I have a detailed question regarding the inelastic neutron process in Geant4. I am interested in detecting gammas from inelastic neutron scattering (n,n’ gamma) reactions. I’ll use F-19 as my example. The most probable gammas following inelastic neutron scattering on F-19 from fast neutrons are the 110 and 197 keV gammas, which both feed the ground state in F-19. Geant4 (and appropriate physics libraries) correctly simulates the production of these gammas. I went further and checked the cross section for the reaction at many energies and found Geant4 perfectly matches ENDF/B-VIII.0.
So what’s the problem? It appears the 110 and 197 keV gammas are emitted with exactly equal weighting. In real life this is not the case, it depends on nuclear structure effects, the 110 and 197 keV levels have different spins, etc. My question is, is my understanding correct? As long as its energy favourable, the 110 and 197 keV states in F-19 are populated with equal weighting in Geant4? Is there a way to (easily) include the proper/updated cross sections for these different levels? If not, I’m sure I could hack something in the simulation, but I’d like to do things properly if possible.