Dynamical and geometrical aspects of isoscaling

Christian Rene Escudero Ayala, University of Texas at El Paso

Abstract

In order to determine the origin, dynamical evolution and geometrical aspects of isoscaling we perform several classical molecular dynamics simulations and numerical calculations. In this way, simulations of 40Ca + 40Ca, 48Ca + 48Ca, and 52Ca + 52Ca, at beam energies ranging from 20 MeV/A to 85 MeV/A were performed. ^ The analysis included a study of the time evolution of this effect. The simulations show that isoscaling exists at all energies in these reactions from the early primary isotope distributions (produced by systems not yet in thermal equilibrium) all the way to 5000 fm/c. ^ In order to understand more deeply the properties of isoscaling in nuclear fragmentation, we use a simple bond percolation model with "isospin" added as an extra degree of freedom. We show that with the assumption of fair sampling and with homogeneous probabilities it is possible to solve the problem analytically. Then, we perform numerical percolations of hundreds of thousands of grids of different sizes and with different N to Z ratios. These numerical calculations confirm this prediction with remarkable agreement. ^ With these results, we concluded that isoscaling emerges even in the simple case of a classical non-interacting system such as two-species percolation under the assumption of fair sampling; if put in the nomenclature of the minimum information theory, isoscaling in percolation appears to require nothing more the existence of equiprobable configurations in maximum entropy states. ^

Subject Area

Physics, Nuclear

Recommended Citation

Escudero Ayala, Christian Rene, "Dynamical and geometrical aspects of isoscaling" (2007). ETD Collection for University of Texas, El Paso. AAI1444112.
http://digitalcommons.utep.edu/dissertations/AAI1444112

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