Isoscaling of mass image reconstructed quasiprojectiles from collisions in the Fermi energy regime

Isoscaling studies of fragments with image from reconstructed quasiprojectiles of mass image from the image, 112Sn and image, 112Sn reactions at beam energy of 45 MeV/nucleon were performed. After initial efforts to obtain isoscaling with the “traditional” approach of using pairs of systems differing in their isospin asymmetry (or neutron-to-proton ratio image), “intra-system” isoscaling for each of these four systems was obtained using fragment sources restricted in two narrow image regions (one neutron-rich and one neutron-poor). The observed isoscaling behavior was excellent and the isoscaling parameter α was found to decrease with increasing excitation energy. Corrections due to undetected neutrons were also taken into account in the source image determination by using the theoretical models DIT (Deep Inelastic Transfer) and SMM (Statistical Multifragmentation Model) along with a software replica of the experimental setup. These corrections were applied to the determination of the parameter Δ (expressing the difference in the isospin asymmetry of the two sources used in the isoscaling). The reduced isoscaling parameter image was obtained and found to decrease as the excitation energy of the quasiprojectile source increases, in good agreement with recent work on reconstructed mass image quasiprojectiles. This decrease of image may point to a decrease of the symmetry energy coefficient with increasing excitation energy.