Alpha-particle on 2H, neutron spectra is different from experimental

Dear FLUKA expert,

I am trying to calculate Alpha-Particle bombardment of Deuterium and get the neutron yield and spectrum in forward solid angle. I found some literatures and calculated according to the conditions in literatures, but my FLUKA result is very different from the experimental data, I browsed the relevant topics on the forum and changed my input, but the result is still incorrect.
The Alpha-Particle energy is 100MeV, the gas target is 2H, on both surface there are Havar metal, I score the neutron yield and spectrum in 2 degree solid angle from Havar2 to Record1 using USRBDX, and convert the flux into cross-section, here are my result and experimental data in literature. I compare the neutron cross section at 0°, let’s ignore the numbers for a moment, the spectrum shape are different, the experimental result has two strong neutron peaks, and FLUKA result only has one, I read 3 papers with different incident energy, the neutron spectra all have two peaks, so could you help me check my input file, where is the problem?

Here is my input file.
25MeV-D2.inp (7.7 KB)

Can you please indicate the experimental references you mention/show? Thanks

Here are the experimental references, please have a look, thank you! :grinning:

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Thanks. While the lower energy peak in the forward direction is consistent with deuteron stripping, which is a mechanism implemented in the FLUKA model of deuteron reactions, the higher energy peak appears to be originated by alpha stripping, with one neutron of the projectile flying forward with the initial velocity. This other mechanism (the stripping of the reaction partner) is presently not implemented in the reactions involving deuterons, so you cannot get its signature from the simulation.

Oh,then I understand, thank you for your reply!