncertainty components. The standard uncertainty in calibration of air thermometers estimated in this study was 17 mK or less in the range of 10 °C to 80 °C, which was less than the target uncertainty of 25 mK.