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Leo Szilard - Patenting the Atomic Bomb.


Leo Szilard

Leo Szilard

Courtesy Department of Energy

Why was Leo Szilard Important?:

Hungarian physicist, Leo Szilard was the first person to conceive of the nuclear chain reaction and the atomic bomb. He was noted for his contributions to the fields of thermodynamics, biophysics, nuclear physics, and the development of atomic energy.

Leo Szilard was part of the group of scientists that invented the atomic bomb as part of the Manhattan Project.

Leo Szilard - Nuclear Chain Reaction Patent:

On July 4, 1934 Leo Szilard filed the first patent application for the method of producing a nuclear chain reaction aka nuclear explosion. His British patent included a description of a "neutron induced chain reactions to create explosions", and the concept of critical mass. Supposedly he came up with the idea of nuclear The patent was given to the British War Office as part of the war effort.

The Manhattan Project had a conflict with Leo Szilard, when he wanted financial compensation for the patent he had on nuclear chain reactions before the U.S. began working on the bomb.

Leo Szilard - Nuclear Fission Reactor :

Leo Szilard was the co-inventor with Enrico Fermi of the first nuclear reactor (U.S. Patent 2,708,656).

Leo Szilard - Famous Quotes:

"We turned the switch, saw the flashes, watched for ten minutes, then switched everything off and went home. That night I knew the world was headed for sorrow" - Leo Szilard reflecting on the first nuclear chain reaction

Leo Szilard - Manhattan Project:

Leo Szilard and Enrico Fermi were behind the first phase of the atomic bomb project in 1940. In 1942, at the University of Chicago, they obtained the first controlled chain reaction, using uranium surrounded by graphite.

Leo Szilard Biography February 11, 1898 – May 30, 1964:

Leo Szilard was born in Budapest. His father was a civil engineer.


In 1916, Leo Szilard began engineering studies at Budapest Technical University until he was drafted into the Austro-Hungarian Army. In 1919, he returned to his studies and transferred to the Institute of Technology in Berlin. Leo Szilard switched from engineering to physics, and was taught by Albert Einstein, Max Planck, and Max von Laue. In 1923, Leo Szilard received his Ph.D. degree in physics from the Humboldt University of Berlin.

Early Inventions

After graduation, Leo Szilard remained in Berlin and taught physics at the University of Berlin. While in Berlin he filed a 1928 German patent application for a linear accelerator, a 1929 German patent application for a cyclotron, and worked with Albert Einstein on a refrigerator without moving parts (US patent 1,781,541 on November 11, 1930).

Nuclear Chain Reaction

In 1933, Leo Szilard fled to London to escape Nazi persecution under Hitler.

At that time, the idea that atomic energy had no practical use was widely accepted. However, that concept bothered Leo Szilard so greatly that it led to his conception of the nuclear chain reaction and his patent, GB patent 630726.

In 1938, Leo Szilard moved to New York to conduct further research with Enrico Fermi at Columbia University. The duo discovered the neutron multiplication properties of uranium, proving that a nuclear chain reaction and nuclear weapons were possible.

At the same time, the German army was attempting to produce a nuclear chain reaction (for a nuclear weapon) using graphite. However, Leo Szilard realized that the graphite needed to be 100% pure. Szilard beat the Germans and demonstrated the first controlled chain reaction on December 2 1942 at the University of Chicago.

The Manhattan Project

Leo Szilard was the actual author of the letter sent to Roosevelt warning about the possibility of a German nuclear weapon. Szilard asked Albert Einstein to sign and deliver the letter.

However, Leo Szilard was against the use of nuclear weapons and urged the U.S. government to only use the atomic bomb as a threat.

In 1961, Leo Szilard published a book of short stories, The Voice of the Dolphins. He died in La Jolla, California of a heart attack.

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