Americium-241

<p>Americium-241 (241Am, Am-241) is an <a href="/facts/Isotope_of_americium/aqoWt39B">isotope of americium</a>. Like all isotopes of americium, it is <a href="/facts/Radioactive/Ya6FVjt4">radioactive</a>, with a <a href="/facts/Half-life/kGVH8BAB">half-life</a> of 432.2 years. 241Am is the most common <a href="/facts/Isotope/KD9B1y6o">isotope</a> of <a href="/facts/Americium/rxL9Yc64">americium</a> as well as the most prevalent isotope of americium in <a href="/facts/Nuclear_waste/MjYh5tlu">nuclear waste</a>. It is commonly found in ionization type <a href="/facts/Smoke_detector/WX5HPBPV">smoke detectors</a> and is a potential fuel for long-lifetime <a href="/facts/Radioisotope_thermoelectric_generators/Tsjjvp5h">radioisotope thermoelectric generators</a> (RTGs). Its common parent nuclides are <a href="/facts/Beta_decay/vxTBlckp">β−</a> from 241Pu, <a href="/facts/Electron_capture/EIccoV1u">EC</a> from 241Cm, and <a href="/facts/Alpha_decay/rCsHNIUE">α</a> from 245Bk. 241Am is not <a href="/facts/Fissile/XJR9qoxW">fissile</a>, but is <a href="/facts/Fissionable/XJR9qoxW">fissionable</a>, and the <a href="/facts/Critical_mass/wRAnE21M">critical mass</a> of a bare sphere is 57.6–75.6 kilograms (127.0–166.7 lb) and a sphere diameter of 19–21 centimetres (7.5–8.3 in). Americium-241 has a <a href="/facts/Specific_activity/KIv7s4N4">specific activity</a> of 3.43 <a href="/facts/Curie_(unit)/LeS60aVv">Ci</a>/<a href="/facts/Gram/sRSW5RJb">g</a> (126.91 <a href="/facts/Becquerel/4C3yrsqp">GBq</a>/g). It is commonly found in the form of <a href="/facts/Americium_dioxide/8jrEHRKM">americium-241 dioxide</a> (241AmO2). This isotope also has one <a href="/facts/Nuclear_isomer/L8DHcqnk">meta state</a>, 241mAm, with an excitation energy of 2.2 <a href="/facts/Electronvolt/YMT1fqX9">MeV</a> (0.35 <a href="/facts/Joule/9ndq9jD2">pJ</a>) and a <a href="/facts/Half-life/kGVH8BAB">half-life</a> of 1.23 μs. The presence of 241Am in <a href="/facts/Plutonium/4bUw9zH3">plutonium</a> is determined by the original concentration of <a href="/facts/Plutonium-241/vUyJGFrs">plutonium-241</a> and the sample age. Because of the low penetration of alpha radiation, americium-241 only poses a health risk when ingested or inhaled. Older samples of plutonium containing 241Pu contain a buildup of 241Am. Chemical removal of americium-241 from reworked plutonium (e.g., during reworking of <a href="/facts/Plutonium_pit/8HGl80tM">plutonium pits</a>) may be required in some cases.
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Americium-241 open-in-new

Americium-241