July 18, 2000

Particle physicist who worked with the Americans on the Hiroshima bomb but later came to oppose the military use of nuclear energy

 

A great leader of science, able to inspire his students by his enthusiasm and optimistic outlook on life: Oliphant, photographed in 1997

 

SIR MARK OLIPHANT

 

Sir Mark Oliphant, AC, KBE, FRS, physicist, was born on October 8, 1901. He died on July 14 aged 98

 

One of the most distinguished members of Lord Rutherford's Cambridge school of nuclear physics, Mark Oliphant was also one of the last direct links with that golden age of elementary particle research. In those years of spectacular discoveries at Cambridge from 1933 onwards, he worked with Rutherford on the experiments which led to the discovery of the tritium isotope of hydrogen, a step fundamental to the production of special types of nuclear bombs with very high explosive yields.

Oliphant went on to design a large particle accelerator at Birmingham University, where he moved from Cambridge, and during the Second World War he made a major input into the development of centimetric radar, whose importance to the winning of the battle against the U-boats and in the bomber offensive against Germany was fundamental. Later on in the war he went to America and worked on the Manhattan Project to develop the atom bomb. But like others who were so involved, he was appalled by the devastation and loss of human life caused by the bomb when it was used against Japan. When the war was over he argued strongly against an American monopoly on nuclear technology. In a long article published in the News of the Worldon October 21, 1945, he grimly prophesied to his readers: "If war ever developed between the USA and Russia, England is bound to be obliterated whichever side she is on."

Returning to his native Australia in 1950, he directed nuclear research at the Australian National University in Canberra for the next 13 years. There he was increasingly concerned with the problems of harnessing nuclear energy for peaceful means.

Finally, in retirement from this post, he served from 1971 to 1976 as Governor of South Australia. In this office he was in the forefront of opposition to French nuclear testing in the Pacific even, at one point, declaring that he would "join any expedition to try to stop French tests or contribute to the cost of such an expedition".

Born in 1901 in Adelaide, Marcus Laurence Elwin Oliphant was educated at the University of Adelaide. After graduating in physics he came to the Cavendish Laboratory at Cambridge as an 1851 Exhibition Scholar.

In the course of research on the effects of the impact of high-speed ions on surfaces he showed consummate ability in designing and constructing high-vacuum apparatus for studying atoms. In this way he radically raised the Cavendish Laboratory's standards of techniques in this field.

During 1932, after the discovery of Cockcroft and Walton that protons accelerated by only a few thousand volts would cause the disintegration of light nuclei such as lithium and boron, Oliphant was diverted from his previous work by the enthusiastic desire of Rutherford to have a hand himself in this important new field.

Oliphant set to work to build an apparatus to accelerate still larger numbers of protons. In doing so he developed an intense source of protons which was thereupon adopted as a standard component of such accelerators. With this apparatus Oliphant and Rutherford studied in 1933 the disintegration of the lighter elements by high-speed protons.

More important experiments were made possible by the discovery of deuterium (heavy hydrogen) at about this time and by the gift to Rutherford of a small quantity of heavy water by Professor G. N. Lewis. It was now possible to use deuterium nuclei (deuterons) as projectiles, and important new transmutations were discovered.

Deuterons were shown sometimes to interact with each other to produce a new hydrogen isotope of mass number 3 - to which the name tritium was given. This led to the large-scale production of tritium and its use in nuclear weapons and for the development of thermonuclear weapons - as well as for a great deal of important biological research and in medicine.

Oliphant next set to work to design a new two million-volt accelerator for the Cavendish. But he was appointed in 1937 - the year in which he was elected FRS - to the Poynting Chair of Physics at Birmingham before this had been far developed. His first task at Birmingham was to build a new laboratory for nuclear physics and a cyclotron to produce deuterons accelerated to an energy of 20 million electron volts. This project was interrupted by the war and the cyclotron did not come into commission until 1950.

The laboratory was, however, responsible for one of the most important scientific inventions of the war - the resonator magnetron. Developed by Boot and Randall, under Oliphant's direction, it produced powers of 10 kW at a wavelength of 10 centimetres. This invention transformed radar. It made possible the development of short-wavelength apparatus which enabled narrow beams of radio waves to be produced. Transmitted in pulses of concentrated power these could seek out ships, submarines and aircraft as well as cities. This radar, installed in aircraft, played a decisive part in winning the Battle of the Atlantic; it directed the blind firing of the British warships at the battle of Cape Matapan; it guided night fighters on to the German bombers; it enabled Bomber Command for the first time to identify its targets with reasonable certainty; it helped the US Navy to intercept Japanese supply ships and, ultimately, to destroy the Japanese fleet. The sample magnetron, which was taken to the United States by the Tizard Mission in the autumn of 1940, was described by the US publication Scientists at War as the most important contribution of reverse lend lease.

In 1941 and 1943 Oliphant went on a mission to America and by his powerful personality and friendship with US scientists helped in the reopening of collaboration on nuclear energy. From 1943 until the end of the war he worked at Berkeley on the electromagnetic method for separating Uranium 235 from U238 in natural uranium for the Hiroshima bomb.

