| Abelson, who was born in Tacoma, was educated at Washington State College and at the University of California at Berkeley, where he obtained his PhD in 1939. Apart from the war years at the Naval Research Laboratory in Washington, he spent most of his career at the Carnegie Institution, Washington, serving as the director of the geophysics laboratory from 1953, and as president from 1971 to 1978. He subsequently became the editor of a number of scientific journals including the important periodical Science, which he edited from 1962 to 1985. |
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| In 1940 he assisted
Edwin McMillan
in creating the first transuranic element,
neptunium
, by bombardment of
uranium
with
neutrons
in the Berkeley cyclotron. Abelson next worked on separating the
isotopes
of
uranium
. It was clear that a nuclear explosion was possible only if sufficient quantities of the rare
isotope
uranium-235
(only 7 out of every 1000 uranium atoms) could be obtained. The method Abelson chose was that of thermal diffusion. This involved circulating
uranium
hexafluoride vapor in a narrow space between a hot and a cold pipe; the lighter
isotope
tended to accumulate nearer the hot surface. Collecting sufficient
uranium-235
involved Abelson in one of those massive research and engineering projects only possible in war time. In the Philadelphia Navy Yard, he constructed a hundred or so 48-foot (15-meter) precision- engineered pipes through which steam was pumped. From this Abelson was able to obtain
uranium
enriched to 14 U-235 atoms per 1000. |
|
| Although this was still too weak a mixture for a bomb, it was sufficiently enriched to use in other separation processes. Consequently a bigger plant, consisting of over 2000 towers, was constructed at Oak Ridge, Tennessee, and provided enriched material for the separation process from which came the fuel for the first atom bomb. |
|
| After the war Abelson extended the important work of Stanley Miller on the origin of vital biological
molecules
. He found that amino acids could be produced from a variety of gases if
carbon
,
nitrogen
,
hydrogen
, and
oxygen
were present. He was also able to show (1955) the great stability of amino acids by identifying them in 300-million-year-old fossils and later (1956) identified the presence of fatty acids in rocks. |
|