Measurement of the neutron capture and fission cross sections of $sup 239$Pu and $sup 235$U, 0.02 eV to 200 keV, the neutron capture cross sections of $sup 197$Au, 10 to 50 keV, and neutron fission cross sections of $sup 233$U, 5 to 200 keV
The neutron absorption and fission cross sections for $sup 239$Pu and $sup 235$U have been measured over the neutron energy range from 0.02 eV to 200 keV. In addition, the neutron capture cross section for $sup 197$Au was measured from 10 to 50 keV and the fission cross section of $sup 233$U was measured from 0.1 to 100 keV. Normalization of the $sup 239$Pu and $sup 235$U data was made over the energy region from 0.02 to 0.4 eV to the ENDF/B-III neutron cross sections for these isotopes, Mat 1159 and 1157, respectively. The capture cross section for $sup 197$Au was normalized using the saturated resonance method for the 4.9-eV resonance. For $sup 233$U fission, the normalization was made using the results of Weston et al. The neutron flux was measured using the $sup 10$B(n,$alpha$) reaction; the energy variation used for this reaction was that given in ENDF/B-III. A large liquid scintillator about 40 m from the neutron source was used to detect the prompt gamma-ray cascades resulting from neutron absorption in the sample. In general for $sup 239$Pu and $sup 235$U, these experiments indicated lower neutron fission cross sections than contained in ENDF/ B-III for energies above 10 keV. The measured values of the ratio $alpha$, neutron capture-to-neutron fission, for $sup 239$Pu agree within errors with those derived from ENDF/B-III, Mat 1159. For the present measurements, the uncertainty on $alpha$ for $sup 239$Pu is approximately 11 percent at 10 keV and increases to approximately 30 percent at 100 keV. The experimental results for the neutron capture cross section for $sup 197$Au are approximately 15 percent lower than the ENDF/B-III values. The measurements of the ratio of the neutron fission cross section for $sup 233$U to that for $sup 235$U are generally higher than the ENDF/B-III values by approximately 5 percent. 15 tables, 11 figures. (auth)
- Research Organization:
- Oak Ridge National Lab., TN
- NSA Number:
- NSA-33-027761
- OSTI ID:
- 4093952
- Journal Information:
- Nucl. Sci. Eng., v. 59, no. 2, pp. 79-105, Journal Name: Nucl. Sci. Eng., v. 59, no. 2, pp. 79-105; ISSN NSENA
- Country of Publication:
- United States
- Language:
- English
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*GOLD 197-- NEUTRON REACTIONS
*PLUTONIUM 239 TARGET-- NEUTRON REACTIONS
*PLUTONIUM 239-- NEUTRON REACTIONS
*URANIUM 235 TARGET-- NEUTRON REACTIONS
*URANIUM 235-- NEUTRON REACTIONS
643406*
CAPTURE-- GAMMA RADIATION-- GOLD 198-- PLUTONIUM 240-- URANIUM 236
CAPTURE-TO-FISSION RATIO
CROSS SECTIONS
N68951 --Physics (Nuclear
Experimental)--Nuclear Properties & Reactions
190 <= A <= 219--Nuclear Reactions & Scattering
N69161* --Physics (Nuclear
Experimental)--Nuclear Properties & Reactions
A >= 220--Nuclear Reactions & Scattering--Spontaneous & Induced Fission:734
RESONANCE FISSION-- URANIUM 233-- URANIUM 233 TARGET