Enrico Fermi
1901-1954
American Physicist
Enrico Fermi discovered a way to induce artificial radiation in heavy elements by shooting neutrons into their atomic nuclei. Using this technique he produced the first transuranium elements; that is, heavy elements that appear after uranium in the periodic table. For these accomplishments, Fermi was awarded the Nobel Prize in Physics in 1938. He was also instrumental in the design and construction of the world's first nuclear reactor at the University of Chicago. December 2, 1942, when a self-sustaining chain reaction was first achieved there, is often considered to be the beginning of the Atomic Age.
Fermi was born on September 29, 1901, in Rome, the son of railroad employee Alberto Fermi and his wife, Ida de Gattis. A precocious student, Fermi had decided to become a physicist before he had graduated from high school. He received his doctorate in physics at the University of Pisa in 1922. After postdoctoral studies with Max Born (1882-1970) at Göttingen and Paul Ehrenfest (1880-1933) in Leiden, he lectured in mathematics at the University of Florence. There, he published his first importanttheoretical papers. By the age of 25, he had obtained a professorship at the University of Rome and begun his experimental work. Fermi married Laura Capon in 1928. Their daughter Nella was born in 1931, and their son Giulio followed in 1936.
Enrico Fermi. (Library of Congress. Reproduced with permission.)In 1934, the French physicists Frédéric (1900-1958) and Irène Joliot-Curie (1897-1956) had first produced artificial radioactivity by bombarding atoms with helium nuclei, or alpha particles. However, this technique ran into difficulties with heavy elements, which had many positively charged protons in their nucleus to repel the positively charged alpha particles. The newly discovered neutron, with no charge at all, seemed to Fermi to be a good projectile to throw at these heavy atoms. The neutrons were even more effective when slowed down by collisions with the atoms in hydrogen-rich materials such as water or paraffin.
Fermi began announcing transuranium elements in 1934. It was not until 1939, after Otto Hahn (1879-1968) and Fritz Strassmann (1902-1980) had performed the same experiment, that Lise Meitner (1878-1968) and her nephew Otto Frisch (1904-1979) realized that Fermi had also been the first to split the atom. "We did not have enough imagination," he later wrote. Meitner realized that nuclear fission was accompanied by the release of enormous amounts of energy, in accordance with the famous equation of Albert Einstein (1879-1955), E = mc2.
While Fermi had been working on his neutron bombardment experiments, he and his wife, who was Jewish, had grown increasinglyconcerned about the Fascist regime in Italy. Having received permission to leave the country to pick up Fermi's Nobel Prize in Sweden in 1938, the family fled to the United States. After three years at Columbia University, he went on to the University of Chicago.
Fermi was alarmed by the possibility of Hitler's Germany harnessing the massive destructive power of nuclear fission. With this in mind, he helped compose a letter signed by several eminent physicists and delivered to President Roosevelt by Einstein, urging him to establish what came to be called the Manhattan Project. Fermi's role was to develop the nuclear reactor, or "atomic pile" as he called it. The reactor was built in an unused squash court at the University of Chicago and went into operation in 1942. Fermi became an American citizen in 1944. He continued with the Manhattan Project in Los Alamos, New Mexico, where the first atomic bomb was tested on July 16, 1945. A few weeks later, bombs were dropped on Hiroshima and Nagasaki.
After the war, Fermi returned to the University of Chicago. His later research concentrated on nuclear particles, especially mesons. A meson is a packet of energy, or quantum, corresponding to the strong force that holds the nucleus together, just as the photon is a quantum of light. Fermi died in Chicago on November 28, 1954.
This is the complete article, containing 645 words
(approx. 2 pages at 300 words per page).
