Uses of Alpha Radiation
Alpha radiation has a very short range – only a few cm in air. It is easily stopped by any obstruction, and all the energy is absorbed by it's immediate surroundings.
Because it has a very short range and is easily stopped, it is suitable for use in smoke detectors. The smoke particles reduce the amount of radiation reaching the detector. When the detector senses that the amount of radiation reaching it has fallen, the alarm is triggered.
Alpha radiation has another, more sinister use. When the Russian government wishes to assassinate someone, they may send one of their agents along to have a meal with the victim. When the victim is not looking, the assassin might sprinkle a substance containing a short lived source of alpha radiation on their food. Once eaten, the alpha source decays, emitting radiation which is totally absorbed by the body because the range of alpha radiation is so short. The victim experiences radiation sickness, followed often by death.