I am simulating Am-241 alpha particles incident on C-13. I expect to see O-16 produced via the (alpha,n) reaction, but I am also seeing unexpected production of O-17 at the same order of magnitude as O-16. I get the same result using QGSP_BIC_HP and QGSP_BERT_HP physics lists.
Can anyone provide some insight into how Geant4 models alpha particle interactions? If this is purely a cross section issue, is it possible to view the tables that are being used? I wonder if it could be related to how the (alpha,n) reaction is modeled, and somehow an inelastic reaction occurs without the neutron being emitted.