State densities with linear momentum and their application to preequilibrium and photoabsorption reactions

Conference · Tue Jan 01 04:00:00 EST 1991

OSTI ID:6188620

Chadwick, M B ^[1]; Oblozinsky, P ^[2]

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1. Los Alamos National Lab., NM (United States)
2. Slovenska Akademia Vied, Bratislava (Czechoslovakia). Fyzikalny Ustav

We discuss the concept of state densities with linear momentum and describe their application to preequilibrium reaction theory as well as nuclear photoabsorption via the quasideuteron mechanism. An exciton model is presented for particle emission in nucleon-induced reactions in which linear momentum conversion is included. The nucleon emission contributions from the first two preequilibrium stages are calculated by determining exact particle-hole state densities with a specific energy and linear momentum in a Fermi-gas model of the nucleus. Angular distributions arise naturally from our treatment and do not have to be added in an ad hoc way. The angular distributions that we obtain from the first two preequilibrium stages are identical to those found using the Kikuchi-Kawai quasifree scattering kernel. Since many preequilibrium analyses are based upon an equidistant single-particle model of the nucleus, we also determine the state densities wit linear momentum (and hence angular distributions) in such a model. A no-parameter quasideuteron model of photoabsorption is presented in which the Levinger parameter and Pauli-blocking function are determined theoretically, using state densities with linear momentum. Comparisons with data are shown, and the temperature dependence of the photoabsorption cross section is calculated. 45 refs., 6 figs.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: DOE; NATO; USDOE, Washington, DC (United States); North Atlantic Treaty Organization, Brussels (Belgium)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6188620
• Report Number(s): LA-UR-91-3455; CONF-9111117--1; ON: DE92002520
• Country of Publication: United States
• Language: English

Related Subjects

663300 -- Nuclear Reactions & Scattering
General-- (1992-)
663410* -- Photonuclear Reactions & Photon Scattering-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ABSORPTION
ANGULAR DISTRIBUTION
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DENSITY MATRIX
DEUTERON REACTIONS
DISTRIBUTION
EXCITONS
FERMI GAS MODEL
LINEAR MOMENTUM
MATHEMATICAL MODELS
MATRICES
NUCLEAR MODELS
NUCLEAR REACTIONS
PHOTONUCLEAR REACTIONS
PRECOMPOUND-NUCLEUS EMISSION
QUASI PARTICLES