Radioactive isotopes which emit alpha particles can be used in smoke detectors.Smoke detectors make use of the ionising properties of alpha particles. They contain an ionisation chamber which consists of a positive and negative electrode along with a very small amount of the radioisotope Americium-241. Americium-241 has a half life of 432 years and is a good source of alpha particles. The long half life is useful as it ensures a continuous source of alpha particles meaning the detector is very reliable and will not stop functioning. It also means the alarm does not require regular replacement; however the battery does require regular replacing and to even indicate to you it does your alarm will make a slight beeping noise.
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