In 1946 he returned to Birmingham to build a new type of accelerator for protons, which he had conceived in 1943. Known as a proton synchrotron, it was to produce hydrogen projectiles having an energy of more than a billion electron volts.

Before its completion Oliphant was offered the post of head of the School of Physical Sciences in the Australian National University and went there in 1950. In 1954 he became the first President of the Australian Academy of Sciences, a post which he held until 1957, and he was largely responsible for its very remarkable dome-shaped building in Canberra.

During the latter part of his life Oliphant took a very active interest in the political problems arising from the use of nuclear weapons in war. He served for a time as Australian scientific representative in the United Nations Atomic Energy Commission. He delivered many speeches on the problems of control of nuclear energy. He became chairman of the Atomic Energy Committee of Australia, and worked to obtain collaboration between Australia and Britain in this difficult technological field. He was a great leader of science, able to inspire his students by his enthusiasm and optimistic outlook on the world. For many years he took an active role in the Pugwash conferences on science and world problems, held regularly by scientists alarmed about the possible misuse of nuclear energy.

Mark Oliphant was appointed KBE in 1959 and a Companion of the Order of Australia (AC) in 1977. He married in 1925 Rosa Wilbraham of Adelaide, who died in 1987. He is survived by his daughter.

 

 

 

Marcus Oliphant Dies at 98; Helped Develop Atom Bomb

 

By Wolfgang Saxon,, July 18, 2000

 

Mr. Marcus Oliphant, Australia's leading nuclear physicist and a key figure in the making of the atom bomb -- a creation he came to loath -- died Friday in Canberra. He was 98.

Dr. Oliphant entered the field in England under the guidance of Ernest Rutherford, director of the famous Cavendish Laboratory at Cambridge University, where the atom was first split by artificially accelerated particles in 1932. The center was a world leader in nuclear and experimental physics. Dr. Oliphant, known as Mark, became its assistant director of research in 1935.

He investigated nuclear disintegration and made his reputation with the design of heavy high-voltage apparatus. With the equipment he was able to produce intense beams of protons and of the nuclei of heavy hydrogen, and then study their interactions with light nuclei.

The sheer intensity of the beams made it possible for him to study such events at far lower voltages than had been required before. What was particularly significant was his work with the lithium nucleus, in which he separated the two lithium isotopes by electromagnetic means.

Working as a team, he, Lord Rutherford and Dr. Paul Harteck drew worldwide attention to Cavendish in 1934 when they discovered a third type of hydrogen. Known as triple-weight hydrogen, or tritium, its existence had been suspected, but it took them and their atom smasher to prove it.

Dr. Oliphant was named director of physics laboratories and Poynting Professor of Physics at Birmingham University in 1937, posts he filled until 1950. He first visited America in 1941 in connection with his work on what became radar. In 1943 he was chosen to lead a group of British scientists to the United States to share their advanced knowledge of nuclear physics with American colleagues.

The group joined the profoundly secret workings of the Manhattan Project, which built the bombs dropped in 1945 on Hiroshima and Nagasaki, ending the war against Japan. The reality of such bombs destroying whole cities and their people so horrified Dr. Oliphant that he was to observe later that his part in their creation had made him a "war criminal."

For the rest of his life he pressed for the peaceful use of atomic energy and spoke out against all weapons capable of mass destruction. Starting in 1945 he insisted that the world must "get rid of war or die," and that the use of nuclear arms would be a "moral crime."

Using nuclear weapons, he said, was "a dirty, rotten way to kill people" that could not be justified "in any circumstances," even in retaliation. The West, he said in 1950, was "foolish" to engage in a nuclear arms race with the Soviet Union.

The following year he was blocked from attending a conference in Chicago. His visa application had not been rejected, but no visa was forthcoming, a predicament he shared with the author Graham Greene and Dr. Ernest Chain, who won the Nobel Prize for his work on penicillin.

All three appeared to have run afoul of the 1950 McCarran Internal Security Act, and passport authorities were still mulling over their cases while their travel dates came and went. Because of these cases, Congress modified the act to spare the United States the embarrassment of similar visa troubles and the headlines they spawned.

Marcus Laurence Elwin Oliphant was born in Adelaide in South Australia on Oct. 10, 1901. He graduated with honors from Adelaide University in 1927 and received a Ph.D. from Trinity College at Cambridge in 1929.

After he returned to Australia in 1950 he directed the Research School of Physical Sciences at the fledgling Australian National University until 1963, then headed the university's research unit on ionized gases. He also served as chairman of a committee that advised the Canberra government on the development of nuclear power stations.

He was a founder and past president of the Australian Academy of Sciences. In recognition of his accomplishments, he was appointed governor of the state of South Australia in 1971, a ceremonial post he held until 1976. Britain named him a Knight of the British Empire in 1959.

Dr. Oliphant's wife, Rosa Wilbraham Oliphant, died in 1987 after 52 years of marriage. He is survived by a daughter, Vivian Wilson; three grandchildren, and two great-grandchildren.

His biographer, David Ellyard, said in Australia that his role in the Manhattan Project never gave him peace. "There was that pride of achievement and shame of being associated with it," he said in a radio interview there. "Those contradictions, I think, remained with him until the end."


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© 2000 by Neil Mishalov