REPROOUCEDAT THE NATIONAL
ARCHIVES
“2a
Hence the increase in radiation after the "Able" shot relative to
cosmic ray background is twice that shown in the graph.
While it is felt that the effect observed after "Able"
4s real, the details of time dependence of the counting rate can-
not be taken too seriously, owing to the crudeness of the experimental technique.
The behavior of the counting rate after "Baker
follows qualitatively the cosmic ray intensity pattern observed
by Dr. Scott Forbush at the Carnegie Institution in Washington.
His lonization chamber was covered by a considerable quantity of
lead and would not be expected to respond to radiation of the
type given off by fission products.
During this period two other
Geiger counters were operated at some distance from the laboratory
by Dr. C.
P.
Baker,
His results showed the same general behavior
as that shown in the graph.
From these observations it would seem reasonable to
conclude that at a distance of 7000 miles in the direction of
the prevailing winda it was possible to detect the effects of an
atomic bomb exploded in the air, but no effect froma similar
bomb exploded under water was observed,
J. W. DeWire
October 25, 1946
INED TO BE &N
STRATIVE MARKING
5, Section 6-10
Sy paces