On the trail of element 110.

On the trail of element 110

The heaviest element that exists naturally on earth is uranium, atomic number 92. Since the 1940s, physicists have tried to manufacture heavier and heavier elements in their laboratories. Part of this is curiosity about the structure of such elements; part is the hope of finding things that might last long enough to be useful. All elements heavier than uranium that have been found so far are subject to radioactive decay, but there is a strong hope that somewhere above element 110 there is a range of stable or relatively stable elements.

Confirmed discoveries of transuranic elements now go as far as element 109. Recently physicists from the Dubna laboratory in the Soviet Union reported a possible finding of element 110. However, Dubna does not have the facilities for confirming such a discovery to the satisfaction of physicists generally. The confirmation comes by observing the decay of the supposed element 110 into a lighter element with emission of an alpha particle. Then the lighter element decays to something still lighter, and so on until the chain reaches a stable nucleus. The spectrum of alpha particles emitted during this chain of decay should uniquely identify element 110.

The Gesellschaft fur Schwerionenforschung (GSI) in Darmstadt, West Germany, has the facilities for observing such alpha spectra, and, according to Paul Kienle of GSI, the Dubna report prompted GSI experimenters to start attempts to confirm element 110. At the time of the American Physical Society meeting the experiments were still in progress, and Kienle could give no results.