Physics List for a 30 MeV Proton beam, with tracking of neutrons produced

Hello all, I’m still new to Geant4 and to Nuclear Phyiscs in general.
Currently I have been attempting to modify or create a physics list that provides a plausible simulation of a 30 MeV proton beam onto Tungsten. I have a physics list that calls for ProtonHPData but the penetration range and produced particles do not seem to be correct.

The physics list I am currently using has:

Hadron Elastic Scattering: G4HadronElasticPhysicsXS
Hadron Inelastic: G4HadronPhysicsQGSP_BIC_ALLHP
Ion Elastic Scattering: G4IonElasticPhysics
Ion Inelastic: G4IonPhysicsXS
Stopping Particles: G4StoppingPhysicsFritofWithBinaryCascade
EM Physics: G4EmStandardPhysics
Decay: G4DecayPhyics
Radioactive Decay: G4RadioactivDecayPhysics

Whenever I use any EM physics, Almost all the process calls are for hIoni instead of hadElastic or protonInelastic.
Also with EM physics enabled there is nearly no penetration because the protons are stopped instantly.

I’ve been struggling for a while to learn what physics would be optimal for a 30 MeV proton beam. I have not come across much information on a proton beam around this energy.

Any suggestions/help or questions would be immensely appreciated, I’m very confused about what physic to use. I am fairly novice in this subject but I would like to become more knowledgeable.

-Sincerely Jason


to understand proton beam interaction with W target you may check $G4INSTALL/examples/extended/electromagnetic/TestEm7 - hadronic interaction is enabled there as well.

We recommend for more accurate Bragg peak simulation using EM Opt4 or Opt3 physics. The default EM provides large steps of protons, less accurate near Bragg peak.

You also misinterpret tracking verbose information - process which limit the step is not necessary the only process happens with the tracking particle.


Hello, civanch
I am still confused, is there any more information or detail you could provide.
I’m trying to simulate a 30 MeV proton beam onto Tungsten and track the produced neutrons.