OPERATION HARDTACK I -
DATE:
TIME:
PPG Time
6 May 1998
0615
Cactus
GMT
Sponsor:
5 May 1958
1815
SITE:
TOTAL YIELD: 18 kt
LASL
PPG - Eniwetok - Yvonne
11° 33' 23" N
162° 21' 15" E
Site elevation:
FIREBALL DATA:
Time to lst minimum:
12 msec
Time to 2nd maximum:
130 msec
Radius at 2nd maximum:
656 ft
HEIGHT OF BURST:
Sea level
3 ft
TYPE OF BURST AND PLACEMENT:
Surface burst - Platform on
coral soil
CRATER DATA:
Diameter:
Depth:
Lip Height:
Lip Width:
340 ft
34.5 ft
CLOUD TOP HEIGHT:
19,000 ft MSL
CLOUD BOTTOM HeIGie:
NM
8 to 14 ft
115
to 170 ft
REMARKS:
Only individual island dose rates are available.
These were obtained
from helicopter surveys at H+4 hours made by the Radiological Safety
organization.
The helicopter survey technique called for the pilot
either to land the aircraft at the desired spot, so that a ground
reading could be obtained, or to make a slow pass over the desired
spot at an elevation of 25 feet.
Readings taken at 25 feet were
multiplied by a factor of © in order to obtain a reasonable approximation of the true ground reading.
The basic instrument used in
the aerial surveys was the AN/PDR- 39 survey meter modified to read
up to 500 r/hr.
The t-!+? decay approximation was used to extrapolate
the H+ hour dose-rate readings to H+l hour.
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