feted etetenetd
-10-
of U255 as depicted by Hunter and Ballou (1951).
From their Figure
1 the following approximate slopes were obtained graphically: 20-100
days, -1.2; 200-547 days, -1.8, 2-6 years, -1.3; 10-25 years, -0.7;
150-180 years,
-3.7.
Thus, the mean slope for the Eniwetok samples is slightly
steeper than that of
Hunter
period from 2 to 6 years,
and
Ballou up to 100 days; then,
in the
the Eniwetok samples tend to be at first
less steep, and toward the end of the period, steeper.
Future counting
may show whether these curves will level slightly to -0.7 as does
Hunter and Ballou's curve at about 10 years.
For the first six curves (Table 1) of pre-Mike samples involving
products of the Greenhouse tests the curves tend to be steeper than for
corresponding periods for post-Mike samples.
Contamination of post-
Mike samples by the older products from Greenhouse would tend to pro-
duce an effect in this direction, but so marked an effect is rather surprising.
In contrast to the general
tendency
of the slopes to become steeper
as
noted above for the average
after 3 years, certain
curves
a slower decay than average may be of special importance.
showing
Curve 49
for rat muscle decayed most slowly of all those studied,
with a half
life during the
In gamma
last 3
years,
of more than 30 years.
spectroscopy of this plate only Cs!37 was detected.
A listing of those