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Norman Ramsey Jr.

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"Norman Ramsey" redirects here. For the U.S. federal judge, seeNorman Park Ramsey.

Norman Foster Ramsey Jr.
Born(1915-08-27)August 27, 1915
Washington, D.C., U.S.
DiedNovember 4, 2011(2011-11-04)(aged 96)
Wayland, Massachusetts,U.S.
Education
Known forRamsey interferometry
RelativesAnne Ramsey(cousin)
Awards
Scientific career
FieldsPhysics
Institutions
Doctoral advisorIsidor Isaac Rabi
Doctoral students
Other notable studentsSunney Chan(post doc)

Norman Foster Ramsey Jr.(August 27, 1915 – November 4, 2011) was an Americanphysicistwho was awarded the 1989Nobel Prize in Physicsfor the invention of the separated oscillatory field method (seeRamsey interferometry), which had important applications in the construction ofatomic clocks.Aphysicsprofessor atHarvard Universityfor most of his career, Ramsey also held several posts with such government and international agencies asNATOand theUnited States Atomic Energy Commission.Among his other accomplishments are helping to found theUnited States Department of Energy'sBrookhaven National LaboratoryandFermilab.

Early life

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Norman Foster Ramsey Jr. was born inWashington, D.C.,on August 27, 1915, to Minna Bauer Ramsey and Norman Foster Ramsey. His mother was the daughter of German immigrants and an instructor at theUniversity of Kansas.[1]His father, who was of Scottish descent, was a 1905 graduate of theUnited States Military AcademyatWest Pointand an officer in theOrdnance Departmentwho rose to the rank ofbrigadier generalduringWorld War II,commanding theRock Island Arsenal.[2]He was raised as anArmy brat,frequently moving from post to post, and lived in France for a time when his father was Liaison Officer with theDirection d'Artillerieand AssistantMilitary Attaché.[3]This allowed him to skip a couple of grades along the way, so that he graduated fromLeavenworth High SchoolinLeavenworth, Kansas,at the age of 15.[1]

Ramsey's parents hoped that he would go to West Point, but at 15, he was too young to be admitted. He was awarded a scholarship to theUniversity of Kansas,but in 1930 his father was posted toGovernors Island,New York.[1][4]Ramsey therefore enteredColumbia Universityin 1931 and began studyingengineering.He became interested inmathematicsand switched to this as hisacademic major.By the time he received hisBAfrom Columbia in 1935, he had become interested inphysics.[1][5]Columbia awarded him aKellett FellowshiptoCambridge University,where he studied physics atCavendish LaboratoryunderLord RutherfordandMaurice Goldhaber,and encountered notable physicists, includingEdward Appleton,Max Born,Edward Bullard,James Chadwick,John Cockcroft,Paul Dirac,Arthur Eddington,Ralph Fowler,Mark OliphantandJ. J. Thomson.[1]At Cambridge, he took thetriposin order to studyquantum mechanics,which had not been covered at Columbia, resulting in being awarded a second BA degree by Cambridge.[6]

A term paper Ramsey wrote for Goldhaber onmagnetic momentscaused him to read recent papers on the subject byIsidor Isaac Rabi,[6]and this stimulated an interest inmolecular beamsand in doing research for aPhDunder Rabi at Columbia.[1][7]Soon after Ramsey arrived at Columbia, Rabi inventedmolecular-beam resonance spectroscopy,for which he was awarded theNobel prize in physicsin 1944.[8]Ramsey was part of Rabi's team that also includedJerome Kellogg,Polykarp Kusch,Sidney MillmanandJerrold Zacharias.Ramsey worked with them on the first experiments making use of the new technique and shared with Rabi and Zacharias in the discovery that thedeuteronwas a magneticquadrupole.[9]This meant that theatomic nucleuswas not spherical, as had been thought.[10]He received his PhD in physics from Columbia in 1940[5]and became a fellow at theCarnegie Institutionin Washington, D.C., where he studiedneutron–protonand proton–heliumscattering.[1]

World War II

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Radiation laboratory

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The Northrop P-61 Black Widownight fighterwas specifically designed to take advantage of the new radar.

