Dr. W. F. Libby
Fig. 5 is a curve of the compilation of data from your project in
Chicago for 1953 through 1956. I believe that it clearly shows a correlation between the CASTLE series and the tritium measurements in yain
water. I cannot convince myself that there is any other marked correlation between the data and any of the known nuclear tests including the
Soviet tests. The thing I would like to direct your attention to is the
dashed line which I believe may show a growth d tritium background from
1953 through 1956 which is more likely to have been produced by the
increased releases of tritium into the troposphere from production
operations, I believe if we were to continue to follow the curve beyond
June 1956 that the apparent increase in March through June will reveal
itself as just another perturbation in the background level of tritium more
likely caused by releases from production operations at some of the
sources indicated in Fig. 1 with Savannah River being a real contributing
source from February to June 1956.
.
Fig. 6 shows the tritium content in water vapor measured at
Butler, Pennsylvania in the spring of 1956. The red line indicating the
beginning of the REDWING series is preceded by a number of high points
of tritium activity including the point of the very day of the shot which
could not conceivably have been due to the first REDWING shot. I believe
these points were definitely associated with production operations rather
than with the tritium from nuclear tests.
Fig. 7 shows tritium in rain water at Boston. The first shot of the
REDWING series is represented by a vertical red line and again you see
substantial high values prior to the REDWING first shot. The high value
after the REDWING series got underway is not very much higher than the
peak shown in Fig. 6 which is clearly not due to REDWING. For this
reason in Fig. 7 it is not possible for us to say that the highest value for
middle of June is due uniquely either to production operations or to
REDWING debris. In Fig. 7 you will note that the high activity produced
by CASTLE in 1954 rain water at Boston diminishes very rapidly to
background levels. I consider the center of gravity of the background
data possibly indicates an increase of tritium background in the atmosphere
near Boston due to the production operations.
Fig's. 8 and 9 represent rain water and humidry meastrements in
Chitosa, Japan and Tokyo, Japan. The thing that is noteworthy here is
that the background level does not appear to be rising as significantly