Realization of an infrared spectral radiant power response scale on a cryogenic bolometer

Abstract

The National Institute of Standards and Technology (NIST) has developed an infrared (IR) radiant power response scale for the spectral range from 2 µm to 20 µm. The scale has been realized on a cryogenic bolometer. The response of this bolometer has been determined by multiple ties to a primary standard, the NIST High Accuracy Cryogenic Radiometer (HACR). These transfers were made using three intermediate detectors over three different spectral regions. In addition, an independent method was used to determine the relative response of the bolometer over the entire spectral range. An IR spectral response scale over the entire 2 µm to 20 µm range was determined from these measurements, with the interlocking nature of the multiple independent measurements providing improved overall confidence and reduced uncertainties. The overall scale combined standard uncertainty for the entire spectral range of 2 µm to 20 µm is of the order of 0.25 %, with the typical combined standard uncertainty of an individual measurement made with the bolometer being ~0.8 %.