When a target is irradiated with neutrons there a number of different nuclear reactions that can occur. In neutron capture, which neutron energy regime is most dominant? I can't seem to find any specific literature about neutron capture and neutron energy, but most of the general stuff I've read leads me to believe the most dominant would be thermal neutrons. Fast: >0.5 MeV. Intermediate: 1 keV to 500 keV. Resonance: 1 eV 1000 eV. Epithermal: 0.025 eV 0.2 eV. Thermal: ~0.025 eV.