What type of radiation does carbon dating use
The energy source for this device was a rod of plutonium-238 weighing approximately 2.5 kilograms and providing a thermal power of approximately 1250W.
Plutonium-238 is a non-fissile isotope of plutonium that decays by alpha particle emission with essentially zero associated gamma emissions.
Some smoke detectors contain a small amount of Americium-241, an alpha emitter (and low energy gamma emitter) with a half life of 460 years.
It consists of an ionisation chamber linked to a simple electronic alarm circuit The Americium ionises the air between the plates, causing a current to flow.
As the rate of radioactive decay of any particular isotope is known, the age of a specimen can be worked out from the ratio of the remaining isotope and its decay product.
Electrical circuitry is then set up to ensure that a constant rate is maintained.