Physics and cuts
How do production cuts (in range) work in Geant4 ? Are they also used
in tracking ? If a particle has an energy lower than the converted cut
in energy for the given material and the distance to the next boundary
is smaller than the cut in range, is the particle killed ?
Geant4 does NOT have a "tracking cut".
The toolkit's default behaviour is to track particles down to zero range
(i.e. zero energy). Of course, it is possible for the user to create and
register a process that kills particles below a certain energy or range;
this is however NOT provided by default
in Geant4. So there's NO "tracking cut".
For example, suppose a particle that is nearing zero energy will at some
point be proposed by its Ionisation process to undergo one final step,
from its current energy down to zero energy. This is still only a
proposal. If during this step the particle crosses a boundary, then the
transportation will limit the step at a length smaller than the
Ionisation -- so the particle will still see and cross the relevant
boundary, and another step will occur on the other side of that boundary.
In summary the "production threshold" range and its equivalent in energy
are not utilised as a "tracking cut". A particle is not abandoned by
Geant4 below a certain range/energy unless the user registers a process
to do this by him/her-self.