RADIOACTIVITY VS. HEIGHT IN NUCLEAR CLOUDS
=- 100
—
i
iW
—
a, 80
=
x=
a.
7
qT
é
TT
/
—_—
oe
rc
OQ
a)
639
0 go
_
Oo
f
—
—
=
_
YO
Z 40
UY
~
a
—~
a 20 -—
PL
—
a
0
1073
=
1074
|
1073
I
107?
|
107!
I
“10°
CUMULATIVE PERCENT OF TOTAL ACTIVITY
|
10!
107
Fig. 5—Cumulative activity as a function of height in the nuclearcloud
for air bursts.
this curve may represent an overestimation of the activity in the lower
part of the stem for the larger yields (above about 200 kt).
Cumulative Activity with Height in the Nuclear Cloud for Air Bursts
With the use of the stem-activity curve in Fig. 3, an estimate of
the cumulative activity with height in the nuclear cloud was derived.
The solid portion of the curve in Fig. 5 was obtained from the stemactivity curve by using an average stem height of 40,000 ft and by as-
suming the stem-top height (or visual cloud base) to be 63% of the
cloud-top height (the average for the Dominic I series). Since the entire stem appears to contain less than 1% of the total activity, it is
obvious that the activity must increase rapidly with height at or above
the base of the cloud, The dashed portion of the curve represents a
subjective estimate (based, in part, on the Redwing data for surface
detonations) of the distribution of activity in the mushroom portion of
the cloud. The activity in the mushroom is assumed to be distributed
as follows:
Layer, % of cloud-top height
65
70
73
80
85
90
935
to
to
to
to
to
to
to
70
75
80
85
90
95
100
Fraction of total activity, %
0.6
14
295
29
15
15
a