|Message: Re: Problem with He4 neutron detector simulations||Not Logged In (login)|
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I had the same problem than you when simulating the interactions of cosmic rays with the atmosphere of Jupiter. The precense of 4He in the atmosphere was the source of an important loss of neutrons at lower energy.
The reason of this bug comes most probably from the NeutronHP model. In the G4NDL database no data are present for the inelastic scattering of neutron on He4 and the data for the inelastic scattering of n on He3 are used instead. The reaction n(He3,H)p has an important CS and is therfore the source of an important loss of neutron.
I did summit a bug report (#900) concerning this problem. To solve this problem you have to create artificial elastic data file in the G4NDL database for He4 where you should put very small cross sections value. Just copy the He3 files to He4 equivalent files and change the CS.
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