If our infinite plane is emitting n, gamma photons per square foot
per second at time t, and the average energy of the photons is E,, the
radiation flux incident on the element volume is,
ar
=
dadi
BE
“to
-l-:e ar
"5
> fs
mM > Ey
e -~Alar
mE,
e ““€ar
2
400
dr
Mev /ft3/sec
Then,
I
ea
=
IN,
=
JAax
Dividing by “Za
I
=
LYXz
d(ZZ,r)
This is of the forn,
I
=
Wk,
nt E,
;
J > ax =
3g
®
By (3/4)
which can be evaluated from "Tables of Sine, Cosine and Exponential Integrals,
Vol. II", Federal Works Agency, New York, 190.
The contribution from circles
of various radii is given in Appendix A.
Derivation of Dose Function
The absorption factor,Ka, is equal to 1.06 x 1073 ft.~l for the
average gamma energy of the mixed fission products.
This absorption coeffi-~
cient is for the loss of Compton electrons in air, the only significant
absorption loss.
I
=
This gives a value of 5.30 for the exponential integral.
9:30 mt Ey
we 2.65 ny B
BYi
=a
™:
tee
sR =. te
Do.
="
os
mma
on
- Paes
NAN atk, a
st
~
4
,
=
8
Sy
ke
“ey
oO
.
“
==
ee
RO
Se
Se,
S
Se Ta
Tee
~
«
%
:
nomore geneaLsmear gnaMARRSERE Se Up Ene RNETOTORRmo
Mev/ft.?/sec