10
1.3
REFECUS
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Superficial Doses ot Radiation
From Beta and Soft Gamma
Radiattor
Trere Can Beno deutt thar the closes of ride
tion to the surfice ad the trst few mu limerer-
of the body were sulstantidhy ligher ‘han one
mid-line dose of gamina radiation as a cesuls of
physical consigerations of gamma energy une
depth dose
dh add nen. the cleneal rbser va
tions of the skin lesions pee Chap
I]t) force
fully demonstrated hat the dose to che «Ki
varied considerably between or dividuals ini
over the surface of say given individ:
Awill become evirlent 1 the following discussion
of surface dose it
~ sious Chat any
NENbeL -
presented are at best omnis estinuites and rere
sent an approx mation fosome minimal waite
In areas where leSTOTIS WETE SeYeTe TUE clase
must have been agrateanthy higher thar pasos
damaged areas
To arrive at some pnysi ol estimate
of ove
skin dose. an a tempo must oe made te add wp
the contributions of the high energy gaminia
the very soft gamma. cnd the higher energy ber.
radiation from he iarge planar souree on whie ,
the individual ere of NeCPSSITV eXIsting
However, as al uded to above aud emphasize!
in Chapter [I] the irgest component afk
irradiation resulted trem: the spotty oear de
posits of fallout tareria. on exposed surface-
of the body. Tue dose from: deposited maters
is Impossible te estinvate
rowepVel. that. fron
the large pianur source may be rougnis est
mated as follows
The beta dose rite ii ar 3 feet above thy
surface of an infin.te plane contaminated so
mixed 24 hour old fission produets vs estitniates
17°
NG RADIATION
he expected tobe 3 (16) (0.6) or about < times
he aic-line dose, if both are taken at 2 feet off
hie Srenna
Such a depth dose measurement
te
Moire Lo.with all data as percent of the 3 centineter dose With the diverging initial radiatan from the point of explosion, the exit dose
wis seen to be 65 percent of the 3 cm. dose, but
sith the ditfuse residual field of fission products
rrosiding a semi-infinite planar source, a sur-
face dove some 8 times greater than the 3 em. and
lepper tose from the harder gamma components
was observed. This is seen to be of the same
rder ef magnitude as that estimated above.
\t heights above and belowthe 3 foot level this
-urface dose would become lower and higher
respect vely. but since it is due to soft radiation
‘f shor? range, it probably would not exceed 50
‘imes the 3 foot air gammadose or 80 times the
iid ine close, even in contact with the ground.
\n estimate of skin dose due to ground contami-
nation for the Ronyelap case would result, for
example. ia figure of about 2.000 rep at the
eve of the dorsum of the foot, 600 rep at the hip
eve ard 300 rep at the head /f continuous exposure with no xhielding occurred.
This portion in turn os estimated tone bat
cent of the yamma close measured inary
mnstrument
phantom
Poaus te cose at (he surfiee
expo-ed
radiation from ou
|
EXP
CTASIOT
te
¢
Unknown
sartitien > dose undoubtedly resulted. from
Jueida g@ and movement. [t thus seems probitie that the external beta dose from local direct
hin contamination far outweighed that from
he zroand in importance, since the latter was
or high enough to produce the observed lesions.
‘othing probably reduced the beta dose from
hegroimd by 10 to 20 percent.
1.44
to be about thre» tine: the total aor CAND LL ast
The mid dine gimme dose os approxiniaters +
percent of the vir ose remaming after exe tad
ing that portion of the cose below st 7
~ on ftiet peen made experimentally at a previ-
wis est using a plantom man exposed to both
he mirial and residual radiation (5).
The
teptli doses for each situation are shown in
Summary
Raparon Doses from gamma rays originating
externa dy were calculated for the 267 individuik
the were avendentally exposed to fallout
“allowrig the nuelear detonation at che Pactfie
Prone Crround in the Spring of 1954.
The
oredr
ose estimations were made ustng information
cxterad. olane soup oe ny
eta from radiological safety surveys on