Raytek (Germany)

Recent progress in the technology of radiation thermometers has improved their accuracy significantly. The best Transfer Radiation Thermometers achieve accuracies of 0.1 K or 0.1 %. Based on this improvement in the calibration accuracies of primary standards, the calibration of industrial radiation thermometers viewing blackbody radiation sources has also increased in accuracy. But typical measuring objects for industrial radiation thermometers are often show a non‐gray spectral and non‐lambertian angular emissivity characteristic. Typical emissivity uncertainties in industrial measurements are 3 % to 10 %. Especially for long‐wavelength radiation thermometers the resulting measuring accuracy is in such cases dominated by the emissivity uncertainty. To improve this situation, the authors started a project to develop an emissivity measurement station that meets the needs of industrial radiation thermometry. The station is able to measure the spectral emissivity of samples as a function of their temperature, the emission angle and the polarization. For industrial use, it was most important to design the setup as a fully automatic station.