Enrico Fermi ( ; Italian: Ã, [en'ri: ko 'fermi] 29 September 1901 - November 28, 1954) is an Italian-American physicist and creator of the world's first nuclear reactor, Chicago Pile-1. He has been called "the architect of the nuclear age" and "the architect of the atomic bomb". He is one of the very few physicists in history who excel both theoretically and experimentally. Fermi holds several patents related to the use of nuclear power, and was awarded the 1938 Nobel Prize in Physics for his work on radioactivity induced by neutron bombing and the discovery of transuranic elements. He made significant contributions to the development of quantum theory, nuclear physics and particles, and statistical mechanics.
Fermi's first major contribution was to statistical mechanics. After Wolfgang Pauli announced his exceptions principle in 1925, Fermi followed with a paper in which he applied the principle to the ideal gas, using a statistical formulation now known as the Fermi-Dirac statistic. Today, particles that adhere to the principle of exclusion are called "fermions". Then Pauli postulates the existence of invisible particles charged emitted with electrons during beta decay, to meet the law of conservation of energy. Fermi took this idea, developing a model that incorporated the postulated particle, which he named "neutrino". His theory, later referred to as Fermi interaction and then as a weak interaction, represents one of the four fundamental forces of nature. Through experiments inducing radioactivity with newly discovered neutrons, Fermi found that slow neutrons are more easily captured than quickly, and developed the Fermi age equation to illustrate this. After bombarding thorium and uranium with slow neutrons, he concludes that he has created a new element; although he was awarded the Nobel Prize for this discovery, the new elements were later revealed to be fission products.
Fermi left Italy in 1938 to evade the new Italian Racial Law affecting his Jewish wife, Laura Capon. He emigrated to the United States where he worked at the Manhattan Project during World War II. Fermi led the team that designed and built Chicago Pile-1, which became critical on December 2, 1942, demonstrating the first homemade nuclear chain reaction. He was on hand when the X-10 Graphite Reactor in Oak Ridge, Tennessee, became critical in 1943, and when Reactor B on Hanford Site did so the following year. At Los Alamos he leads the F Division, partly working on the "Super" thermonuclear bomb of Edward Teller. He was present at the Trinity test on July 16, 1945, where he used the Fermi method to estimate the bomb result.
After the war, Fermi served under J. Robert Oppenheimer on the General Advisory Committee, who advised the Atomic Energy Commission on nuclear issues and policies. After the first Soviet fission bombing of August 1949, he strongly opposed the development of hydrogen bombs on moral and technical grounds. He was one of the scientists who testified on behalf of Oppenheimer in the 1954 trial which resulted in the denial of the last security clearance. Fermi does an important job in particle physics, especially with regard to pion and muon, and he speculates that cosmic rays arise through matter that is accelerated by magnetic fields in interstellar space. Many awards, concepts, and institutions are named Fermi, including the Enrico Fermi Award, the Enrico Fermi Institute, the Fermi Gamma-ray Space Telescope, the Enrico Fermi Nuclear Generating Station, and the fermium synthetic elements, making it one of 16 scientists who have named element as its name.
Video Enrico Fermi
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Enrico Fermi was born in Rome, Italy, on 29 September 1901. He is the third son of Alberto Fermi, the head of the division of Capo Divisione ) at the Ministry of Railways, and Ida de Gattis, a primary school teacher. Her only brother, Maria, is two years older than her, and her sister Giulio is a year older. After the two boys were sent to a rural community for dampening, Enrico reunited with his family in Rome when he was two and a half years old. Although he was baptized Roman Catholic according to the wishes of his grandparents, his family was not very religious; Enrico was an agnostic throughout his adult life. As a boy, he shares a similar interest with his brother Giulio, building an electric motor and playing with electric and mechanical toys. Giulio died during the administration of anesthesia for surgery on a throat abscess in 1915. Maria died in a plane crash near Milano in 1959.
One of Fermi's first sources for physics studies is a book he found in the local market at Campo de 'Fiori in Rome. Published in 1840, a 900-page Elementorum physicae mathematicae , written in Latin by Jesuit Father Andrea Caraffa, a professor at Collegio Romano. It includes mathematics, classical mechanics, astronomy, optics, and acoustics, as far as this discipline is understood when the book is written. Fermi befriends other scholarly students, Enrico Persico, and together they work on scientific projects such as building gyroscopes and trying to accurately measure Earth's gravitational acceleration. Fermi's interest in physics was further encouraged by his fellow colleague, Adolfo Amidei, who gave him several books on physics and mathematics, which he read and assimilated quickly.
