Obituaries Australia

Mark Oliphant, by Jack Mulligan, 1962

State Library of New South Wales, 13415

Sir Mark Oliphant, who died on 14 July, founded the Research School of Physical Sciences at the ANU and was one of those who pioneered the creation in Canberra of a national university dedicated to research at the highest international level. A tall, handsome man, with a shock of white hair, and a distinctive voice and laugh, he was well informed on a wide range of scientific matters and expressed firm views on their social consequences. He enjoyed wide respect throughout the nation as a great Australian scientist.

Mark Oliphant was born in Adelaide on 8 October 1901. Always good with his hands, he supported his studies at Adelaide University by working as a cadet in the Physics Department. After completing his Honours degree, he commenced his research career by working on surface tension with Dr Roy Burdon. Oliphant's interest in modern physics was greatly stimulated by the visit to Adelaide of Ernest Rutherford, the New Zealand-born physicist who was, at that time, head of the famous Cavendish Laboratory in Cambridge. Following Rutherford's visit Oliphant obtained an 1851 Exhibition Scholarship that took him to Cambridge.

When Oliphant joined the Cavendish, the laboratory contained a number of brilliant young physicists, most of them Fellows of the Royal Society in the sight of God, and several actual or potential Nobel Prize winners, including John Cockcroft, who became Oliphant's closest friend and a future Chancellor of the ANU. Oliphant worked directly with Rutherford, building a new accelerator and carrying out fundamental work on nuclear transmutations, for which he was made a Fellow of the Royal Society in 1937. His work on nuclear reactions with the isotopes of hydrogen was particularly important and forms the basis for the production of nuclear fusion energy, still one of the Holy Grails of energy research.

Oliphant had done excellent work with Rutherford in Cambridge but wanted to run his own show and in 1937, despite Rutherford's strong objections, he accepted the Chair of Physics at Birmingham University, and began the construction of the largest cyclotron in Europe. But, as Britain prepared for war, Oliphant was one of a small number of mainly ex-Cavendish men who were informed of Britain's secret radar work. He and his group in Birmingham made an outstanding contribution to British radar research by developing the cavity magnetron, which provided a source of centimetre wavelength radiation for airborne radar.

Otto Frisch and Rudolf Peierls were physicists of German origin, working in Birmingham. Because of their status, Oliphant could not arrange for them to join in the secret radar program. But they could work on nuclear fission and the practicality of constructing an atomic bomb. Frisch and Peierls wrote a famous letter, in which they calculated that the critical mass of a fission bomb could be as little as a few pounds of separated fissile material. Oliphant recognised the importance of this conclusion and was able to introduce the Frisch-Peierls letter to senior defence science officials in Whitehall, and then in the United States. The British atomic energy group, including Oliphant's team, eventually transferred to the United States and Canada. Oliphant's skill and determination, and his friendship with the American cyclotron physicist Ernest Lawrence, were important factors in the establishment of the Manhattan Project and the development of the atomic bomb.

At the end of the war, Oliphant returned to the task of completing the Birmingham accelerators. There were also exciting opportunities offering in Canberra, where a new, national, research university was being planned. Oliphant accepted an invitation to join the group of senior academics in the UK that was providing academic advice on the new university. The advisers were eventually offered appointments as directors of planned research schools in the university. Only Oliphant accepted. He frequently repeated Howard Florey's comment at the time that all he could expect to find would be a "hole in the ground" and a mountain full of promises.

Oliphant was enthusiastic about developing a new accelerator in Canberra. He was always interested in the possibility of new designs and wanted to build machines that stretched technology to the limits. His ambition was to construct a novel machine that would operate at a higher energy than any other machine in the world but which, at the same time, could be built at a fraction of the cost. He did not like large teams and looked back nostalgically to the machines that he and research students had built in Cambridge. The Canberra machine went through a number of design changes and name changes, including the cyclo-synchrotron, the synchro-cyclotron and the proton synchrotron, but was not completed as an accelerator. An unfortunate accident, in which one person was blinded, occurred with the NaK (sodium/potassium) system of the homopolar generator, the power source for the accelerator. The generator was rebuilt using carbon brushes in place of NaK and completed as a stand-alone machine, which was used as a high-power source for a range of plasma and laser experiments.

In addition to leading the work of his own group in high-energy accelerator physics, Oliphant, as Director, expanded the work of the research school in astronomy, mathematics, geophysics, theoretical physics, atomic and molecular physics, nuclear physics and particle physics. The research school became a major centre for Australian research and postgraduate training in the physical sciences.

After he retired as Director, Oliphant returned to some of his earliest work on the interactions between positive ions and solids.

In 1971, Sir Mark Oliphant began a new career when he was appointed Governor of South Australia, a post he filled with dignity and distinction. He spoke very strongly in favour of environmental issues, especially in defence of the Adelaide Hills, and of the perils of nuclear armaments.

Sir Mark always had the loving support of his family, especially that of his gentle wife, Rosa, and his daughter, Vivian.