The isotope of element 110 which was discovered has an atomic mass number of 269 (i.e. 269 times heavier than hydrogen), thereby making it the heaviest man-made atom ever produced. Chemically, the element 110 is a heavy brother of the elements nickel, palladium, and platinum. Unlike these lighter atoms, element 110 decays after a small fraction of a thousandth of a second into lighter elements by emitting alpha-particles which are the nuclei of helium atoms.
The new element was produced by fusing a nickel and a lead atom together. This was achieved by accelerating the nickel atoms to a high energy in the heavy ion accelerator UNILAC at GSI. This rare reaction occurs only at a very specific velocity of the nickel projectile. Over a period of many days, many billion billion nickel atoms must be shot at a lead target in order to produce and identify a single atom of element 110. The atoms produced in the nickel-lead collisions are selected by a velocity filter and then captured in a detector system which measures their decay. The energy of the emitted helium nuclei serves to identify the atom.
The element 110 is the fourth element discovered at GSI. Between 1981 and 1984 the elements Nielsbohrium (107), Hassium (108), and Meitnerium (109) were produced and identified there. By discovering the element 110, the scientists at GSI have succeeded in a yet another spectacular experiment which opens the way to even heavier elements.
Reference:
Production and Decay of (269)110;
S.Hofmann, V.Ninov, F.P.Heßberger, P.Armbruster, H.Folger,
G.Münzenberg, H.J.Schött
Gesellschaft für Schwerionenforschung, D-64220 Darmstadt, Germany
A.G.Popeko, A.V.Yeremin, A.N.Andreyev
Flerov Laboratory of Nuclear Reactions, JINR, 141 980 Dubna, Russia
S.Saro, R.Janik
Department of Nuclear Physics, Comenius University, SK-84215 Bratislava,Slovakia
M.Leino
Department of Physics, University of Jyväskylä, SF-40100 Jyväskylä, Finland
To be published in Zeitschrift für Physik, December 1994
Dr. Günter Siegert GSI, WD Stab Postfach 11 05 52 D-64220 Darmstadt Germany Telefon: ++4961513592598 E-Mail G.Siegert@gsi.de