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Scuola Normale Superiore in Pisa
Fermi graduated from high school in July 1918 and, at Amidei's encouragement, applied to the Scuola Normale Superiore in Pisa. After losing one son, his parents were reluctant to let him move out of the house for four years while attending it, but in the end they agreed. The school provides free lodging for students, but the candidates must take a difficult entrance exam including an essay. The theme given is "Voice Special Characteristics". The 17-year-old Fermi chose to derive and solve partial differential equations for vibrating bars, applying Fourier analysis in solution. The examiner, Professor Giulio Pittarelli of Sapienza University of Rome, interviewed Fermi and praised him, saying that he would become an extraordinary physicist in the future. Fermi reached first place in the entrance exam classification.
For years at the Scuola Normale Superiore, Fermi worked with a student named Franco Rasetti with whom he would enjoy a light joke and who would later become Fermi's close friends and collaborators. In Pisa, Fermi was suggested by the director of the physics laboratory, Luigi Puccianti, who admitted that there was little he could teach Fermi, and often asked Fermi to teach him something. Fermi's knowledge of quantum physics reached such a high level that Puccianti asked him to organize a seminar on the topic. During this time Fermi studied tensor calculus, a mathematical technique invented by Gregorio Ricci and Tullio Levi-Civita needed to demonstrate the principles of general relativity. Fermi initially chose mathematics as his department, but soon turned to physics. He remained largely self-taught, studied general relativity, quantum mechanics, and atomic physics.
In September 1920, Fermi was accepted into the Physics department. Since there are only three students in the department - Fermi, Rasetti, and Nello Carrara - Puccianti let them freely use the laboratory for whatever purpose they choose. Fermi decides that they should research X-ray crystallography, and all three work to produce Laue photographs - X-ray crystals. During 1921, his third year at the university, Fermi published his first scientific work in the Italian journal Nuovo Cimento . The first one entitled "On the dynamics of the rigid system of electrical charges in translational motion" ( Sulla dinamica in un sistema rigido in cariche elettriche in moto traslatorio ). The sign of things to come is that the mass is expressed as a tensor - a mathematical construction commonly used to describe something moving and changing in three-dimensional space. In classical mechanics, mass is a scalar quantity, but in relativity it changes with speed. The second paper is "On the electrostatic of a uniform gravitational field of electromagnetic load and electromagnetic load" ( Sull'elettrostatica di un campo gravitazionale uniforme e sul peso delle masse elettromagnetiche ). Using general relativity, Fermi shows that the load has a weight equal to U/c 2 , where U is the electrostatic energy of the system, and c is the speed of light.
The first paper seems to indicate a contradiction between electrodynamic theory and the relativist theory of electromagnetic mass calculation, since the former predicts a value of 4/3 U/c 2 . Fermi discusses this next year in his paper "Regarding the contradiction between electrodynamics and the relativistic theory of electromagnetic masses" in which he points out that the apparent contradictions are a consequence of relativity. The paper was considered good enough to be translated into German and published in the German scientific journal Physicalische Zeitschrift in 1922. That year, Fermi submitted his article "On a phenomenon occurring near the world line" ( Sopra i phenomeni che avvengono di vicinanza in una linea oraria ) to the Italian journal I Rendiconti dell'Accademia dei Lincei . In this article he examines the Principle of Equality, and introduces the so-called "Fermi coordinates". He proved that on a world line close to the timeline, space acts as if it were an Euclidean space.
Fermi submitted his thesis, "Theorem of probability and some of its applications" ( Un theorem in calcolo delle probabilitá ed alcune sue applicazioni ), to Scuola Normale Superiore in July 1922, and received his laurea at a remarkable young age of 20. This thesis on X-ray diffraction images. Theoretical physics has not been considered a discipline in Italy, and the only thesis to be accepted is one on experimental physics. For this reason, Italian physicists are slow in embracing new ideas such as the relativity that comes from Germany. Since Fermi is quite comfortable in the lab doing experimental work, this does not create an insurmountable problem for him.
When writing an appendix to the Italian edition of Einstein's Religion Fundamentals by Kopff August 1923, Fermi is the first to show that hidden in the famous Einstein equation ( E = mc 2 ) is a very large nuclear potential energy to be exploited. "It seems unlikely, at least in the near future," he wrote, "to find a way to release this terrible energy - all of which for good because the first effects of the explosion as a terrible amount of energy will destroy smithereens physicists who have the misfortune to find a way to do it. "
In 1924 Fermi was initiated into Freemasonry at Masonic Lodge "Adriano Lemmi" from Grand Orient Italy.
