Anderson spent the entirety of his career at Caltech; he was Research Fellow (1930–1933) and Assistant Professor to Associate Professor of Physics (1933–1939), before finally becoming Professor of Physics in 1939—a position he held until his retirement in 1976.[4]
In 1946, Anderson married Lorraine Bergman, with whom he had two sons.[3]
Photo by Anderson of the first positron ever observed, 15 March 1933
Under the supervision ofRobert Millikan, Anderson began investigations intocosmic 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 theelectron, but with oppositeelectric charge.
This discovery, announced in 1932 and later confirmed by others, validatedPaul Dirac's theoretical prediction of the existence of thepositron. Anderson first detected the particles in cosmic rays. He then produced more conclusive proof by shootinggamma rays produced by the natural radioactive nuclide ThC'' (208Tl)[6] into other materials, resulting in the creation of positron-electron pairs.
For this work, Anderson shared the 1936Nobel Prize in Physics withVictor Hess.[7] 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.[8]
In 1936, Anderson and his first graduate student,Seth Neddermeyer, discovered themuon[9] (or 'mu-meson', as it was known for many years), asubatomic 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 apion, a particle whichHideki Yukawa had postulated in his theory of thestrong interaction. When it became clear that what Anderson had seen wasnot the pion, the physicistI. I. Rabi, puzzled as to how the unexpected discovery could fit into any logical scheme ofparticle physics, quizzically asked "Who orderedthat?" (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 ofsubatomic 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."[10]
^Anderson, Carl David; Anderson, David A.K. (1999).The Discovery of Anti‑Matter: The Autobiography of Carl David Anderson, the Second Youngest Man to Win the Nobel Prize. World Scientific Publishing.ISBN9789810236809.
^ThC" is a historical designation of208Tl, seeDecay chains
Weiss, Richard J. (1999).The Discovery of Anti-matter: The Autobiography of Carl David Anderson, the (Second) Youngest Man to Win the Nobel Prize. Singapore: World Scientific.ISBN978-981-02-3680-9.
