Analyses of fast neutron inelastic scattering cross sections to higher (vibrational) states of /sup 232/Th and /sup 238/U. II. Intrinsic unified formalism

Journal Article · Wed Sep 01 04:00:00 EDT 1982 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.26.861· OSTI ID:6699048

Chan, D W.S.; Sheldon, E

From the standpoint of nuclear theory, the consistency of the unified (statistical S-matrix) formalism, even in its most basic form as treated in this paper, represents a fundamental improvement over the standard approach involving the incoherent addition of compound-nucleus and direct-interaction contributions to a net angle-integrated cross section. A previous paper dealt with standard analyses of /sup 232/Tn(n,n') and /sup 238/U(n,n') level excitation functions from threshold to E/sub n/ = 2.5 MeV, and foreshadowed the successful application of the unified formalism in illustrative analyses of (n,n') scattering to triads of K = 0/sup -/ octupole vibrational states in each of the above nuclei. For these deformed actinide nuclei, a coupled-channels treatment is appropriate: The unified approach intrinsically entails this as a central feature. This paper describes the results of such unified computations for the /sup 232/Th and /sup 238/U scattering cross sections to each of 21 principal collective (quadrupole and octupole vibrational) states in /sup 232/Th up to E* = 1208.7 keV, and to 17 such levels in /sup 238/U up to E* = 1269.4 keV, using the relative coupling strengths as the only adjustable parameter. When compared with the measured data, the unified fits were generally of equivalent or superior quality to those derived from the standard treatment, with the same (Bruyeres) optical potential parameters employed throughout. Comparisons with (composite) evaluated neutron data file values reveals discrepancies which indicate an evident need for reevaluation. Corrections to the basic unified data will be considered in a subsequent paper.

• Research Organization: Department of Physics and Applied Physics, University of Lowell, Lowell, Massachusetts 01854
• OSTI ID: 6699048
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 26:3; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BARYON REACTIONS
BARYONS
COUPLED CHANNEL THEORY
CROSS SECTIONS
DEFORMED NUCLEI
ELEMENTARY PARTICLES
ENERGY LEVELS
EVEN-EVEN NUCLEI
EXCITATION FUNCTIONS
EXCITED STATES
FAST NEUTRONS
FERMIONS
FUNCTIONS
HADRON REACTIONS
HADRONS
HEAVY NUCLEI
INELASTIC SCATTERING
ISOTOPES
NEUTRON REACTIONS
NEUTRONS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUCLEONS
RADIOISOTOPES
SCATTERING
TARGETS
THORIUM 232
THORIUM 232 TARGET
THORIUM ISOTOPES
URANIUM 238
URANIUM 238 TARGET
URANIUM ISOTOPES
VIBRATIONAL STATES
YEARS LIVING RADIOISOTOPES