Discovery of einsteinium

Einsteinium was discovered in the debris from Ivy Mike, the first thermonuclear explosion, which was detonated by the United States at Enewetak Atoll in the Pacific in November 1952. Scientists at the University of California, Berkeley, including Albert Ghiorso, noticed that the radioactive material collected from the fallout contained atoms heavier than any known, produced by the capture of many neutrons in the extreme neutron flux of the explosion. The discovery was kept secret until 1955 because of its military context. The element, atomic number 99, was named after Albert Einstein, who died in 1955. Einsteinium is a soft, silvery, intensely radioactive metal that has been prepared only in tiny quantities in nuclear reactors, and it has no practical uses outside research.

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