ENERGY ABSORPTION
BUILDUP
FUNCTION
1000
@
GOLDSTEIN AND WILKINS
APPROXIMATE
0.5 Mev
(REF. 4)
CALCULATIONS
0.5 mev
‘Oo
_— 3mev
Gm
3mev
lomev
{- MEAN-FREE PATHS
20
22
24
it
26
2
)
n', p is the density of the
ar dV in units of mean free
‘tem is in spherical coordiingles respectively.
buildup function value of
> to modify this and write
; to be justified it must be
|
4
|
6
|
8
|
IiO0—s
tT
2
{
4
|
|
16 18
|
20
|
22
|
24
4
26
Fia. 2. Buildup factors for Fe.
confined to a region where du,,diy (2) being the source energy) has a regular
behavior. For this reason and because this is the region for which our experimental data are applicable, we restrict Eq. (2) to the energy region where the
material is a Compton scatterer.
Substituting Eq. (2) in Eq. (1) we get an answerin terms of the incomplete
gamma funetion:
(3)
[= PHRi
Cee f0 el + at)? dt = eM
PeE(g + 1, 1/a).
Pte