Element 95 in our International Year of the Periodic Table series is americium. Americium is used in home smoke detectors and could also be used as an alternative to plutonium in space probes in the future.
Today, microgram amounts of americium are used in home smoke detectors. The alpha radiation emitted by americium ionises air particles and compares the current generated to a sealed reference chamber. If smoke particles enter the ionisation chamber, ionised air particles attach to them and current flow is prevented, triggering the alarm.
In the future, americium may be used as a means of nuclear propulsion for spacecraft. Currently, plutonium is commonly used, but dwindling supplies mean that an alternative may be required in the near future. The European Space Agency has previously considered using americium as an alternative power source.
Remember, you can keep track of all of the previous entries in this series on the site here, or on the Royal Society of Chemistry’s dedicated page.