Americium-242

Americium-242m is one of the isotopes of americium, with 95 protons and electrons and 147 neutrons and a mass of 242.0595492 g/mol. It is one of the rare cases, like tantalum-180m, where a higher-energy nuclear isomer is more stable than the lower-energy one, Americium-242. Am is fissile (because it has an odd number of neutrons) and has a low critical mass, comparable to that of plutonium-239. It has a very high cross section for fission, and i... more

Americium-242m is one of the isotopes of americium, with 95 protons and electrons and 147 neutrons and a mass of 242.0595492 g/mol. It is one of the rare cases, like tantalum-180m, where a higher-energy nuclear isomer is more stable than the lower-energy one, Americium-242. Am is fissile (because it has an odd number of neutrons) and has a low critical mass, comparable to that of plutonium-239. It has a very high cross section for fission, and if in a nuclear reactor is destroyed relatively quickly. Another report claims that Am has a much lower critical mass, can sustain a chain reaction even as a thin film, and could be used for a novel type of nuclear rocket. less