where discrepancies of findings were resolved.
This center ensued from the difficulties en-
countered in resolving discrepancies of results between the various surveys of Operation Castle
months after the operation had taken place.
UC
1.3 THEORY
A large number of orgainzations have devoted much effort toward the erection of models of
the fallout processes (Reference 4), A discussion of these is outside the scope of this report.
Briefly, the models consist of certain partly rational, partly empirical assumptions of cloud
and stem dimensions and distribution of particle size and activity therein and the projection of
this distribution on the earth’s surface by the precipitation of these particles through the existing wind pattern.
It is apparent that the accumulation of fallout particles on the earth’s surface is an integrative
process and that information pertinent to the original spatial distribution of the particles is lost
to integrated measurements on this plane. Additional information can be obtained by exploring
the time sequence of the integrative process, i.e., the use of time-versus-dose-rate recorders
and incremental collectors. Such added information restricts the freedom of the model by additional terms, but not to the extent of permitting a unique determination of the original spatial
distribution.
The surface expression of the fallout is a highly empirical finding, and veracity of similitude
to other detonations in other environments cannot be assumed. Thus, the findings must be used
as a spot check upon a model, erected on this and other evidence, that is sufficiently comprehen-
sive and versatile to accomodate the introduction of very-different materials and processes.
Failing this, the findings become merely “The Distribution of Radioactivity Following Shot Dig-
ger on Pokofuaku Island of Bikini Atoll, 06:31, 21 May 1956”.
As an attack on the fallout problem, the surface data are merely supporting evidence for
more-highly embracing cogitation, except as they apply directly to the overall disposal problem
of which fallout is only a part.
Another order of empiricism is introduced by the existence of “clean weapons.” Heretofore,
with high-fission weapons, the environmental influences on total activity have been negligible,
and the factors influencing the fallout process have been only the gross physical and chemical
nature of the environment. In the case of the clean weapons, however, the total activity may be
greatly influenced by microchemical constituents of the environment and the processes to which
they are subjected. In partial confirmation of this is the predominance of Zn® in the organisms
of the Pacific following Operation Castle (Reference 5). i
—
1.4 REPORT ORGANIZATION
The overall task accomplished by Project 2.62 is actually the sum of several smaller tasks.
Each of the smaller tasks possesses a degree of completeness within itself.
Asa result, the
report is organized so that each of the chapters, from Numbers 2 through 5, is a complete report covering a specific task. Chapters 1 and 6 apply to the overall project.
Chapter 4, the report concerning deep-moored stations, is particularly detailed, because it
is felt that this method of collecting data is especially applicable to test series of this type, as
well as to other scientific and military problems.
Stations is presented in Appendix B.
The complete procedure for installing these
1.5 OCEANOGRAPHIC AND BACKGROUND RADIOACTIVITY SURVEY
Of the objectives listed in Section 1.1, the first, and part of the second, have been answered
in the Project 2.62b report (Reference 6).
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