I want to know the effect of magnetic field generated by an electron beam incident on the material and the secondary electrons on the distribution of the secondary electrons. Whether these effects have been taken into account in the physics list of G4 (like G4EmStandardPhysics)? Or I need to add the additional magnetic field generated by the incident electrons and secondary electrons to study?
No, Geant4 does not take into account dynamical fields generated by the particles in an event. You may want to look into either Garfield or possible COMSOL or something to do this.
You might be able to write your own field subclass to try to do this, but it’s not obvious that it will ever work properly.
Geant4 does not do a “time evolution” simulation:
- A track is followed from the time it is created until the time it is killed (usually at zero energy or at a decay).
- Secondaries created everywhere along that track are time-stamped, but they are not actually tracked until after the main track has finished.
- Then, the new tracks get processed in “reverse order” (last in, first out).
- In some cases, a track may be “paused” while individual secondaries get tracked, but even that won’t be fully time-following.
Geant4 does not maintain the full event history. Each track is followed individually to its end, then another track is followed, and so on. At no time do you have a “bundle” or “beam” of multiple tracks at once.
Consequently, if you try to write a field class that “accumulates” the effects of multiple tracks, you aren’t going to be getting the information you need in a meaningful and causal order.