all fell into the rerion vhere a 100 to 150 micron diameter sand particle
(density 2.6 gm/cm3) would fall from avproxinately the center of the mushroom
clowi. This indicates that the numerical median particle diameter of the soil j
at “Yevada Proving Grounds should be approximately 125 microns.
According to ~ u
Dr. G. Felt of J-Division, Los Alamos, the soil ‘MD at “levada Proving Grounds
ig 125 to 150 microns (Dr. Felt attributes this to the work of I. T, Alexanier.
of the Department of Agriculture) (See Reference 3).
- Felt assumes that the
NMD of: the fall-out particles during Trinity was 100 microns. The existence
of distinct maximum fall-out areas that agree so well with the Stokes! Law
relation {s remarkable.
If it is assumed that the H+l hourtotal activity
of 1 KT bomb is 3 x 108 curtes, ani that 3 x 104 curtes/ souare mile produces
a dose rate of 100 mr/hr of gamma rays at a distance of 3 ft. above the ground
then the following relation may be used?
ne
0.2y°
_eee
ew
SB
At~°*“D
eee
Where
,
ec.
~~
.
-£
.
.
;
F
a
an
.
.
ee
ee. ww
po
i.
:
.
nr)
=
vation
1] ‘ -..
-
a pS
Lette
mos
*- !7 _
2
oF
Phas
we
ORR
tot tee
mete
4
to:
P=Percentage of the total Hel.hour bomb activity deposited‘on the’.
ground by fall-out in an area bounded by a _BivenAnfinity dose Line...
D = Infinity Dose
,
- Bon
Sais
te. Se we
4 = ‘Area in square.niles tnclosed by a given. infinity dose lines.” ~
Tae
=:
tae oe BL yr.
y = Total yield, of “the‘Domb ia res we AE:
2
x
He
oY
.
+
\
S-average time of Tali-out ofradioactivity within the area. 5 pe
i The terivation of Zquation 1 is as‘follows: ones.
wD
a
7
22
Ry ‘1. -
Oe 2
“
= Rp2
: . Where° oY :
:
ee le
* aos
a.
:
:
ese rrr rt ree eee Rquatios 20
oewite
R = Dose rate in
a roontgonefie 2
ee
ft
8 roa .
a
a * .
Oe et
**
a ae 7 oo
pee
:
fee
_
t2 = Average time of ‘fall-out in area pounded by a“given infinity dose L
. is
a
line.
oF
.
tt
,
ies
:
£
i
te
’
Ss
en
se
-
Tyby
\--+-"Equation 3
|
wi TEL
.
ae a C3-5372, oo Cars
Ege
lb sg!
pth‘ene weehoes.
nee
wee we ta
+ \fé