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SUMMARY
The Problem
This is the sixth in a series of reports devoted to the study of
radioactive fallout particles originating from the detonations of
nuclear weapons in various types of physical environment. The fallout
particles described Lere were collected following a tower shot in
Operation REDWING, at the Eniwetok Proving Grounds.
As in previous
fallout particle studies, the chemical composition and structure of the
particles and the distribution of radioactivity within them was desired
Findings
The chemical compositions and structures of the particles were
determined by studying thin sections of the particles under the petrographic microscope. The distribution of radioactivity within the
particles was found by making radioautographs of the thin sections.
Determinations of the chemical compositions were also made by X-ray
diffraction analysis.
Three types of radioactive fallout particles were found. The most
common type was composed of radioactive dicalcium ferrite surrounding
an inner core of altered calcium oxide. These particles were formed
by the interaction of the iron dnd radioactive elements condensing in
the cooling fireball with drops of melted calcium oxide derived from
the coral sand which was carried up into the fireball by atmospheric
turbulence. <A second type consisted wholly of radioactive iron oxide
and was formed by the melting but incomplete vaporization of the steel.
tower with subsequent oxidation of the liquid iron drops. The third
type consisted of unmelted coral sand grains with small, black, radioactive spheres adhering to their surfaces. The small, black spheres
were presumably formed by the direct condensation of vaporized material
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in the fireball.
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