Fermi decided to travel abroad, and spent a semester studying under Max Born at the University of GÃÆ'¶ttingen, where he met with Werner Heisenberg and Pascual Jordan. Fermi then studied in Leiden with Paul Ehrenfest from September to December 1924 at an alliance of the Rockefeller Foundation gained through intercession from mathematician Vito Volterra. Here Fermi meets Hendrik Lorentz and Albert Einstein, and becomes good friends with Samuel Goudsmit and Jan Tinbergen. From January 1925 to the end of 1926, Fermi taught mathematical physics and theoretical mechanics at the University of Florence, where he collaborated with Rasetti to conduct a series of experiments on the effects of magnetic fields on mercury vapors. He also participated in seminars at Sapienza University of Rome, giving lectures on quantum mechanics and solid state physics. While giving a lecture on new quantum mechanics based on the extraordinary accuracy of the Schrödinger equation prediction, Italian physicists often say, "No business fits in well!"
After Wolfgang Pauli announced his exceptions principle in 1925, Fermi responded with a paper "Regarding the quantization of the perfect monoatomic gas" (Sulla quantizzazione del gas perfetto monoatomico ), where it applies the principle of exclusion to the ideal gas. This paper is particularly important for the Fermi statistical formulation, which describes the distribution of particles in a system of many identical particles that adhere to the principle of exclusion. It was developed independently soon after by the British physicist Paul Dirac, who also showed how it relates to Bose-Einstein statistics. Thus, now known as Fermi-Dirac statistics. Following Dirac, the particles that adhere to the principle of the current exception are called "fermions", while those not called "bosons".
Professor in Rome
Professorship in Italy is awarded by competition ( concorso ) for vacant seats, the applicants are judged on their publication by the professor's committee. Fermi applied for the chair of mathematical physics at the University of Cagliari in Sardinia, but narrowly passed in favor of Giovanni Giorgi. In 1926, at the age of 24, he enrolled for a professorship at Sapienza University of Rome. This is a new chair, one of the first three in theoretical physics in Italy, which was created by the Minister of Education at the insistence of Professor Orso Mario Corbino, who is professor of experimental physics University, Director of the Institute of Physics, and Benito Mussolini's cabinet member. Corbino, who also leads the selection committee, hopes that the new chairman will improve the standards and reputation of physics in Italy. The committee chose Fermi in front of Enrico Persico and Aldo Pontremoli, and Corbino helped Fermi recruit his team, which was soon followed by renowned students such as Edoardo Amaldi, Bruno Pontecorvo, Ettore Majorana and Emilio SegrÃÆ'¨, and by Franco Rasetti, whom Fermi had designated as his assistants. They were immediately nicknamed "Via Panisperna children" after the path where the Institute of Physics was located.
Fermi married Laura Capon, a science student at the University, on July 19, 1928. They had two children: Nella, born in January 1931, and Giulio, born in February 1936. On March 18, 1929, Fermi was made a member of the Royal Italian Academy by Mussolini , and on 27 April he joined the Fascist Party. He then opposed Fascism when the 1938 racial law was enacted by Mussolini to bring Italy's Fascism closer to German National Socialism. These laws threatened Laura, who was a Jew, and made many research assistants Fermi not working.
During their time in Rome, Fermi and his group made important contributions to many practical and theoretical aspects of physics. In 1928, he published his book Introduction to Atomic Physics ( Introduzione alla fisica atomica ), which gives Italian students the latest and accessible text. Fermi also holds public lectures and writes popular articles for scientists and teachers to spread the knowledge of new physics as widely as possible. Part of his teaching method is to gather colleagues and graduate students together at the end of the day and discuss problems, often from his own research. The sign of success is that foreign students are now starting to come to Italy. The most important of these is the German physicist Hans Bethe, who came to Rome as a fellow of the Rockefeller Foundation, and collaborated with Fermi on the 1932 paper "On Interaction between Two Electrons" (German: ÃÆ'Ã… "Ber die Wechselwirkung von Zwei Elektronen ).
At this time, physicists are confused with beta decay, in which electrons are emitted from atomic nuclei. To fulfill the law of conservation of energy, Pauli postulates the existence of invisible particles without charge and little or no mass is also emitted at the same time. Fermi took this idea, which he developed in a tentative paper in 1933, and then a longer paper the following year that incorporated postulated particles, called Fermi as "neutrino". His theory, later referred to as Fermi interaction, and still later as a weak interaction theory, illustrates one of the four fundamental forces of nature. Neutrinos are detected after his death, and his interaction theory shows why it is so difficult to detect. When he submitted his paper to the British journal Nature, the journal's editor rejected it because it contained speculations that "too far from physical reality to be of interest to the reader". So Fermi saw the theories published in Italian and German before being published in English.
