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Born on this day
Imre Kertész
Imre Kertész is a Hungarian author of Jewish descent and a Nobel Prize award winner.
45th week in year
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Norman Foster Ramsey, Jr. 27.8.1915

Wikipedia (17 Apr 2014, 09:40)
Norman Foster Ramsey, Jr. (August 27, 1915 – November 4, 2011) was an American physicist who was awarded the 1989 Nobel Prize in Physics, together with Hans G. Dehmelt from University of Washington, for the invention of the separated oscillatory field method, which had important applications in the construction of atomic clocks. A physics professor at Harvard University for most of his career, Ramsey also held several posts with such government and international agencies as NATO and the United States Atomic Energy Commission. Among his other accomplishments are helping to found the United States Department of Energy's Brookhaven National Laboratory and Fermilab.


At the end of the war, Ramsey returned to Columbia as a professor and research scientist. Rabi and Ramsey picked up where they had left off before the war with their molecular beam experiments. Ramsey and his first graduate student, William Nierenberg, measured various nuclear magnetic dipole and electric quadrupole moments.With Rabi, he helped establish the Brookhaven National Laboratory on Long Island. In 1946, he became the first head of the Physics Department there. His time there was brief, for in 1947, he joined the physics faculty at Harvard University, where he would remain for the next 40 years, except for brief visiting professorships at Middlebury College, Oxford University, Mt. Holyoke College and the University of Virginia. During the 1950s, he was the first science adviser to NATO, and initiated a series of fellowships, grants and summer school programs to train European scientists.

Ramsey's research in the immediate post-war years looked at measuring fundamental properties of atoms and molecules by use of molecular beams. On moving to Harvard, his objective was to carry out accurate molecular beam magnetic resonance experiments, based on the techniques developed by Rabi. However, the accuracy of the measurements depended on the uniformity of the magnetic field, and Ramsey found that it was difficult to create sufficiently uniform magnetic fields. He developed the separated oscillatory field method in 1949 as a means of achieving the accuracy he wanted.

Ramsey and his PhD student Daniel Kleppner developed the atomic hydrogen maser, looking to increase the accuracy with which the hyperfine separations of atomic hydrogen, deuterium and tritium could be measured, as well as to investigate how much the hyperfine structure was affected by external magnetic and electric fields. He also participated in developing an extremely stable clock based on a hydrogen maser. Since 1967, the second has been defined based on 9,192,631,770 hyperfine transition of a cesium-133 atom; the atomic clock which is used to set this standard is an application of Ramsey's work. He was awarded the Nobel Prize in Physics in 1989 "for the invention of the separated oscillatory fields method and its use in the hydrogen maser and other atomic clocks". The Prize was shared with Hans G. Dehmelt and Wolfgang Paul.

In collaboration with the Institut Laue–Langevin, Ramsey also worked on applying similar methods to beams of neutrons, measuring the neutron magnetic moment and finding a limit to its electric dipole moment. As President of the Universities Research Association during the 1960s he was involved in the design and construction of the Fermilab in Batavia, Illinois. He also headed a 1982 National Research Council committee that concluded that, contrary to the findings of the House of Representatives Select Committee on Assassinations, that acoustic evidence did not indicate the presence of a second gunman's involvement in the assassination of President John F. Kennedy.

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