 Discovery Information
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| Who: G. T. Seaborg, R. A. James, L. O. Morgan, A. Ghiorso |
| When: 1945 |
| Where: United States |
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| Name Origin
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| From America by analogy with europium. |
| "Americium" in different languages. |
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| Sources
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| Produced by bombarding plutonium with neutrons.
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| Uses
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| Americium-241 is currently used in smoke detectors. |
| The element has also been employed to gauge glass thickness to help create flat glass. |
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| History
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| Americium was first isolated by Glenn T. Seaborg, Leon O. Morgan, Ralph A. James, and Albert Ghiorso in late 1944 at the wartime Metallurgical Laboratory at the University of Chicago (now known as Argonne National Laboratory).
The team created the isotope 241Am by subjecting 239Pu to successive neutron capture reactions in a nuclear reactor. This created 240Pu and then 241Pu which in turn decayed into 241Am via beta decay.
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| The discovery of americium and curium was first announced informally on a children's quiz show in 1945.
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| Notes
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| Pure americium has a silvery and white lustre. At room temperatures it slowly tarnishes in dry air. It is more silvery than
plutonium or neptunium and apparently more malleable than neptunium or uranium. Alpha emission from 241Am is approximately three times that of radium.
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| 18 radioisotopes of americium have been characterized, with the most stable being 243Am with a half-life of 7370 years, and 241Am with a half-life of 432.2 years. All of the remaining radioactive isotopes have half-lives that are less than 51 hours, and the majority of these have half-lives that are less than 100 minutes.
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| Hazards
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| Americium is radioactive. Alpha emission from 241Am is approximately three times that of radium. Gram quantities of 241Am emit intense gamma rays which creates a serious exposure problem for anyone handling the element.
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