The energy spectra of neutrons from the fission of U235, U233, and Pu239 have been studied with seven high-energy activation detectors covering the range 0.6 to 16 Mev. Interpretation is in terms of the Maxwellian spectral function E1/2 exp(-E/T). By means of a unique cavity arrangement within a moderator to obtain pure thermal-neutron-induced fission neutrons, the average energies of the three spectra are found to be in the ratios
U235: U233: Pu239= (1): (1.016+or-0.003): (1.039+or-0.003).
Differences between the normalized spectra are most pronounced at high energies as exemplified by the relative Pu239:U235 flux ratios 1.17+or-0.013 for 611 Mev.
Level of Degree
Physics & Astronomy
First Committee Member (Chair)
Christopher Pratt Leavitt
Second Committee Member
Victor H. Regener
Third Committee Member
John Root Green
Grundl, James A.. "Study of Fission Neutron Spectra With High-Energy Activation Detectors." (1963). https://digitalrepository.unm.edu/phyc_etds/193