# Fluence

The quotient of [math]dN[/math] by [math]da[/math], where [math]dN[/math] is the number of particles incident on a sphere of cross-sectional area [math]da[/math], thus:

[math]\Phi = \frac{dN}{da}[/math]

The unit of fluence is ^{m-2}.

(Adapted from ICRP Publication 116, 2010)

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### from ICRP Publication 103, 2007; ICRP Publication 110, 2008; ICRP Publication 119, 2012

The quotient of [math]dN[/math] by [math]da[/math], where [math]dN[/math] is the number of particles incident on a small sphere of cross-sectional area [math]da[/math], thus:

[math]\Phi = \frac{dN}{da}[/math]