In 1940, he married Elinor Jameson ofBrooklyn, New York,and accepted a teaching position at theUniversity of Illinois at Urbana–Champaign.The two expected to spend the rest of their lives there, but World War II intervened.[1]In September 1940 the BritishTizard Missionbrought a number of new technologies to the United States, including acavity magnetron,a high-powered device that generatesmicrowavesusing the interaction of a stream ofelectronswith amagnetic field,which promised to revolutionizeradar.Alfred Lee Loomisof theNational Defense Research Committeeestablished theRadiation Laboratoryat theMassachusetts Institute of Technologyto develop this technology.[11]Ramsey was one of the scientists recruited by Rabi for this work.[12]

Initially, Ramsey was in Rabi's magnetron group. When Rabi became a division head, Ramsey became the group leader.[6]The role of the group was to develop the magnetron to permit a reduction inwavelengthfrom 150 centimetres (59 in) to 10 centimetres (3.9 in), and then to 3 centimetres (1.2 in) orX band.Microwave radar promised to be small, lighter and more efficient than older types.[13]Ramsey's group started with the design produced by Oliphant's team in Britain and attempted to improve it. The Radiation Laboratory produced the designs, which were prototyped byRaytheon,and then tested by the laboratory. In June 1941, Ramsey travelled to Britain, where he met with Oliphant, and the two exchanged ideas. He brought back some British components, which were incorporated into the final design. Anight fighteraircraft, theNorthrop P-61 Black Widow,was designed around the new radar. Ramsey returned to Washington in late 1942 as an adviser on the use of the new 3 cm microwave radar sets that were now coming into service,[7]working forEdward L. Bowlesin the office of theSecretary of War,Henry L. Stimson.[6]

Manhattan Project

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In 1943, Ramsey was approached byRobert OppenheimerandRobert Bacher,who asked him to join theManhattan Project.Ramsey agreed to do so, but the intervention of the project director, Brigadier GeneralLeslie R. Groves Jr.,was necessary in order to prise him away from the Secretary of War's office. A compromise was agreed to, whereby Ramsey remained on the payroll of the Secretary of War and was merely seconded to the Manhattan Project.[6][14][15]In October 1943, Group E-7 of the Ordnance Division was created at theLos Alamos Laboratorywith Ramsey as group leader, with the task of integrating the design and delivery of thenuclear weaponsbeing built by the laboratory.[15]

Ramsey signs theFat Manused at Nagasaki.

The first thing he had to do was determine the characteristics of the aircraft that would be used. There were only twoAlliedaircraft large enough: the BritishAvro Lancasterand the USBoeing B-29 Superfortress.[15]The United States Army Air Forces (USAAF) wanted to use the B-29 if at all possible, even though it required substantial modification.[16]Ramsey supervised the test drop program, which began atDahlgren, Virginia,in August 1943, before moving toMuroc Dry Lake, California,in March 1944. Mock-ups ofThin ManandFat Manbombs were dropped and tracked by anSCR-584ground-based radar set of the kind that Ramsey had helped develop at the Radiation laboratory. Numerous problems were discovered with the bombs and the aircraft modifications, and corrected.[17]

Ramsey's Los Alamos badge

Plans for the delivery of the weapons in combat were assigned to the Weapons Committee, which was chaired by Ramsey and answerable toCaptainWilliam S. Parsons.[18]Ramsey drew up tables of organization and equipment for theProject Albertadetachment that would accompany the USAAF's509th Composite GrouptoTinian.Ramsey briefed the 509th's commander, Lieutenant ColonelPaul W. Tibbets,on the nature of the mission when the latter assumed command of the 509th.[19]Ramsey went to Tinian with the Project Alberta detachment as Parsons's scientific and technical deputy. He was involved in the assembly of the Fat Man bomb and relayed Parsons's message indicating the success of thebombing of Hiroshimato Groves in Washington, D.C.[20]

Research

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At the end of the war, Ramsey returned to Columbia as a professor and research scientist.[1]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 nuclearmagnetic dipoleandelectric quadrupolemoments. With Rabi, he helped establish theBrookhaven National LaboratoryonLong 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 atHarvard University,where he would remain for the next 40 years, except for brief visiting professorships atMiddlebury College,Oxford University,Mt. Holyoke Collegeand theUniversity of Virginia.During the 1950s, he was the first science adviser toNATOand initiated a series of fellowships, grants and summer school programs to train European scientists.[1][6][21]

The Harvard cyclotron during construction in 1948. Shown are Ramsey (left) andLee Davenport(right).

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.[1]

Ramsey and his PhD studentDaniel Kleppnerdeveloped the atomic-hydrogenmaser,looking to increase the accuracy with which thehyperfineseparations of atomichydrogen,deuteriumandtritiumcould 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. From 1967 until 2019,the second has been definedbased on 9,192,631,770 Hz hyperfine transition of acesium-133atom; theatomic clockwhich is used to set this standard is an application of Ramsey's work.[22]He was awarded theNobel Prize in Physicsin 1989 "for the invention of the separated oscillatory fields method and its use in the hydrogen maser and other atomic clocks".[23]The Prize was shared withHans Georg DehmeltandWolfgang Paul.[23]

In collaboration with theInstitut Laue–Langevin,Ramsey also worked on applying similar methods to beams of neutrons, measuring theneutron magnetic momentand finding a limit to itselectric dipole moment.[1]As president of theUniversities Research Associationduring the 1960s he was involved in the design and construction of theFermilabinBatavia, Illinois.[1][21][24]He also headed a 1982National Research Councilcommittee that concluded that, contrary to the findings of theHouse of Representatives Select Committee on Assassinations,acoustic evidence did not indicate the presence of a second gunman's involvementin theassassination of President John F. Kennedy.[24]

