Photoneutron detection

Physics Lists
1

Dear all,

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:

Screenshot 2020-09-19 at 22.15.45
Screenshot 2020-09-19 at 22.15.45812×946 34.8 KB

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!

2

Hi Efraín
I suggest you post this on the Physics Processes Forum.
John

1 Like
3

Thanks for your suggestion. I just did.

4

you must add G4EmExtraPhysics

1 Like
5

Thank you, Maire! Photoneutron production is working now :grinning:

1 Like
6

Hello Dr.Salinas ,
Greetings

I am trying to simulate and detect the secondary photo-neutrons in high energy linac , but I am new in geant 4 and have a beginner skills in C++ language I have tried to run Medical_linac example i get the following message which failed my visualization

Untitled
Untitled1920×1080 207 KB

***** COMMAND NOT FOUND </OnlyVisio true> *****

***** Batch is interrupted!! *****

------- WWWW ------- G4Exception-START -------- WWWW -------
** G4Exception : UIMAN0123
issued by : G4UImanager::ApplyCommand
ommand aborted (100)
rror code : 100
** This is just a warning message. ***
------- WWWW -------- G4Exception-END --------- WWWW -------
command not found: “/control/execute C:\Users\96654\Geant4\11.0\share\Geant4-11.0.0\examples\advanced\medical_linac-build\ml2.mac”

your responde is hilghy appreciated :slight_smile: