Joseph William Kennedy | |
|---|---|
 Joseph William Kennedy | |
| Born | (1916-05-30)May 30, 1916 |
| Died | May 5, 1957(1957-05-05) (aged 40) |
| Alma mater | University of California, Berkeley University of Kansas Stephen F. Austin State University |
| Known for | First Isolation of Plutonium |
| Awards | Medal for Merit (1946) |
| Scientific career | |
| Fields | Chemistry |
| Institutions | Los Alamos National Laboratory Washington University in St. Louis |
| Thesis | Studies of nuclear isomerism in tellurium, element 43, and zinc (1939) |
| Doctoral advisor | George Ernest Gibson |
Joseph William Kennedy (May 30, 1916 – May 5, 1957) was an Americanchemist who co-discoveredplutonium, along withGlenn T. Seaborg,Edwin McMillan, andArthur Wahl. DuringWorld War II, he led the CM (Chemistry and Metallurgy) Division at theManhattan Project'sLos Alamos Laboratory, where he oversaw research onto thechemistry andmetallurgy ofuranium and plutonium. After the war, he was recruited as a professor atWashington University in St. Louis, where he is credited with transforming a university primarily concerned with undergraduate teaching into one that also boasts strong graduate and research programs. He died of cancer of the stomach at the age of 40.
Joseph William Kennedy was born inNacogdoches, Texas, on May 30, 1916, the son of Joseph and Mattie Kennedy. He lived inCenter, Texas, for seven years before entering college. He attendedStephen F. Austin State Teachers College, from which he received aBachelor of Arts (BA) degree, and theUniversity of Kansas, which awarded him aMaster of Arts (MA) degree. He then entered theUniversity of California, Berkeley,[1] where he earned hisDoctor of Philosophy (PhD) degree, writing his thesis on "Studies of nuclear isomerism in tellurium, element 43, and zinc",[2] under the supervision ofGeorge Ernest Gibson.[3]
In February 1940,Glenn Seaborg andEdwin McMillan producedplutonium-239 by bombardinguranium withdeuterons. This producedneptunium, element 93, which underwentbeta-decay to form a new element, plutonium, with 94protons.[4] Kennedy built a series of detectors and counters to verify the presence of plutonium. He usedmica sliced razor thin to produce a window to countalpha particle emissions, and anionization chamber with a magnetic field to separate the beta particles from the neptunium from alpha particles from the plutonium.[5]
On March 28, 1941, Seaborg, physicistEmilio Segrè, and Kennedy demonstrated not only the presence of plutonium, but that it was alsofissile, an important distinction that was crucial to the decisions made in directingManhattan Project research.Arthur Wahl then began exploring the chemistry of the newly discovered element.[5] In 1966, Room 307 ofGilman Hall on the campus at Berkeley, where they did this work, was declared a U.S.National Historic Landmark.[6]
Kennedy was one of the early recruits to Manhattan Project'sLos Alamos Laboratory, arriving in March 1943.[1] He became acting head of the Chemistry and Metallurgy (CM) Division. Some project leaders had doubts about Kennedy, who was only 26 years old. An approach was therefore made toCharles Thomas fromMonsanto. Thomas agreed to co-ordinate the Chemistry efforts of the different Manhattan Project laboratories, but he did not wish to move to New Mexico.[7] Despite his youth, Kennedy officially became CM Division leader in April 1944.[8]
The CM Division was responsible for the purification and fabrication of materials for the bomb, including thecore,tamper andinitiator.[8] The chemistry and metallurgy of uranium was fairly well known, although it did yield a few surprises, but that of plutonium was almost completely unknown. The element had only been discovered a short time before, and existed only in microgram amounts. Educated guesses about its chemistry tended to be wrong, and as research progressed it was found to have unusual properties, including no less than sixallotropes. There was rivalry between its discoverers, with Wahl and Kennedy's group at Los Alamos competing with Seaborg's in Chicago to produce the best process for purifying the metal. This competition ended abruptly when Segrè's group at Los Alamos discovered that high levels of a hitherto undiscoveredplutonium-240 isotope in reactor-produced plutonium meant that animplosion-type nuclear weapon was required, and a high degree of purity was therefore unnecessary.[9]
Kennedy's chemists were able to reduceuranium hydride touranium-235 metal with 99.96% efficiency, and the metallurgists worked out how to cast and press it into the required shapes.[10] While the chemists worked out how to purify plutonium, the metallurgists had to figure out how to cast it into a solid sphere.Eric Jette's CM-8 (Uranium and Plutonium Metallurgy) group found that they could stabilise plutonium in its malleable δ phase by alloying it withgallium.[11] For his services, he was awarded theMedal for Merit by thePresidentHarry S. Truman in 1946.[12]
In the 2023 filmOppenheimer, Joseph W. Kennedy is portrayed by actor Troy Bronson.[13] Directed byChristopher Nolan, the film highlights the importance of plutonium. While the project was a collaborative effort withGlenn T. Seaborg,Edwin McMillan, andArthur Wahl, Nolan’s portrayal honors the collective endeavor while also crediting Kennedy as the key discoverer, adeptly balancing team dynamics with individual achievement.
In real life, PresidentHarry S. Truman, portrayed byGary Oldman, awarded Kennedy theMedal for Merit for his contributions. The Medal for Merit was the highest civilian decoration of the United States, with only four awardees from the Manhattan Project at Los Alamos:J. Robert Oppenheimer,John von Neumann,Enrico Fermi, and Kennedy.
The filmOppenheimer won a total of seven Oscars at the 2024 Academy Awards, including Best Picture. The film is based on the bookAmerican Prometheus.[14][15][16]
In 1945, Kennedy was recruited to be a professor atWashington University in St. Louis, which installed him as chairman of the department of chemistry in 1946, a role he continued in until his death.[1][12] Kennedy brought with him Wahl, Lindsay Helmholz, David Lipkin, Herbert Potratz, and Samuel Weissman, who all served on the faculty at Washington University.[17] Up to this time, Washington University was primarily concerned with undergraduate teaching. Kennedy is credited with transforming it into a university that also has boasts strong graduate and research programs.[12]
Along with Seaborg, McMillan and Wahl, Kennedy received $400,000 from theAtomic Energy Commission in compensation for their scientific work.[1] He died on May 5, 1957, at the age of 40 after a battle with cancer of the stomach.[18] The Kennedy Lecture series is named in his honor. It is given every year in Washington University.[12]
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