Continuing the discussion from Dose rate from activation simulation:
Dear @adonadon and other experts
I still agree with you on the explanation you provided above. But I gave deep thought to my simulation, and I still got some questions.
Some neutrons get moderated by the paraffin wax in the central part of the drum, and I would expect the dose rate contribution of gamma-rays following the radiative capture by a hydrogen atom, in addition to the dose rate for the decaying radionuclide. Also, there is neutron leakage out of the drum because not all the neutrons are moderated and attenuated by the material of the drum. As a result, I would expect to get their dose rate contribution.
I considered a simple situation where a neutron source is placed in the drum without metal foil in place, performed a normal simulation (not activation), and I get a high neutron dose rate.
I feel like I am underestimating the dose rates. Can you please clarify this issue?