In the introduction to the English translation of 1968, physicist Fred L. Wilson noted that:
Fermi's theory, in addition to supporting Pauli's proposal of neutrino, has a special meaning in the history of modern physics. It must be remembered that only what happens naturally? emitters were known at the time the theory was put forward. Then when positron decay is discovered, the process is easily included in the original framework of Fermi. On the basis of his theory, the arrest of the orbital electrons by the nucleus is predicted and finally observed. With time a lot of experimental data has accumulated. Although the peculiarities have been observed many times? decay, Fermi's theory is always the same as the challenge The consequences of the Fermi theory are very broad. As an example, ? spectroscopy was established as a powerful tool for studying nuclear structures. But perhaps the most influential aspect of Fermi's work is that particular form of it? interactions form patterns that are appropriate for learning other types of interactions. It is the first successful theory of the creation and destruction of material particles. Previously, only photons were known to be made and destroyed.
In January 1934, IrÃÆ'¨ne Joliot-Curie and Frà © monie Joliot announced that they had bombarded the elements with alpha particles and induced radioactivity in them. In March, Fermi's assistant, Gian-Carlo Wick has provided a theoretical explanation using the Fermi beta decay theory. Fermi decided to move on to experimental physics, using neutrons, which James Chadwick discovered in 1932. In March 1934, Fermi wanted to see if he could induce radioactivity with a Rasetti polonyium-beryllium neutron source. Neutrons have no electrical charge, so they will not be deflected by positively charged nuclei. This means that they require less energy to penetrate the nucleus than charged particles, thus requiring no particle accelerator, which is not owned by the Via Panisperna children.
Fermi had an idea to replace the neutron source of polonium-beryllium with radon-beryllium, which he made by filling a glass ball with beryllium powder, emptying air, and then adding 50 mCi of radon gas, provided by Giulio Cesare. Trabacchi. This creates a stronger neutron source, its effectiveness decreases with radon half-life of 3.8 days. He knew that this source would also emit gamma rays, but, based on his theory, he believed that this would not affect the results of the experiment. He started by bombarding platinum, an element with a high atomic number available, with no results. He switches to aluminum, which emits alpha particles and produces sodium, which then decomposes into magnesium by the emission of beta particles. He tries to lead, without results, and then fluorine in the form of calcium fluoride, which emits alpha particles and produces nitrogen, decomposes into oxygen by beta particle emissions. Overall, it induces radioactivity in 22 different elements. Fermi quickly reported the discovery of neutron-induced radioactivity in the Italian journal La Ricerca Scientifica on March 25, 1934.
The natural radioactivity of thorium and uranium makes it difficult to determine what happens when these elements are bombarded with neutrons but, after completely eliminating the presence of elements lighter than uranium but heavier than lead, Fermi concludes that they have created elements of a new element, which he called hesperium and ausonium. Chemist Ida Noddack criticized this work, pointing out that some experiments can produce elements that are lighter than lead rather than a heavier new element. His advice was not taken seriously at the time because his team did not experiment with uranium, and his claim had found masurium (technetium) debated. At that time, fission was considered impossible if not impossible on a theoretical basis. While physicists expect elements with higher atomic numbers to form from neutrons bombing lighter elements, no one expects neutrons to have enough energy to divide heavier atoms into two light element fragments in the way Noddack suggests.
Children Via Panisperna also noticed some unexplained effects. The experiment seemed to work better on a wooden table than a marble table. Fermi recalls that Joliot-Curie and Chadwick had noted that paraffin wax was effective for slowing down neutrons, so he decided to give it a try. When neutrons are passed through paraffin wax, they induce a hundred times more radioactivity in silver than when bombarded without paraffin. Fermi suspects that this is due to hydrogen atoms in paraffin. Those who use wood also explain the difference between wood and marble tables. This is confirmed by repeating the effect with water. He concluded that a collision with a hydrogen atom slows down a neutron. The lower the number of nucleus atoms that collide with it, the more energy a neutron loses per collision, and therefore the less collisions it takes to slow down a certain number of neutrons. Fermi realizes that this induces more radioactivity because slow neutrons are easier to catch than fast neutrons. He developed a diffusion equation to describe this, which came to be known as the Fermi age equation.
