The main instrument for metrological control of the precise measurements for the incoherent optical radiation power characteristics is the black-body model (BBM), i.e., the heat radiator the power output of which can be calculated beforehand with sufficiently high accuracy. For obtaining a black-body model with the preset metrological characteristics, the procedures for optimization of the emitting cavities geometric parameters are worked out depending on the emissive properties of materials and required working temperatures. The main technical problem to be tackled when elaborating the black-body model is to ensure isothermal characteristics of its emitting cavity. In this case, when the temperature rises, the non- uniformity of heating reduces as a rule.
Lev V. Vlasov,
N. A. Ibragimov,
A. O. Pominov,
"Standard infra-red sources", Proc. SPIE 2161, CIS Selected Papers: Photometry, (31 December 1993); doi: 10.1117/12.166357; https://doi.org/10.1117/12.166357