Facts about Americium-241


What is Americium-241 (AM-241) used for?

Am-241 is used in some medical diagnostic devices and in a variety of industrial and commercial devices that measure density and thickness. Tiny Am-241 sources are also present in smoke detectors.

Where does it come from?

Am-241 is a manmade metal that is produced from plutonium. Am-241 found in the environment is the result of past nuclear weapons testing.

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What form is it in?

Am-241 found in the environment is in the form of microscopic dust. Am-241 used in industrial, medical, or commercial devices is in the form of coin-sized metal or plastic discs. The Am-241 source present in a smoke detector is inside a metal cylinder that is about the size of a pencil eraser.

What does it look like?

Am-241 is a silver-white metal that is solid under normal conditions.

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How can it hurt me?

As a dust or fine powder, Am-241 can cause certain cancers. When Am-241 powder is swallowed, absorbed through a wound, or inhaled it can stay in the body for decades. Am-241 concentrates in the bones, liver, and muscles, exposing these organs to alpha particles.


Half-life: 432.2 years

Mode of decay: Alpha particles and weak gamma radiation

Chemical properties: Crystalline metal that is solid under normal conditions. Am-241 can be combined with beryllium to produce neutrons.

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