Calibration of Thermocouple by Comparison against Standard Radiation Thermometer in a Blackbody Comparator

Abstract

A set-up to calibrate thermocouple up to 1500 °C by comparison against radiation thermometer is recently established in Research Center for Metrology – LIPI (RCM – LIPI). A blackbody cavity, made of silicon carbide, is put in a single-zone-controller furnace as a comparator block. A radiation thermometer standard (worked at λ = 650 nm) is employed to determine the reference temperature of the calibration. In this work, a type B thermocouple is calibrated in the range of 1000 – 1500 °C. The expanded uncertainty (k = 2) is evaluated to be 2.4 °C at 1500 °C. The uncertainty due to inhomogeneity of the thermocouple contributes more than 50% (1.4 °C) of the total uncertainty.