Neutron emission from U233, U235 and Pu239 fission fragments

Symmetric and asymmetric yields in the photofission of232Th,235U,238U and239Pu

“…For the extraction of the interesting distributions a special interpolation method [12] has been developed and employed in order to avoid grid fluctuations, which may produce spurious periodic structures in the mass distributions. The neutron evaporation has been taken into account by an iterative procedure using experimental neutron multiplicity data of Apalin et al [13] or reasonable interpolations. Since at our photon energies higher chance fission occurs possible, we estimated a slightly reduced mean mass number of the fissioning nucleus, taking the higher chance fission probabilities of the different nuclei into account.…”

Event-by-event study of photon observables in spontaneous and thermal fission

“…They aligned the photon and fragment detectors coaxially to determine the number of photons emitted from individual fragments separately. The measured fragment masses and kinetic energies were corrected for prompt neutron emission to obtain the preneutron emission values of A and TKE using a smoothed version of the Apalin 235 U data on ν(A) [6], the average neutron multiplicity as a function of A, assumed to be independent of TKE. Since they collected their data on paper tape, they had to correct for the dead time of the paper-tape punch.…”

The scission point configuration of fissioning nuclei

“…(20,24) for the relation between the excitation energy and neutron multiplicity. There could be also other reasons, like the use of assumption that each point on the deformation energy surface is populated with a probability given by the canonical distribution (12).…”

“…10 we compare the excitation energy available for the prompt neutron emission, E x (A) − 0.5S n with the experimental value of neutron multiplicity [22,24] multiplied by the half of two-neutron separation energy S 2n (in order to remove the rapid fluctuations due to the odd-even effect in S n ). One can see that there is some discrepancy up to 5 MeV at large mass asymmetries, but on the average the saw-tooth structure is rather well reproduced.…”