In 1938 Fermi received the Nobel Prize in Physics at the age of 37 for "demonstration of the existence of new radioactive elements produced by neutron irradiation, and for the discovery of nuclear-related reactions caused by slow neutrons". After Fermi received a gift in Stockholm, he did not return to Italy, but proceeded to New York City with his family in December 1938, where they applied for permanent residence. The decision to move to America and become a US citizen is primarily caused by Italian racial laws.
Manhattan Project
Fermi arrived in New York City on January 2, 1939. He immediately offered a post at five universities, and received a post at Columbia University, where he had given a summer lecture in 1936. He received the news that in December 1938, the German chemist Otto Hahn and Fritz Strassmann have detected barium elements after bombarding uranium with neutrons, which Lise Meitner and his nephew Otto Frisch correctly interpreted as a result of nuclear division. Frisch confirmed the experiment on January 13, 1939. News of Meitner and Frisch's interpretation of the discovery of Hahn and Strassmann crossed the Atlantic with Niels Bohr, who was going to college at Princeton University. Isidac Isaac Rabi and Willis Lamb, two Columbia University physicists working at Princeton, found out about it and brought it back to Columbia. Rabbi said he told Enrico Fermi, but Fermi then gave credit for Lamb:
I remember very clearly in the first month, January 1939, that I started working at the Pupin Laboratory because things began to happen very quickly. In that period, Niels Bohr was attending a lecture at Princeton University and I remember one afternoon Willis Lamb was again very excited and said that Bohr had leaked the good news. The big news that has leaked is the discovery of fission and at least the outline of its interpretation. Then, somewhat later that same month, there was a meeting in Washington where the possibility of a newly discovered physiological phenomenon was first discussed in a semi-jocular effort as a possible source of nuclear power.
Noddack proved right. Fermi has rejected the possibility of fission based on his calculations, but he does not take into account the binding energy that will arise when nuclides with neutron neutrons absorb extra neutrons. For Fermi, the news came as a very shameful thing, because the transuranic elements he had gained as a Nobel Prize for his discovery were not transuranic elements at all, but fission products. He added a footnote to this effect on his Nobel Prize acceptance speech.
Scientists at Columbia decided they should try to detect the energy released in nuclear uranium splits when bombarded by neutrons. On January 25, 1939, in the basement of Pupin Hall in Columbia, an experimental team including Fermi conducted the first nuclear fission experiment in the United States. Other members of the team are Herbert L. Anderson, Eugene T. Booth, John R. Dunning, G. Norris Glasoe, and Francis G. Slack. The next day, the 5th Washington Conference on Theoretical Physics began in Washington, D.C. under the joint assistance of George Washington University and the Carnegie Institution of Washington. There, news about nuclear fission spreads further, encouraging more experimental demonstrations.
French scientist Hans von Halban, Lew Kowarski, and Frà © jÃÆ'  © ric Joliot-Curie have shown that the uranium bombarded by neutrons emits more neutrons than is absorbed, suggesting a possible chain reaction. Fermi and Anderson did it a few weeks later. LeÃÆ'³ SzilÃÆ'¡rd acquired 200 kilograms (440 pounds) of uranium oxide from Canadian radiator manufacturer Eldorado Gold Mines Limited, enabling Fermi and Anderson to experiment with fission on a much larger scale. Fermi and SzilÃÆ'¡rd collaborate on device design to achieve an independent nuclear reaction - a nuclear reactor. Due to the absorption rate of neutrons by hydrogen in water, it is unlikely that the independent reaction can be achieved with natural uranium and water as a moderator of neutrons. Fermi suggests, based on his work with neutrons, that the reaction can be achieved with uranium and graphite oxide blocks as a moderator instead of water. This will reduce the catch rate of neutrons, and in theory make the chain reaction self-sufficient as possible. SzilÃÆ'¡rd came up with a workable design: a pile of uranium oxide blocks interspersed with graphite bricks. SzilÃÆ'¡rd, Anderson, and Fermi published a paper on "Neutron Production in Uranium". But the habits and personality of their work are different, and Fermi has trouble working with SzilÃÆ'¡rd.
Fermi was among the first to warn military leaders of the potential impacts of nuclear energy, lecture about it at the Navy Department on March 18, 1939. His response was less than he expected, even though the Navy agreed to provide $ 1,500 toward further research at Columbia. Later that year, SzilÃÆ'¡rd, Eugene Wigner, and Edward Teller sent a famous letter signed by Einstein to US President Roosevelt, warning that Nazi Germany was likely to build an atomic bomb. In response, Roosevelt formed the Uranium Advisory Committee to investigate the issue.
