The even-odd effects in prompt emission received less attention compared to the extensively studied Z even-odd effects in fragment distributions. In this context, the present work is focusing on the even-odd effects (in both Z and N) appearing in the prompt emission of even-even nuclei fissioning spontaneously (~(252)Cf, ~(236,238,240,242,244)P_u) _(and) by thermal neutron induced fission (~(233,235)U, ~(239)Pu). The study shows that these effects are mainly due to the Z even-odd effects in fragment distributions and △Z and the N even-odd effects in average neutron separation energies. The most pronounced even-odd effect in prompt emission is observed for the prompt neutron multiplicity, its global size decreasing with increasing fissility. The N even-odd effect in , influences the global even-odd effect in prompt neutron multiplicity often in an opposite way compared to the Z even-odd effect. The global N even-odd effect in is considerably higher in the case of ~(236-244)Pu(SF) compared to other neutron induced fissioning nuclei with comparable mass. (TKE) shows an increase of the Z even-odd effect with increasing TKE. Compared to ~(233,235)U(n_(th),f), ~(239)Pu(n_(th),f) and ~(252)Cf(SF) for which these effects show a decrease for heavier fissioning systems, in the case of ~(236-244)Pu(SF) this behaviour is not visible. The comparison of even- odd effects of ~(240)Pu(SF) and ~(239)Pu(n_(th),f) showed i) a higher even-odd effect in Y(Z) and AZ for SF confirming the Z even-odd effect decrease with increasing excitation energy and ii) the higher N even-odd effect in for SF impacts the prompt emission leading to a lower Z even-odd effect in prompt neutron multiplicity of ~(240)Pu(SF) compared to ~(239)Pu(n_(th),f).
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