Enrico Fermi
Enrico Fermi was born in Rome, Italy, on the 29th of September 1901. He grew up at Via Gaeta 19 with his parents Alberto and Ida de Gattis. His father worked as a division head in the Ministry of Railways while his mother taught elementary school. Enrico had an older sister named Maria and a younger brother named Giulio. The family lived together until two young boys were sent to a rural community for wet nursing. Enrico rejoined them when he was two and a half years old.
At a local market called Campo de' Fiori, Fermi found a physics book titled Elementorum physicae mathematicae. This 900-page volume was written in Latin by Jesuit Father Angelo Secchi. It covered mathematics, classical mechanics, astronomy, optics, and acoustics as they were understood in 1840. Fermi pursued projects with a scientifically inclined friend named Enrico Persico. They built gyroscopes and measured the acceleration of Earth's gravity.
Fermi often met his father after work in front of his office. In 1914 he encountered Adolfo Amidei, a colleague who walked part of the way home with Alberto. Young Fermi asked Adolfo about geometry. Adolfo realized the boy meant projective geometry and gave him a book by Theodor Reye. Two months later Fermi returned it having solved all problems including some difficult ones. Adolfo declared him a prodigy regarding geometry. He provided more books on physics and mathematics. Fermi had such good memory that he could return books after reading them because he remembered their content perfectly.
Wolfgang Pauli formulated his exclusion principle in 1925. Fermi followed with a paper applying this principle to an ideal gas. His statistical formulation described particle distribution in systems obeying the exclusion principle. This became known as Fermi-Dirac statistics. Particles following the rule are now called fermions while others are bosons. Paul Dirac independently developed similar ideas shortly after.
Pauli postulated an uncharged invisible particle emitted during beta decay to satisfy energy conservation laws. Fermi took up this idea developing a model incorporating the particle. He named it neutrino. His theory later referred to as weak interaction described one of four fundamental forces. The neutrino was detected only after his death. His interaction theory explained why detection proved so difficult.
In January 1934 Irène Joliot-Curie and Frédéric Joliot announced bombarding elements induced radioactivity. By March Fermi's assistant Gian-Carlo Wick provided theoretical explanation using beta decay theory. Fermi decided switching to experimental physics using neutrons discovered by James Chadwick in 1932. Neutrons had no electric charge meaning they penetrated nuclei without deflection. They required less energy than charged particles needing accelerators.
Fermi created a stronger neutron source replacing polonium-beryllium with radon-beryllium. He filled glass bulbs with beryllium powder evacuating air then adding 50 mCi of radon gas. This source effectiveness declined with radon's 3.8-day half-life. Starting with platinum he found no success turning to aluminium producing sodium decaying into magnesium. Lead failed but fluorine in calcium fluoride emitted alpha particles creating nitrogen decaying into oxygen. In total he induced radioactivity in 22 different elements reporting discovery on the 25th of March 1934 in La Ricerca Scientifica.
Natural radioactivity made thorium and uranium hard to analyze when bombarded. Fermi concluded creating new elements called ausenium and hesperium. Chemist Ida Noddack suggested experiments produced lighter elements rather than heavier ones. Her suggestion ignored because her team lacked uranium experiments or theoretical basis. Fission seemed improbable if not impossible theoretically at that time.
Experiments worked better on wooden tables than marble tabletops. Fermi remembered paraffin wax slowed neutrons effectively. Passing neutrons through paraffin induced hundred times more radioactivity in silver compared without it. Hydrogen atoms explained differences between wood and marble confirming water repetition. Collisions with hydrogen slowed neutrons losing energy per collision requiring fewer collisions overall. Slow neutrons captured more easily than fast ones developing diffusion equation known as Fermi age equation.
Fermi received the Nobel Prize in Physics at age 37 for demonstrating existence of new radioactive elements via neutron irradiation. He discovered nuclear reactions brought about by slow neutrons. After receiving prize in Stockholm he did not return home continuing instead to New York City with family in December 1938 applying for permanent residency. Decision moved America becoming US citizens primarily due to racial laws in Italy.
Laura Capon his wife was Jewish threatening her safety under Mussolini's regime. These laws put many research assistants out of work. Fermi opposed Fascism when 1938 racial laws promulgated bringing Italian Fascism ideologically closer to German Nazism. The decision left Italy escaping persecution targeting his family members. They arrived in New York City on the 2nd of January 1939 immediately offered positions accepting one at Columbia University where summer lectures occurred previously in 1936.
