Appendix C
ALTITUDE ABSORPTION MEASUREMENTS
DURINGPREVIOUS OPERATIONS
Aerial dose-rate measurements above contaminated
curve, except the Plumbbob gamma doserates that
areas have been abstracted from records of previous
have been related to the surface measurement.
Figures
and surveys over water containing fresh fission
C.1 and C.2 arealtitude plots for land and water, respectively. The agreement with the calculated attenuation curve is within the limits of error imposed by
altitude measurement and instrumentcalibration. A
single surface reading, i.e., 3-foot dose rate over
Site, between operations and prior to Operation Castle.
dicted from the readings at higher altitudes.
weapon tests.
These data include surveys over land
contaminated with old and with fresh fission products,
nroducts.
Table C.1 contains cita collected over land contaminated with old fission products, at the Nevada Test
TABLE C.1
.
Altitude
ft
land, usually deviates markedly from the value pre-
This isa
ALTITUDE ASSORPTION MEASUREMENTS
OVER LAND, OLD FISSION PRODUCTS
T*
pet
Absorption of Radiation
P F
°
mr/hr
pct
at
mr/hr
pet
3
100
4.3
57,128
4.3
50
50
100
—
—_—
—
—_
—
—_
2.0
1.8
40
36
200
25
0.79
22
1.0
22
400
—_
0.56
13.5
0.75
15.5
500
10
0.40
11
0.38
800
_—
0.11
4
—_—
8.2
_—
* NTS, 1951, old shot site, scintilog TH-2, normalized
from a series of ground and aircraft readings.
}~ Janet Island, Eniwetok Atoll, prior to Operation Castle,
scintameter TH-3, P2V aircraft.
{~ Janet Island, Eniwetok Atoll, prior to Operation Castle,
scintameter TH-3, helicopter.
During Operations Teapot and Plumbbob, careful
measurements were made 3 feet from the surface, in
conjunction with simultaneous aerial measurements.
Data abstracted from these surveys (Reference 12) are
included in Table C.2.
Fresh fission products in water volume were exam~
ined during Operation Wigwam (Reference 4), and the
altitude absorption measurements are contained in
Table C.3.
All data have been normalized to the theoretical
66
function of the nonhomogeneous contamination on the
small areas viewed close to the surface and the unevenness of the surface. The NTS {Table C.1, No. 1)
and Plumbbob (Table C.2, Nos. 2 and 3) data are based
on careful surface measurements, made by survey
over an extended area and averaged; and the 3-foot
value agrees with the predicted values. Measurements
over water are difficult to obtain, because a ship will
distort the radiation field. Data below 50 feet from sea
surface are not available.