CHAPTER 3
i
INSTRUMENTS
From the beginning it was thought that the fall-out from Mike shot would consist of both
solid and liquid radioactive samples. The solid particulate samples were expected to come
from the destruction of the shot island, and the liquid samples were expected to consist of rain
and any lagoon water blown into the air by the explosion, Therefore instruments were especially designed to collect either type of fall-out.
Furthermore, because of the limitations imposed by the geography of Eniwetok Atoll, the
instruments had to be adaptable to both land and sea stations for a 360° coverage to be made
around the shot island.
3.1
DESIGN CRITERIA
The instrument designs were based on specific collecting requirements and limited by
certain mechanical and electrical restrictions. Estimates of the problems posed by the action
of the bomb and effects arising from environment in which the instruments were to be used
were also considered in establishing the criteria for instrument design.
3.1.1
Collecting Requirements
The instruments were designed to meet the following collecting requirements:
1. To collect solid or liquid fall-out segregated with respect to time of arrival.
2. To collect total fall-out.
3. To collect particles for their size measurements.
3.1.2
Mechanical and Electrical Restrictions
The mechanical and electrical restrictions that were imposed on the design of the equipment required that it be simple to manufacture, utilizing commercial products wherever possible. It was to be light and easy to service in the field. Furthermore the equipment was to
operate simply and positively under all rigorous conditions of field use,
3.1.3
Pressure and Thermal Effects Expected from the Bomb Burst
The problems posed by the bomb burst primarily involved designing the equipmentto with-
stand the estimated pressures and heat produced when the bomb was detonated, In general, the
equipment was designed or shielded to withstand at least a pressure of 7 psig, which pressure
was estimated to occur about 5 miles from ground zero for a 5-Mt bomb, The estimated ther mal effects were from 25 to 50 cal/sq cm for this same distance, and*the equipment was designed to withstand at least the lower value for short exposure. Considerable time was spent
in testing materials for their thermal resistance properties.
18
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