The Uranium Advisory Committee provided money for Fermi to buy graphite, and he built a pile of graphite bricks on the seventh floor of the Pupin Hall lab. In August 1941, he had six tons of uranium oxide and thirty tons of graphite, which he used to build a larger pile at Schermerhorn Hall in Columbia.
The S-1 section of the Office of Scientific Research and Development, as the Uranium Advisory Committee is now known, met on December 18, 1941, with the US now engaged in World War II, making its work urgent. Most of the efforts sponsored by the Committee have been directed to producing enriched uranium, but Committee member Arthur Compton determined that a viable alternative would be plutonium, which could be mass-produced in a nuclear reactor by the end of 1944. He decided to concentrate plutonium. working at the University of Chicago. Fermi reluctantly moved, and his team became part of the new Metallurgical Laboratory there.
The probable outcome of an independent nuclear reaction is unknown, so it does not seem advisable to build the first nuclear reactor on the U. C. campus in the middle of the city. Compton found its location in the Argonne Woods Protected Forest, about 20 miles (32 km) from Chicago. Stone & amp; Webster was contracted to develop the site, but the work was stopped by industrial disputes. Fermi then persuaded Compton that he could build a reactor on a squash field under the Stagg Field U booth of C. Construction of the pile began on 6 November 1942, and Chicago Pile-1 became critical on December 2. The shape of the pile is meant to be roughly round, but when the work goes, Fermi calculates that criticality can be accomplished without completing the entire pile as planned.
This experiment is a landmark in the search for energy, and that's typical of the Fermi approach. Each step is carefully planned, each calculation done thoroughly. When the first independent nuclear chain reaction was reached, Compton made a coded telephone call to James B. Conant, chairman of the National Defense Research Committee.
I picked up the phone and called Conant. He was contacted at the President's office at Harvard University. "Jim," I said, "you'd be interested to know that the Italian navigator has just landed in a new world." Then, half apologizing, as I had led the Sl Committee to believe that it would be another week or so before the pile could be completed, I added, "the earth is not as big as he thinks, and he arrives in a new place, the world is faster than that hopefully. "
"That's it," was Conant's delightful response. "Are native people friendly?" "Everyone landed safely and happily."
To continue research where it would not pose a public health hazard, the reactor was dismantled and transferred to the Argonne Woods site. There Fermi directs experiments on nuclear reactions, enjoying the opportunities provided by the reactor's abundant free reactor neutrons. The laboratory soon branched off from physics and engineering using reactors for biological and medical research. Initially, Argonne was run by Fermi as part of the University of Chicago, but he became a separate entity with Fermi as its director in May 1944.
When the X-10 Air-cooled Graphite Reactor at Oak Ridge became critical on November 4, 1943, Fermi was on hand in case something went wrong. The technician wakes him up early so he can see it happen. Getting X-10 operational is another milestone in the plutonium project. It provides data on reactor design, training for DuPont staff in reactor operation, and produces the first small amount of plutonium produced by the reactor. Fermi became an American citizen in July 1944, the earliest date permitted by law.
In September 1944, Fermi inserted the first uranium fuel slug into Reactor B on the Hanford Site, a production reactor designed to breed plutonium in large quantities. Like the X-10, it has been designed by the Fermi team at the Metallurgy Laboratory, and built by DuPont, but much larger, and water-cooled. Over the next few days, 838 tubes are loaded, and the reactor becomes critical. Shortly after midnight on September 27, operators began to pull the control rod to start production. Initially all looked good, but at about 3am, the power level started to fall and by 6:30 the reactor was completely dead. The Army and DuPont asked for help from the Fermi team. Cooling water is investigated to see if there are any leaks or contamination. The next day the reactor suddenly rises again, only to be turned off again a few hours later. The problem is traced to neutron poisoning from xenon-135, a fission product with a half-life of 9.2 hours. Fortunately, DuPont has deviated from the original design of the Metallurgical Laboratory where the reactor has 1,500 tubes arranged in a circle, and has added 504 tubes to fill the corners. Scientists initially thought the excessive engineering was a waste of time and money, but Fermi realized that if all 2004 tubes were loaded, the reactor could reach the required power level and efficiently produce plutonium.
