Fast neutron inelastic scattering cross sections in /sup 232/Th
Inelastic scattering cross sections for fast neutrons have been measured for levels near 1 MeV in excitation of the actinide nucleus /sup 232/Th. Both (n,n',..gamma..) and (n,n') techniques were used for these measurements in the incident energy region 0.7 to 2.1 MeV. A total of 74 transitions from 46 levels above the first excited state at 49.32 keV were observed. Gamma-ray branching ratios and production cross sections have been determined. The level cross sections obtained from this method were complemented with direct neutron time-of-flight measurements in the outgoing energy region 200 to 400 keV. Comparison of these two independent measurements indicates the presence of EO transitions which do not involve gamma transitions. Theoretical estimates of neutron inelastic scattering cross sections in this incident energy region were obtained based on compound nucleus and direct interaction mechanisms. A significant direct interaction contribution to the inelastic scattering is evident at incident energies as low as 1.1 MeV. Comparison of theoretical calculations to the data shows that a simple sum of the contributions from these two mechanisms does not give a completely satisfactory quantitative account of the observed cross-section characteristics above 1.4 MeV. The experimental results are compared to previous measurements and the Evaluated Nuclear Data File (ENDF/B-V). The present measurements suggest that in the threshold energy region for the inelastic scattering of /sup 232/Th the cross sections are significantly overestimated in ENDF/B-V.
- Research Organization:
- Lowell Univ., MA (USA)
- OSTI ID:
- 5227741
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
A=220 & above
Experimental-- Nuclear Reactions & Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BARYON REACTIONS
CROSS SECTIONS
DATA
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
HADRON REACTIONS
HEAVY NUCLEI
INELASTIC SCATTERING
INFORMATION
ISOTOPES
MEV RANGE
MEV RANGE 01-10
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUMERICAL DATA
RADIOISOTOPES
SCATTERING
TARGETS
THORIUM 232
THORIUM 232 TARGET
THORIUM ISOTOPES
YEARS LIVING RADIOISOTOPES