I have more than one volume in detector construction. Now I have a radioactive source which radiates gamma along all the directions uniformly . Now How can I get the energy spectrum in a particular volume only due to inter detector scattering not for the gamma coming from the source ? Or basically how can I distinguish the energy depositions due to events coming directly from the source and after scattering from neighboring detector ?
a simple solution could be to set the G4TrackStatus to fStopAndKill at the output boundary of the detector volumes (check postStep for g4StepStatus fGeomBoundary).
If you are interested in aggregated properties (dose, spectra, …), you can then subtract the two results from once with the StopingAndKilling, and once without. This does not work on the single event level, obviously