photon spherical irradiance
photon fluence rate
mean value of photon irradiance on the outer curved surface of a very small (real or imaginary) sphere at a point in space
Note 2 to entry: The photon spherical irradiance is expressed in second to the power minus one per square metre (s−1·m−2).
Note 3 to entry: This entry was numbered 17-934 and 17-926 in CIE S 017:2011.