Arthur Holly Compton
1892–1962, Wooster, Ohio, United States, Berkeley, California, United States
American physicist who discovered the Compton effect — the wavelength shift of X-rays scattered by electrons — decisive evidence for the particle nature of light; he received the 1927 Nobel Prize in Physics.
Compton was born in Wooster, Ohio, into an academic family — his father was a professor and later president of the College of Wooster. He earned his PhD at Princeton in 1916, then taught at Washington University in St. Louis, where he performed his celebrated X-ray scattering experiments. In 1923 he moved to the University of Chicago.
His results showed that scattered X-rays emerge at longer wavelengths by a law explicable only if light consists of momentum-carrying photons. During the Second World War he directed the Metallurgical Laboratory in Chicago within the Manhattan Project, overseeing Fermi's first self-sustaining nuclear reactor. From 1946 he served as chancellor of Washington University in St. Louis.
Nobel-winning work
In experiments at Washington University in 1922, Compton measured the wavelengths of X-rays scattered by quasi-free electrons in graphite and found a secondary component shifted to longer wavelengths, the shift growing with scattering angle. His 1923 paper explained the effect as an elastic collision between a photon and an electron, yielding Δλ = (h/mc)(1 − cos θ); Wilson cloud-chamber photographs subsequently revealed the recoiling electrons just as predicted.
The effect furnished decisive evidence for Einstein's photon picture: electromagnetic radiation exchanges energy and momentum in discrete quanta. Compton shared the 1927 Nobel Prize in Physics with C. T. R. Wilson 'for his discovery of the effect named after him'.
Workplaces: Washington University in St. Louis, University of Chicago
United States