Cobalt, fast neutrons and physical models: Nuclear data and measurements series
Energy-averaged neutron total cross sections of cobalt were measured from approx. =0.5 to 12.0 MeV. Differential elastic- and inelastic-scattering cross sections were measured from approx. =1.5 to 10.0 MeV over the scattering-angle range approx. =18/sup 0/ to 160/sup 0/, with sufficient detail to define the energy-averaged behavior. Inelastic neutron groups were observed corresponding to ''levels'' at: 1115 +- 29, 1212 +- 24, 1307 +- 24, 1503 +- 33, 1778 +- 40, 2112 +- 40, 2224 +- 35, 2423 +- 39, 2593 +- 41 and 2810 keV. The experimental results were interpreted in terms of the spherical optical-statistical and coupled-channels models. An unusually successful description of observables was achieved over a wide energy range (<-15.0 to > 20.0 MeV) with a spherical model having energy-dependent strengths and geometries. The energy dependencies are large below approx. =7.0 MeV (i.e., approx. =19.0 MeV above the Fermi energy), but become smaller and similar to those reported for ''global'' potentials at higher energies. The imaginary strength is large and decreases with energy. These imaginary-potential characteristics are attributed to neutron shell closure and collective-vibrational processes. The weak-coupling model also offers an explanation of the unusual negative energy slope and relatively small radius of the imaginary potential. The spherical optical model derived from the neutron-scattering results was extrapolated to bound energies using the dispersion relationship and the method of moments. The resulting real-potential strength and radius peak at approx. =-10.0 MeV, while concurrently the real diffuseness is at a minimum. The extrapolated potential is approx. =8% larger than that implied by reported particle-state energies, and approx. =13% smaller than indicated by hole-state energies. 68 refs., 15 figs., 1 tab.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 5955657
- Report Number(s):
- ANL/NDM-101; ON: DE88000611; TRN: 87-036206
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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COBALT 59 TARGET
NEUTRON REACTIONS
COUPLED CHANNEL THEORY
ELASTIC SCATTERING
INELASTIC SCATTERING
NICKEL 60
YRAST STATES
OPTICAL MODELS
ANGULAR DISTRIBUTION
DIFFERENTIAL CROSS SECTIONS
EXPERIMENTAL DATA
MEV RANGE 01-10
MEV RANGE 10-100
BARYON REACTIONS
CROSS SECTIONS
DATA
DISTRIBUTION
ENERGY LEVELS
ENERGY RANGE
EVEN-EVEN NUCLEI
HADRON REACTIONS
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOTOPES
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NICKEL ISOTOPES
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUMERICAL DATA
SCATTERING
STABLE ISOTOPES
TARGETS
651620* - Nuclear Properties & Reactions
A=59-89
Experimental