Obituary: Professor Arthur Charlesby

Arthur Charlesby will be remembered as the father of radiation chemistry. A physicist by training, he was endowed with an acute intellect reinforced by a remarkable practical and commercial flair. These talents bore fruit in later life in an astonishing number of original papers and patents largely concerned with the effect of high energy radiation on polymeric materials.

Charlesby was educated in London and Antwerp, and graduated from the Imperial College of Science in London, where he studied diffraction phenomena in organic crystals under G.I. Finch and G.P. Thompson. His early professional career was interrupted by the Second World War, in which he served in the RAF in the vital field of operational analysis, and was mentioned in dispatches. This work involved collaboration with the United States Air Force on the effectiveness of Allied bombing.

Immediately after the war Charlesby became responsible for the planning of air traffic in post-war Europe, and was involved as an adviser during the Berlin airlift of 1948-49. He then joined the Atomic Energy Research Establishment (AERE) at Harwell working on the effects of radiation on materials.

After a period with Tube Investments (TI), heading a small research laboratory at Hinxton Hall, Cambridge, he moved in 1957 to the Royal Military College of Science at Shrivenham (the technical university of the army, today known as Cranfield University; it moved to Shrivenham from Woolwich in 1946) as Professor of Physics and Head of Department.

This inaugurated a particularly fertile period in original work when Charlesby's enthusiasm for fundamental research produced a plethora of scientific papers devoted to the effects of radiation on polymers. His significant contribution to this field lay in the discovery that a flexible polymer such as polyethylene could be "cross-linked" and rendered rigid by exposure to high-energy radiation. (The story goes that when at Harwell, where he worked in the metals department, Charlesby put something in the reactor and forgot about it; when he looked at it again he noticed that its plastic container had undergone a substantial change, so he determined to start work on polymers.)

Many commercial applications were evident, leading to an extensive range of patents world-wide. Recognition that foodstuffs could be effectively sterilised by radiation within sealed plastic packages followed. A further development was the now widespread use of radiation for sterilisation of medical equipment.

Charlesby's flair for showmanship was evident at this time. To make the point that sterilising food and drink by radiation was inherently harmless, he astonished an audience of brigadiers and major-generals by pouring out a glass of irradiated beer and drinking it during the lecture.

While it is certainly true to acknowledge the strong commercial thrust of these radiation studies, Charlesby remained keenly interested in problems of theoretical physics, notably in relativity theory. His brilliant yet simple approach to the quantisation of time and space bore fruit in his closing years. He was actively working on further developments of this topic during his final illness. Earlier papers in this series were published in the Journal of Radiation Physics and Chemistry, of which he was founder and editor-in- chief.

For many years he travelled widely directing research throughout the world, from China to Zagreb. His long- lasting collaboration with the Polytechnic University of Ldz in Poland was acknowledged by the award of the Marie Curie Medal for radiation work in 1989 and by an honorary doctorate in 1990.

His friends will recall with pleasure Arthur Charlesby's engaging friendliness and spontaneous hospitality with Irene his wife at their home in Watchfield, distinguished by an incredible array of drinks and cordials from every corner of the globe.

Arthur Charlesby, radiation physicist: born London 12 October 1915; Professor of Physics, Royal Military College of Science, Shrivenham 1957-80 (Emeritus); married 1958 Irene Goulding; died Swindon, Wiltshire 13 June 1996.