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.
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.
Smoke alarms typically use photo-electric sensors or alpha-particle emitters, although the photo-electric sensors are much better for detecting smoldering fires.
Alpha radiation is used in various applications, such as smoke detectors and some types of cancer treatment, because it is highly ionizing and has a short range in tissue. This makes it effective in targeting and destroying specific cells while minimizing damage to surrounding healthy tissue.
The main difference between a photoelectric smoke alarm and an ionization smoke alarm is the way they detect smoke. Photoelectric alarms use light to detect smoke particles, while ionization alarms use radioactive particles. Photoelectric alarms are better at detecting smoldering fires, while ionization alarms are more sensitive to fast-flaming fires.
Alpha radiation: Smoke detectors use alpha radiation to detect smoke particles in the air. Beta radiation: Medical imaging techniques like positron emission tomography (PET) scans use beta radiation to create detailed images of the body's tissues and organs. Gamma radiation: X-rays and gamma rays are forms of electromagnetic radiation used in medical imaging, such as X-ray scans and radiation therapy for cancer treatment.
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
There are many types of smoke DETECTORS and self-contained smoke ALARMS. Some smoke detectors use ionizing radiation; others use photo-electric sensors. More sophisticated sensors use chemical reactions to detect specific types of smoke or to measure specific chemical composition and concentration of smoke. Photo-electric sensors are said to be more sensitive to smoldering fires (large particles) than ionizing detectors, meaning you may get an earlier warning from photo-electric.
Alpha particles are used in various applications, including smoke detectors, nuclear power generation, and as a treatment for certain types of cancer. Their relatively large mass and high ionization ability make them effective for disrupting and destroying cancer cells in targeted radiation therapy.
Correct me if I am wrong but I believe alpha rays do not exist. There are alpha particles, and gamma rays, but I do not think alpha rays exist. Alpha particles are most commonly used in smoke detectors, but have been used in the past of kill isolated areas of cancer cells.
Some other household appliances that use radiation are microwave ovens and smoke detectors. Microwaves use non-ionizing radiation to heat food quickly and efficiently. Smoke detectors use a small amount of ionizing radiation to detect smoke particles in the air and trigger an alarm.
Smoke alarms use ionisation of air by an alpha source. A small pellet of the isotope of Americium sets up a current of a few micro Amps across an air gap and this is monitored by the electronic circuit. When smoke enters the ionisation cell the current is reduced as the smoke particles neutralise the charged ions. The dip in current causes the alarm to sound.
Photoelectric smoke alarms are beneficial for fire detection and safety in homes because they are effective at detecting smoldering fires, provide early warning of potential danger, reduce false alarms from cooking smoke, and are less sensitive to dust and other particles, making them more reliable for long-term use.