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More about transport along a line…
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
−
−
−
− −
−
=
=
=
=
Net energy release from a step
i
(“collapsed” solid angle
D
W,
kernel=
A
e
-
a
:
(
)
(
)
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
D
DW
DW
−
−
−
=
=
−
Transport of radiant energy along line:
1
e
i
a
i
i
R R
−
−
=
Local dose absorption:
1
2
i
i
i
R R
D a
−
+
i
R
D
+