Parent Particle Information

Hi Geant4 users,

I’m seeking help with the information of the parent particle information. I got only ParentID which either 0 or 1. Is there any way to obtain the Parent Name as same as Particle Name ?!

Thank you
Kind regards,


By default, once a daughter particle is tracked, its Parent particle has been deleted, so the information is lost, and only the ParentID is kept in the daughter.
There are possible ways to keep more information about the parent, but for that, you should provide more information about what you need. The way will not be unique, as, if a mode would allow to keep all parents, the memory might become saturated…


Hi Marc,

Many thanks for reply.

I’m working on monitoring the recoil proton that produced from fast neutrons in proton therapy applications. So what I need is distinguish the produced recoil protons if they were produced from fast neutrons [the fast neutrons will produce from Primary Protons nuclear-interaction] or another interactions.
The only information that I have for the parent of the recoil proton, as you said the ParentID.
If the ParentID > 0 its mean is a secondary particle and have parent but I don’t know how to define the parent name.
Moreover, I tried to implement a Trajectory class but unfortunately its crash and I couldn’t fix it.

I hope the issue is clear and I will be grateful if you have another way to extract the parent name information.

Thank you
Kind regards