Angular Distributions of Intermediate Mass Fragments Emitted in 30 MeV/u 40Ar Induced Reactions

The angular distributions of intermediate mass fragments with charge numbers from 3 to 24 emitted in 30 MeV/u 40Ar+58,64Ni and 115In reactions over an angular range of 5o-140ohave been measured.In different angular region an exponential distribution function dσ/dΩ=N exp(-θ/α)was used to fit the measured angular distributions.The decay factor a which can be connected with the interaction time T and the factor N which is related to the intensity of the emission sources have been extracted.The relationship ofα(Z)and N(Z)with Z for different reaction systems and different angular regions has been discussed.The different behavior of dσ/dΩ,α(Z),and N(Z)for the three studied reaction systems exists mainly in the middle and backward angular regions.The dependencies of angular distributions on isospin and the size of reaction systems have also been discussed.