Norman Foster Ramsey, Jr.

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Norman Foster Ramsey, Jr.
Born (1915-08-27)August 27, 1915
Washington, DC
Died November 4, 2011(2011-11-04) (aged 96)
Wayland, Massachusetts
Residence United States
Nationality United States
Alma mater Columbia University, University of Cambridge
Known for Separated oscillatory field method
Awards IEEE Medal of Honor
1989 Nobel Prize in Physics
Scientific career
Fields Physics
Institutions Harvard University

Norman Foster Ramsey, Jr. (August 27, 1915 – November 4, 2011) was an American physicist. A physics professor at Harvard University since 1947, Ramsey also held several posts with such government and international agencies as NATO and the United States Atomic Energy Commission. He was awarded the 1989 Nobel Prize in Physics for the invention, in 1949, of the separated oscillatory field method, which had important applications in the construction of atomic clocks. The Prize was shared with Hans G. Dehmelt and Wolfgang Paul. Among his other accomplishments are helping to found the United States Department of Energy's Brookhaven National Laboratory and Fermilab.[1][2]

Ramsey Method

In 1949, while working at Harvard, Ramsey applied a key insight to improve Columbia University physicist Isidor Rabi's method of studying atoms and molecules. In 1937, Rabi used alternating magnetic fields to characterize atomic matter. Ramsey exposed the atoms to the magnetic field only as they entered or exited his device. Ramsey called it the separated oscillatory fields method; today it is simply called the Ramsey Method.

Dr. Ramsey's work led, ultimately, to nuclear magnetic resonance spectroscopy, and to the magnetic resonance imaging (MRI) machine.[3]

The Ramsey Method also was key in developing the atomic clock. As of 1967, a second of time was no longer defined by a fraction of the earth's revolution around the sun, but rather as 9,192,631,770 radiation cycles of a cesium atom.

In 1960, Ramsey invented an atomic clock based on the hydrogen maser, a design used today in Global Positioning System satellites.


Ramsey was born in Washington, DC on August 27, 1915 to Minna Bauer Ramsey, a mathematics teacher, and Norman Foster Ramsey, an Army officer. He earned his B.A. and Ph.D. in physics from Columbia University in 1935 and 1940, respectively. He stayed on as a member of the Columbia faculty until 1947, when he moved to Harvard University.[1] He died on November 4, 2011.



  1. 1.0 1.1 Lua error in Module:Citation/CS1 at line 746: Argument map not defined for this variable.
  2. doi:10.1038/480182a
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  3. Norman Ramsey Dies at 96; Work Led to the Atomic Clock, New York Times on-line, November 6, 2011

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