Definition
A man-made radioactive chemical element (symbol Am, atomic number 95) used in small, sealed quantities as the ionizing source in many smoke detectors, including those installed in aircraft cabins and lavatories.
Plain English
A radioactive material used in tiny, sealed amounts inside smoke detectors to help them sense smoke. The amount used is very small and shielded, so it is safe in normal use.
Context Anchor
Seen in aircraft maintenance manuals, parts information, and labels on some aircraft smoke detectors.
Derivation
Named after America, where the element was first produced in 1944 during nuclear research. The name follows the same pattern as europium, named for Europe.
Why Pilots Care
It enables fast, reliable smoke detection that supports early fire warning and emergency procedures.
Intuition Check
Americium does not mean “American-made.” It is the name of a specific radioactive chemical element.
Example Sentence 1
The lavatory smoke detector uses a small americium source to sense smoke particles in the air.
Example Sentence 2
Smoke detectors containing americium continuously monitor the cabin for combustion particles.