Trapping stripped uranium ions.A uranium uranium (y  rā`nēəm), radioactive metallic chemical element; symbol U; at. no. 92; at. wt. 238.0289; m.p. 1,132°C;; b.p. 3,818°C;; sp. gr. 19. atom stripped of all but one of its 92 electrons
represents an extreme example of the simplest possible atomic system.
Consisting of just one electron bound to a highly charged, heavy
nucleus, such a hydrogenlike ion serves as a testing ground Noun 1. testing ground - a region resembling a laboratory inasmuch as it offers opportunities for observation and practice and experimentation; "the new nation is a testing ground for socioeconomic theories"; "Pakistan is a laboratory for studying the use of American for theories
of atomic structure.
For the first time, researchers have now managed to produce, trap, and bring to rest both hydrogenlike and bare uranium ions. Ross E. Marrs and his coworkers at the Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory: see Lawrence Berkeley National Laboratory. (body) Lawrence Livermore National Laboratory - (LLNL) A research organaisatin operated by the University of California under a contract with the US Department of Energy. in Livermore, Calif., describe their achievement in the June 27 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 used an electron-beam ion trap ion trap n. A device, such as a magnet, used to prevent ions in an electron beam from striking other apparatus. ion trap to create and capture uranium ions (SN: 11/20/93, p.324). By probing the trap's contents, they determined that the trap contained about 500 hydrogenlike and 10 fully stripped uranium ions. The ratio of bare to hydrogenlike ions provided a measure of the rate at which collisions between electrons and uranium ions can strip additional electrons from the ions. The experimentally observed rates failed to match theoretical predictions. "Our measurements suggest that the theoretical [rates] are too low," the researchers conclude. |
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