Photo from the Nobel Foundation archive.
Born: 5 February 1915, New York, NY, USA
Died: 17 November 1990, Stanford, CA, USA
Affiliation at the time of the award: Stanford University, Stanford, CA, USA
Prize motivation: "for his pioneering studies of electron scattering in atomic nuclei and for his thereby achieved discoveries concerning the structure of the nucleons."
Prize share: 1/2
Matter is composed of atoms with small nuclei surrounded by electrons. Robert Hofstadter developed apparatus for studying nuclei's internal structure. A high-energy electron beam from an accelerator was directed towards nuclei and by examining the scattering of the electrons, he could investigate how charges were distributed. He could also investigate how the magnetic moment within the nuclei's protons and neutrons was distributed. Nuclei were thereby proven not to be homogeneous, but to have internal structures.