Element 95 · Actinide
Americium
Americium is the radioactive isotope inside household smoke alarms — strictly regulated for disposal.
Element Facts
SYMBOL
Am
ATOMIC NO.
95
ATOMIC WEIGHT
243
CATEGORY
Actinide
PERIOD
Period 7
GROUP
Group 3
History
Americium was first synthesised in 1944 by Glenn Seaborg, Ralph James, Leon Morgan, and Albert Ghiorso at the Metallurgical Laboratory in Chicago as part of the Manhattan Project. Named after the Americas. It was initially created secretly and only announced publicly in 1945. Seaborg revealed the discovery on a US children’s radio programme (Quiz Kids) before the scientific paper was published, to the surprise of the show’s audience.
Uses Today
Americium-241 is the ionisation source in virtually every household ionisation smoke detector — billions are in use worldwide. A tiny amount (approximately 37,000 disintegrations per second) ionises air between two electrodes; smoke particles disrupt this current, triggering the alarm. Small quantities of americium are also used in industrial thickness gauges and in medical research.
Why We Don't Buy It
Why QuickStop Metals doesn’t buy Americium:
Although americium appears in consumer smoke detectors, each device contains only about 1 microcurie (less than 1 microgram) of americium-241, far too small to extract economically. The material is classified as radioactive waste under UK regulations. Used smoke detectors should be returned to manufacturers or disposed of via council hazardous waste collection — not in general scrap.
Value & Pricing
Americium-241 is produced at approximately £1,200/gram at research facilities such as Oak Ridge National Laboratory. No commercial scrap market exists.