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John Randall (physicist)


Sir John Randall,FRSE, (March 23, 1905 – June 16, 1984) was a British physicist, credited with radical improvement of the cavity magnetron, an essential component of centimetric wavelength radar, which was one of the keys to the Allied victory in the Second World War. It is also the key component of microwave ovens. He also led the King's College London team which worked on the structure of DNA; his deputy Maurice Wilkins, shared the 1962 Nobel Prize for Physiology or Medicine, together with James Watson and Francis Crick of the University of Cambridge, for the determination of the structure of DNA. His other staff included Rosalind Franklin, Raymond Gosling, Alec Stokes and Herbert Wilson.



John Randall was born on 23 March 1905 at Newton-le-Willows, St Helens, Lancashire, the only son and the first of the three children of Sidney Randall, nurseryman and seedsman, and his wife, Hannah Cawley, daughter of John Turton, colliery manager in the area. He was educated at the grammar school at Ashton-in-Makerfield and at the University of Manchester, where he was awarded a first-class honours degree in physics and a graduate prize in 1925, and an MSc in 1926. He married Doris, daughter of Josiah John Duckworth, a colliery surveyor, in 1928. They had one son.

From 1926 to 1937 Randall was employed on research by the General Electric Company at its Wembley laboratories, where he took a leading part in developing luminescent powders for use in discharge lamps. He also took an active interest in the mechanisms of such luminescence.

The Magnetron

By 1937 he was recognized as the leading British worker in his field, and was awarded a Royal Society fellowship to the University of Birmingham, where he worked on the electron trap theory of phosphorescence in Professor Marcus Oliphant's physics faculty. When the war began in 1939 Randall transferred to the large group working on centimetre radar. At the time limited transmitter output was the greatest single obstacle in the development of this type of radar.

Simple two-pole magnetrons had been developed in the 1920s but gave relatively low power outputs. A more powerful multi-cavity resonant magnetron had been developed in 1935 [1] by Hans Erich Hollmann in Berlin. By 1940 Randall and Dr Harry Boot produced a working prototype similar to Hollman's cavity magnetron, but added liquid cooling and a stronger cavity. However Randall and Boot soon managed to increase its power output 100-fold. Later James Sayers (physicist) provided the final breakthrough to a practical device.

The importance of a powerful cavity magnetron was immense. Centimetric radar could detect much smaller objects. The combination of the small-sized cavity magnetron, small antennas and high resolution allowed small high quality radars to be installed in aircraft to detect submarines and other aircraft. This advance eventually defeated the German U-boats and so won the Battle of the Atlantic. This allowed Britain to be supplied and then re-armed from across the Atlantic, ultimately allowing for the the liberation of continental Europe. Other applications of radar included aerial interception of bombers at night, better navigation of Allied bombers (H2S radar), better anti-aircraft batteries and naval gunnery and proximity fuses. One million magnetrons were produced by Bell Labs alone in the USA before the end of the war, and many millions since have been incorporated into cookers and a wide range of other appliances. An official American historian described magnetron number 12 that was taken to the USA in September 1940 as follows: "When the members of the Tizard Mission brought one to America in 1940, they carried the most valuable cargo ever brought to our shores."

In 1943 Randall left Oliphant's physical laboratory at Birmingham to teach for a year in the Cavendish Laboratory at Cambridge. In 1944 Randall was appointed professor of natural philosophy at University of St Andrews and began planning research in biophysics (with Maurice Wilkins) on a small Admiralty grant.

Double Helix
William Astbury
Oswald Avery
Francis Crick
Erwin Chargaff
Max Delbrück
Jerry Donohue
Rosalind Franklin
Raymond Gosling
Phoebus Levene
Linus Pauling
Sir John Randall
Erwin Schrödinger
Alec Stokes
James Watson
Maurice Wilkins
Herbert Wilson

King's College London

In 1946 he moved to the Wheatstone chair of physics at King's College London, where the Medical Research Council set up the Biophysics Research Unit with Randall as the director (now known as Randall Division of Cell and Molecular Biophysics) at King's College London. During his term as director the experimental work leading to the discovery of the structure of DNA was made there by Rosalind Franklin, Raymond Gosling, and Maurice Wilkins. Maurice Wilkins shared the 1962 Nobel Prize for Physiology and Medicine with James Watson and Francis Crick; Rosalind Franklin had already died from cancer in 1958.

In addition to the X-Ray diffraction work the unit conducted a wide-ranging programme of research by physicists, biochemists, and biologists. The use of new types of light microscopes led to the important proposal in 1954 of the sliding filament mechanism for muscle contraction. Randall was also successful in integrating the teaching of biosciences at King's College.

In 1951 he set up a large multidisciplinary group working under his personal direction to study the structure and growth of the connective tissue protein collagen. Their contribution helped to elucidate the three-chain structure of the collagen molecule. Randall himself specialized in using the electron microscope, first studying the fine structure of spermatozoa and then concentrating on collagen. In 1958 he began to study the structure of protozoa. He set up a new group to use the cilia of protozoa as a model system for the analysis of morphogenesis by correlating the structural and biochemical differences in mutants.

Later years

In 1970 he retired to Edinburgh University, where he formed a group which applied a range of new biophysical methods to study various biological problems. He continued that work with characteristic vigour until his death.

In science Randall was not only original but even maverick. He made extremely important contributions to biological science when he set up, at the right time, a large multidisciplinary biophysical laboratory where his staff were able to achieve much success. His contributions as an individual worker in biophysics were possibly not so outstanding as those in physics. In science and elsewhere he showed good judgement. He had unusual capacity to see the essentials of a situation and had outstanding skill in obtaining funds and buildings for research. He was ambitious and liked power, but his ambition worked very largely for the common good. The informal and democratic side of his character contrasted strongly with his self-assertion. He showed great dedication and enthusiasm in his scientific work, just as he did in the extensive gardening he much enjoyed.


In 1938 Randall was awarded a DSc by the University of Manchester. In 1943 he was awarded (with H. A. H. Boot) the Thomas Gray memorial prize of the Royal Society of Arts for the invention of the cavity magnetron. In 1945 he became Duddell medallist of the Physical Society of London and shared a payment from the Royal Commission on Awards to Inventors for the magnetron invention, and in 1946 he was made a fellow of the Royal Society and became its Hughes medallist. Further awards (with Boot) for the magnetron work were, in 1958, the John Price Wetherill medal of the Franklin Institute of the state of Pennsylvania and, in 1959, the John Scott award of the city of Philadelphia. In 1962 he was knighted, and in 1972 he became a fellow of the Royal Society of Edinburgh.

DNA structure research at King's College London 1947-1959
Rosalind Franklin | Raymond Gosling | John Randall | Alec Stokes | Maurice Wilkins | Herbert Wilson

Books featuring Sir John Randall

  • Chomet, S. (Ed.), D.N.A. Genesis of a Discovery, 1994, Newman- Hemisphere Press, London.
  • Wilkins, Maurice, The Third Man of the Double Helix: The Autobiography of Maurice Wilkins ISBN 0-19-860665-6.
  • Ridley, Matt; "Francis Crick: Discoverer of the Genetic Code (Eminent Lives)" first published in July 2006 in the USA and then in the UK. September 2006, by HarperCollins Publishers ISBN 0-06-082333-X.
  • Tait, Sylvia & James "A Quartet of Unlikely Discoveries" (Athena Press 2004) ISBN 184401343X
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "John_Randall_(physicist)". A list of authors is available in Wikipedia.
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