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SESSION I DISCUSSION
FREILING: Is there anyone here from Stanford Research Institute
who can speak about their results? Has anyone else looked at the data
from this point of view? [No response. ]
CROCKER: It appeared to me from what Dr. Miller presented
that the roentgens per hour were less than one expects. He presented
his data so fast that I had difficulty in making sure, but it appeared to
me that his value was too low. I also find the dose rate too low for the
amount of fission products that were deposited on the ground,but I
think the effect is much greater than Dr. Miller showed.
LOYSEN: I don’t have any questions, but I would like to mention
that Mr. Wood from Litton Systems, Inc., handed me a Set of preliminary photographs just a short time ago which were taken from a highvolume impactor flight at approximately 120,000 ft last week. If there
are people who are interested in seeing these, I would be happy to show
them later on,
DREVINSKY: I would like to ask Mr. Nielsen for the estimate of
accuracy for ‘Be measurements and **Na measurements with the use
of his analyzer.
NIELSEN: For #*Na, I can give you an example of our measure-
ments: 0.36 + 0.03; in other words, about 10%. Our accuracy was limited
by the counting time chosen. If one wanted better accuracy, he would
have to count longer,
,
HEFT: I would like to ask Dr. Drevinsky about the remark he
made relative to the cerium/strontium ratios exhibiting no fractionation from altitude to altitude and from particle size to particle size.
How did the observed ratios compare to expected values? Did they
fractionate relative to the expected ratios? Was there no fractionation as a function of particle size ?
DREVINSKY: We did not attempt to date the debris found in the
size ranges studied by using activity ratios such as “*Ce/*Sr because
of the uncertainties in assigning a particle size distribution to residual,
long-lived activities such as Sr. In the two particle size ranges with
radii less than 0.15 u, the “*ce/"Sr activity ratios were close to the
production ratio of 40 except for the 21- to 30-km interval in March
and September 1962. My main point on the constancy of the M4 ce/MSy
activity ratio was that it did not vary with particle size in those size
ranges that contained most of the activity. I did not mean to indicate
that this ratio is invariant with altitude as well as with particle size
for all flights as dramatically shown for the May 1963 flight. There
are some differences. For example, the September 1962 data show a
decrease in the ratio with increasing altitude. Presumably, this is an