Fiberoptic infrared multi-spectral radiometers for emissivity and temperature measurements of gray bodies near room temperatures

Two fiberoptic infrared multi-spectral radiometers were constructed for measurements of the temperature and the emissivity of gray bodies whose temperatures were close to room temperature (40-70°C). In one radiometer, the different spectral regions were obtained by using standard bulk interference filters, and in a second radiometer, the different spectral regions were obtained by using hollow glass waveguides (HGWs) as filters. Using these two radiometers, we carried out temperature and emissivity measurements of three gray bodies which had high emissivity (ε=0.97), medium emissivity (ε=0.71) and low emissivity (ε=0.025). We present the results obtained for these gray bodies and discuss the advantages and disadvantages in using each of the radiometers.