Abstract
High emissivity is a key performance parameter for blackbody calibrators, reducing calibration sensitivity to the thermal background and blackbody emittance non-uniformity. The Visible Infrared Imaging Radiometer Suite (VIIRS) blackbody element on the Suomi National Polar-orbiting Partnership (NPP) satellite and the upcoming Joint Polar-orbiting Satellite System (JPSS) have an emittance requirement greater than 0.996. In order to achieve a high value over a large aperture (~12.5 cm diameter), we combine a low reflectance specular coating with an innovative repeating v-groove cavity design. The emittance is then characterized with a custom laser test station that measures the Total Integrated Reflectance (TIR) from the blackbody. Measurements show that the resulting emissivity is greater than 0.997 at 3.39 µm. Details on the experimental setup and data analysis and results are presented herein and discuss the drivers and uncertainties that go into testing a high emittance design.
Characterization of the VIIRS Blackbody Emittance
High emissivity is a key performance parameter for blackbody calibrators, reducing calibration sensitivity to the thermal background and blackbody emittance non-uniformity. The Visible Infrared Imaging Radiometer Suite (VIIRS) blackbody element on the Suomi National Polar-orbiting Partnership (NPP) satellite and the upcoming Joint Polar-orbiting Satellite System (JPSS) have an emittance requirement greater than 0.996. In order to achieve a high value over a large aperture (~12.5 cm diameter), we combine a low reflectance specular coating with an innovative repeating v-groove cavity design. The emittance is then characterized with a custom laser test station that measures the Total Integrated Reflectance (TIR) from the blackbody. Measurements show that the resulting emissivity is greater than 0.997 at 3.39 µm. Details on the experimental setup and data analysis and results are presented herein and discuss the drivers and uncertainties that go into testing a high emittance design.