The original measurements were extremely simple as only the total
mixed fission product beta activity was required,
These data gave in-
formation on the arrival of fallout and to some extent on the relative fallout contribution at different locations,
In the first network of 10 stations set up for the United States in
the spring of 1951, the collector was a metal tray having an area of about
<A layer of water was maintained in the tray and every twenty-
se
9 square feet,
four hours the contents were filtered to obtain the particulate activity. The
water, including any rainfall, was collected in a polyethylene bottle.
These
samples were prepared for beta counting and measured with Geiger tubes against
Radium D+E standards,
For the fall 1951 tests the network was expanded to 61 stations and
20 of these had gummed paper samplers as well as trays.
These stations were
operated for the Atomic Energy Commission by the U. S. Weather Bureau,
The
gummed papers were forwarded to the Health and Safety Laboratory for ashing
The results on these stations were reported by the Health and
ben neneg
and counting.
Safety Laboratory in 1952, (2)
The network in the United States for the spring 1952 tests included
109 deposition stations with gummed paper samplers.
The data were reported
in 1953 by Eisenbud and Harley, (3)
During the fall 1952 Pacific tests the network consisted of 51 gummed
paper stations in the continental United States and 60 elsewhere in North
America and overseas.
All later samplings were with a gummed acetate film
instead of gummed paper which gave a smaller amount of ash,
In the spring
1953 Nevada series, 96 U.S, stations and 29 others were in operation, and
rea
re
in the spring 1954 Pacific series, the network was 39 U. S. stations plus