German nuclear physicist · born 1944
Sigurd Hofmann
Sigurd Hofmann led the GSI experiments in Darmstadt that discovered elements 110, 111 and 112, darmstadtium, roentgenium and copernicium, in the 1990s.
- Elements credited
- 3
- Discoveries
- 1994–1996
- Co-discoverers
- 2
- Where
- Germany
Discovery timeline
1994 · Germany
Darmstadtium is a synthetic, radioactive element expected to be a heavy relative of platinum.
1994 · Germany
Roentgenium is a synthetic element predicted to be a heavier relative of gold.
1996 · Germany
Copernicium is a synthetic element in the same group as zinc, cadmium and mercury. It may be a volatile liquid or gas.
The discoveries
After hassium in 1984 the GSI lab spent a decade upgrading its accelerator and detectors, because the chance of making each heavier element dropped about tenfold. Under Hofmann’s leadership the team found darmstadtium in November 1994 by firing nickel at lead, and roentgenium a month later using nickel on bismuth.
Copernicium followed in February 1996 from zinc fired at lead, after weeks of beam time produced a single atom. Each was identified through its decay chain into known nuclei.
Life and career
Hofmann was born in Bohemia and studied physics in Darmstadt. He joined GSI in the 1970s and worked on the SHIP separator for the rest of his career, becoming head of the superheavy element group.
He also discovered proton radioactivity from the ground state of a nucleus in 1981, a rare decay mode that had been predicted but never seen.
Also known for
- Discovery of ground-state proton radioactivity