they are bad
alpha radiation
It is used in smoke detectors as it cannot travel far in air. Alpha radiation is emitted and as long as the detector in the device is receiving the alpha radiation, then no smoke is present. When smoke particles are present, they interrupt the radiation, and so the detector doesn't pick up the radiation, causing the alarm to go off.
Alpha radiation is emitted from the amercium button in a smoke detector. When smoke goes into the smoke detector it blocks the stream of alpha particles emitted from the americium. That triggers an alarm.
It can be used for smoke detectors
Americium-241 this is an emitter of alpha radiation, which is used in smoke detectors as it is very ionising and will not be able to travel through smoke. Therefore, in a fire the detector will not receive any alpha radiation and hence the alarm will go off.
The commonest use of alpha particles is probably in smoke detectors. The americium in the smoke detectors emits alpha particles. If smoke is present, it stops the alpha particles more efficiently than air, creating ions in the detection area of the device. The ions make the air more conductive, and the conductivity is sensed by the detector, which sets of the alarm. Alpha particles are also used in the radioisotope thermoelectric generators that power pacemakers and space probes.
Most smoke alarms use Americium-241 to detect smoke and hot air, thus triggering the alarm. Some gamma radiation is emitted by the smoke alarm but all the alpha radiation is blocked by the black box. Living for a year within 1 metre of a smoke alarm would give you a radiation dose of 1.5 millimeters per year, which is about 1/1000th of the radiation that we receive normally. If you held a smoke alarm in your hand then you would get a significant dose, but you're not going to do that are you? The Americium is chosen because of it's very high melting point (it's designed to work in a fire). Even in a house fire, the material will not melt and would not be a health hazard. But there are some safety things to remember - Never hold a smoke alarm in your hand to long - Never attempt to disassemble the radioactive elements housing or damage it as will release radiation still capable of causing a health hazard
Alpha radiation is used for people's smoke detectors.
There are two types of smoke detectors:Photoelectric Smoke detectorsIonizing Smoke DetectorsIonization smoke detectors are more commonly used. The smoke detector uses an ionization chamber and a source of ionizing radiation to detect smoke.Alpha particles are emitted from from the chamber, which ionize the air, so that the air conducts electricity and a small current flows.If smoke enters the alarm, it absorbs the alpha particles causing the current to reduce, and the alarm sounds.Generally, smoke detectors use a weak source made of Americium-241 (241Am95).Note: Alpha particles are the nuclei of a Helium Atom (4He2).
Alpha is used because it rarely effects our bodies from the outside. This is because it only travels approximately 5cm. Beta and Gamma are more dangerous as they can travel through your skin.
we use alpha radiation to know whether smoke has been let off in the school at home so if it has we can run out without being inflicted with pain
Alpha particles are useful in smoke detectors because they are easily absorbed by smoke particles. When this happens, the flow of electrical current between the electrodes, said flow being comprised of alpha particles, is reduced and causes the alarm to activate.