Bombarding-energy dependence of the+reaction
- 1 July 1980
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review C
- Vol. 22 (1), 128-147
- https://doi.org/10.1103/physrevc.22.128
Abstract
A previous study of the strongly damped reaction + at 1130 MeV has been extended to the lower bombarding energy of 940 MeV. With the same experimental technique, angular, energy, and atomic charge distributions and their correlations have been measured. The angular distribution of the reaction products is sideways peaked, but less strongly focused than at the higher bombarding energy. The energy spectrum extends far below the Coulomb energy calculated for touching spherical ions, indicating large deformations of the final fragments. The charge distributions are Gaussians approximately centered around the initial fragmentation. Examination of the correlations between experimental observables confirms that the energy-loss parameter is the most suitable quantity to describe the time evolution of the reaction. The relationship between energy loss and the width of the charge distribution is studied to gain information on the contribution of the nucleon exchange process to the total dissipated energy. The bombarding-energy dependence of this relationship suggests that the Pauli blocking of occupied single particle levels is an important effect, leading to a smaller dispersion of the fragment distribution for a given energy loss than expected from a classical theory. A quantitative analysis establishes the nucleon exchange as the dominant mechanism for the dissipation of kinetic energy. With the aid of a phenomenological model, a decomposition of the reaction cross section in partial waves is performed. Classical trajectory calculations assuming spherical ions are compared to an empirically determined deflection function, energy loss, and interaction times. These calculations do not provide a consistent description of the experimental results, since the energy loss is systematically underestimated. From the interaction times and widths of the charge distributions, an angular momentum dependent proton number diffusion coefficient is derived, which shows a pronounced saturation behavior for angular momenta less than of the grazing angular momentum. The total probability for sequential fission of the targetlike fragment is determined to be 30% for all inelastic events. A simple model is presented which allows calculation of this probability on the basis of known fission properties of heavy elements.
Keywords
This publication has 50 references indexed in Scilit:
- A new method for calibrating the pulse-height defect in solid state detectorsNuclear Instruments and Methods, 1978
- Mechanisms of very heavy-ion collisions: The 209Bi + 136Xe reaction at ELab = 1130 MeVPhysics Reports, 1978
- Generalized fresnel model for very heavy ion scattering (I)Nuclear Physics A, 1978
- Damped Heavy-Ion CollisionsAnnual Review of Nuclear Science, 1977
- Elastic scattering ofandonandat 7.2 and 8.5 MeV /NPhysical Review C, 1976
- A calibration procedure for the response of silicon surface-barrier detectors to heavy ionsNuclear Instruments and Methods, 1974
- Diffraction scattering of charged particlesAnnals of Physics, 1972
- Diffraction Systematics of Nuclear and Particle ScatteringPhysical Review Letters, 1971
- Range and stopping-power tables for heavy ionsAtomic Data and Nuclear Data Tables, 1970
- Strong absorption model for elastic nuclear scattering. Part IAnnals of Physics, 1963