In 1994, the first atom of element 110 was detected at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany, by an international group of scientists lead by Peter Armbruster and Sigurd Hofmann. A thin lead foil target was bombarded with accelerated nickel atoms. A lead nucleus fused with a nickel nucleus to form a new nucleus of element 110, an isotope with atomic mass number of 269. After a small fraction of a thousandth of a second, it decayed into lighter elements by emitting alpha-particles which are the nuclei of helium atoms. It was known as ununnilium, symbol Uun until named in 2003 as darmstadtium, symbol Ds. In the 1980's, elements 107 (Bh), 108 (Hs), 109 (Mt) were also created there.