IR spectral characterization of customer blackbody sources: first calibration results

We summarize recent progress in our infrared (IR) spectral radiance metrology effort. In support of customer blackbody characterization, a realization of the spectral radiance scale has been undertaken in the temperature range of 232 degrees C to 962 degrees C and spectral range of 2.5 mu m to 20 mu m. We discuss the scale realization process that includes the use of Sn, Zn, Al and Ag fixed-point blackbodies (BB), as well as the transfer of the spectral radiance scale to transfer standard BBs based on water, Cs and Na heat pipes. Further we discuss the procedures for customer source calibration with several examples of the spectral radiance and ernissivity measurements of secondary standard BB sources. For one of the BBs, a substantial deviation of emissivity values from the manufacturer specifications was found. Further plans include expansion of the adopted methodology for temperatures down to 15 degrees C and building a dedicated facility for spectral characterization of IR radiation sources.