Energy Dependence of Fission Product Yields from {sup 235}U, {sup 238}U and {sup 239}Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

Journal Article · Fri Jan 15 00:00:00 EST 2016 · Nuclear Data Sheets

DOI:https://doi.org/10.1016/J.NDS.2015.12.006· OSTI ID:22572374

Arnold, C. W. ^[1]; Becker, J. A. ^[2]; Bhatia, C. ^[3]; Bhike, M. ^[4]; Bond, E. M.; Bredeweg, T. A. ^[1]; Fallin, B. ^[4]; Fowler, M. M. ^[1]; Howell, C. R. ^[4]; Kelley, J. H. ^[5]; Krishichayan, ^[4]; Macri, R. ^[2]; Rusev, G. ^[1]; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P. ^[2]; Tornow, W. ^[4]; others, and

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1. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
3. McMaster University, Ontario (Canada)
4. Department of Physics, Duke University,Durham, North Carolina 27708 (United States)
5. Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States)

Fission Product Yields (FPY) have historically been one of the most observable features of the fission process. They are known to have strong variations that are dependent on the fissioning species, the excitation energy, and the angular momentum of the compound system. However, consistent and systematic studies of the variation of these FPY with energy have proved challenging. This is caused primarily by the nature of the experiments that have traditionally relied on radiochemical procedures to isolate specific fission products. Although radiochemical procedures exist that can isolate all products, each element presents specific challenges and introduces varying degrees of systematic errors that can make inter-comparison of FPY uncertain. Although of high importance in fields such as nuclear forensics and Stockpile Stewardship, accurate information about the energy dependence of neutron induced FPY are sparse, due primarily to the lack of suitable monoenergetic neutron sources. There is a clear need for improved data, and to address this issue, a collaboration was formed between Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL) and the Triangle Universities Nuclear Laboratory (TUNL) to measure the energy dependence of FPY for {sup 235}U, {sup 238}U and {sup 239}Pu. The measurements have been performed at TUNL, using a 10 MV Tandem Van de Graaff accelerator to produce monoenergetic neutrons at energies between 0.6 MeV to 14.8 MeV through a variety of reactions. The measurements have utilized a dual-fission chamber, with thin (10-100 μg/cm2) reference foils of similar material to a thick (100-400 mg) activation target held in the center between the chambers. This method allows for the accurate determination of the number of fissions that occurred in the thick target without requiring knowledge of the fission cross section or neutron fluence on target. Following activation, the thick target was removed from the dual-fission chamber and gamma-ray counted using shielded HPGe detectors for a period of 1-2 months to determine the yield of various fission products. To the extent possible all irradiation and counting procedures were kept the same to minimize sources of systematic errors. FPY have been determined at incident neutron energies of 0.6, 1.4, 2.4, 3.5, 4.6, 5.5, 8.9 and 14.8 MeV.

• OSTI ID: 22572374
• Journal Information: Nuclear Data Sheets, Vol. 131; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0090-3752
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ENERGY DEPENDENCE
FISSION
FISSION CHAMBERS
FISSION PRODUCTS
GAMMA RADIATION
HIGH-PURITY GE DETECTORS
LAWRENCE LIVERMORE NATIONAL LABORATORY
LOS ALAMOS
MEV RANGE 01-10
MEV RANGE 10-100
NEUTRON FLUENCE
NEUTRON SOURCES
NUCLEAR FORENSICS
PLUTONIUM 239
RADIOCHEMISTRY
URANIUM 235
URANIUM 238
VAN DE GRAAFF ACCELERATORS