Measurement of A sub y (. theta. ) for n + sup 208 Pb from 6 to 10 MeV and the neutron-nucleus interaction over the energy range from bound states at minus 17 MeV up to scattering at 40 MeV

Journal Article · Fri Nov 01 04:00:00 EST 1991 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.44.2006· OSTI ID:5024804

Roberts, M L; Felsher, P D; Weisel, G J; Chen, Z; Howell, C R; Tornow, W; Walter, R L ^[1]; Horen, D J ^[2]

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1. Department of Physics and Triangle Universities Nuclear Laboratory, Duke University, Durham, North Carolina (USA)
2. Oak Ridge National Laboratory, Oak Ridge, Tennessee (USA)

High-accuracy measurements of {ital A}{sub {ital y}}({theta}) data for elastic scattering and inelastic scattering to the first excited state for {ital n}+{sup 208}Pb have been performed at 6, 7, 8, 9, and 10 MeV. In addition, {sigma}({theta}) was measured at 8 MeV. These data provide an important subset for the growing database for the {ital n}+{sup 208}Pb system from bound-state energies to energies above 40 MeV, the limit of the range of interest here. This database has been interpreted via several approaches. First, a conventional Woods-Saxon spherical optical was used to obtain three potential representations for the energy range from 4 to 40 MeV: best fits'' at each energy, constant-geometry global fit with linear energy dependences for the potential strengths for the range 4.0--40 MeV, and an extension of the latter model to allow a linear energy dependence on the radii and diffuseness. A preference for a complex spin-orbit interaction was observed in all cases. Second, the dispersion relation was introduced into the spherical optical model to obtain a more realistic'' representation. In our approach, the strength and shape of the real potential was modified by calculating the dispersion-relation contributions that originate from the presence of the surface and volume imaginary terms. Two potentials were developed, one based only on the scattering data (from 4.0 to 40 MeV) and another based additionally on single-particle and single-hole information down to a binding energy of 17 MeV. In addition, the {sigma}({theta}) and {ital A}{sub {ital y}}({theta}) measurements were compared to earlier conventional and dispersion-relation models. One of the latter of these included an {ital l} dependence in the absorptive surface term, and we applied this model in the 6- to 10-MeV region to describe all the {sigma}({theta}) and the new {ital A}{sub {ital y}}({theta}).

• DOE Contract Number: AC05-76ER01067; AC05-84OR21400
• OSTI ID: 5024804
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 44:5; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651920* -- Nuclear Properties & Reactions
A=190-219
Experimental
653003 -- Nuclear Theory-- Nuclear Reactions & Scattering
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANALYZING POWER
BARYON REACTIONS
COUPLING
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
DISPERSION RELATIONS
ELASTIC SCATTERING
ENERGY RANGE
HADRON REACTIONS
INELASTIC SCATTERING
INTERMEDIATE COUPLING
L-S COUPLING
LEAD 208 TARGET
MEV RANGE
MEV RANGE 01-10
MEV RANGE 10-100
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
OPTICAL MODELS
SCATTERING
TARGETS