Refined treatment of angular momentum in the event-by-event fission model freya

The treatment of angular momentum in the event-by-event fission model Fission Reaction Event Yield Algorithm (freya) has been refined to ensure conservation of angular momentum both at scission and during neutron evaporation. While the effect on previously calculated quantities is relatively minor, as expected, the refined model gives a more consistent description of directional correlations.

Figure 1

The angular correlation between evaporated neutrons with kinetic energies greater than 0.5 MeV, as obtained from the three scenarios for ${}^{252}\mathrm{Cf}$(sf).

Figure 2

The angular distribution of evaporated neutrons relative to the direction of the angular momentum of the emitting nucleus, as obtained for ${}^{252}\mathrm{Cf}$(sf) in the three scenarios.

Figure 3

The photon multiplicity distribution obtained for the three scenarios considered compared to the DANCE data [11].

Figure 4

The distribution of the angle between the postevaporation fragment angular momentum and that of the initial compound nucleus, $\Delta \theta$, for $c_S=0,0.1,1.0$, with $d$TKE having been adjusted in each scenario to yield $\overline{\nu }=2.75$.