C
Dr. W. F. Libby
at these Japanese stations as at Chicago, Boston, Butler and Ottawa.
Again only the CASTLE series shows up as distinct from production
operations. If the tritium we are measuring is slowly filtering down
from a stratosphereic tank then the buildup curve observed in your
data at Chicago and our data at Boston should also be observed in Japan,
and I believe that Fig's 8 and 9 show that this upward trend does not
occur at Japan and, therefore, lends some weight to the argument that
the increases observed in Chicago, Boston and Ottawa are due to
production operation increases rather than to nuclear tests filtering
from the stratosphere.
Fig.
10 is introduced to show individual peaks of activity measured
at Hawaii in water vapor and rain water during the period March though
June of the CASTLE series. Here it is noteworthy that the peaks produced by the shots rapidly decay to relatively low levels going up high
on the next shot or two and then decaying rapidly again indicating that
this tritium is in direct streaming of tropospheric air from Eniwetok
and not tritium that filters down slowly from the stratosphere. We were
interested in this data in the hope that the tritium activity might indicate
something about the thermonuclear yield of the CASTLE shots. Unfortunately, there is no correlation in our data at Hawaii between thermonuclear yield and tritium measurements,
Fig. 11 is the only data we have on atmospheric hydrogen, t should
remind you that the ordinates in this case are in tritium atoms/10!
hydrogen atom since we are dealing with the tritium atmospheric hydrogen
rather than with hydrogen in the water vapor phase. First, I would like
to point out the trend line which, Starting from 1951, could be interpreted
as indicating an increasing level of tritium activity in atmospheric hydrogen.
Second, I would like to point ait to you the three trends that are indicated
by slopes a, bandc. Tritium releases from production sources are
known to increase intensively just prior to test series such as GREENHOUSE
CASTLE,
TEAPOT and REDWING,
These known releases of tritium in
preparation for weapons tests then diffuse and decay as indicated by the
slopes {a) and (b).
However, in the case of slope (c), there appears to
have been something different happening in 1956 than in any preceding year
and we believe that this increasing tritium concentration in the spring
of 1956 is correlated with the considerable increases in Savannah River
production releases indicated in Fig. 1l{top). These increased releases
also produced corresponding increases in the tritium concentration in
water vapor tabulated in Fig. 4.
All the data that we have been able to
——
nS a
AE
monk”
5