Coding question on killed particles

I am looking at the survival biasing coding in the physics.cpp source, function void sample_neutron_reaction(Particle& p).

Russian roulette is applied at the end of the function. If the particle is killed, then p.alive() is /false/.

My question is this: should this event be scored in one of the internal tallies, such as TallyEvent::KILLED ? Or is it sufficient that the reduced particle weight from implicit capture is accounted for in the absorption() function, where p.keff_tally_absorption() is incremented.

Hi @AlexandreTrottier, I’m not sure I understand your question. The TallyEvent enum is mostly used to check whether a scattering reaction occurred for tallies that requires post-collision information, so TallyEvent itself is not an “internal tally”. Could you elaborate a bit on what you mean?

Hi - thanks for responding quickly. Your answer makes sense, I was trying to understand how removal is accounted for. I’ve since had a better look at the source and I think I understand.