Dear all, I just started using geant 4 to simulate neutron transport in the air considering three different types of collisions: elastic collision, inelastic collision, and neutron capture. Is there any similar examples in Geant 4 that I can refer to and play with? I know this is not a so hard code. Basically I can build a cylinder containing only air. Then for the physics processes of neutron, I need to add elastic, inelastic, and neutron capture. If you happens to do similar work or you are good at Geant 4, would you please share some experience? Thank you.