What are some radioactive elements used in smoke detectors?

Most commonly used radioactive material in the smoke detectors is Americium 241. Most of the detectors being operated on ionization principle, they need a radioactive material. Am-241 is used in smoke detectors because it is a strong alpha particle emitter. read more

Ionization smoke detectors contain radioactive material, and photoelectric types do not. Most modern ionization smoke detectors use the synthetic radioisotope americium-241 in small sealed sources to ionize the air in the sense chamber. Soviet smoke detectors in the RID family often used plutonium (reactor plutonium, predominantly Pu-239) instead. read more