1124-1125 / 2239
More about transport along a line…
l
i
L
Factorization of attenuation:
3
1
2
e e
e e e ...
e
i
i
i
i
i
a
a
a
a
a
aL
i
L
−
−
−
− −
−
=
∑
=
=
=
∑
∏
l
l
l
l
l
l
Transport of radiant energy along line:
e
a
R R
− ⋅
=
l
21
Net energy release from a step
l
i
(“collapsed” solid angle
∆
Ω,
kernel=
A
e
-
a
l
:
(
)
(
)
2
attenuation
0
from point
energy release
of release
per length
to exit at
e
d
1 e
i
i
i
i
a
a
i
i
i
i
i
A
A
R T
T
a
a
∆
ρ ∆Ω
ρ ∆Ω
′
− ⋅
−
− ⋅
′
′
= ⋅ ⋅
⋅
= ⋅ ⋅
⋅
−
∫
l
l l
l
l
l
l
14243
142443
1
i
i
i
−
Local dose absorption:
1
2
i
i
i
R R
D a
−
+
≈
i
R
∆
+