The Australian physicist who first observed fusion of hydrogen isotopes in 1934 at the Cavendish Laboratory — the experiment that proved light nuclei could fuse and release energy.
ReviewedLast reviewed: 9 Aug 2026·Category: Scientists & Pioneers
Life and Career
Sir Marcus (Mark) Laurence Elwin Oliphant (8 October 1901 – 14 July 2000) was born in Adelaide, South Australia. He studied physics at the University of Adelaide and earned his Ph.D. at the Cavendish Laboratory, Cambridge, under Ernest Rutherford (1929). He later held professorships at the University of Birmingham (1937–1950) and the Australian National University (1950–1967), and served as Governor of South Australia (1971–1976).[1]
Discovery of Fusion Reactions
1934 experiments: Using accelerated deuterium nuclei from a particle accelerator, Oliphant bombarded deuterium and lithium targets and observed three nuclear reactions: D + D → 3He + n, D + D → T + p, and the production of tritium (which he identified as the mass-3 hydrogen isotope). He also discovered helium-3 as a stable isotope. These were the first observations of nuclear fusion reactions on Earth.
The 1934 results were published in the Proceedings of the Royal Society with Rutherford and Paul Harteck as co-authors.[2]
Later Work
At Birmingham, Oliphant developed the cavity magnetron concept (later crucial for radar) and designed a proton synchrotron. During World War II he contributed to the Manhattan Project. After the war, he became a vocal advocate for peaceful uses of atomic energy and opposed nuclear weapons.[3]
Legacy
Oliphant’s 1934 experiments provided the direct experimental proof that light nuclei can fuse — the physical basis for all fusion energy research. He died in Canberra on 14 July 2000 at age 98.[1]
Sources
Cockburn, S. and Ellyard, D. Oliphant: The Life and Times of Sir Mark Oliphant. Axiom Books, 1981.
Oliphant, M.L.E., Harteck, P., and Rutherford, E. "Transmutation Effects Observed with Heavy Hydrogen." Proceedings of the Royal Society A, 144(853), 692–703, 1934.
"Sir Mark Oliphant." Australian Academy of Science biographical memoir.