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General Kenneth Nichols and the Manhattan Project
Nichols
The Oak Ridger has published the latest in a series of articles about General Kenneth D. Nichols, the Manhattan Project, and the 1954 Atomic Energy Act. The series has been produced by Nichols’ grandniece Barbara Rogers Scollin and Oak Ridge (Tenn.) city historian David Ray Smith. Gen. Nichols (1907–2000) was the district engineer for the Manhattan Engineer District during the Manhattan Project.
As Smith and Scollin explain, Nichols “had supervision of the research and development connected with, and the design, construction, and operation of, all plants required to produce plutonium-239 and uranium-235, including the construction of the towns of Oak Ridge, Tennessee, and Richland, Washington. The responsibility of his position was massive as he oversaw a workforce of both military and civilian personnel of approximately 125,000; his Oak Ridge office became the center of the wartime atomic energy’s activities.”
Takashi Nakamura, Masahiko Fujii, Kazuo Shin
Nuclear Science and Engineering | Volume 83 | Number 4 | April 1983 | Pages 444-458
Technical Paper | doi.org/10.13182/NSE83-A18648
Articles are hosted by Taylor and Francis Online.
The energy spectra of neutrons emitted by thick targets of carbon, iron, copper, and lead at angles of 0, 15, 30, 45, 75, and 135 deg to the incident beam of 30- and 52-MeV protons were obtained by unfolding the pulse height distributions measured with an NE-213 scintillator. The angular distribution of neutrons above 3 or 4 MeV was obtained by integrating the measured spectra. The measured spectra were compared with a Monte Carlo calculation based on the Fermi free gas model of intranuclear cascades and evaporation. This comparison revealed that the calculated spectra are harder and stronger in the forward direction, but softer and weaker in the backward direction than are the experimental spectra. There is good agreement between the two at ∼75 deg. This experimental result showed that the calculational model is not adequate in the energy region below ∼100 MeV, where nuclear structure has a great influence on neutron production. The total neutron yield was obtained by estimating the neutron yield below a few million electron volts by fitting the spectra measured above that energy to the Maxwellian distribution and showed good agreement with other experimental results.
