Analyses of nucleon scattering based on the modified statistical Hauser-Feshbach-Weidenmueller formalism

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1981

OSTI ID:6244149

Chan, D W.S.

An S-matrix formalism of the statistical theory of nuclear reactions has been developed by Weidenmueller et al., based upon the Engelbrecht-Weidenmueller transformation and extended to cases where direct reactions are present as a means of deriving expressions for the fluctuation cross section going beyond the framework of conventional Hauser-Feshbach theory. This unified approach, from which a coherent sum of fluctuation and direct-interaction cross sections is combined to yield a net reaction cross section, provides a means of deriving a comprehensive and accurate theoretical description of the scattering process. Although a framework for the formal theory has been constructed, it had not previously been applied to the qualitative analyses of scattering data. As described in this thesis, a computer program NANCY has been compiled by modifying Tamura's coupled-channels code JUPITOR-1 (through modifications suggested by Moldauer) and incorporating Smith's optical model routine SCAT, as a means of generating the entire symmetric S-matrix. Using this program, computations were undertaken to determine numerically the energy-averaged cross sections for inelastic neutron scattering on /sup 232/Th and /sup 238/U from threshold to several MeV. With appropriate variation of coupling strengths between the ground state rotational band and vibrational levels good fits to the experimental data were attained, which compared favorably with theoretical results generated from conventional approaches.

• Research Organization: Lowell Univ., MA (USA)
• OSTI ID: 6244149
• Country of Publication: United States
• Language: English

Related Subjects

652015* -- Nuclear Properties & Reactions
A=220 & above
Theoretical-- Nuclear Reactions & Scattering-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYON REACTIONS
COMPUTER CODES
CROSS SECTIONS
DATA
DIRECT REACTIONS
ENERGY LEVELS
EXCITED STATES
GROUND STATES
HADRON REACTIONS
INELASTIC SCATTERING
INFORMATION
MATHEMATICAL MODELS
MATRICES
N CODES
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUMERICAL DATA
ROTATIONAL STATES
S MATRIX
SCATTERING
STATISTICAL MODELS
TARGETS
THEORETICAL DATA
THORIUM 232 TARGET
URANIUM 238 TARGET
VIBRATIONAL STATES