Dose 2016
Derivation of formalism to convert ionisation in plastic to dose to water Derivation of depth scaling factor
Depth scaling, from exponential attenuation law, for a monoenergetic photon beam and when Compton interactions dominates :
(
)
ρµ
z
e − Φ=Φ
s s
(
)
in solid phantom
ρµ
z
e − Φ=Φ
ww
s
o
in water
w
o
µ
( ) s ρ
(
) cm in z
s
s
=
µ
∝ = z
z z
z
w
s
w s
we s
depth scaling factor
µ
w
s
(
)
(
) 2 cmg in z
ρµ
µ
=
=
z ∝
( ) s ρ
s
z z
z
(
)
w
s
s
we s
ρµ
ρ
w
w
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