Later life

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Ramsey eventually became theEugene Higgins professor of physicsat Harvard and retired in 1986. However, he remained active in physics, spending a year as a research fellow at theJoint Institute for Laboratory Astrophysics(JILA) at theUniversity of Colorado.He also continued visiting professorships at theUniversity of Chicago,Williams Collegeand theUniversity of Michigan.In addition to the Nobel Prize in Physics, Ramsey received a number of awards, including theErnest Orlando Lawrence Awardin 1960,Davisson–Germer Prizein 1974, theIEEE Medal of Honorin 1984, theRabi Prizein 1985, theRumford Premium Prizein 1985, the Compton Medal in 1986, and theOersted Medaland theNational Medal of Sciencein 1988.[1]In 1990, Ramsey received the Golden Plate Award of theAmerican Academy of Achievement.[25]He was an elected member of theAmerican Academy of Arts and Sciences,[26]the United StatesNational Academy of Sciences,[27]and theAmerican Philosophical Society.[28]In 2004, he signed a letter along with 47 otherNobel laureatesendorsingJohn Kerryfor President of the United States as someone who would "restore science to its appropriate place in government".[29]

His first wife, Elinor, died in 1983, after which he married Ellie Welch of Brookline, Massachusetts. Ramsey died on November 4, 2011. He was survived by his wife Ellie, his four daughters from his first marriage, and his stepdaughter and stepson from his second marriage.[7][24]

Bibliography

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Notes

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  1. ^abcdefghijklmn"Norman F. Ramsey – Autobiography".The Nobel Foundation.RetrievedJune 13,2013.
  2. ^Cullum 1950,p. 101.
  3. ^Cullum 1930,pp. 669–670.
  4. ^Cullum 1940,pp. 167–168.
  5. ^ab"Norman F. Ramsey".Soylent Communications.RetrievedJune 11,2013.
  6. ^abcdef"Norman F. Ramsey, an oral history conducted in 1991 by John Bryant".IEEE History Center.RetrievedJune 11,2013.
  7. ^abcTucker, Anthony (November 18, 2011)."Norman Ramsey obituary".The Guardian.RetrievedFebruary 13,2010.
  8. ^"Isidor Isaac Rabi".Nobel Media.RetrievedAugust 17,2012.
  9. ^Kellogg, J. M. B.; Rabi, I. I.; Ramsey, N. F. Jr.; Zacharias, J. R. (October 1939). "The Magnetic Moment of the Proton and the Deuteron. The Radiofrequency Spectrum of2H in Various Magnetic Fields ".Physical Review.56(8): 728–743.Bibcode:1939PhRv...56..728K.doi:10.1103/PhysRev.56.728.
  10. ^Wineland, D.(2011)."Norman Ramsey (1915–2011)".Nature.480(7376): 182.Bibcode:2011Natur.480..182W.doi:10.1038/480182a.PMID22158235.
  11. ^Conant 2002,pp. 209–213.
  12. ^Conant 2002,p. 204.
  13. ^Rigden 1987,pp. 135–135.
  14. ^Hoddeson et al. 1993,p. 59.
  15. ^abcHoddeson et al. 1993,pp. 378–379.
  16. ^Groves 1962,p. 254.
  17. ^Hoddeson et al. 1993,pp. 380–382.
  18. ^Hoddeson et al. 1993,p. 248.
  19. ^Hoddeson et al. 1993,pp. 387–388.
  20. ^Hoddeson et al. 1993,pp. 392–393.
  21. ^ab"The Passing of a Scientific Giant: Norman F. Ramsey (1915–2011)".National Geographic.Archived fromthe originalon November 12, 2011.RetrievedJune 11,2013.
  22. ^"Nobel Prize press release".The Nobel Foundation.RetrievedJune 13,2013.
  23. ^ab"The Nobel Prize in Physics 1989".The Nobel Foundation.RetrievedJune 13,2013.
  24. ^abc"Norman Ramsey Dies at 96; Work Led to the Atomic Clock".New York Times.November 6, 2011.RetrievedNovember 7,2011.
  25. ^"Golden Plate Awardees of the American Academy of Achievement".achievement.org.American Academy of Achievement.
  26. ^"Norman Foster Ramsey".American Academy of Arts & Sciences.RetrievedDecember 16,2022.
  27. ^"Norman F. Ramsey".nasonline.org.RetrievedDecember 16,2022.
  28. ^"APS Member History".search.amphilsoc.org.RetrievedDecember 16,2022.
  29. ^"48 Nobel Winning Scientists Endorse Kerry-June 21, 2004".George Washington University.RetrievedJuly 6,2013.

References

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