We have calculated, to first order, the apparent emissivity of the bounding diffuse surfaces of a high-emissivity cylindrical–spherical cavity enclosure. Our calculations indicate that to achieve emissivities close to a perfectly absorbing blackbody cavity along the bounding surfaces of the spherical enclosure, the radius of the sphere must be equal to or greater than a factor of 4 times the cylinder radius Rs≥4Rc. Furthermore, to achieve emissivities approaching a blackbody cavity along the lower bounding surfaces of the cylindrical enclosure, the length of the cylinder must be a factor of 4 times greater than the radius of the cylinder L≥ 4Rc. In addition, we present the mathematical framework necessary to calculate radiant transfer within a cavity enclosure that contains obscuration. These results can be applied to the design of high-emissivity blackbody calibration cavities and to the reduction of stray light in terrestrial and spaceborne optical systems.
© 2004 Optical Society of America
(120.5630) Instrumentation, measurement, and metrology : Radiometry
(120.5700) Instrumentation, measurement, and metrology : Reflection
(120.6810) Instrumentation, measurement, and metrology : Thermal effects
(160.4670) Materials : Optical materials
(220.4830) Optical design and fabrication : Systems design
Steven R. Meier, Richard I. Joseph, and Spiro K. Antiochos, "Radiation characteristics of a high-emissivity cylindricalspherical cavity with obscuration," J. Opt. Soc. Am. A 21, 104-112 (2004)