Simulate gamma detector with geant4 in python

Hello ,

Under python ( geant4_pybind package ) , I tried to simulate a gamma detector with 2 scenarios :

Shielded Script:

It defines a Cobalt-60 core / emission source with some dimensions.
It places a steel container around the Cobalt-60 source.
The physics list includes necessary processes for gamma radiation.

Unshielded Script:

The Cobalt-60 source is defined with the same dimensions as in the shielded script.
It correctly removes the steel container around the source.
The physics list is identical to the shielded script, which is expected as the physics processes for gamma radiation should not change between shielded and unshielded scenarios.

The curves i obtained for both scenarios ( unshielded and shielded ) are the same which is not plausible.

Thank you for help

_Geant4 Version: Geant4-11.1
_Operating System: Windows 10
_Compiler/Version: Unkown
_CMake Version: cmake version 3.28.0-rc2

shielded_geant11.txt (6.0 KB)
unshielded_geant11.txt (5.3 KB)