Am241

Americium-241 (241Am) is a radioactive isotope of the element americium (atomic number 95). It has a half-life of 432.2 years and decays primarily by alpha emission to neptunium-237. The alpha decay is accompanied by a gamma emission of 59.5 keV in a small fraction of decays, which allows detection by gamma spectroscopy. The radiation consists mainly of alpha particles, which are highly ionizing but have very limited penetration in matter; shielding typically requires only light materials for external exposure, though ingestion or inhalation poses health risks.

Am-241 is not naturally abundant and is produced in nuclear reactors as a decay product of plutonium isotopes. Plutonium-241 forms via neutron capture and subsequent beta decay, and it decays to Am-241 with a half-life of about 14.3 years, making Am-241 a long-lived product of plutonium production. The isotope is then separated from spent fuel for various commercial and research uses.

The most well-known application of Americium-241 is as a small sealed source in household smoke detectors. In these devices, about 1 microcurie (approximately 37 kilobecquerels) of Am-241 provides ionization for detecting smoke. Am-241 is also used in some industrial gauging devices to measure material thickness or density and in certain laboratory instruments.

Safety and regulatory considerations are central to handling Am-241. Although external exposure is typically low due to alpha's limited penetration, ingestion or inhalation of radioactive material is hazardous. Sealed sources minimize release to the environment, and handling, transport, and disposal are governed by national and international radiation safety regulations.