82
O'BRIEN, LOWDER, AND SOLON
10
9
8r—
X%
BERNSTEIN, WEISS ANO
KUPER (REF 8)
7
© GOLDSTEIN AND WILKINS (REF 4)
an
APPROXIMATE CALCULATIONS
6r—
x
3—
ye
i Tht
T
_f-(t) NORMALIZED TO 4 MEAN FREE PATHS
4-—
L- MEAN - FREE PATHS
Lge
4
ft
§
|
i
6
t
7
|}
8B
bt
9
WOW
|
HW
ft
2
tt
132
tf
4
Hb
16
Fic. 4, Comparison of theoretical and experimental buildupfactors for 0.28-Meyv
photons on H,.O
Asthis equation is rather difficult to solve exactly except for simple boundaries,
we introduce another approximation. Let us expand Eq. (2) binomially, terminating it at n terms, where nis the largest integer less than 6 + 2. This approximation is, of course, exact when @ is integral. A partial solution for Eq. (9) is then
10
(10)
f=-
Eu. ,
pu:
0
l
ip
fr adsin be ' & At’ |?
0
ste
4a
2
vp!
iy