I modified the B1 example by changing geometry and particle gun for 15*15 cm2 gamma from a distance of 10 cm. Dose scored in the scoring volume is around 4E-16 Gy/pr while for same geometry, cutoff(i.e. around 1keV) in FLUKA value is 12E-16 Gy/pr.
Also used /run/setCut 0.2 um in .mac file and G4Modularphysics QBBC is used.
I tried other physics lists like G4Emstandard_option4 etc. but no much difference is observed.
I have attached modified files, please suggest the reasons of this discrepancy.
SteppingAction.cc (3.0 KB)
EventAction.cc (2.5 KB)
RunAction.cc (5.7 KB)
PrimaryGeneratorAction.cc (3.3 KB)
DetectorConstruction.cc (15.2 KB)