The finite-difference equation method is used to derive expressions for the directional-hemispherical transmittance as measured in the integrating sphere; and for the correction factor necessary with a one-port sphere to account for changes in the enclosure caused by substituting the open port (the standard device) for the sample. Expressions are also derived for the hemispherical reflectance, since this quantity is necessary to compute the correction factor. It is also shown that no correction factor is necessary with a two-port (comparative) sphere.

1 aKessel, Jeffrey uhttps://windows.lbl.gov/publications/transmittance-measurements-integrating-sphere00888nas a2200133 4500008004100000050001400041245009800055210006900153260002700222520032900249100002000578700002700598856012900625 1984 eng d aLBL-1728400aIntegrating Sphere Measurements of Directional-Hemispherical Transmittances of Window Systems0 aIntegrating Sphere Measurements of DirectionalHemispherical Tran aSt. Louis, MOc08/19843 aEquations are presented that express the directional-hemisphericalstransmittance of window systems in terms of the experimental parameterssof an integrating sphere. The construction and operation of a 2-meter diameterssphere is described. Experimental results are given for bothsconventional and novel window systems.

1 aKessel, Jeffrey1 aSelkowitz, Stephen, E. uhttps://windows.lbl.gov/publications/integrating-sphere-measurements-directional-hemispherical-transmittances-window-systems