New precompound decay model: Angular distributions
- 7210E Calabria Court, San Diego, California 92122 (United States)
- University of California, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
A new Monte Carlo precompound decay model is used to calculate double-differential spectra using an approach based on conservation of linear momentum between an incident nucleon and the three quasiparticles activated in the collisions of the equilibration process. The angular distribution theory is presented as it is applied to the individual three-exciton cascades of the precompound model. The importance of multiple precompound decay beyond two nucleons per nucleus is illustrated for {sup 90}Zr(p,xn) reactions for incident protons up to 256 MeV. These components are shown to be important for extending the useful range of the precompound approach to energies beyond 80 MeV. The contribution to nucleon spectra due to hole conversion processes is illustrated. We compare results of the formulation described with experimental angular distributions for {sup 90}Zr(p,xn) reactions at incident energies of 45, 80, and 160 MeV, and for the {sup 90}Zr(p,xp) reactions at incident energies of 80, 160, and 200 MeV. Additionally, {sup 208}Pb(p,xn) spectra at 7.5{degree}, 30{degree}, 60{degree}, 120{degree}, and 150{degree} are compared with two experimental data sets for 256 MeV incident proton energy, and {sup 90}Zr(p,xn) spectra at the same five angles are compared with predicted results for 256 MeV incident protons. At 256 MeV incident proton energy, the higher energy emission spectra are seriously overpredicted at 60{degree}. All other results are reproduced quite well, including back-angle yields. The quasielastic peak measured at 7.5{degree} at 256 MeV incident proton energy is shown to be in quite reasonable agreement with experimental results. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 565997
- Journal Information:
- Physical Review, C, Vol. 57, Issue 1; Other Information: PBD: Jan 1998
- Country of Publication:
- United States
- Language:
- English
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