Note 1 to entry: Photon cylindrical irradiance is sometimes also defined as the arithmetic mean of the vertical photon irradiance, E_p,v, at a point

${\displaystyle E_{\text{p}\text{,c}}=\frac{1}{\text{2}\pi }{\displaystyle \underset{0}{\overset{2\pi }{\int }}{E}_{\text{p}\text{,v}}\text{d}\phi }}$

where E_p,v is the vertical photon irradiance for an area element with its normal in the direction φ, and φ is the angle in the plane perpendicular to the axis of the cylinder.

Note 2 to entry: The corresponding radiometric quantity is "cylindrical irradiance". The corresponding photometric quantity is "cylindrical illuminance".

Note 3 to entry: The photon cylindrical irradiance is expressed in second to the power minus one per square metre (s⁻¹·m⁻²).