Do smoke detectors have radioactive sources in them in order for them to work?
Yes most contain a small quantity of americium-241 which emits alpha-particles. As long as these can cross the gap to the ‘detector’ in the circuitry the alarm stays off. As soon as smoke particles stop the alpha-particles reaching the detector in sufficient numbers then the alarm is triggered … usually meaning that the toast is now ready for breakfast in our house! 😉 It is radioactive, but, as the previous answerer says, you’re statistically more likely to come to harm from a house fire than from this radioactive isotope.
