Carl David Anderson

Carl David Anderson (September 3, 1905 – January 11, 1991) was an American particle physicist who shared the 1936 Nobel Prize in Physics with Victor Francis Hess for his discovery of the positron.

Biography

Anderson was born in New York City, the son of Swedish immigrants. He studied physics and engineering at Caltech (B.S., 1927; Ph.D., 1930). Under the supervision of Robert A. Millikan, he began investigations into cosmic rays during the course of which he encountered unexpected particle tracks in his (modern versions now commonly referred to as an Anderson) cloud chamber photographs that he correctly interpreted as having been created by a particle with the same mass as the electron, but with opposite electrical charge. This discovery, announced in 1932 and later confirmed by others, validated Paul Dirac's theoretical prediction of the existence of the positron. Anderson first detected the particles in cosmic rays. He then produced more conclusive proof by shooting gamma rays produced by the natural radioactive nuclide ThC'' (²⁰⁸Tl)<ref>ThC" is a historical designation of ²⁰⁸Tl, see Decay chains</ref> into other materials, resulting in the creation of positron-electron pairs. For this work, Anderson shared the 1936 Nobel Prize in Physics with Victor Hess.<ref>The Nobel Prize in Physics 1936. nobelprize.org</ref> Fifty years later, Anderson acknowledged that his discovery was inspired by the work of his Caltech classmate Chung-Yao Chao, whose research formed the foundation from which much of Anderson's work developed but was not credited at the time.<ref name="Chinese">Template:Cite journal</ref>

Also in 1936, Anderson and his first graduate student, Seth Neddermeyer, discovered a muon (or 'mu-meson', as it was known for many years), a subatomic particle 207 times more massive than the electron, but with the same negative electric charge and spin 1/2 as the electron, again in cosmic rays. Anderson and Neddermeyer at first believed that they had seen a pion, a particle which Hideki Yukawa had postulated in his theory of the strong interaction. When it became clear that what Anderson had seen was not the pion, the physicist I. I. Rabi, puzzled as to how the unexpected discovery could fit into any logical scheme of particle physics, quizzically asked "Who ordered that?" (sometimes the story goes that he was dining with colleagues at a Chinese restaurant at the time). The muon was the first of a long list of subatomic particles whose discovery initially baffled theoreticians who could not make the confusing "zoo" fit into some tidy conceptual scheme. Willis Lamb, in his 1955 Nobel Prize Lecture, joked that he had heard it said that "the finder of a new elementary particle used to be rewarded by a Nobel Prize, but such a discovery now ought to be punished by a 10,000 dollar fine."<ref>Willis E. Lamb, Jr. (December 12, 1955) Fine structure of the hydrogen atom. Nobel Lecture</ref>

Anderson spent all of his academic and research career at Caltech. During World War II, he conducted research in rocketry there. He was elected to the United States National Academy of Sciences and the American Philosophical Society in 1938.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> He was elected a Fellow of the American Academy of Arts and Sciences in 1950.<ref name=AAAS>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> He received the Elliott Cresson Medal of the Franklin Institute in 1937 and the Golden Plate Award of the American Academy of Achievement in 1975.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> He died on January 11, 1991, in San Marino, California. His remains were interred in the Forest Lawn, Hollywood Hills Cemetery in Los Angeles, California. In 1946, he married Lorraine Bergman, with whom he had two sons.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Select publications

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Further reading

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External links

• 1983 Audio Interview with Carl Anderson by Martin Sherwin Voices of the Manhattan Project

• American National Biography, vol. 1, pp. 445–446.
• Annotated bibliography for Carl David Anderson from the Alsos Digital Library for Nuclear Issues
• Carl Anderson and the Discovery of the Positron
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• National Academy of Sciences Biographical Memoir
• Oral History interview transcript with Carl D. Anderson on 30 June 1966, American Institute of Physics, Niels Bohr Library and Archives
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