r elution column of
actinide elements Seaborg remained at the University of California, Berkeley, for post-doctoral research. He followed
Frederick Soddy's work investigating
isotopes and contributed to the discovery of more than 100 isotopes of elements. Using one of Lawrence's advanced cyclotrons,
John Livingood, Fred Fairbrother, and Seaborg created a new isotope of iron,
iron-59 in 1937. Iron-59 was useful in the studies of the
hemoglobin in human blood. In 1938, Livingood and Seaborg collaborated (as they did for five years) to create an important isotope of
iodine,
iodine-131, which is still used to treat
thyroid disease. (Many years later, it was credited with prolonging the life of Seaborg's mother.) As a result of these and other contributions, Seaborg is regarded as a pioneer in nuclear medicine and is one of its most prolific discoverers of isotopes. In 1939 he became an instructor in chemistry at Berkeley, was promoted to assistant professor in 1941 and professor in 1945. University of California, Berkeley, physicist
Edwin McMillan led a team that discovered element 93, which he named
neptunium in 1940. In November, he was persuaded to leave Berkeley temporarily to assist with urgent research in
radar technology. Since Seaborg and his colleagues had perfected McMillan's oxidation-reduction technique for isolating neptunium, he asked McMillan for permission to continue the research and search for element 94. McMillan agreed to the collaboration. Seaborg first reported
alpha decay proportionate to only a fraction of the element 93 under observation. The first hypothesis for this
alpha particle accumulation was contamination by uranium, which produces alpha-decay particles; analysis of alpha-decay particles ruled this out. Seaborg then postulated that a distinct alpha-producing element was being formed from element 93. Thus, on March 28, 1941, Seaborg, physicist
Emilio Segrè and Berkeley chemist
Joseph W. Kennedy were able to show that
plutonium (then known only as element 94) was
fissile, an important distinction that was crucial to the decisions made in directing
Manhattan Project research. In 1966, Room 307 of
Gilman Hall on the campus at the Berkeley, where Seaborg did his work, was declared a US
National Historic Landmark. In addition to plutonium, he is credited as a lead discoverer of
americium,
curium, and
berkelium, and as a co-discoverer of
californium,
einsteinium,
fermium,
mendelevium,
nobelium and
seaborgium, the first element named after a living person. He shared the
Nobel Prize in Chemistry in 1951 with
Edwin McMillan for "their discoveries in the chemistry of the first transuranium elements." ==Scientific contributions during the Manhattan Project==