I am examining the effects of neutron activation in materials. I have been simulating 2.45 MeV neutron interactions in xenon, and I have noticed that metastable states don’t appear to be properly registered. Take Xe131m for example: I would expect both “neutronInelastic” interactions on Xe131 and “nCapture” processes on Xe130 to potentially generate Xe131m. In looking at the event data, I do indeed see gammas at the appropriate energy level for Xe131m, but at no point is a particle with particle ID or name corresponding to Xe131m generated. Additionally, the gammas are listed as being created by the “neutronInelastic” or “nCapture” process, rather than any sort of decay of Xe131m.
I am currently using GEANT4 10.3, I have the NeutronHP physics list enabled, and I’m using the Binary Cascade model, but I’m wondering if there is some other physics I’m missing, or perhaps if there is missing cross section/decay data in the NeutronHP library that causes metastable states to remain unpopulated.
I’m by no means an expert with GEANT4, and while I did try looking through the G4NDL files as well as the source code for neutron and hadronic processes, but things started going over my head, and I didn’t immediately see what may lead to the generation of metastable states.
I did come across this topic, which seems to suggest that QGSP_BIC populates metastable states in neutron interactions, but not QGSP_BIC_HP, so that may be my problem.
Still, any help or definitive answer is appreciated! As well as pointers on suggested routes for getting the best results for neutron activation physics.