Killing Particles of Certain Types in Certain Areas

[Laurie Nevay]

We should provide clearer instructions and more features to control a simulation in a particular region. Example:

killing all pions that undergo hadronic interactions in a given volume

Requires investigation of whether negative biasing would work or whether a kill in the stepping action is more effective.

[Laurie Nevay]

One thought it we could define (yet another) parallel world where we define simple boxes as specified by the user (size + placement). Each box has a set of particle IDs associated with it. We define a custom physics process that will kill any particles that lie inside a box in the parallel world. The boxes effectively represent geometric zones where the physics process to kill particles would apply.

Need to read further in Geant4 if there’s already a mechanism for this.

Another typical way would be via the tracking action, but this would only be at the creation of a track and not part way along it. Perhaps both ways would be useful. Generally, kill all pions, or only kill pions in this area.