Edward Bryant Nelson

Abstract

Edward Bryant Nelson’s long professional career as a physics teacher and research physicist is identified principally with Columbia University and the University of Iowa. He died of age-related complications on 30 April 2004 in Gainesville, Florida, where he and his wife Judith moved after his retirement from the Iowa faculty in 1983.Born on 26 July 1916 in McHenry, Kentucky, Nelson earned a BS (1937) from Western Kentucky State Teachers College in Bowling Green, an MS (1938) from Vanderbilt University, and a PhD (1949) from Columbia University, all in physics. During the period 1938–49, he taught physics at Western Kentucky and at Columbia and was a research physicist in the Columbia component of the Manhattan Project.Nelson and John E. Nafe, fellow graduate students in I. I. Rabi’s laboratory at Columbia, used the atomic beam magnetic resonance method to make the first experimental measurements of the hyperfine structure of atomic hydrogen and deuterium. The findings of Nafe, Nelson, and Rabi were published in the Physical Review in 1947. Behind the closed door of their laboratory, the two hard-working students referred to their mentor as “I. I.,” as in “Aye, aye, sir,” after responding to his frequent inquiry, “Any results yet?”In an extended follow-up paper (Physical Review, 1948), Nafe and Nelson reported values of the hyperfine transition frequencies with improved precision, namely 1420.410 (±0.006) MHz for hydrogen and 327.384 (±0.003) MHz for deuterium. The relatively small (0.25%) but glaring discrepancy between their experimental values and the prevailing theoretical expectations for the electron spin-flip transition in the ground state of these atoms led theorists to identify the “anomalous” magnetic moment of the electron in the context of relativistic quantum electrodynamics. In a quite different context, the Nafe–Nelson value for the hyperfine transition frequency in hydrogen facilitated the search for the corresponding emission from atomic hydrogen in remote astrophysical systems. Such emission, discovered by Harold I. Ewen and Edward M. Purcell in 1951, soon became a major component of radio astronomy. Nelson and Nafe also collaborated on two closely related Physical Review papers (1949), “The Hyperfine Structure of Tritium” and “A Comparison of the g Value of the Electron in Hydrogen with That in Deuterium,” based on their respective PhD dissertations.In 1949, Nelson joined the physics faculty at Iowa and turned his talents to teaching and to research in experimental nuclear physics using proton beams from Iowa’s nuclear accelerators. In collaboration with James A. Jacobs, Richard R. Carlson, and a sequence of graduate students, he specialized in nuclear gamma rays, nuclear energy levels, and the spectra and angular correlations of the products resulting from the bombardment of a wide variety of elements. After Iowa acquired a large Van de Graaff accelerator, he conducted experiments with helium-3 beams up to 6.2 MeV and with lithium beams up to 13.8 MeV.Throughout his long tenure at Iowa, Nelson was a devoted and enthusiastic teacher. He was a leader in the development and supervision of the undergraduate laboratories and in the training of graduate teaching assistants. His Physics Laboratory Manual —the first edition was published in 1961 (William C. Brown)—was used for many years at Iowa and elsewhere. The career total of enrollments in his courses exceeded 10 000 student-semesters. He was active in the programs of the Iowa Academy of Science and the American Association of Physics Teachers, and he wrote and edited examinations for the American College Testing Service.During the 1960s, Nelson helped design the new buildings for housing the physics and astronomy department and gave special attention to lecture rooms and teaching laboratories. From 1963 until his retirement in 1983, he served as associate head of the department and as principal adviser of undergraduate majors.Nelson is remembered with affection and admiration by his colleagues at Iowa and elsewhere and by many friends in Iowa City and Gainesville.Edward Bryant NelsonPPT|High resolution© 2004 American Institute of Physics.