Hi All, I have a basic question. I am still new to nuclear engineering so this maybe a stupid question, but what is the typical energy efficiency of a neutron source? (I.E. power of neutrons emitted/power input for neutron generation) I recognize that the efficiency can depend on the neutron flux, especially since the power loss does not scale linearly with the neutron flux, but what is the typical energy efficiency of a neutron source with a particle flux of 1E14 to 1E15 neutrons per square cm? Finally, how are these neutrons generated if controlled materials (like U-235 or Pu-239) aren't used? (like photoneutrons, neutrons from deuterium fusion, etc.) I'm interested because I want to try using a DIY neutron source to store electrical energy by transmuting Th-232 into U-233 and then burning that U-233 in a pile.