A Cryogenic Infrared Calibration Target

Abstract

A compact cryogenic calibration target is presented that has a peak diffuse reflectance, $R\le 0.003$, from $800-4,800{\mathrm{cm}}^{-1}$ $(12-2\mu$m). Upon expanding the spectral range under consideration to $400-10,000{\mathrm{cm}}^{-1}$ $(25-1\mu$m) the observed performance gracefully degrades to $R\le 0.02$ 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 $\sim 4$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.

References in corpus (3)

• Calibrator Design for the COBE Far Infrared Absolute Spectrophotometer (FIRAS)
• Design and Calibration of a Cryogenic Blackbody Calibrator at Centimeter Wavelengths
• A Cryogenic Infrared Calibration Target

Cited by in corpus (6)

• A Compact Cryogenic Thermal Source for Detector Array Characterization
• A Cryogenic Infrared Calibration Target
• A Broadband Micro-machined Far-Infrared Absorber
• Permittivity and permeability of epoxy-magnetite powder composites at microwave frequencies
• Thin flexible multi-octave metamaterial absorber for millimetre wavelengths
• Development of epoxy-based millimeter absorber with expanded polystyrenes and carbon black