Projectile-target Systems Research Articles

Charge transfer prior to fusion

In reactions between very asymmetric projectile-target systems charge is preferably transferred from the lighter to the heavier nucleus. This leads to a decrease of the potential barrier between the nuclei and increase of the fusion cross-section. We perform trajectory calculations with energy dissipation and proton transfer to estimate the magnitude of the effect.

Intranuclear cascade calculation of high-energy heavy-ion interactions

We have extended the intranuclear cascade model of Chen et al. to high-energy reactions between two heavy ions. The results of the calculations are compared with experimental results for the inclusive proton and pion cross sections, two-particle correlations, particle multiplicity distributions, and spallation cross section distributions from light ($^{12}\mathrm{C}$ + $^{12}\mathrm{C}$) to heavy ($^{40}\mathrm{Ar}$ + $^{238}\mathrm{U}$) projectile-target systems in the laboratory bombarding energy range $\frac{E}{A}=250\ensuremath{-}1000$ MeV. The comparison shows that the model is fairly successful in reproducing the various aspects of high-energy reactions between heavy ions. The discrepancies between the calculations and the experimental results are probably due to shortcomings of the present calculation, particularly the neglect of interactions between cascade particles, and do not provide strong evidence for cooperative phenomena in high-energy heavy-ion reactions. We also show that the assumption that high particle multiplicities are indicative of central (small impact parameter) collisions is well founded for heavy projectile-target systems.NUCLEAR REACTIONS Compared predictions of intranuclear cascade model for high-energy heavy-ion reactions with experimental results for inclusive proton and pion cross sections, two-particle correlations, particle multiplicities, spallation cross sections. $E=250\ensuremath{-}1000$ MeV/nucleon. $^{12}\mathrm{C}$+$^{12}\mathrm{C}$, $^{20}\mathrm{Ne}$+$^{20}\mathrm{Ne}$, $^{40}\mathrm{Ar}$+$^{40}\mathrm{Ar}$, $^{20}\mathrm{Ne}$+$^{238}\mathrm{U}$, $^{20}\mathrm{Ne}$+$^{208}\mathrm{Pb}$, $^{40}\mathrm{Ar}$+$^{208}\mathrm{Pb}$.

Theoretical interpretations of the energy dependence of electronic stopping power

Models for the electronic stopping power of heavy ions at low velocity are investigated in which account is taken of the distribution of charge states of the projectile in the stopping medium. The basic model we employ is that developed by Firsov as modified to include Hartree-Fock atomic wave functions. Within the context of this model we consider several procedural variants. From comparisons of the results of calculations for a variety of projectile-target systems with experimental data, we have found that the inclusion of charge-state distributions does not lead to correct predictions for the velocity dependence of the electronic stopping power for ν> ν 0 within the context of these models. We suggest, instead, a semiempirical method in which the modified Firsov model is used for projectile velocities ν< ν 0 and a scaling law for ν> ν 0.