It seems there is an anomalous energy deposition for ions in G4EmStandardPhysics_option4 and option3.
Some strange continuous tail is added for about 30% of events, which lead to energy deposition larger than total kinetic energy of incoming ion. See pictures attached for option4 and option0.
This can be reproduced with TestEm1, macro attached. Switch between physics lists to reproduce.
It seems to happen with almost all ions - I tested about 5, all had some artifacts in energy deposition, except 1 MeV 206Pb. But when I increased its energy to 12 MeV, the tail was added.
I saw it in 11.4.0, updated to 11.4.2 and saw the same thing.
The problem seems to be connected to G4NuclearStopping. I see the same anomalous tail if I use it in my user-defined physics list.
This is energy deposition spectrum for 1 MeV 16O with option4:
If you take a look at the stepping action of TestEm1 you will see that energy deposition is added regardless of whether the particle is a primary or secondary. This means that if secondary particles are generated in an event, the cumulative energy deposition tally of that event can exceed the defined primary particle’s energy.
Yes, it does add energy from both secondaries and primary, but I’m not sure this explains the effect. Energy is transferred to them from the parent, its is not created. Without some nuclear reactions or decay or some source of additional energy I don’t think we should have a total energy deposit larger than initial kinetic energy of primary.
And if it was an intended behavior from secondaries - it would be strange if it only worked that way in 2 particular physics list constructors.
