The backtracing method is applied to the system ⁶⁴Ni + ²⁰⁸Pb at 8.39 A.MeV incident beam energy measured with the DeMoN detector. We determine the initial thermal energy available in the parent compound nucleus and the total neutron multiplicity distributions. The experimental neutron energy spectra of one, two and three detected neutrons in coincidence with symmetric binary events are used as observables for this procedure.