A compact cryogenic calibration target is presented that has a peak diffuse reflectance, R≤0.003, from 800−4,800cm−1(12−2μm). Upon expanding the spectral range under consideration to 400−10,000cm−1(25−1μm) the observed performance gracefully degrades to R≤0.02 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 ∼4K. 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.
@article{arxiv.1403.6667,
title = {A Cryogenic Infrared Calibration Target},
author = {Edward J. Wollack and Robin E. Kinzer and Stephan A. Rinehart},
journal= {arXiv preprint arXiv:1403.6667},
year = {2014}
}