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A positron may be generated by positron emission radioactive decay, or the interaction of photons of energy greater than 1.022 MeV with matter. This process is called pair production, as it generates both an electron and a positron from the energy of the photon.

The existence of positron was first postulated in 1928 by Paul Dirac. In 1932, a positron was observed by Carl D. Anderson, who gave the positron its name. Interestingly, Anderson also suggested, unsuccessfully, to rename electrons to "negatron."

1 The Positron in Fiction

The most famous use of the positron in fiction was Isaac AsimovIsaac Asimov (c. January 2, 1920 April 6, 1992) was a Russian-born American author and biochemist, a highly successful and exceptionally prolific writer best known for his works of science fiction and for his science books for the lay person. He also wrot's use in his robots' Positronic brainA positronic brain is a fictional technological device, originally conceived by science fiction writer Isaac Asimov. Its role is to serve as a central computer for a robot, and, in some unspecified way, to provide it with a form of consciousness recognisas. It is likely that he chose to use positrons because they were relatively newly-discovered when he was first writing about the robots. Perhaps in an homage to Asimov, in the Star TrekStar Trek collectively refers to six science fiction television series, ten motion pictures, and hundreds of novels, video games, and other works of fiction all set within the same fictional universe created by Gene Roddenberry in the early to mid 1960s. universe, the android DataBrent Spiner as Data on Star Trek: The Next Generation Data played by Brent Spiner, is a character in the Star Trek fictional universe. He has served as the second officer and operations manager on the USS Enterprise D and USS Enterprise E. Data appeared (and his brother LoreIn the fictional Star Trek universe, Lore is the name of a prototype for the android Data, often referred to as his evil brother' and was played by the same actor: Brent Spiner. Lore was built on Omicron Theta after B-4, but before Data, by Dr. Noonien So, "daughter" Lal, and other sundry related androids) also has a Positronic Brain.

2 See also

• electron
• radioactive decay
• list of particles

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Positron emission tomographyPositron emission tomography (PET is a nuclear medicine medical imaging technique which produces a three dimensional image or map of functional processes in the body. Description A short-lived radioactive tracer isotope which decays by emitting a positron PositronA positron is the antiparticle of the electron. It is antimatter, has an electric charge of +1, a spin of 1/2, and the same mass as an electron. When a positron annihilates with an electron, their mass is converted into energy in the form of two gamma ray PositroniumPositronium is a quasi-stable system consisting of a positron and an electron bound together into an " exotic atom. Its set of energy levels is similar to that of the hydrogen atom (electron and proton). However, because of the different reduced mass, the Positronic brainA positronic brain is a fictional technological device, originally conceived by science fiction writer Isaac Asimov. Its role is to serve as a central computer for a robot, and, in some unspecified way, to provide it with a form of consciousness recognisa Positron emissionPositron emission is a type of beta decay, referred to as "beta plus" (β+). In beta plus decay, a proton is converted to a neutron via the weak nuclear force and a beta plus particle (a positron) and a neutrino are emitted. Isotopes which emit positr Positron electron annihilation reactionThe positron electron annihilation reaction refers to the physical phenomena of a positron particle (the physical opposite of an electron), generated by a beta decay and slowed to "thermal speeds", and combines/reacts with an electron. The two particles c Positron emission tomography scanner