Edward Mills Purcell
1912–1997, Taylorville, Illinois, United States, Cambridge, Massachusetts, United States
American physicist, co-discoverer of nuclear magnetic resonance and discoverer of the 21-cm hydrogen line in radio astronomy.
Purcell studied electrical engineering at Purdue and physics at Harvard, staying at Harvard to research and teach for nearly his entire career. During the Second World War he worked on microwave radar at MIT's Radiation Laboratory; his experience with microwave equipment enabled his measurement of nuclear magnetic resonance in solids and liquids in 1945–46. In 1951 he and graduate student Harold Ewen detected the 21-cm emission line of neutral hydrogen, opening modern radio astronomy; he is also known for the magnetic self-amplifying 'Purcell effect' in magnetic resonance.
Nobel-winning work
In late 1945 and early 1946, Purcell, with Robert Pound and Henry Torrey at Harvard, measured the resonant absorption of radio waves by protons in paraffin placed in a magnetic field — the discovery of nuclear magnetic resonance (NMR) in bulk matter, independent of Felix Bloch's group at Stanford. Purcell's technique directly measured the energy absorbed from the magnetic field and was well suited to precisely determining proton and other nuclear magnetic moments.
NMR quickly became the standard method for measuring nuclear magnetic moments and probing chemical structure, and later the foundation of magnetic resonance imaging. In 1951, with Harold Ewen, Purcell also detected the 21-cm line of hydrogen in radio astronomy. Purcell shared the 1952 Nobel Prize in Physics with Bloch 'for their development of new methods for nuclear magnetic precision measurements and discoveries in connection therewith'.
Workplaces: Harvard University
United States