Tracking interactions of secondary particles


I was wondering if there is a way to track interactions of secondary particles.

I have a task: to create run with electrons as primary particles. Electrons run through a tantalum target and emit bremsstrahlung gamma-particles that then interact with target’s nuclei that then emit neutrons. A brief sceme: e- → gamma → n

I was able to create a sequence of runs, where in furst run I check properties of the emitted gamma particle. In second run I generate gamma-particle with the same properties and then check its interactions. It is the only way I actually saw neutrons.

If anyone know how to correctly do this in one run, I would greatly appreciate help.
Thank you in advance.

Best regards,