Hello, I am very new to using Geant4 and encountered a problem I can’t wrap my hand around. In my setup, I shoot neutron with an energy of 5.5 MeV at a detector. The whole setup is located in a box with air and therefore I used the Geant4 Material G4_AIR. With this setup, the neutrons lose all their energy after about 1cm, which is not realistic.
To understand the problem I build “air” from the ground up with the exact material proportions as G4_AIR should be consist of. (I used https://geant4.web.cern.ch/sites/geant4.web.cern.ch/files/geant4/collaboration/working_groups/geometry/training/D1-Materials.pdf page 18 for that). My code for this looks like this:
With this material, the neutrons lose their energy after around 4.2 cm, which is the expected value. So I am a little bit confused about why this divergence occurs and I would like to understand it.