Geant4 Version: geant4/11.1.2 Operating System: Windows
Hi,
I’ve run some simulations about photoneutron production, and my results are strange.
It appears that there are significant changes in the way photon-neutron production is calculated, which yields a stair-like shape in my energy spectrum.
So I was wondering, can physics lists overlap with each other? And if multiple physics lists have different methods for calculating a process, how does Geant4 determine which method to use?
I’m using a lot of physics lists (it feels like it is too many ):
I would like to improve my comprehension and selection of physics lists. If you have any advice/knowledge about this, I would be very happy to receive some help!
If two physics lists are valid for the same particle in the same energy range for the same process, it will default to the first one used because it houses them in vectors that stops at the first valid one.
Generally speaking, the best way to avoid problems with physics list collisions is to just start with one of the examples. It seems like you want decay, em, neutron, gamma, and hadronic physics. Is there anything missing if you just use the rdecay02 physics list?
Creating a physics list from scratch (or making significant modifications) is a challenging task.
Even advanced users are recommended to identify an existing physics list appropriate for their application area, for use or as a starting point. In many cases, after validation, they will find it addresses their requirements. If not, it will serve as a reliable starting point for small modifications, such as substituting an element, e.g. using the G4EMStandardPhysics_option4 builder.
You can find an overview of PhysicsLists and the different ways to create them in the Physics Lists lecture at this year’s Geant4 Advanced course. I mention also the recording of the talk on the same topic in 2024.
Hi, thank you for your answer and sorry it took me some time to understand the different physics lists… rdeacy02 seems great and complete about hadronic processes. The only problem is that I would like to look at photoneutron and it does not include G4PhotoNuclearCrossSection. I believe photoneutron aspects are taking care of by the G4EmExtraPhysics but I don’t know if it is enough by its own or if I need to use both of them :/.
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