I'm simulating a titanium prosthesis of a human leg. The setup is very simple. A cube of water in which I put the prosthesis (cylinder). I then illuminate the prosthesis with a photon beam perpendicular to the cylinder axis. I'm interested in the doses (energy deposits) in front of and behind the prosthesis. For a homogeneous cube of water, you would observe a decreasing energy deposit as a function of the depth in the water. When you place the titanium prosthesis however you should observe a raise just in front of it. If I use the default threshold cut of 1mm I miss totally that raise. I had to go down to a value of 0.0001mm to observe something. What I would like to do is keep the threshold cut at 1mm or so, force secondaries to be produce below the threshold and only track them if they are close to a boundary. I tried to use the ApplyCutFlag but it doesn't seem to make any difference. Not sure I'm doing the right thing though. By the way, when the ApplyCut flags are on for gamma, e- and e+, the low energy electromagnetic processes seem to crash. It works with the standard ones.
It seems to be related with energy loss processes.
In the coming Geant4 V4.0 the production cut has been removed from the (standard) Compton and Photo Electric processes. The results of your simulation must be insensitive to the production cut.
