added to the Hardtack schedule in June 1958.
Because of its nature and
possible tactical interest, three new Program 2 projects were created and
an existingGla@.extended in order to document the nuclear effects.
Three
projects of Program 34 (Projects 34.8, 34.9, and 34.10) were placed under
{ technical direction of Program 2.
Quince
These are discussed in Sec. 2.4.
As a result, the Fig event was added
to ‘the schedule ‘and detonated on August 18, 1958.
The yield was
Project 1.4, Crater Measurements, measured the size of the crater
produced by the:**"~
There were no project personnel in
the EPG, as only a contractor survey was required.
It was found that the
crater produced was elliptical in shape, with the long axis roughly corres~
ponding to that of the device.
measured from lip to lip.
lip above grade.
The diameters were —
The depth was
respectively,
below grade with a
At the time of measurement, D + 3 days, there was evi-
dence of earth slides which resulted from severe rains that had occurred
since the detonation. The crater was briefly observed on D + 1 day, prior
to the slides. Based upon this observation and the measurements made a
day later, it is estimated that the original crater was
deeper and
:
smaller in diameter from lip to lip immediately following the detonation.
The objectives of Project 1.7, Overpressure Measurements, were to
document the overpressure measurements resulting from a:
and verify or extend existing scaling laws. The instrumentation consisted of 36 standard PT and Q gages containing pressure capsules located
at ranges from 40 to 700 ft fram ground zero. As the yield of the device
was uncertain, it was necessary to provide the above instrumentation to accomodate a wide range of pressures.
The Fig device produced a nuclear yield of
‘as measured by
radiochemistry. Twenty-eight of the 36 instruments provided good records.
Some failures were experienced due to undetermined causes at the close-in
ranges. It is felt that these could be the result of heavy ground shock and
motion, which in some instances shattered the glass recording discs. Pressures recorded varied from
The points plotted against curves scaled up from
and down
high explosive
of nuclear yield showed a reasonably close fit.
There
was, however, a minor deviation in the slope of the recorded curve which
cannot be explained without further study of the records and investigation of
possible sources of experimental error due to the closeness of the instruments to the detonation. Preliminary field analysis of the data indicates
that, using existing scaling laws, pressures can be predicted for
detonations with reasonable accuracy.
Neutron flux measurements made by Project 2.4 were discussed in
some detail in the Program 2 portion of this report. During the field phase
of the operation, project participation was extended to include the Quince and
Fig events and had as its objective the documenting of the neutron flux and
spectra for the
Two neutron lines were established to obtain the desired data. One was in the direction of the extended long axis of
the device and ran out to a distance of 1039 yd, and the other was perpendicular to the device's long axis and extended for a distance of 900 yd.
38