I am running simulations passing 2.5 and 14.1 MeV neutrons through D2O with the detector surrounding the full 4-pi solid angle. However, only about 50% of my neutrons show up in the detector, which is not accounted for by absorption. Since this is in 4-pi, I expect around 100% of neutrons to be seen.
On a few of my 14.1 MeV runs, I get a G4Exception issued by G4ParticleHPEnAngCorrelation::Sample saying “Too many trials were done. Exiting current loop by force. You may have Probably, the result violating (baryon number) conservation law will be obtained).” This exception occurs on 3-50% of events, depending on D2O moderator thickness. It occurs for 14.1 MeV neutrons, but not 2.5 MeV. In addition, I’ve found that it only seems to occur when the detector covers the 4-pi solid angle. In comparison, 2-pi seems to be fine. I’m wondering if this exception has to do with why we don’t see all neutrons in the detector. Can you provide guidance on this exception? Are these events abandoned, or is there some way we can correct for this exception?