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° Steprinted from Science, August 22, 1958, Vol, 128, No. 3821, pages 309-402.
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Because of their mass, it is not prac
tical to present the detailed analytical
results in this article (2). This presentation, therefore, is limited to a conden-
sation of the cumulative fallout observa-
| Long-Term Fallout
tions.
by the gummed-film network of the AECis presented.
A primary technique in studying long-
range fallout is the measurement of the
rate of deposition and the cumulative
Merril Eisenbud and John H. Harley
Several papers have described the phenomena of long-range fallout and the
methods by which it is routinely moni-_
tored (1). This paper presents estimates
of strontium-90 deposition and external
gamma dose which were obtained from
the world-wide gummed film network of
deposit per unit area. For-this purpose, —
three types of samples are currently
used: soils, pots or funnels, and gumm
‘the U.S. Atomic Energy Commission
- film. -
through June 1957, Results for the continental United States and other stations
are tabulated in Table 1; results for the
worldwide network are mapped in Fig.
1. In addition, the estimates of stron-
tium-90 deposition as obtained by the
gummed-film method are compard with
measured values obtained bysampling
with open pots.
Soil samples represent the accumulated fallout at a given location, but
these samples require tedious radiochemical analyses for the determination of
specific isotopes. Moreover, soil sampling
does not permit one to estimate the external gamma‘dose delivered by the isotopes becauseof difficulty in analysis and |
uncertainty in the time of fallout,
Open samplers, such as pots or fun-
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The authors are on the staff of the Health and
Safety Laboratory, New York Operations Office,
U.S. Atomic Energy Commision.
-
Sampling and Measurement
-
A summary of measurements made through June 1957
,