In mid-1944, Robert Oppenheimer persuaded Fermi to join Project Y at Los Alamos, New Mexico. Upon arriving in September, Fermi was appointed associate director of the laboratory, with extensive responsibility for nuclear and theoretical physics, and was assigned to the F Division, named after him. F Division has four branches: F-1 Super and General Theory under Teller, which investigates "Super" (thermonuclear) bombs; F-2 Water Boiler under L. D. P. King, which maintains a homogenous water research reactor "water boiler"; F-3 Super Experimentation under Egon Bretscher; and F-4 Fission Studies under Anderson. Fermi observed the Trinity test on July 16, 1945, and conducted experiments to estimate the bomb result by dropping paper into an explosion wave. He paced from the distance they were blown by the explosion, and counted the results as ten kilotons of TNT; the actual result is about 18.6 kilotons.
Together with Oppenheimer, Compton, and Ernest Lawrence, Fermi is part of a scientific panel advising the Interim Committee on the selection of targets. The panel agrees with the committee that the atomic bomb will be used without warning of the industry target. Like the others at the Los Alamos Laboratory, Fermi learned about the atomic bombings of Hiroshima and Nagasaki from the public address system in the technical field. Fermi does not believe that atomic bombs will prevent countries from starting a war, nor do they think the time has come for world government. He therefore did not join the Los Alamos Association of Scientists.
Post-war work
Fermi became Charles H. Swift Distinguished Professor of Physics at the University of Chicago on July 1, 1945, although he did not leave Los Alamos Laboratory with his family until December 31, 1945. He was elected a member of the US National Academy of Sciences. in 1945. The Metallurgy Laboratory became the Argonne National Laboratory on July 1, 1946, the first of a national laboratory founded by the Manhattan Project. The short distance between Chicago and Argonne allows Fermi to work in both places. At Argonne he continued his experimental physics, investigating the scattering of neutrons with Leona Marshall. He also discussed theoretical physics with Maria Mayer, helping him develop his insights into the spin-orbit clutch that would cause him to receive the Nobel Prize.
The Manhattan Project was replaced by the Atomic Energy Commission (AEC) on January 1, 1947. Fermi served on the AEC's General Advisory Committee, an influential scientific committee headed by Robert Oppenheimer. He also likes to spend several weeks each year at Los Alamos National Laboratory, where he collaborates with Nicholas Metropolis, and with John von Neumann on Rayleigh-Taylor instability, the science of what goes on the border between two liquids with different densities..
Following the bombing of the first Soviet fission bomb in August 1949, Fermi, along with Isidor Rabi, wrote the report aloud to the committee, opposing the development of hydrogen bombs on moral and technical grounds. Nonetheless, Fermi continues to participate in working on the hydrogen bomb at Los Alamos as a consultant. Together with Stanislaw Ulam, he calculates that not only the amount of tritium required for the Teller thermonuclear weapon model becomes a barrier, but fusion reactions are still uncertain to spread even with this large amount of tritium. Fermi was among the scientists who testified on behalf of Oppenheimer at the Oppenheimer security trial in 1954 that resulted in the denial of Oppenheimer's security clearance.
In his later years, Fermi continued to teach at the University of Chicago. His PhD students in the postwar period included Owen Chamberlain, Geoffrey Chew, Jerome Friedman, Marvin Goldberger, Tsung-Dao Lee, Arthur Rosenfeld, and Sam Treiman. Jack Steinberger is a graduate student. Fermi undertook important research in particle physics, especially with regard to pawns and muons. He made the first prediction of pine-nucleon resonance, relying on statistical methods, because he reasoned that the exact answer was not needed when the theory was wrong anyway. In a paper co-written with Chen Ning Yang, he speculates that the pawn is actually a composite particle. The idea was expounded by Shoichi Sakata. Since then it has been replaced by the quark model, in which the pawn consists of quarks, which solve the Fermi model, and justify its approach.
Fermi wrote the paper "On the Origin of Cosmic Radiation" in which he proposed that cosmic rays arise through matter that is accelerated by a magnetic field in interstellar space, causing differences of opinion with Teller. Fermi examines the problem surrounding the magnetic field in the arm of the spiral galaxy. He reflects on what is now called the "Fermi Paradox": the contradiction between the probability of the possibility of existence of extraterrestrial life and the fact that contact has not been made.
Toward the end of his life, Fermi questioned his faith in the wider community to make wise choices about nuclear technology. He says:
Some of you might ask, what is the point of working so hard just to gather some facts that will not bring pleasure except to some long-haired professors who like to collect such items and will not be of any use to anyone because few of the best specialists will be able to understand them ? In answer to such a question [s] I can explore a fairly safe prediction.
