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in with the atomic clouds Na
ya question will be raised as to whether
such a large quantity of sand does in reality get mixed in with the mushrooa
of an atonic cloud or are the calculations off by a large factor, In order to
answer this question’ a study was made of the crater volumes of the different
‘:
tower shots,
According: to Reines of Los Alamos the Trinity Crater had a measured
volume of 1.3 x 10°
cu, ft. which represents a displacement of approximately.
1 x 1012 ga of sand (110,000 tons ofsoil),
~
The Trinity. bomb was 20KT and it-
was exploded from a 100. ft. tower; therefore, it would de ‘reasonable to assune|
that approximately 254 of, the Hl hour.total bomb activity, could ‘have been |
deposited on the’ ground as fall-out within 100 niles: of “ground zero. From
Equation 7 it can be shownthat undersuch 4n assumption nearly 5.25 x 1010 ga
of soil were mixed into the nushroom of the Trinity cloud. Since the crater
displacement is greater than the calculated amount of soil mixed into the aushroom of the atomic cloud the calculated’ values are seen to be reasonable,
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De Relation Between Sand ang Rain Scavenging |me a Cy wt 7
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. ‘Kecording to Gauvin andagai (ny ordinary raind 0. 15 ‘inchesfour as
a liquid water content ‘of 0.2 gn/m» and the record rain in the U. S. had 4 ea.
of water per cubic meter ofair,
It will be assumed that 0.15 inches/hr of yi:
rain has a velocityof. from 500 to 600 cm/sec and the raindrop diameters are ‘5, ~
from 500 to 1000 microns. , Under these circumstances’ ordinary rain would produce =
from 50 to 400 raindrops per cubic meterof air. The number of’"sand particles i>
_in each cuble aeter of airduring §fall-out may be Biven.by!“thefollowing relations
wah
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8“derined previously,“gadWhere.at“Us'sassun
that the radioactive”particles”start” their fall at’ approximately_6. 5 miles
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Table vI indicates the‘umber of radioactive‘sand ‘particles per cubic. meter of =
air for the areas bounded by the given infinity dose lines, If.the sand particles
are considered equivalent to rain drops, then ordinary.‘rain.“would occur in the: -..
areas bounded by 0.5 r to 2 r infinitydose‘lines; moderate, to, heavy _rain would-..
occur in the areas ‘bounded by the 5 r to_ lor lines; and the. areas bounded by3:-
20 r to 50 r lines ‘would receive. ‘recordamounts of rain“as that from a cloud * ~ 7
burst.
But it wasshown earlier that the radioactive. sand “particles are approxi--
mately 125 microns in diameter.
According to Figure 7of Anderson's report (5).
particles (raindrops)| with diameters of| 500 to “1000 microns. have approximately ;
two to four ‘times the’ collection efficiency of ‘particles."whosediameters are‘; ‘—
125 microns, However, _ since the fireball envelopes the”“sand particles and sub=— 2
sequently these ‘particles aresucked up into the young cloud and rise with it- *to maximum height before they begin to fall, it is only fair to assune that the
collection efficiencyof.the sand particles must be somewhat greater than that
.
indicated by simply considering their size. It will be assumed that the effi-._
clency_ of. collection of rain Grops is twice that, for 125micron sand particles neo
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