In my simulation I am shooting gamma photons of different energies (higher than 15 MeV) at a carbon shielding slab (volume in white), which in theory should produce photoneutrons, which then I would detect in a water sphere sensitive detector (volume in blue), as showed in the following image:
Unfortunately, no photoneutrons are being produced. I have tested detecting other particles and everything works fine, I double checked this by activating the Verbose and indeed no photodisintegration processes were listed. I have tried different materials, such as tungsten or other high-Z materials, as well as higher gamma energy photons and increasing the number of samples up to a couple of millions but still no photoneutrons are being produced.
Perhaps the problem is related to the Physics Lists? These are the ones that I am using in my simulation:
- THE FOLLOWING ELECTROMAGNETIC PHYSICS LIST HAS BEEN ACTIVATED: G4EmLivermorePhysics
- THE FOLLOWING ELECTROMAGNETIC PHYSICS LIST HAS BEEN ACTIVATED: G4EmStandardPhysics_option3
- THE FOLLOWING HADRONIC INELASTIC PHYSICS LIST HAS BEEN ACTIVATED: HadronPhysicsQGSP_BIC_HP()
- THE FOLLOWING HADRONIC INELASTIC PHYSICS LIST HAS BEEN ACTIVATED: G4IonBinaryCascadePhysics()
- THE FOLLOWING HADRONIC INELASTIC PHYSICS LIST HAS BEEN ACTIVATED: G4RadioactiveDecayPhysics()
- G4PhysListFactory::GetReferencePhysList <QGSP_BERT_HP> EMoption= 0
<<< Geant4 Physics List simulation engine: QGSP_BERT_HP
<<< Reference Physics List QGSP_BERT_HP is built
I am using Geant4 10.5.0 version.
Any help with this matter would be greatly appreciated.
Thank you in advance!