Norman Ramsey, who shared the 1989 Nobel Prize in physics for his research into atomic energy levels that led to the creation of the atomic clock and MRI machines, has died. He was 96.
Ramsey died in his sleep Nov. 4 at a nursing home in Wayland, Mass., said his wife, Ellie Ramsey.
Ramsey, an emeritus professor of physics at Harvard University, wrote in his autobiography for the Nobel Prize he shared with Hans Dehmelt and Wolfgang Paul that he was inspired by failure in molecular beam magnetic resonance experiments in the late 1940s to invent a new technique of measuring the frequency of radiation from atoms using two electromagnetic fields.
The technique is known as the separated oscillatory fields method, or more informally among physicists, the Ramsey method, said his protege and longtime friend, Daniel Kleppner, a physics professor emeritus at the Massachusetts Institute of Technology.
It was used in the hydrogen maser, developed to measure the effect of gravity on time, Kleppner said. It led to the development by others of the world's most accurate timekeeper, the cesium atomic clock. Since 1967, the second has been defined as the time during which the cesium atom makes 9,192,631,770 oscillations.
In 1989, after winning the Nobel, Ramsey called it a "valuable application" that has been used in radio astronomy, satellite navigation, space exploration and to test the theory of relativity.
Ramsey's research also led to the invention of the MRI machinery now used extensively in medicine, Kleppner said.
"His work has had a broad impact, and his concepts are pervasive," he said.
After learning he had won the Nobel Prize, Ramsey attributed his long interest in science to the fact that "it's fun."
"Basically, I'm interested in all the laws of nature," Ramsey said at the time.
Ramsey was born Aug. 27, 1915, in Washington, D.C. His mother was a college mathematics teacher and his father was a West Point graduate and career Army officer.
Ramsey said he developed an interest in physics at a young age when he read an article on the quantum theory of the atom. He graduated from high school at the age of 15 and because he was too young to attend West Point, he enrolled at Columbia University in 1931.
During World War II, he worked on radar projects at MIT and as a radar consultant to the secretary of War, ultimately contributing to the Manhattan Project that developed the atomic bomb.
He helped establish the Brookhaven National Laboratory in New York after the war and in 1947 joined the faculty at Harvard, where he taught until 1986.
Ramsey's first wife, Elinor, died in 1983. In addition to his wife, survivors include four children, two stepchildren, eight grandchildren and nine great-grandchildren.