Charged particle spectra: 140 MeV. cap alpha. particle bombardment of /sup 27/Al, /sup 58/Ni, /sup 90/Zr, /sup 209/Bi, and /sup 232/Th
Complete energy spectra and angular distributions of the light charged particles (A < or = 4) were measured for the bombardment of /sup 27/Al, /sup 58/Ni, /sup 90/Zr, /sup 209/Bi, and /sup 232/Th with 140 MeV ..cap alpha.. particles. The spectral shapes of a given emitted particle are very similar for all target nuclei except in the region of the evaporation peak. The slopes of the energy spectra in the forward direction become steeper as the mass of the observed particle decreases and vary very rapidly with angles. The experimental data can be characterized by compound nuclear evaporation processes at low energies, or at backward angles, and by direct reactions, nonequilibrium components and projectile breakup processes at high energies and forward angles. The breakup cross section for ..cap alpha.. particles is found to be appreciable. The total yield of light charged particles is approximately a factor approx. 2 to 3 larger than the total reaction cross section for /sup 27/Al, /sup 58/Ni, and /sup 90/Zr and is approx. 0.7 of reaction cross section for /sup 209/Bi and /sup 232/Th. The nonequilibrium light charged particle yield is of the order of 1000--1800 mb. The experimental results were analyzed using the pre-equilibrium exciton model, the compound nuclear evaporation model and a Serber type of model for the ..cap alpha.. particle breakup. The pre-equilibrium model calculations using a 5p-1h initial configuration reproduced the experimental angle-integrated energy spectra rather well.
- Research Organization:
- Department of Physics and Astronomy, University of Maryland, College Park, Maryland 20742
- OSTI ID:
- 6134023
- Journal Information:
- Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 19:3; ISSN PRVCA
- Country of Publication:
- United States
- Language:
- English
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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA REACTIONS
ALUMINIUM 27 TARGET
ANGULAR DISTRIBUTION
BISMUTH 209 TARGET
BREAKUP REACTIONS
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
COMPOUND-NUCLEUS REACTIONS
CROSS SECTIONS
DEUTERON SPECTRA
DIFFERENTIAL CROSS SECTIONS
DISTRIBUTION
ENERGY RANGE
ENERGY SPECTRA
EVAPORATION MODEL
MATHEMATICAL MODELS
MEV RANGE
MEV RANGE 100-1000
NICKEL 58 TARGET
NUCLEAR MODELS
NUCLEAR REACTIONS
PROTON SPECTRA
SPECTRA
TARGETS
THORIUM 232 TARGET
TRITONS
ZIRCONIUM 90 TARGET