Hello, For a given excitation energy, why a nucleus "choose" to evaporate preferentially a neutron or a proton? I mean, let us take for example the isotope 208Pb. Its neutron separation energy is 7367.87 keV while its proton separation energy is 8004 keV. If this isotope has an excitation energy of 9 MeV, it has enough energy to evaporate one proton or one neutron but I am pretty sure that it will much more often a neutron instead of a proton. Why?