Biographical Memoirs Volume 75 (1998) / Chapter Skim
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Henry Herman Barschall
Henry Herman Barschall
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13io,qraphicat Memoirs VOLUME 75
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a significant contribution to meclical physics, and his administrative work for the Physics Section of the National Academy of Sciences and, especially, for the American Physical Society en c! the American Institute of Physics, led to an unprecedented memorial session of the American Physical Society after his cleath.
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Marianus Czerny taught "an excellent experimental physics laboratory." At the Technical University Heinz stucliec! experimental physics uncler Gustav Hertz en c!
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the theoretical physics text of Georg loos, along with fellow student Werner Stein, a convincec! anti-Nazi who "macle a point of being friencIly With Heinz]
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Kanner was a fellow graduate student, who Heinz consicIerec! a brilliant experimentalist (Kanner cliec!
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through interactions with the recently discovered rare isotope 235U, they demonstrated that the fast neutron fission was clominatec! by neutron interactions with the primary isotope 238U.
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by the recoils of the helium nuclei struck by the neutrons, corresponclecI, with only a transformation of units, to the neutron scattering angular distribution in the center of mass system. The partial wave analysis introclucec!
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to Los Alamos were especially important. At that time "fast" roughly meant energies greater than a few keV up to a few MeV, the maximum energies easily achievable at that time, while "slow" was applier!
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a program of measurements of neutron cross sections of different elements as a function of energy, which clemonstratec! the existence of broacI, discrete resonances in the total cross-section in elements as heavy as leacI.
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to fit the ciata with an optical model, where the nuclei acted as simple square wells clear crystal balls with an inclex of refraction representing the interaction strength. Such behavior was quite unexpected at a time when the liquicI-cirop moclel of nuclei with very short nucleon mean free-paths was still generally accepted.
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Herman Feshbach, MIT graduate student Charlie Porter, en c! Viki Weiskopf solver!
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Barschall wrote later, "From 1946 to 1970 our group at Wisconsin investigated all aspects of the interaction of MeV neutrons with nuclei." The "all" included measurements of the angular distributions and polarizations of the neutrons scattered from nuclei, their absorption cross-sections, and further total cross-sections measured with better resolutions at the high energies that became available. The angular distribution and polarization measurements on heavy nuclei further defined the optical model, the same measurements on light nuclei established the neutron-proton scattering length fundamental to nuclear forces and through neutron-helium scattering measurements finished the seminal study of spin-orbit forces he began at Princeton as a graduate student.
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on the laboratory's nuclear physics programs, often with one of his students from Wisconsin. In the course of these periods at Los Alamos, Heinz met Eleanor Folsom, who taught school there.
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to investigate journal pricing policies, evaluating the costper-worc! of library subscriptions to the various physical journals, en c!
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he never again worker! in nuclear physics research.
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to Maclison in 1973 with a joint appointment in the Department of Nuclear Engineering en c! the Physics Department.
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Perhaps Barschall's most characteristic service to the American Physical Society was, on the surface, the least characteristic. The Forum on Physics en c!
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For many years, his former graduate students, the Barschall alumni, met at clinner with Heinz annually at the Washington meeting of the American Physical Society. There were special celebrations on his sixtieth en c!
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Study of uranium and thorium fission produced by fast neutrons of nearly homogeneous energy.
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Energy dependence of fast neutron activation cross sections.
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94:192. 1986 The cost of physics journals.
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