Chicago Pile-1 went critical on the 2nd of December 1942 demonstrating first human-created self-sustaining nuclear chain reaction. Construction began the 6th of November 1942 in squash court under Stagg Field stands. Shape intended roughly spherical but calculations showed criticality achievable without finishing entire pile planned. Compton made coded phone call to James B. Conant chairman National Defense Research Committee upon achievement.
Fermi directed experiments reveling opportunities provided reactor abundant production free neutrons. Laboratory branched from physics engineering into biological medical research initially run by Fermi as part University Chicago becoming separate entity with him director May 1944. X-10 Graphite Reactor Oak Ridge went critical the 4th of November 1943 Fermi present just case something wrong technicians woke early seeing happen providing data training DuPont staff producing small quantities plutonium bred reactors.
B Reactor Hanford Site September 1944 inserted first uranium fuel slug designed breed plutonium large quantities water-cooled much larger than X-10. Over next few days loaded 838 tubes reactor went critical shortly midnight the 27th of September operators withdrew control rods initiating production power level dropped shutting down completely 06:30. Problem traced neutron poisoning xenon-135 half-life 9.1 to 9.4 hours absorbing neutrons sabotaging fission process.
Trinity test occurred the 16th of July 1945 first full nuclear bomb explosion test. Fermi observed conducting experiment estimating yield dropping strips paper blast wave. He paced distance blown calculating ten kilotons TNT actual yield about 18.6 kilotons. Along Oppenheimer Compton Ernest Lawrence advised Interim Committee target selection agreeing atomic bombs used without warning industrial targets.
Fermi found out bombings Hiroshima Nagasaki public address system technical area not believing atomic bombs deter nations starting wars thinking time ripe world government joining Association Los Alamos Scientists. In April 1943 raised Robert Oppenheimer possibility using radioactive byproducts contamination German food supply background fear German atomic bomb project advanced stage sceptical developing quickly enough Oppenheimer discussed promising proposal Edward Teller suggesting strontium-90 James B. Conant Leslie Groves briefed Oppenheimer wanted proceed plan enough food contaminated weapon kill half million people.
Mid-1944 Oppenheimer persuaded Fermi join Project Y Los Alamos New Mexico arriving September appointed associate director laboratory broad responsibility nuclear theoretical physics placed charge F Division named after him. Four branches included Super General Theory under Teller investigating thermonuclear bomb Water Boiler aqueous homogeneous research reactor under L.D.P. King Super Experimentation Egon Bretscher Fission Studies Anderson.
After first Soviet fission bomb detonated August 1949 Fermi Isidor Rabi wrote strongly worded report committee opposing hydrogen bomb development moral technical grounds. Nonetheless continued participating work hydrogen bomb Los Alamos consultant Stanislaw Ulam calculated amount tritium needed Teller model thermonuclear weapon prohibitive fusion reaction assured propagate even large quantity tritium. Among scientists testified Oppenheimer behalf 1954 hearing resulting denial security clearance.
Fermi became Charles H. Swift Distinguished Professor Physics University Chicago the 1st of July 1945 departing Los Alamos Laboratory family the 31st of December 1945 elected member US National Academy Sciences 1945. Manhattan Project replaced Atomic Energy Commission January 1947 served AEC General Advisory Committee influential scientific committee chaired Robert Oppenheimer liked spend few weeks yearly Los Alamos collaborating Nicholas Metropolis John von Neumann Rayleigh-Taylor instability science border fluids different densities.
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Common questions
When and where was Enrico Fermi born?
Enrico Fermi was born in Rome, Italy on the 29th of September 1901. He grew up at Via Gaeta 19 with his parents Alberto and Ida de Gattis.
What did Enrico Fermi discover about slow neutrons?
Fermi discovered that passing neutrons through paraffin slowed them effectively to induce hundred times more radioactivity in silver. This process led to the development of the diffusion equation known as Fermi age equation.
Why did Enrico Fermi move from Italy to New York City?
Fermi moved to New York City in December 1938 because racial laws under Mussolini's regime threatened his Jewish wife Laura Capon. The decision allowed him to escape persecution targeting his family members and become a US citizen.
When did Chicago Pile-1 go critical?
Chicago Pile-1 went critical on the 2nd of December 1942 demonstrating the first human-created self-sustaining nuclear chain reaction. Construction began the 6th of November 1942 in a squash court under Stagg Field stands.
How old was Enrico Fermi when he received the Nobel Prize in Physics?
Enrico Fermi received the Nobel Prize in Physics at age 37 for demonstrating existence of new radioactive elements via neutron irradiation. He won this award after discovering nuclear reactions brought about by slow neutrons.