Leo Szilard Biography (1898-1964)


Szilard was born in Budapest on February 11, 1898. He had studied only a yearat the Technical Academy in Budapest before he was drafted into the army. His military experience was so unpleasant that he became a life-long pacifist.

After returning to civilian life, Szilard left Hungary to enroll first at theTechnical Academy at Charlottenburg and then at the University of Berlin, where he received a Ph.D. in nuclear physics in 1922. The rise of Hitler convinced Szilard, as it did so many other Jewish scientists at the time, to flee Germany. He traveled first to London in 1934 and then, four years later, to the United States. He became an American citizen in 1943.

While in London, Szilard conceived of the notion of a nuclear chain reaction."It occurred to me," he wrote, "that a chain reaction might be set up if anelement could be found that would emit two neutrons when it swallowed one neutron." Szilard first considered using beryllium for such a reaction, but, ashe notes, "for some reason or other the crucial experiment was never carriedout."

Only a few years later, the discovery of nuclear fission by Hahn and Strassman presented another possibility. Szilard realized that the fission of uraniumnuclei, with its release of neutrons, could be used to produce a chain reaction. Further, he saw the potential for using such a reaction in an atomic bomb.

Horrified by the thought of such a weapon in German hands, Szilard convincedhis American colleagues not to publish their research on fission. He saw thisdecision as the only way of preventing the Germans from keeping up to date with fission research and constructing their own weapon. Along with two otherHungarian emigrés, Edward Teller and Eugene Wigner, Szilard convincedAlbert Einstein (1879-1955) to write President Franklin D. Roosevelt about the potential of nuclear fission and the need for the United States to build afission bomb.

Szilard's role in the ensuing Manhattan Project was the development of the first self-sustaining chain reaction. He worked with Enrico Fermi (1901-1954) on this project at the University of Chicago. Szilard and Fermi found that graphite could be used as a moderator to slow down neutrons produced during thefission of uranium. These slowed-down neutrons were more efficient at producing other fission reactions.

This research was critical in the development of the first atomic bombs. However, Szilard was among those bomb researchers who argued against the weapon'suse over populated areas, a position that was not adopted by the United States government.

After the war, Szilard decided to leave the field of nuclear research. In 1946, he became professor of biophysics at the University of Chicago. He devotedmuch of his time and energy on efforts to ban nuclear weapons testing and nuclear warfare. In 1959, he received the Atoms for Peace Award. He joined theSalk Institute for Biological Studies in 1956 and died in La Jolla, California, on May 30, 1964.

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