5.4.1
Shot
1
Fourteen, ‘diffe-ertinl fallout collecters were recovered from
‘the lend ard lagoon sta‘ions after Shot 1.
Of these, eight cd sannled |
properly end the data therefrom sre presented in Anpendix C (Figs. C-°
- throuch C16). Of the 40 sampling increments, Samples 10 and 1), 20
and 21, and 30 and 31 were collected over the same time interval (see
points A »B, and C of Figs. C-° throurh C-16.) ith perfect sampling
these increments would collect identiesl amounts of fallout and the
reduced data could then be used t9 determine not only the period of
fallout ut also the rate of errival,
However, es indicated from
inererent groups A,B, and C, the levels of activity varied by as much aan order of mepnitude. This variation was undoubtedly the result of
samnling small amounts of meterial over a small area ror short time
intervals. This deficiency does not affect the usefulness of the i‘trument in performing its primery function of determining the time of
arrival tut it does exnvlain the orratic nature of the curves. Relative
counts of each increment were mede vith a gamma scintillation counter
under fixed geometry.
The leve2 of activity as indicated in Figs. C-9
ooN
through C-16 should not be construed as indicative of the rate of arrival
of fallout material.
Several differential fallout collectors that failed to trigger
were analyzed to determine the “ield backrreund of the collecting increments, Figure C-17 shows the fenerel] level of contamination found in
a non-orerating sampler located at station 251.09 that was exposed to
fallout.
Table 5.6 tabuletes time of arrival period and time of cessation of fallout within the 3ikini Atoll area. Data collected from Project 2,2 and Project 2.5a time-intensity recorder traces are also presented.
TAsLE 5.6 - Time of Arrival |of Fallout
Station
Arrival
(min)
250.05
Differential Collector
250,22
Differential Collector .0+35
251.04
Differential Collector
251.06
Differential Collector
; 250.06
;
Time of 7
Sampler
| 250.24
251.05
251.10
251.03
' Dog
jOboe
Differential Collector | O+# 25
=
Differential Collector
{|
Differential Collector!
|
0 + 20
, Period
: (min)
0+ 25
!
0+ 230 .:
0+35
0+ 25
:
125
115
60
125
|
Differential Collector
0+ 40
.
ye Intensity Recorder), C #15
{a)proj. 2.2
<o+*15
Proj. 2.2
<0 + 15
|
|
(a) See Neference 2 for an account of this project
69
80
90
70
50
-
-
-
Time of
j/ Cessation
(min)
O + 145
0 + 140
Or
O+
95
95
0 + 155
O + 125
O+
O+
-
-
-
95
90