largely with fall-out and included utilization of several newly deveioped collection and record-
ing devices.
Total dose was measured with film badges on both shots, many badge stations being es-
tablished on radial lines extending from bomb zero. Close-in intensity vs time (one tenmillionth of a second time resolution) was measured with phosphor-photocell —oscilloscopecamera combinations for the first few seconds. More distant intensity vs time measurements
(a few seconds time resolution) were made with ionization-chamber-recorder combinations.
Fall-out samples were collected over both land and water at selected points ranging from a
few to several hundred miles from bomb zero.
On Mike Shot nearly all the film-badge stations were destroyed. Meager data will be extracted from those more than 4500 yd from zero, however. High time-resolution intensity records were obtained in sufficient quantity to indicate the pronounced effect of the shock wave
and to measure the time between the two fission phases of the device. Lower time-resolution
intensity records were obtained on seven islands of Eniwetok Atol!. Thus far no such data have
been recovered from the off-atoll stations, although fall-out has been recorded on Kusaie and
Ujelang Atolls. Usable fall-out samples (some of them as a function of time) were collected on
the islands of Eniwetok Atoll, on rafts within the lagoon, on buoy-type sea stations, and at
other atolls. It is expected that an analysis of these samples and the ionization-chamberrecorder data will definitely augment the understanding of the over-all fall-out hazard problem,
particularly because of the time dependence of portions of the data,
On King Shot the film-badge stations out to 1200 yd were destroyed, apparently by a large
block of concrete which rolled down the line, wrecking both {ilm-badge and neutron-detector
stations. The remainder of the badges were recovered and are undergoing analysis. Usable,
intensity vs time data were obtained with both slow and fast time resolution. It is interesting
to note that the peak radiation level on Runit (2000 yd from zero) was 5000 r/hr 5 sec after ©
zero and had dropped to Y, r/hr approximately 1 min later. No significant fall-out was recorded
on any other {sland of the atoll, and none had been reported at any off-atoll station at the time
of writing. Samples were obtained from 24 fall-out collector stations on islands of the atoll.
These samples exhibited extremely low activity, however, indicating very slight to no fall-out.
2.6 PROGRAM 6, BLAST MEASUREMENTS
This program was designed to study the characteristics of the Mike and King blast waves;
their propagation through air, water, and earth; and their transient effects on those media. In
particular, data were sought to document the following:
1, Pressure vs time as a function of distance from zero at the surface.
2. Material velocity behind the shock front at known positions in space.
3. Shock wind, afterwind, and sound velocity before, during, and after blast-wave passage.
4, Water-surface motions in both deep and shallow water.
5. Subsurface earth accelerations,
6. Subsurface pressures in both deep and shallow water, including acoustic pressure
waves at great distances.
7. Air density vs time before, during, and after shock-wave passage.
8. Free-air pressure vs time at known positions in space.
The tremendous energy release associated with Mike Shot and the quasi-operational nature
of the King Shot airdrop assured that great interest would be shown in this program by both the
AEC and the DOD.
The experimental techniques utilized to obtain the above-mentioned data were too many
and too varied to allow description in a summary of this type. As an example, they included
tiny self-recording Indenter gauges and completely instrumented bomber-type aircraft.
Many usable data were obtained, every project reporting at least partial successin its
cursory report, in spite of unforeseen difficulties due to inclement weather. Sometentative
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