TABLE 5.2 - Experimental Field Decay Data
a
|
oe ere
Type of Decay
:
Slope ofDecayCurve over Period Indicated
{
2-10
|
_|Recorder, How Island-:
1.19
‘Gamma Ionization
1
‘Time-Intensity
|
_.-.(nrafter ABD)
10 - 48
48 = 480
0.815
1.52
-
1.50
Shot 1
Gamma Ionization
Task Force Rad Safe
T1B Survey
501.2
-
Exnerimental Laboratory Decay
Table 5.3 summarizes the slopes of the decay curves obtained
from samples measured in the latoratory on two instruments. Gamma decay
was measured vith a 4m gamma ionization chamber and a gamma scintilla-
tion counter. The average slope of the decay curves measured on 6 individual fallout particles with a gamma scintillaticn counter is -2.08
from 9 to 30 days and -1,50 from 39 to 60 days.
Prosect 2.6a reporteal&/
an average slope of-2.11 for measurements with a similar gamma scintillation counter on the first four shots from total collector samples over
the period 0 + 7 to 0 # 22 days, The Jecay curve slones obtained from
meesurenents on the 4r gamma ionization chamber are of more general —
interest since its response is close to that of the AN/PDR-T1B survey
meter. A comparison of Samples 1, 18, and 21 (Tebdle 5.3) shows that the
decay curves of these fallout samples have comparable slopes; however,
the liquid fraction of Sample 18 has a slope of -1.22 while the solid
fraction has a slope -1.60.
The ionization-counted gummed paper samples
from Shot 2 have ar average slope of -1.41 from 170 to 480 hr; for Shot
3 samples the slope was -1.73 from 200 to 600 hr, These slopes suggest
that the leaching of activity preferentially removed the longer lived
nuclides both in the case of Sample 18, Shot 3 and the rain- and sea~
washed gummed papers from Shots 2 and 3. It further suggests that the
gumied paper collectors lost a portion of their collected fallout from
leaching by sea spray and rain.
Tne data are consiatent with little fractionation of activity
within the sampling area.
5.2
PARTICLE SIZE
Fallout particles from the differential fallout collector were
analyzed for size distribution with respect to both time and distance.
Data are presented primarily for Shot 1 with limited data on Shot 6.
Ths amount of visible particulate collected after Shots 2, 4, and 5 was
55