Precise measurement and analysis of neutron transmission through /sup 238/U

Journal Article · Tue Mar 01 04:00:00 EST 1977 · Nucl. Sci. Eng.; (United States)

OSTI ID:7316107

Olsen, D K; de Saussure, G; Perez, R B; Silver, E G; Difilippo, F C; Ingle, R W; Weaver, H

The transmissions of 0.52- to 4000-eV neutrons through 3.62, 1.08-, 0.254-, 0.0762-, 0.0254-, and 0.0127-, and 0.0036-cm-thick samples of uranium, enriched in the /sup 238/U isotope, have been measured at 42 m with a 1.0-mm-thick /sup 6/Li glass detector using the Oak Ridge Electron Linear Accelerator pulsed neutron source. To obtain resonance parameters, the seven transmissions of neutrons having energies ranging from 0.52 to 1086.8 eV have been shape-fitted by least-squares analysis to a multilevel Breit-Wigner cross-section formalism with ''picket-fence'' terms to account for truncation effects. This simultaneous fit yielded a chi/sup 2/ per degree of freedom near unity. Averaged over this energy range, an s-wave strength function of (0.968 +- 0.036) x 10/sup -4/ cm and an effective radius of (0.944 +- 0.005) x 10/sup -12/ cm were obtained. In addition, these transmission data yielded an average radiation width of 23.1 +- 1.0 meV for the 12 lowest energy s-wave resonances with radiation widths of 23.0 +- 0.8, 22.8 +- 0.8, and 22.9 +- 0.8 meV for the 6,67-, 20.9/sup -/, and 36.8-eV resonances, respectively. The derived radiation widths for these three resonances are shown to depend on the cross-section formalism employed. This work suggests that a multilevel formalism with truncation compensation is required to adequately represent the /sup 238/U total cross section.

• Research Organization: Oak Ridge National Lab., TN
• OSTI ID: 7316107
• Journal Information: Nucl. Sci. Eng.; (United States), Journal Name: Nucl. Sci. Eng.; (United States) Vol. 62:3; ISSN NSENA
• Country of Publication: United States
• Language: English

Related Subjects

652026* -- Nuclear Properties & Reactions
A=220 & above
Experimental-- Spontaneous & Induced Fission-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYON REACTIONS
CROSS SECTIONS
HADRON REACTIONS
LEAST SQUARE FIT
LEVEL WIDTHS
MAXIMUM-LIKELIHOOD FIT
NEUTRON REACTIONS
NEUTRON SPECTRA
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUMERICAL SOLUTION
RESONANCE
SPECTRA
TARGETS
TOTAL CROSS SECTIONS
TRANSMISSION
URANIUM 238 TARGET