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Groves made good on his
timetable when he scheduled a meeting of the Military Policy Committee
on November 12 and a meeting of the S-1 Executive Committee on
November 14. The scientists at each of the institutions doing
isotope separation research knew these meetings would determine the
separation method to be used in the bomb project; therefore, the keen
competition among the institutions added to the sense of urgency
created by the war.
Berkeley remained a hotbed
of activity as Lawrence and his staff pushed the electromagnetic
method into the lead. The S-1 Executive Committee even toyed
with the idea of placing all its money on Lawrence but was dissuaded
by Conant.
Throughout the summer and
fall, Lawrence refined his new 184-inch magnet and huge cyclotron to
produce "calutrons", as the tanks were called in honor of
the University of California, capable of reliable beam resolution and
containing improved collectors for trapping the enriched uranium
235. The S-1 Executive Committee visited Berkeley on September
13 and subsequently recommended building both a pilot plant and a
large section of a full-scale plant in Tennessee.
The centrifuge being
developed by Jesse Beams at the University of Virginia was the big
loser in the November meetings. Westinghouse had been unable to
overcome problems with its model centrifuge. Parts failed with
discouraging regularity due to severe vibrations during trial runs;
consequently, a pilot plant and subsequent production stages appeared
impractical in the near future. Conant had already concluded
that the centrifuge was likely to be dropped when he reported to Bush
on October 26. The meetings on November 12 and 14 confirmed his
analysis.
Gaseous diffusion held some
promise and remained a live option, although the Dunning group at
Columbia had not yet produced any uranium 235 by the November
meetings. The major problem continued to be the barrier; nickel
was the leading candidate for barrier material, but there was serious
doubt as to whether a reliable nickel barrier could be ready in
sufficient quantity by the end of the war.
While the centrifuge was
cancelled and gaseous diffusion received mixed reviews, optimism
prevailed among the pile proponents at the Metallurgical Laboratory in
Chicago. Shortages of uranium and graphite delayed construction
of the Stagg Field pile (CP-1; Chicago Pile Number One), but this
frustration was tempered by calculations indicating that a completed
pile would indeed produce a chain reaction. With Enrico Fermi's
move to the Met Lab in April (from Columbia), all pile research was
now being conducted at Chicago as Compton had planned, and Fermi and
his team anticipated a successful experiment by the end of the
year.
Further optimism stemmed
from Glenn Seaborg's inventive work with plutonium, particularly his
investigation on plutonium's oxidation states that seemed to provide a
way to chemically separate plutonium from the irradiated uranium to be
produced in the pile. In August, Seaborg's team produced a
microscopic sample of pure plutonium, a major chemical achievement and
one fully justifying further work on the pile.
The only dark cloud in the
Chicago sky was the scientists' disappointment when they learned that
construction and operation of the production facilities (including the
semi-works), now to be built near the Clinch River in Tennessee at
Site X, would be turned over to a private firm (du Pont). A
second experimental pile (CP-2) would be built in the Argonne Forest
Preserve just outside Chicago, but the Metallurgical Laboratory
scientists would have to cede their claim to pile technology to an
organization experienced enough to take the process into construction
and operation.
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