LABORATORI NAZIONALI DI LEGNARO
Isoscaling is the property that fragment yields of similar, but isotopically different, reactions depend exponentially on the neutron (N) and proton (Z) numbers through R21(N,Z)= {Y2(N, Z)}/{Y1(N, Z)} µexp(alfaN+betaZ) with alfa and beta fitting parameters. We have estudied the origin and dynamical evolution of isoscaling using classical molecular dynamics simulations of 40Ca+40Ca, 48Ca+48Ca and 52Ca+52Ca at beam energies ranging from 20MeV/A to 85 MeV/A. We show that isoscaling can be detected very early in the evolution, even when non-equilibrium effects are clearly present. In order to get a deeper understanding of the origin of this effect we use a generalized bond percolation model, with N colors and in D-dimensions. Color is assigned to each node in an independent way. It is shown that isoscaling can be obtained when analysing the ratio of the yields of bond fragmentation of two lattices of sizes A1 and A2 with, say, A1

DATA: 06-12-2005

Sito Collegato : http://www.lnl.infn.it/~seminari/2005/6_Dic_05.htm