American nuclear scientist · 1915–2010
Albert Ghiorso
Albert Ghiorso is credited with more element discoveries than anyone who has ever lived. Over three decades at Berkeley he helped add 11 heavy elements to the periodic table, from americium in 1944 to seaborgium in 1974, without ever taking a doctorate.
- Elements credited
- 11
- Discoveries
- 1944–1974
- Co-discoverers
- 11
- Where
- United States; Russia and United States
Discovery timeline
1944 · United States
Americium is a radioactive, silvery metal found in nearly every household smoke detector.
1944 · United States
Curium is a hard, dense, radioactive metal that glows red-purple in the dark.
1949 · United States
Berkelium is a radioactive metal made only in tiny amounts in high-flux nuclear reactors.
1950 · United States
Californium is a radioactive metal and an intense neutron source. It is one of the most expensive materials ever made.
1952 · United States
Einsteinium is a radioactive metal first found in the debris of the first hydrogen bomb test.
1952 · United States
Fermium is a radioactive metal also discovered in the debris of the Ivy Mike hydrogen bomb test.
1955 · United States
Mendelevium is a synthetic radioactive element named after the father of the periodic table.
1961 · United States
Lawrencium is the last actinide, a synthetic element made by bombarding californium with boron ions.
1964 · Russia and United States
Rutherfordium is the first transactinide element. It behaves like a heavier version of hafnium.
1968 · Russia and United States
Dubnium is a synthetic, radioactive transition metal studied a few atoms at a time.
1974 · United States
Seaborgium is a synthetic, radioactive transition metal and a heavier relative of tungsten.
The discoveries
Ghiorso was the instrument man. Heavy elements are made a few atoms at a time and vanish within seconds or minutes, so finding them depends on detecting their radioactive decay faster and more precisely than anyone else. He designed the counters, pulse analysers and fast transfer systems that made those signals readable.
His first discoveries came with Glenn Seaborg’s group during the Second World War: americium and curium, both identified in 1944. After the war came berkelium and californium, made in the Berkeley cyclotron, and then einsteinium and fermium, which turned up unexpectedly in debris from the first hydrogen bomb test in 1952.
In 1955 his team made mendelevium from a sample of einsteinium so small it was invisible, and identified the new element from just 17 atoms, the first element discovered one atom at a time. Lawrencium followed in 1961. Rutherfordium and dubnium were claimed by both Berkeley and the Soviet lab at Dubna, and the credit is officially shared. His final discovery, seaborgium, was named for his longtime colleague.
Life and career
Ghiorso was born in Vallejo, California, and grew up in Alameda. He studied electrical engineering at the University of California, Berkeley, graduating in 1937, and spent his early career building radiation detectors for the military and for the Radiation Laboratory.
Seaborg brought him to the wartime Metallurgical Laboratory in Chicago, part of the Manhattan Project, and the two worked together for more than fifty years. Ghiorso stayed at the Lawrence Berkeley Laboratory for the rest of his career and kept designing equipment, including a heavy-ion accelerator, the SuperHILAC, into his retirement.
Also known for
- Credited with 11 elements, a record
- Built the detectors used to identify single atoms of new elements
- Never earned a PhD, yet received several honorary doctorates
Legacy
Every element from 95 to 106 except nobelium, which went to Dubna, carries his fingerprints. No element is named after him, though his colleagues once floated the idea, and the techniques he developed are still the foundation of how superheavy elements are found today.