the quotient of df by dt where df is the increment of particle fluence in the time interval dt:
Fluence can be defined as the total number of particles (typically Gamma Ray Photons ) crossing over a sphere of unit cross section which surrounds a Point Source of Ionising Radiation . The Fluence rate is the number of particles crossing per unit time (which is numerically equal to the product of number of particles and their average speed). Thi....