Trapping and storing frigid antimatter.When electron meets positron positron: see antiparticle. positron Subatomic particle having the same mass as an electron but with an electric charge of +1 (an electron has a charge of −1). It constitutes the antiparticle (see antimatter) of an electron. , the two particles promptly annihilate an·ni·hi·late v. an·ni·hi·lat·ed, an·ni·hi·lat·ing, an·ni·hi·lates v.tr. 1. a. To destroy completely: The naval force was annihilated during the attack. each other, disappearing in a puff of radiation. So trapping and storing positrons--the positively charged, antimatter antimatter: see antiparticle. antimatter Substance composed of elementary particles having the mass and electric charge of ordinary matter (such as electrons and protons) but for which the charge and related magnetic properties are opposite in sign. counterparts of electrons--in the midst of ordinary matter is a delicate operation. Now, researchers have developed a convenient technique for capturing and chilling positrons in an environment suited to the production of antiatoms. This achievement represents a key step toward creating antihydrogen an·ti·hy·dro·gen n. The antimatter equivalent of hydrogen. antihydrogen The antimatter that corresponds to hydrogen. , which consists of a positron orbiting a negatively charged antiproton an·ti·pro·ton n. The antiparticle of the proton. antiproton The antiparticle that corresponds to the proton. Noun 1. nucleus. Physicists Gerald Gabrielse, L.H. Haarsma, and K. Abdullah of Harvard University describe their method in a paper to be published in Physical Review Letters Physical Review Letters is one of the most prestigious journals in physics.[1] Since 1958, it has been published by the American Physical Society as an outgrowth of The Physical Review. . The researchers use radioactive sodium-22 as a source of high-energy positrons. Guided by strong magnetic fields, a fraction of these positrons strikes a tungsten crystal, which slows down the particles (see diagram). Rebounding from the crystal, some of these slow-moving positrons enter a trap created by a web of electric and magnetic fields. This trap confines the particles to a small volume, which is as free as possible of stray atoms. Gabrielse and his coworkers have stored up to 35,000 positrons in this high-vacuum environment at a temperature of 4.2 kelvins. The researchers have already developed a similar apparatus for trapping and cooling antiprotons. To create antihydrogen, they need to increase the number of trapped positrons by a factor of at least 10, then bring together the laggard positrons and antiprotons so they can snare each other. |
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