Szilárd, Leó

He started his university studies at the Technical University

of Budapest, then he continued to study at the Technical University of Berlin

at the department of chemistry, but later, as he became interested in physics, he transferred to the Humboldt University of Berlin.

There were several Nobel laurates physicists teaching there, among others Albert Einstein.

A close relationship was established between Szilárd and Einstein, and several patents derive from their co-operation as the Einstein-Szilárd refrigerator.

During his activity in Berlin Szilárd solved a problem related to the physical measurement of the value of information and in connection with this he introduced an important notion, negative entropy.

After the nazis had come into power he went to London where he made an important discovery in the field of artificial radioactivity (Szilárd-Chalmers effect).

As a result of the discovery of the neutron he elaborated his theory on the chain reaction of neutrons: due to this chain reaction the nuclear energy hidden in the strong nuclear bond is released. Nobody took his idea seriously at that time.

Leó Szilárd and Enrico Fermi heard about it in America, in Chicago, that Otto Hahn and Friedrich Strassmann had discovered the fission of the nucleus of the uranium atom, i.e. the process Szilárd had worked out earlier. The chain reaction of the splitting of the uranium threatened with the monster of a new weapon of terrifying effect.

It was then that Szilárd, with the help of Jenő Wigner and Ede Teller, turned to Einstein and asked him to write the well-known letter to president Roosevelt, emphasising the importance of that by the development of the atomic bomb the United States should overcome Germany.

Under the stands of the stadium of the University of Chicago

with the direction of Fermi and Szilárd there was assembled and was put into operation in December 1942.

the first atomic reactor working on the basis of the splitting of the atom from uranium balls embedded in graphite bricks.

Szilárd also took part in the development of the first atomic bomb (Manhattan Project), and when the bomb was almost ready for action, with many of his colleagues he started a political campaign to prevent its use. Although the press regarded him as the father of the A-bomb, after the war Szilárd became one of the leaders of the fight against the atomic war.

In 1949 he started research in a new field: he used the methods of modern physics to solve problems of biology. Due to his work the biophysics went over a fundamental transformation. He proved the responsiveness of the genetic nature in the course of inactivating bacteria by means of ultraviolet radiation.

He also studied the process of ageing: he realised that the elementary act of ageing is the random inactivation of chromosomes.

In 1960, when his bladder cancer was diagnosed, he took his treatment in own hands treated himself with irradiation of extra large dose, with complete success. He died of a stroke; the pathological findings reported on that the cancer had completely disappeared.

Bibliography: Feld, Bernard T. / Szilard, Gertrud Weiss, Eds.: The Collected Works of Leo Szilard: Scientific Papers. MIT Press City Cambridge, MA ,1972

Szilard's inventions
"Leo Szilard conceived, and filed patent applications on, many of the key inventions of the 20th century including the cyclotron, linear accelerator, electron microscope, nuclear chain reaction, and nuclear reactor. Szilard himself did not build all of these devices, or publish these ideas in scientific journals, and so their credit often went to others. As a result, Szilard never received the Nobel Prize, but two of his inventions did. Ernest Lawrence received the 1939 Nobel Prize for the cyclotron. Ernst Ruska received the 1986 Nobel Prize for the electron microscope."
(From Leo Szilard the Inventor: A Slideshow by Gene Danen.
URL: http://www.dannen.com/budatalk.html)

Szilárd-Chalmers Effect
The rupture of the chemical bond between an atom and the remainder of the molecule of which the atom is originally a part, as a result of a nuclear reaction of that atom

nuclear fission
When a nucleus fissions, it splits into several smaller fragments. Two or three neutrons are also emitted.The sum of the masses of these fragments is less than the original mass. This missing mass (about 0.1 percent of the original mass) has been converted into energy according to Einstein's equation.