I have a simple simulation that shoots photons into a sequence of tungsten foils having a thickness of 8 um and want to observe the generation of photoelectrons. When the cuts are set to 0.3 mm or greater the results seem correct. But when the cuts are set to 0.25 mm or less, the gamma ionizes a tungsten atom, producing an electron as anticipated, but it also generates another gamma. Can someone explain to me what is happening and why the result is sensitive to the setCut value? I have attached a printout of both a normal and what I think is an abnormal event.
I guess what you see is a photon of atomic deexcitation, eg. fluorescence.
This emission is very sensitive to the gamma cut.
To disable fluorescence :
/process/em/fluo false
or, in your PhysicsList : G4EmParameters::Instance()->SetFluo(false)
Concerning the detailed printout, I would suggest to put in your main (see exampleB1.cc) : #include G4SteppingVerbose.hh
…
//use G4SteppingVerboseWithUnits
G4int precision = 4;
G4SteppingVerbose::UseBestUnit(precision);