He-4 production from alpha decay and (n,alpha) reactions?

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Hello there !

I’ve scoured the forums and the documentation for an answer but it does not seem to appear in black and white.
Decay calculations with the default chains do not produce He-4 isotopes, in fact it seems even absent from the full ENDF chain with 3800+ nuclides.

I do remember Serpent (for example) having He-4 in its decay calculations; it may be hard-coded. Is there a way to manually add He-4 so that it is indeed produced without greater modifications in the code ?

Thanks a lot
Boris

EDIT: Corrected He-4 instead of He-2

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Hi @BorisH and welcome to the community! I’m a little confused by your question — 2He (2 protons and 0 neutrons) is not produced to my knowledge by any decay mode or incident neutron reaction. 3He and 4He can and are produced by various means, but not 2He (which would have a half-life of less than a nanosecond).

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Hello Paul and thank you!

Indeed, it seems I should have drunk more coffee this morning; I of course mean He-4.

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Ah, that makes much more sense :smile: :coffee: And it looks like you’re right – OpenMC is not producing those particles from decay when it should. I’m working on a patch right now, should only be a few extra lines of code to handle that case. Thanks for bringing this to my attention!

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Update: a bug fix has been submitted.

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Great news ! Thanks a lot for the prompt response :slight_smile: