Americium

Americium is a radioactive chemical element with the symbol Am and the atomic number 95. In chemistry, it is placed in a group of metal elements named the actinides. Americium is a transuranic element (Transuranic means after uranium as all the elements used after uranium are man-made). Americium does not exist in nature and has to be made by people. It has a silver color. Americium is made by bombarding a plutonium target with neutrons.

It was the fourth transuranic element to be discovered. It was named for America, like Francium was named for France.^[1][2]

The longest half life of any type of americium is 7370 years.^[3]

Uses

Americium is used in ionization-type smoke detectors. The level of radioactivity is not enough to cause cancer, and it cannot get through the smoke detector's plastic case, so it is safe to live in a place where smoke detectors with americium are used. This type of smoke detector is becoming obsolete, and is being replaced by optical smoke detectors, which have fewer false alarms and don't contain radioactive material.