Elements 113 and 115 discovered
TWO SUPER heavy elements, element 113 and element 115, have been discovered by scientists. The team observed atomic decay patterns, or chains, that confirm the existence of these two elements.
In these decay chains, element 113 is produced via the alpha decay of element 115. The observations were made in experiments conducted at the JINR (Joint Institute for Nuclear Research in Russia ) U400 cyclotron with the Dubna gas-filled separator between July 14 and Aug. 10, 2003. Scientists from the Glenn T. Seaborg Institute and the Chemical Biology and Nuclear Science Division at Lawrence Livermore National Lab, worked in collaboration with researchers from the JINR. The results have been published in Physical Review C.
In the experiments, through fusion reaction of calcium-48 nuclei impinging on an amercium-243 target, four atoms each of element 115 and element 113 were produced. The discovery is of interest to chemists as the team observed three similar decay chains consisting of five consecutive alpha decays that combined took less than 30 seconds and terminated in a spontaneous fission of an element 105 (dubnium) isotope with a long half-life (16 hours).
Also observed was an interesting fourth decay chain that consisted of decays that were unlike the previous three chains.
Joshua Patin, Livermore's data analyst on the team, said the three similar decay patterns were a "positive identifier that something good had been seen as the long decay chains just do not happen that often." "This just opens up the horizon on the periodic table," said Ken Moody, Livermore's team leader. "It allows us to expand the fundamental principles of chemistry."
In order to obtain an intense calcium-48 beam, an efficient accelerator is needed. The results have only been achieved to date on the JINR's U400 cyclotron. While Livermore supplied the americium target, associates at JINR's ion-source group produced the intense calcium beams.
``Twenty years ago, no one would have ever thought that this was possible because the technology to produce such an element just wasn't there," Patin said.
"But with the efficiency of the Russian cyclotron and the ability to run the experiments for long periods of time, we were able to achieve this tremendous accomplishment." "This is quite a breakthrough for science," said Chemistry and Materials Science Associate Director Tomas Diaz de la Rubia.
"We've discovered two new elements that provide insight into the makeup of the universe. "For our scientists to find two more pieces of the puzzle is a testament to the strength and value of the science and technology at this Laboratory." — Our Bureau
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