Proceedings of SPIE
Many organizations, including Space Dynamics Laboratory, have built blackbodies with calculated emissivities of 0.995 to 0.9999 and estimated radiance temperature uncertainties of a few hundred mK or less. However, the calculated performance has generally not been demonstrated through testing or comparison with other high-performance blackbodies. Intercomparison is valuable; historically, when equipment or experimental results have been intercompared they are often found to disagree by more than the claimed uncertainties. Blackbody testing has been limited because testing at the required accuracy (0.1% or better in radiance) is a significant expense. Such testing becomes essential when proven, SI-traceble, absolute accuracy is required, such as for the CLARREO mission, which has an absolute accuracy requirement of 0.1 K (3 sigma) at 220 K over most of the thermal infrared and needs high-performance blackbodies to support this requirement. Properly testing blackbodies requires direct measurement of emissivity and accurate measurement of radiance or comparison of radiance from two blackbodies. This presentation will discuss these testing needs, various types of testing, and test results for a CLARREO prototype blacbkody.
Latvokoski, Harri; Watson, Mike; and Topham, Shane, "Testing of Highly Accurate Blackbodies" (2011). Space Dynamics Lab Publications. Paper 77.