50
THE SHORTER-TERM BIOLOGICAL HAZARDS OF A FALLOUT FIBLD
THEORETICAL CALCULATIONS OF THE GAMMA
RADIATION SPECTRUM, ETC.
Figure 15 represents a typical small-yield
bomb.
The theoretical data represented by
the “X” ’s conform amazingly well to the
measured doses, symbolized by the circles.
In the case represented by Figure 16 a very
lowyield device wasfired, and the bomb parameters were such that the relative contribution
of nitrogen capture gammas was small.
For contrast, Figure 17 pertains to a case
wherein nuclear parameters predicted an unusually significant nitrogen capture contribu-
tion and a total gamma dose per KTof yield
D = 2000 yda,
Fler)
Fieure 12.—Initial gamma differential dose spectrum at $,000 yards.
pudding is in the eating.’ It would be desirable
to have field measurements to support these
predictions.
Unfortunately, very little experi-
mental work has been conducted to determine
the spectrum of initial gamma radiation,
except for some general and non-definitive
conclusions to be drawn from absorption and
depth-dose measurements.
Although some
field data based on photon-activated reactions
of high energy threshold do attest to the
presence of at least some very energetic gamma
rays from nuclear detonations, it is difficult
to check definitively the conclusions derived
from the transport theory approach. However,
one can compare theeretical predictions of
total air dose with the well documented film
badge gamma dose-versus-distance data from
weapons field tests in order to determine in a
general wayif the calculated spectra yield dose
information that is consistent with the field
data.
Then, by inference, the spectral informa-
tion leading to the total dose calculations
would also be validated,
COMPARISON OFINITIAL GAMMARADIA.
TION CALCULATIONS WITH FIELD TEST
DATA
Figure
14
presents
the
air
doso-versus-
distance curve for the representative bomb
configuration discussed before.
The compo-
nentsof total dose dueto fission product gammas
and to nitrogen capture gammas are indicated
separately, The composite dose is then de~
termined by adding these. For actual test
nuclear devices, with known bomb parameters,
specifie dose-versus-distance predictions can
be made by the methods that have been dis~
cussed. These can then be corrected by con-~
ventional techniques to the appropriate atmospheric densities and compared with measured
field data.
Still
the calculated points are acceptably close to
the measured data.
1 O * 1000 yda
great interest, but “. .. the proof of the
51
Elifev.)
Fieurs 13.— Initial gamma integral dose spectra.