The history of science and technology has consistently taught us that scientific advances in basic understanding sooner or later lead to technical and industrial applications that have revolutionized our way of life. It seems to me unlikely that the attempt to achieve this material structure should be an exception to this rule. What is less certain, and what we all expect sincerely, is that man will soon grow up to harness the power he gains from nature.
Death
Fermi underwent an exploratory operation at Billings Memorial Hospital on October 9, 1954, after which he returned home. 50 days later, Fermi died at the age of 53 stomach cancer at her home in Chicago, and was buried at Oak Woods Cemetery.
Impact and inheritance
Legacy
Fermi received many accolades in recognition of his achievements, including the Matteucci Medal in 1926, the Nobel Prize for Physics in 1938, the Hughes Medal in 1942, the Franklin Medal in 1947, and the Rumford Prize in 1953. He was awarded the Medal for Merit in the year 1946 for his contribution to the Manhattan Project. Fermi was elected a Foreign Member of the Royal Society (FRS) in 1950. The Basilica of Santa Croce, Florence, known as the Temple of Italian Glories due to the many tombs of artists, scientists and figures in Italian History a plaque commemorating Fermi. In 1999, Time named Fermi in the list of the top 100 people of the 20th century. Fermi is widely regarded as an unusual case of a 20th century physicist who excelled both theoretically and experimentally. The physicist CP Snow wrote that "if Fermi had been born several years before, one could imagine him discovering the nucleus of Rutherford's atom, and then developing Bohr's theory of a hydrogen atom.if this sounds like hyperbole, anything about Fermi sounds like a hyperbole".
Fermi is known as an inspiring teacher, and is renowned for his attention to detail, simplicity, and careful preparation of his lectures. Later, his lecture notes were transcribed into books. His papers and notebooks are now at the University of Chicago. Victor Weisskopf notes how Fermi "always managed to find the simplest and most direct approach, with minimal complications and sophistication." Fermi's ability and success stems from his judgment of possible art, such as from his innate skill and intelligence. He does not like complicated theories, and while he has great mathematical skills, he will never use them when the work can be done more easily. He is famous for getting quick and accurate answers to problems that will make other people stumble. Then, his method of getting answers and quick answers via informal back-of-the-envelope calculations is known as the "Fermi method", and is widely taught.
Fermi is happy to point out that Alessandro Volta, who works in his laboratory, can not know where the study of electricity will lead. Fermi is generally remembered for his work on nuclear power and nuclear weapons, especially the creation of the first nuclear reactor, and the development of the first atomic and hydrogen bombs. His scientific work has survived the test of time. This includes his theory of beta decay, his work with a nonlinear system, his discovery of the slow neutron effect, his study of nuclear collisions, and his Fermi-Dirac statistics. Speculation that a pawn is not a fundamental particle that points the way to the study of quarks and leptons.
Things named in Fermi honor
Many things bear the name Fermi. These include Fermilab particle accelerators and physics labs in Batavia, Illinois, which were renamed in his honor in 1974, and the Fermi Gamma-ray Space Telescope, named after him in 2008, in recognition of his work on cosmic rays. Three nuclear reactor installations are named after them: the Fermi 1 and Fermi 2 nuclear power plants in Newport, Michigan, the Enrico Fermi Nuclear Power Station at Trino Vercellese in Italy, and the Enrico Fermi RA-1 research reactor in Argentina. The synthetic element isolated from the 1952 nuclear test debris of Ivy Mike was named fermium, in honor of Fermi's contribution to the scientific community. This makes it one of 16 scientists who have elements named after them.
Since 1956, the United States Atomic Energy Commission has given the highest honor name, Fermi Award, after him. Award recipients include renowned scientists such as Otto Hahn, Robert Oppenheimer, Edward Teller and Hans Bethe.
Bibliography
- Introduzione alla Fisica Atomica (in Italian). Bologna: N. Zanichelli. 1928. OCLCÃ, 9653646.
- Fisica per i Licei (in Italian). Bologna: N. Zanichelli. 1929. OCLCÃ, 9653646.
- Molecole e cristalli (in Italian). Bologna: N. Zanichelli. 1934. OCLCÃ, 19918218.
- Thermodynamics . New York: Prentice Hall. 1937. OCLCÃ, 2379038. Ã,
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Fisica per Istituti Tecnici (in Italian). Bologna: N. Zanichelli. 1938. Ã, - Fisica per Licei Scientifici (in Italian). Bologna: N. Zanichelli. 1938. Ã, (with Edoardo Amaldi)
- Basic particles . New Haven: Yale University Press. 1951. OCLCÃ, 362513.
Source of the article : Wikipedia
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