nmetbeanenirene eee
z.
S
Radfation furiaz dow time was cot estizated
except
a & Ujelang
where dow tine was in excess of SCé. There the astimate is
also low becacsa no data are availabi+ for the fallout period
BOMED and NECTAR.
Fallout Arrival Tin: Applied to Asrzal Mcatitoring Sata Flight
ALE.
out arrii
imes are not seneraliy own tar tae
Tslands covered in the serial surveys. The fsx sxceptions are
those which were autocratic onitoring installations.
Cumulats
and peak radiation conputatiorns are necessaril, based for tro
mat part on estinated arrival ti:es.
thval time at Rongerik is exactly known fron
the aeeetticcociter record. For other atolls on the sare gene
mete et te
A.
eases
dertal durvey Monitoring
eral, bearing ss Rongerik frou Bikiak, the arrival tines Wtnces
arbitrarily assuned to be proportional ta the respective
from Bikini referred to Rongerik.
3
Allowance vas nade forthe the
i
3
egar 7
Por the other events, the ceak values are taken as those obsess wd
noo
on the D #2 asrial surveys unless later surveys of the Sack
indi-ated aduitiowml falloit after De 1. Inthesecases, se eesat
tlw was arbitcaril, assizd to ba 0 2 and to intans aia eee
ured on the repeat filzht were extregul.ted back oD ¢ 2. Cu a,
lative radiation valuos wore cospated asauciag t7*°°
.
peak Valuas.
For ROMEO, a21 survey values are extrapolated to R &
kk, again to
conform with the arrival at Hajuro. With the lack
of difinitive
data for the time of arrival in all remaining events, it
is assumed
to be D $ 3 as & compromise value,
B. Air Survey Background Radiation. Background: wes recorded
prior
to
atoll
mansurement while the aircraft was savers) niles from
the island. In computing atoll radiation intensities, the backgation catrumentc, aircraft contamination, skyshine, or a combinas
tion of these. It has been reasoned that the background could be
validly subtracted Crom the atoll measurement to obtein a net value
of ground intensity. Intensities were computed by this mans dur:
ing the test series.
initial rapid lateral cloud growth in the first mimtesat or ee ees
wurst. Data obtained from Task Unit-1 indicated that at # i- emt
a
the cloud diamter had grown to 335,000 feet and the rate of mo
v. usd
nad diminished to a relatively slight amount. Pesk radiation
the 4s
were computed cy extrapolating the observed intensities to
mated arrival tires.
rthern Marshall atells on widely different bearings from
Pikintthen Rongerik, hence well removed from the direct fallout
path, the intensities observed during the aerial survey on 3 thon
are the reported peak values in the results. Guzulative rast sho
womputations are based on decay assured to start from these pea:
satensities.
Eh taht BAKER. Fallout definitely occurred at Maduro
during RAYS
a
and the arrival timas vers accurately sstablisved. But
there seams no valid mathod of relating these to the arrival
of
fallout at other atolls in the southeast Marshalia, short
of « detailed analysis of the pertinent mateoroligical situatio
n. ow
ever, over Majuro, BAKER flight on Bg 2 very nearly
ceine ida! with
peak fallout there as measured by the auto +2 monitor,
Arbitrarily the peak intensities for sl] taJands covered by
that flight
tre taken as the observed intensities,
ground value (wiich varied by as mich ag an orde: of pagnitide due
ing any “re xissson) might be attributed to sources such ay navi-
oe
Late in the series, it came to our attention that significant intensities may be emitted from the ocean surface for several daya
after the burat.3 This phenomenon may be another factor in the
measured background and cannot be disessce {ited anicss an addi~
tional background measurement, such ag at a different @icvitude, is
available. For any given measurement, there existe the poasibilit
y
in one extreme that substantially the entire background ia due to
wet mate ene mm
2.
+
os dat
t
B
data.
the rord tos
diractly fra
tatensitles were cbhtainad
iret blanks occur ta Table T, data are uravailebls dus ue ine
strumat failure of incorrect calibration. Tue values listed
are toe greatest intensities rollowing @dca surste
Cumiative values are not corrected for the Slower decey
rate ci
residual contamination from previous bursts. The Neglect
of prew
wious contamination ig part tally compensated by ersion
by wind
and min, a variable factor.
ocean surface intensity.
This value would not be subtracted fro
the atoll measurement. In the other extreme, the entire value of
background aust be subtracted as was done in reporting data during
the series. In no case did the background value exceed a ground
measurement ag might hypothetically occur if currents moved
corn
taminated sea water near an uncontaminated island,
decay fro8 th
<Lj?-