Multifragmentation threshold in ^{93}Nb+{nat}Mg collisions at 30 MeV/nucleon

We analyzed the $^{93}Nb$ on $^{nat}Mg$ reaction at 30 MeV/nucleon in the aim of disentangling binary sequential decay and multifragmentation decay close to the energy threshold, i.e. $\simeq 3$ MeV/nucleon. Using the backtracing technique applied to the statistical models GEMINI and SMM we reconstruct simulated charge, mass and excitation energy distributions and compare them to the experimental ones. We show that data are better described by SMM than by GEMINI in agreement with the fact that multifragmentation is responsible for fragment production at excitation energies around 3 MeV/nucleon.Comment: 16 pages, 12 figures, 5 tables Soumis \`a Nuclear Physics