Characterization of the Temperature Dependence of Optical Components in a Cryo-Vacuum Chamber used for Space Sensor Testing

The space sensor cryo-vacuum chambers at Arnold Air Force Base are world class sensor characterization and calibration facilities. The chambers provide a simulated deep space background and accurate infrared projections. Several large optical systems are used within the chambers to accomplish this. Calibration of the chambers requires the use of a database of the measured optical properties of these components to simulate the output. However, as the information in the database is room temperature information and the chambers run near 20K, some discrepancies exist between the actual output and the model output. The purpose of this work is to translate the room temperature spectral information to cryogenic information as correctly as possible. To achieve this, the relevant temperature dependent material information was collected from literature. A program was written using this information that calculated spectral performance with temperature as a parameter. An ambient calculation and a cryogenic calculation were performed where necessary for each component of interest. The translation between the two calculations was then measured and applied to the measured ambient data of the components to obtain their expected cryogenic performance.