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There are two long-lived alpha-emitters; 243 Am has a half-life of 7,370 years and is the most stable isotope, and 241 Am has a half-life of 432.2 years. The most stable nuclear isomer is 242m1 Am; it has a long half-life of 141 years. The half-lives of other isotopes and isomers range from 0.64 microseconds for 245m1 Am to 50.8 hours for 240 ...
This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds. [1]
Americium-243 has a mass of 243.06138 g/mol and a half-life of 7,370 years, the longest lasting of all americium isotopes. It is formed in the nuclear fuel cycle by neutron capture on plutonium-242 followed by beta decay . [ 15 ]
With its half-life of 432.2 years, the americium in a smoke detector decreases and includes about 3% neptunium after 19 years, and about 5% after 32 years. The amount of americium in a typical new smoke detector is 0.29 micrograms (4.5 × 10 −6 grains) (about 1/3000 the weight of a small grain of sand) with an activity of 1 microcurie (37 kBq ...
3.1 abundance, half-life trace, synthetic, stable by keyboard code 3.2 decay mode ( β − β − ) by keyboard code 3.3 percentage abundance, decay mode formatting
Spectral lines of americium: Other properties; Natural occurrence: synthetic: Crystal structure ... half-life (t 1/2) mode product; 241 Am: synth: 432.2 y:
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At least 3,300 nuclides have been experimentally characterized [1] (see List of radioactive nuclides by half-life for the nuclides with decay half-lives less than one hour). A nuclide is defined conventionally as an experimentally examined bound collection of protons and neutrons that either is stable or has an observed decay mode .