A Cryogenic Infrared Calibration Target
arXiv:1403.6667 · doi:10.1063/1.4871108
Abstract
A compact cryogenic calibration target is presented that has a peak diffuse reflectance, , from m). Upon expanding the spectral range under consideration to m) the observed performance gracefully degrades to at the band edges. In the implementation described, a high-thermal-conductivity metallic substrate is textured with a pyramidal tiling and subsequently coated with a thin lossy dielectric coating that enables high absorption and thermal uniformity across the target. The resulting target assembly is lightweight, has a low-geometric profile, and has survived repeated thermal cycling from room temperature to K. Basic design considerations, governing equations, and test data for realizing the structure described are provided. The optical properties of selected absorptive materials -- Acktar Fractal Black, Aeroglaze Z306, and Stycast 2850 FT epoxy loaded with stainless steel powder -- are characterized and presented.