Two-neutron angular correlation for the spontaneous fission of ²⁴⁰Pu as a function of the angular separation and for a neutron kinetic energy threshold of 1500 keV. Comparison between experimental data (full symbols) and FREYA (open symbols) calculations, shown for several values of the parameter x that defines the partition of the excitation energy between the light and heavy fission fragments. Figure taken from reference [101]. (This figure is subject to copyright protection and is not covered by Creatice Commons License. IEEE, 2018).