How Do Smoke Alarms Use Radiation?

How is alpha radiation used in smoke alarms?

An isotope of americium which emits alpha particles is used in smoke alarms.

Alpha radiation ionises the air and this allows a small current to flow between two electrodes.

Alpha is weakly penetrating so smoke stops it, the current drops and the alarm goes off..

What radiation does americium 241 give off?

The radiation from the decay of americium-241 and its daughters is in the form of alpha particles, beta particles, and gamma rays. Alpha particles can travel only short distances and generally will not penetrate the outer layer of human skin. Gamma rays can penetrate the body.

Why is it safe to use a source of alpha radiation in a house?

An alpha source is used because alpha radiation does not penetrate very far. It is absorbed by a few cm of air. This means that as long as the detector is high up on a wall, or the ceiling, it is safe for humans to be in the same room.

Is it safe to take apart a smoke detector?

Never disassemble or take apart your smoke detector. The yearly dose of radiation from a home containing two smoke detectors can be compared to the background radiation that people receive from the earth and space.

Why do smoke detectors expire?

Smoke Alarms Eventually Expire The National Fire Protection Association recommends that you replace your smoke alarms every ten years. This is because the sensors eventually degrade in quality to the point where they’re no longer effective. Yes, that even includes your more expensive smart smoke alarms.

Does all radiation cause cancer?

Ionizing radiation includes radon, x-rays, gamma rays, and other forms of high-energy radiation. Lower-energy, non-ionizing forms of radiation, such as visible light and the energy from cell phones, have not been found to cause cancer in people.

What happens to DNA if exposed to radiation?

Ionizing radiation directly affects DNA structure by inducing DNA breaks, particularly, DSBs. Secondary effects are the generation of reactive oxygen species (ROS) that oxidize proteins and lipids, and also induce several damages to DNA, like generation of abasic sites and single strand breaks (SSB).

Are smoke alarms safe radiation?

Radiation produced during normal use of ionization smoke detectors is so low it has no noticeable effect. If the ceramic chamber containing the radioactive material is removed and swallowed, exposure is about six times the desirable yearly exposure—still too low to cause acute health effects.

Why is americium not dangerous?

Since alpha particles do not penetrate the skin and the gamma rays released from americium sources are relatively low in energy, external exposure to americium is not usually considered to be a danger to your health. The radiation from americium is the primary cause of adverse health effects from absorbed americium.

Which radiation Cannot penetrate through the skin?

Gamma rays are the most harmful external hazard. Beta particles can partially penetrate skin, causing “beta burns”. Alpha particles cannot penetrate intact skin. Gamma and x-rays can pass through a person damaging cells in their path.

Is americium man made?

Americium (chemical symbol Am) is a man-made radioactive metal that is solid under normal conditions. Americium is produced when plutonium absorbs neutrons in nuclear reactors or during nuclear weapons tests. Americium-241 is the most common form of Americium.

What type of radioactive decay is used in smoke detectors?

The common type of household smoke detector contains a small amount of Am-241, which is a decay product of plutonium-241 originating in nuclear reactors. The Am-241 emits alpha particles which ionise the air and allow a current between two electrodes.

Why is curium 242 not suitable for use inside smoke detectors?

(i) The smoke detector would not work if a radioactive source that emitted only gamma rays was used. (ii) Curium-242 is a radioactive isotope with a half-life of 160 days. It emits alpha particles.

Is americium 241 dangerous?

Americium-241 has the same general hazards as other americium isotopes: it is both extremely toxic and radioactive. Although α-particles can be stopped by a sheet of paper, there are serious health concerns for ingestion of α-emitters.

Why are smoke detectors not dangerous?

Ionization smoke detectors have a small americium source encased in a layer of foil and ceramic, which stops the alpha particles from traveling outside of the smoke detector. Because of this shielding, the smoke detector poses no radiation health risk when they are properly handled.

Which type of radiation has the greatest range in air?

Gamma and X RadiationGamma radiation or x rays are able to travel many feet in air and many inches in human tissue. … X rays are like gamma rays. … Gamma radiation and x rays are electromagnetic radiation like visible light, radiowaves, and ultraviolet light. … Dense materials are needed for shielding from gamma radiation.More items…

What is the difference between irradiation and radioactive contamination?

What is the difference between contamination and irradiation? Radioactive contamination is said to have occurred when there is direct contact with radioactive substances. Irradiation is said to have occurred when an individual is exposed to the rays from radioactive substances.