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Particle Fluence
Energy Fluence
d
A
particle
traversing
sphere
volume dV
[ ]
2
−
=Φ
m
dA
dN
N the expectation value of
the number of particles
striking a finite sphere
surrounding point P
The amount of energy ‘striking’ the sphere
Φ= = =Ψ
E
dA
dN
E
dA
dR
For a monoenergetic beam:
P
d
N
is the number of particles
incident on a infinitesimal
sphere surrounding P of cross
sectional area d
A
For a component of a polyenergetic beam:
E
E
E
dE
d
Φ=
Ψ
=Ψ
With R being the expectation value of the
total energy
(excluding rest mass energy)
or Radiant energy
carried by all particles N, energy fluence in the
quotient of this energy to the cross sectional area dA