text: Fission fragments are usually neutron-rich and always generated in excited states. Thus, daughter decays occur rapidly after scission. Decays occurring within 10s of scission are termed "prompt" and are initially dominated by a series of neutron emissions which remain the dominant decay mode until the fragment energy is reduced to the same order of magnitude as the neutron separation energy (approximately ), when photon emission becomes competitive. Below the neutron separation energy, gamma emission is dominant, characterised by a disordered spectrum of gamma energies with characteristic low-energy peaks corresponding to specific decays as the daughter descends the yrast line, each decay carrying away excess angular momentum. Average total prompt gamma emission is 30% higher from the lighter fragment compared to the heavier, implying the heavier fragment is created with higher initial angular momentum. Finally, internal conversion and x-ray emission complete the prompt emissions. Daughter products created by prompt decays are often unstable against beta-decay, and further photon and neutron emissions are also expected. Such emissions are termed delayed emissions and take place with half-lives ranging from picoseconds to years.
  As a result of the large number of decay pathways presented to a fissioning nucleus, there is a large variation in the final products. Fragment masses are normally distributed about two peaks centred at A ≈ 95 and A ≈ 140. Spontaneous fission does not favour equal-mass fragments, and no convincing explanation has been found to explain this. In rare instances (0.3%), three or more fission fragments may be created. Ternary products are usually alpha-particles, though can be as massive as oxygen nuclei.
  Total energy release across all products is approximately , mostly observed as kinetic energy of the fission fragments, with the lighter fragment receiving the larger proportion of energy. For a given decay path, the number of emitted neutrons is not consistent, and instead follows a gaussian distribution. The distribution about the average, however, is consistent across all decay paths. Prompt neutrons are emitted with energies approximated by (but not precisely fitting) a Maxwell distribution, peaking between 0.5 and 1 MeV, with an average energy of  and maximum energy of approximately . Prompt gamma emission constitutes a further 8 MeV, while beta decay and delayed-gammas contribute a further  and  respectively. Less than 1% of emitted neutrons are emitted as delayed neutrons.