Stop power in G4 compared with SRIM software

Hi, everyone

I am using 100 keV 14N beam hit Ta target. The thickness of target is 1 mm. The physics list is QBBC and I get the depth of stop position is like 40 nm, as shown in the picture.
But using TRIM software do the same simulation, I get the depth of stop position is like 90 nm, as shown in the picture.

Which result is right ?
Thank you for you reply.

1 Like

Are you using same X and Y Axis parameters ? Check once again the density of the material taken in TRIM and your code.

What is the X and Y parameters ? And the density of Ta target for SRIM and G4 simulation is the same, 16 g/cm3.

Ok ! I see, I suggest you to look TestEm1 example. In particular TrackingAction Class and Run Class.

The graph you presented is from the G4Step class. i.e. G4ThreeVector trkPos = step->GetTrack()->GetPosition(); say Z = 1mm, you are scoring under process hits in steppingAction ==> depth = trkPos.getZ();

You can also read comments here “Geant4 and SRIM radon-222 range agreement - #9 by hellinger523


QBBC by default is using Opt0 EM physics configuration, the same result for ion range will be if you will use FTFP_BERT Physics List. I would suggest to try Opt4 and/or Opt3 EM physics, where ion range should be more accurate. The default EM physics is not assumed to be very accurate for low-energy ions.


Thanks @civanch

You can add FTFP_BERT_EMY for Opt3 EM physics and FTFP_BERT_EMZ for Opt4 EM physics under G4PhysListFactory.