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Alpha particles or alpha rays are a form of particle radiation which are highly ionizing and have low penetration. They consist of two protons and two neutrons bound together into a particle that is identical to a helium nucleus, and can be written as He2+. Alpha particles are emitted by radioactive nuclei such as uranium or radium in a process known as alpha decay. This sometimes leaves the nucleus in an excited state, with the emission of a gamma ray removing the excess energy. In contrast to beta decay, alpha decay is mediated by the strong nuclear force.
Alpha rays are easily absorbed by materials and can travel only a few centimeters in air. They can be absorbed by tissue paper or the outer layers of human skin and so are not generally dangerous to life unless the source is ingested or inhaled. If alpha radiation does enter the body, however, it is the most dangerous form of ionizing radiation. They are the most strongly ionizing, and with large enough doses can cause any or all of the symptoms of radiation poisoningRadiation poisoning also called "radiation sickness", is a form of damage to organic tissue due to excessive exposure to ionizing radiation. The term is generally used to refer to acute problems caused by a large dosage of radiation in a short period..
Most smoke detectorA smoke detector is a safety device that detects airborne smoke and issues an audible alarm, thereby alerting nearby people to the danger of fire. Most smoke detectors work either by optical detection or by ionization, but some of them use both detections contain a small amount of the alpha emitter americium-241Americium is a synthetic element in the periodic table that has the symbol Am and atomic number 95. A radioactive metallic element, americium is an actinide that was obtained by bombarding plutonium with neutrons and was the fourth transuranic element to. This isotope is extremely dangerous if inhaled or ingested, but the danger is minimal if the source is kept sealed.
Because alpha particles occur naturally, but can have energy high enough to participate in a nuclear reactionIn nuclear physics, a nuclear reaction is a process in which two nuclei or nuclear particles collide, to produce products different to the initial products. In principle a reaction can involve more than two particles colliding, but such an event is except, study of them led to much early knowledge of nuclear physicsNuclear physics is that branch of physics concerned with the nucleus of the atom. Topics include: Strong interaction Radioactivity Models of the nucleus liquid drop model shell model interacting boson model Fission Fusion Nuclear reactions Applications Nu.
In computer technology, DRAMDRAM is a type of random access memory that stores each bit of data in a separate capacitor. The amount of electric charge stored in the capacitor determines whether the bit is considered 1 or 0. As leakage causes the charge on a capacitor to decay, the i 'soft' errors was linked to alpha particles in 1978 in Intel's DRAM chips. The discovery has led to strict control of radioactive elements in the packaging and semiconductor materials, and the problem was largely considered 'solved'.
See also
- radioactivityRadioactive decay Radioactivity is the process by which unstable atomic nuclei decay. This process normally produces ionizing radiation with a relatively large amount of energy. This energy can be harnessed in the form of nuclear power, or it can be very
- beta particleBeta radiation is a form of ionizing radiation emitted by certain types of radioactive nuclei such as potassium-40. This radiation is in the form of beta (β) particles, which are high-energy electrons or positrons ejected from a nucleus in a process
- gamma ray
- cosmic rays
- nuclear physics
- radioactive isotope
- radioactive decay
