Scission-point model of nuclear fission based on deformed-shell effects

Event-by-event evaluation of the prompt fission neutron spectrum from239Pu(n,f)

“…The dip in the calculation and the data at A ∼ 132 is at the same point as the peak of TKE(A H ) due to the shell-driven fragment deformation pointed out in Ref. [25]. Although the agreement is good, the observed behavior is not perfectly reproduced.…”

“…At A H = 132, the heavy fragment is close to the doubly-magic closed shell having Z H = 50 and N H = 82 and is therefore resistant to distortions away from sphericity, as first discussed in Ref. [25]. Consequently, the scission configuration is fairly compact, causing the TKE to exhibit a maximum even though the complementary light fragment is far from a closed shell and hence significantly deformed.…”

Most Probable Charge of Fission Products in Proton-Induced Fission of 238U and 232Th

“…As the yield of nuclide with N=82 shell may be enhanced, the most probable charge increases and consequently deviates from ZQgg. The same kind of explanation is applicable to the disagreement at other nuclear shell and deformed shell, N=86-88, which is suggested by Wilkins et al 67 The existence of the nuclear shell effect in this energy region was also reported in the isomeric yield ratio measurement. 68 On the other hand, the reason why Zp dose not seem to agree with ZQgg in the 24 MeV proton + 232Th system is probably because of the inadequate correction of emitted neutrons.…”

Dynamical effects in fission investigated at high excitation energy

“…These measurements provided a precise characterization of the fissioning systems at scission and allowed to determine the prescission neutron multiplicities from the isotopic composition of the final fragments and their velocities using momentum conservation and the the kinematic model for fission from Ref. [65]. The results are shown in the upper panel of Fig.…”