Abstract:
The surface temperature of the Thermogage blackbody graphite tube furnace used at the National Measurement
Institute Australia, NMIA, for the calibration of pyrometers was measured using a silica optical fibre and Pt/Pt-
Rh thermocouples. The silica optical fibre was bent using a Hz flame causing some deformation to the bent area.
This resulted in a light leakage from the deformed area, which was experimentally assessed. The optical fibre
measurements were corrected from irradiances from other parts of the graphite tube using view factors obtained
from the literature. These corrections were small and positive near the middle of the tube but large and negative
nearer the end. A model for the uncertainty in the temperature corrections was also developed. The corrected
optical fibre results were found to agree well with measurements made using Pt/Pt-Rh thermocouples. Further
investigation is required to reduce systematic error in the thermocouple data.
