Carl David Anderson

Infobox Scientist
name = Carl David Anderson


caption = Carl Anderson at LBNL 1937
birth_date = birth date|1905|9|3
birth_place = New York City, United States
death_date = death date and age|1991|1|11|1905|9|3
death_place = San Marino, California, USA
nationality = American
field = Physicist
work_institutions = California Institute of Technology
alma_mater = California Institute of Technology
known_for = Discovery of the positron
Discovery of the muon
notable_students = Donald A. Glaser
prizes = Nobel Prize in Physics 1936

Carl David Anderson (3 September 1905 – 11 January 1991) was an American physicist. He is best known for his discovery of the positron, an achievement for which he received the Nobel Prize in Physics in 1936.

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 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 obtained the first direct proof that positrons existed by shooting gamma rays produced by the natural radioactive nuclide ThC" (²⁰⁸Tl) [ThC" is a historical designation of ²⁰⁸Tl, see Decay chains] into other materials, resulting in creation of positron-electron pairs. For this work, Anderson shared the Nobel Prize in Physics for 1936 with Victor Hess. [ [http://nobelprize.org/nobel_prizes/physics/laureates/1936/ Physics 1936 ] ]

Also in 1936, Anderson and his first graduate student, Seth Neddermeyer, discovered the muon (or 'mu-meson', as it was known for many years), a subatomic particle 207 times more massive than the electron. Anderson and Neddermeyer at first believed that they had seen the 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, theoretical physicist I. I. Rabi, puzzled as to how the unexpected discovery could fit into any logical scheme of particle physics, famously 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 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 fine." [http://nobelprize.org/nobel_prizes/physics/laureates/1955/lamb-lecture.pdf]

Death

Anderson spent all of his career at Caltech. During World War II he conducted research in rocketry. He died on 11 January, 1991, and is interred in the Forest Lawn, Hollywood Hills Cemetery in Los Angeles, California.

elected papers

*C.D. Anderson, "The Positive Electron", Phys. Rev. 43, 491 (1933)

ources

*American National Biography, vol. 1, pp. 445-446.

Footnotes and References

External links

*
* [http://alsos.wlu.edu/qsearch.aspx?browse=people/Anderson,+Carl+D. Annotated bibliography for Carl David Anderson from the Alsos Digital Library for Nuclear Issues]
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