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Enrico Fermi, Experimentalist and Theoretician

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by Dr. William Watson   12/12/17

Enrico Fermi

Enrico Fermi

To celebrate 70 years of advancing scientific knowledge, OSTI is featuring some of the leading scientists and works particularly relevant to the formation of DOE, OSTI, and their predecessor organizations and is highlighting Nobel laureates and other important research figures in DOE’s history.  Their accomplishments were key to the evolution of the Department of Energy, and OSTI’s collections include many of their publications.

Enrico Fermi was born in Rome on September 29, 1901.  His aptitude for mathematics and physics was recognized early.  After gaining his doctorate in physics in 1922, Fermi worked with prominent physicists Max Born in Germany and Paul Ehrenfest in Switzerland.  He then returned to Italy in 1924 to be a lecturer in mathematical physics and mechanics at the University of Florence.  It was there that Fermi discovered how elementary particles at a given temperature and chemical potential are distributed over different states of motion when no more than one of each particle can exist in any of those states.  Since the constituents of atoms (electrons, d quarks, and u quarks) behave this way, the law of this distribution plays a significant role in the physics of atoms and of their nuclei—two of the main fields of Fermi’s research career.  

Fermi first concentrated on the physics of atomic electrons after becoming professor of theoretical physics at the University of Rome in 1927, but by the early 1930s, he had begun to focus on atomic nuclei.  Fermi accomplished three significant things in 1934:  He developed his theory of beta radioactivity, demonstrated that nuclei of almost every element undergo transformations when they are bombarded with neutrons, and discovered nuclear reactions produced by slow neutrons.  For the latter two, Fermi was awarded the 1938 Nobel Prize in Physics.

The presentation of the Nobel Prize in Sweden that December provided an occasion for Fermi and his wife Laura to escape the increasing threat of Mussolini’s regime.  Instead of returning to Italy, they proceeded to the United States.  The next year, Fermi was appointed professor of physics at Columbia University. 

Following the discovery of fission in Germany that same year, Fermi was one of several physicists who realized that neutrons emitted by split atoms might produce a chain reaction.  In an experiment that Fermi directed at the University of Chicago, the steady, controlled chain reaction achieved on December 2, 1942 was one of the first major accomplishments of the Manhattan Project.  Fermi also contributed further to the Manhattan Project’s development of the first atomic bomb, whose explosion was a sudden, uncontrolled chain reaction.  Fermi became a U.S. citizen in 1944 before World War II ended; in 1946, after the war, he joined the University of Chicago’s Institute for Nuclear Studies as a professor. 

An idea of the scope of Fermi’s research after his arrival in the United States can be gained from those research reports and patents of his that are available through OSTI’s SciTech Connect.  Not only did Fermi investigate nuclear energy and interactions among neutrons and protons further, but he also studied nuclear interactions with the more recently discovered subatomic particles called pions, how cosmic rays acquired their high energies through interaction with magnetic fields in outer space, and the behavior of a nonlinear mechanical system, which turned out to be very different from what Fermi and his collaborators had expected. 

Another of Fermi’s lasting contributions to science, “Fermi problems,” has been increasingly recognized even though it never appeared in his publications or engineering constructions.  This technique for estimating amounts or quantities based on limited or imprecise information has been made widely known through his students, and nowadays is even a part of many formal curricula. 

Fermi’s “contributions to basic neutron physics and the achievement of the controlled nuclear chain reaction” were recognized before his death in 1956 by a special award from the U.S. Atomic Energy Commission.  Fermi received this award from President Eisenhower in 1954.  Since then, many individuals of international stature have been recognized with the Enrico Fermi Award for “exceptional scientific, technical, policy, and/or management achievements related to the broad missions of the U.S. Department of Energy and its programs.”  Fermi was honored again by the Atomic Energy Commission in their 1969 decision to name a new laboratory being built outside Chicago the Fermi National Accelerator Laboratory; the lab (now also known as “Fermilab”) received its new name at its dedication in 1974 and has been the site of numerous explorations and discoveries about subatomic particles and the forces that govern them.