Empirical estimation of photoneutron energy distribution in high-energy electron accelerators

To assist neutron flux estimation in high-energy electron accelerators, an empirical expression has been obtained for the energy differential neutron yield distributions from the Giant Dipole Resonance (GDR) mechanism for 100 MeV to 2.5 GeV electrons incident on thick targets. Calculated neutron yield distributions from the FLUKA code have been used to generate an expression relating neutron yield energy distribution per unit incident electron energy with target mass, charge, and neutron separation energy. Data for 16 target elements from Ti to U have been fitted to obtain a coupled linear and Maxwellian expression. The GDR and total neutron (including quasi deuteron and delta resonance modes) yields calculated using FLUKA show dominance of GDR neutrons.