Leo Szilard

(1898—1964) Hungarian-born American physicist and molecular biologist

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Hungarian-born US physicist, who played an important role in the development of the atomic bomb.

Born in Budapest, the son of an architect, Szilard studied electrical engineering in Budapest and physics at the University of Berlin, where he gained his PhD in 1922. With the rise of Hitler, Szilard decided to leave Germany and, after a brief period in England, emigrated to the USA in 1938. He became a naturalized US citizen in 1943.

As early as 1934 Szilard had grasped the essentials of a nuclear chain reaction, and had consequently applied for the patents rights, which he assigned to the British Admiralty. Mistakenly, however, Szilard thought the chain reaction was most likely to be sustained by the element beryllium. As a result of the work of Otto Hahn and Lise Meitner, by 1939 he realized that it was uranium rather than beryllium that was the key element in a chain reaction. Determined that the USA rather than Nazi Germany would be the first to develop atomic weapons, Szilard approached Albert Einstein and persuaded him to write a letter to President Roosevelt urging him to provide the backing for research into uranium fission. The letter, dated 2 August 1939, initiated the programme that eventually produced the Hiroshima and Nagasaki atom bombs. Szilard worked on the project himself, mainly with Enrico Fermi in Chicago on the development of the uranium–graphite pile.

Although he was instrumental in its development, Szilard attempted to prevent the dropping of the bomb on Japanese cities by organizing the ‘Szilard petition’ signed by many leading scientists and addressed to politicians. After the failure of this petition, Szilard foresaw the nuclear arms race and campaigned vigorously, and again unsuccessfully, for a programme of disarmament. At this point Szilard, with a number of other disillusioned physicists, turned away from physics, to the emerging discipline of molecular biology. Attending classes, he learnt the basic laboratory techniques and soon developed sufficient competence to design new instruments and to contribute to the development of theory. Academic appointments meant little to Szilard. He was connected with the University of Chicago until his later years, when he moved to the newly formed Salk Institute at La Jolla, California.

Subjects: Warfare and Defence.

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