The temperature calibration of a high temperature X-ray diffraction camera

The accurate measurement, by a thermocouple, of the temperature of fibre specimens in an X-ray high-temperature camera, of the type containing a spherical furnace enclosure, is investigated. Factors affecting the calibration of the thermocouple are discussed, and it is shown experimentally that the chief cause of discrepancies is the abstraction of heat along the thermocouple wires. Methods for calibrating the thermocouple in position, and for reducing the correction required to a minimum, are presented.