Mass and charge distributions in iron-induced reactions and excitation energy division between the fragments of the 672-MeV [sup 56]Fe + [sup 165]Ho reaction

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1993

OSTI ID:7112391

Madani, H

The projectile-like and target-like fragments produced by the 12-MeV/nucleon [sup 56]Fe + [sup 165]Ho reaction were detected in coincidence. The measured parameters were the mass, charge, kinetic energy and, scattering angle of the projectile-like fragments, and the scattering angle of the target-like fragments. The mass and charge distributions of the projectile-like fragments were generated as a function of energy loss, and characterized by their centroids, variances, and correlation coefficients. The neutron drift of the measured projectile-like products is mostly due to evaporative processes, while the charge drift is a result of a net transfer of protons from the projectile-like fragment to the target-like fragment. The result is a weak drift of the system towards mass asymmetry, opposite to the direction that minimizes the potential energy of the composite system. The increase in the variances with energy loss is consistent with a nucleon exchange mechanism as a mean for energy dissipation. The predictions of two nucleon exchange models are compared to the experimental results of the 672-MeV [sup 56]Fe + [sup 165]Ho reaction and other Fe-induced reactions. A better agreement with the data was observed with Tassan-Got's model than with Randrup's model. The coincidence measurement and two-body kinematics are used to reconstruct the pre-evaporation masses of the projectile-like and target-like fragments of the reaction. Statistical evaporation calculations are used to translate these masses into excitation energies of the primary fragments. The excitation energy division between the two fragments is determined as a function of total kinetic energy loss and mass division. The ratio of excitation energy stored in the projectile-like fragment decreases with increasing energy loss. Higher ratios are observed for the 672-MeV [sup 56]Fe on [sup 165]Ho system. Excitation energy partition is correlated to the direction of nucleon transfer for selective energy loss bins.

• Research Organization: Maryland Univ., College Park, MD (United States)
• OSTI ID: 7112391
• Country of Publication: United States
• Language: English

Related Subjects

663450* -- Heavy-Ion-Induced Reactions & Scattering-- (1992-)
663570 -- Nuclear Mass Ranges-- A=150-189-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CHARGE DISTRIBUTION
CHARGED-PARTICLE REACTIONS
DISTRIBUTION
ENERGY
ENERGY RANGE
HEAVY ION REACTIONS
HOLMIUM 165 TARGET
IRON 56 REACTIONS
KINETIC ENERGY
MASS DISTRIBUTION
MEV RANGE
MEV RANGE 100-1000
NUCLEAR FRAGMENTS
NUCLEAR REACTIONS
SPATIAL DISTRIBUTION
TARGETS