Tuesday, March 22, 2022

History discovery of plutonium

Plutonium was first synthetically produced in December 1940 at the University of California at Berkeley, California, by Glenn Seaborg, Arthur Wahl, Joseph Kennedy, and Edwin McMillan. They produced it by bombarding uranium-238 with deuterium nuclei (α-particles) in the 60-inch cyclotron of the Berkeley Radiation Laboratory at the University of California, Berkeley, but the discovery was kept secret. The element was named after the then planet Pluto.

This first produced neptunium-238 with a half-life of two days, and this decayed by beta emission to form element 94 (plutonium). Within a couple of months element 94 had been conclusively identified and its basic chemistry shown to be like that of uranium.

The researchers submitted news of the discovery and the proposed name and symbol to the journal Physical Review but withdrew it when it became apparent plutonium could be used for an atomic bomb. This experiment wasn't shared with the rest of the scientific community until 1946, after World War II.

Early research on plutonium was carried out secretly at the University of Chicago’s Metallurgical Laboratory. A trace quantity of plutonium was isolated and measured for the first time on August 20, 1942. During this time, the nuclear properties of plutonium-239 were also studied.

To begin with, the amounts of plutonium produced were invisible to the eye, but by August 1942 there was enough to see and weigh, albeit only 3 millionths of a gram. In October 1943, construction began on a revolutionary plutonium production reactor in Hanford, WA. The B Reactor, as it came to known, was completed in March 1945 and began producing plutonium for the implosion-type atomic bomb.

Plutonium is used in both nuclear reactors and nuclear weapons. By 1945 the Americans had several kilograms, and enough plutonium to make three atomic bombs, one of which exploded over Nagasaki in August 1945.

Plutonium-238 was used on the Apollo-14 lunar flight in 1971 to power seismic devices and other equipment left on the Moon, and it was also the power supply of the two Voyager supercraft launched in 1977.
History discovery of plutonium

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