Temperatures and Excitation Energies of Hot Nuclei in the Reactions of⁴⁰Ar+^natAg,²⁰⁹Bi at 25 MeV/u

Abstract：

Coincidence measurements of fission fragments and light-charged particles have been performed for the reactions of ⁴⁰Ar+ ^natAg, ²⁰⁹Bi at E/A=25 MeV using 4 PPAC and 11 sets of △ E-Etelescopes. Angular correlations of fission fragments are plotted as a function of the folding angle between the two detected fission fragments. The linear momentum transfer distributions are derived by measured angular correlation. The backward spectra of light particles detected in coincidence with fission fragments having different average < LMT> are analyzed with a Maxwell distribution. After some corrections the initial temperature of the hot nuclei is determined from the energy spectra. The excitation energies corresponding to the different average < LMT> are obtained considering the reaction Qvalues and pre-equilibration emission. In the central collision of the ⁴⁰Ar+ ^natAg, ²⁰⁹Bi reactions, excitation energies are measured to be about 4.2 MeV/u, 2.4 MeV/u and temperatures about 6.1 MeV, 5.5 MeV, respectively. In a semi-central collision, the measured excitation energies and temperatures are about 3.5 MeV/u, 1.9 MeV/u, and 5.8 MeV, 4.8 MeY, respectively.