Scored particles energy is much higher than the source one

Dear Amario , based on your suggestion, I got the neutron spectrum of D-be reaction in GEANT4 and wrote its neutron code, energy, position, directional cosine and particle weight intowj_source_ng1.f.

I was very puzzled by the FLUKA simulation, which showed that the neutron energy spectrum in bin44 was not the same as that in my Geant4, and there were hundreds of MeV energies. I think there is a problem with the wj_source_ng1.f. Can you help me with this? Thank you so much!
Attach all my documents.
cd-1.flair (4.6 KB)
cd-1.inp (7.9 KB)
wj_source.txt (243.2 KB)
wj_source_ng1.f (18.9 KB)

Dear David,

please make sure, that you are using your custom executable with the source routine for the simulation. (You can check the .out file to see if the first 100 record of the phase-space file is printed or not.)

If the custom executable is not used, then the parameters on the BEAM card is used, giving - in you case - 100 MeV neutrons.


P.S. The annular beam profile you set in the BEAM card is ignored by the user routine, you need to enable this in the user routine as well.

Dear Dávid Horváth,

Sorry, I may not have expressed myself clearly. The highest energy in my wj_source_cg1. f file is only 6MeV, so I don’t know why there are hundreds of MeV of energy( picture of the bin24), and what’s even more surprising is that I simulated neutron slowing.

After simulation, it was found that the first 100 records in the phase space are consistent with those in my wj_source.txt, and I have attached my .out file .
cd-1_01002.out (218.7 KB)

Dear David,

I just noticed that you are using the particle code 2 in the wj_source.txt file. This corresponds to antiprotons, which explains the higher energies in the scoring.

The particle code for neutrons is 8.


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Dear Dávid Horváth

I'm sorry for the mistake. Thank you very much for your answer. The problem has been solved.